# KTB Europe > KTB Europe is a family-owned trading company in Hamburg, Germany, founded in 1976. It sources industrial spare parts and MRO materials worldwide, independent of any single manufacturer. This file summarises the website www.ktb-europe.com for language models and AI assistants. It is generated automatically from the published content and updated whenever new articles, glossary terms or pages are published. - Legal name: KTB Import-Export Handelsgesellschaft mbH & Co. KG (KTB Europe) - Founded: 1976, family-owned - Headquarters: Großmoorring 9, 21079 Hamburg, Germany - Business: manufacturer-independent sourcing of industrial spare parts and MRO materials worldwide, by inquiry - Contact: Phone +49 40 766189 0 · E-mail ktb@ktb-europe.com · [Contact and inquiry](https://www.ktb-europe.com/en/contact/) - Website languages: German, English, Spanish, French, Italian, Portuguese, Chinese - Group websites: [ktb-europe.com](https://www.ktb-europe.com/) (Germany (headquarters)) · [ktb-usa.com](https://www.ktb-usa.com/) (USA) · [ktb-argentina.com](https://www.ktb-argentina.com/) (Argentina) · [ktb-brasil.com](https://www.ktb-brasil.com/) (Brazil) · [ktb-china.com](https://www.ktb-china.com/) (China) · [ktb-mexico.com](https://www.ktb-mexico.com/) (Mexico) · [ktb-portugal.com](https://www.ktb-portugal.com/) (Portugal) - Short index: https://www.ktb-europe.com/llms.txt ## Services - [procurement](https://www.ktb-europe.com/en/services/procurement/): MRO procurement from Hamburg: since 1976, KTB Europe has sourced industrial spare parts and MRO items worldwide – reliably, fast and cost-effectively. - [Procurement Outsourcing](https://www.ktb-europe.com/en/services/procurement-outsourcing/): Outsource indirect procurement to KTB: we source MRO items, spare parts and C-parts, compare suppliers and deliver goods checked in our central warehouse. - [Discontinued parts](https://www.ktb-europe.com/en/services/obsolete-parts/): Spare part discontinued? KTB searches its worldwide supplier network for obsolete and hard to find parts and for technically equivalent alternatives. - [spare parts management](https://www.ktb-europe.com/en/services/spare-parts-management/): Spare parts management for maintenance: KTB handles your spare parts procurement, from supplier comparison to goods inspected in our central warehouse. - [cost optimisation](https://www.ktb-europe.com/en/services/cost-optimizations/): Optimize your purchasing processes through strategic supplier consolidation. Reduce material costs & freight costs in technical trade. - [Financing](https://www.ktb-europe.com/en/services/financing/): Professional trade financing & flexible payment terms. Import export financing, factoring & capital commitment for your procurement. - [inspection](https://www.ktb-europe.com/en/services/inspections/): Professional quality control & technical inspection of industrial parts. Goods inspection according to international standards with export packaging. - [Consolidation](https://www.ktb-europe.com/en/services/consolidation/): Efficient bundling of goods & collective deliveries for optimized procurement processes. Reduction of suppliers through central consolidation. - [Logistics](https://www.ktb-europe.com/en/services/logistics/) ## How to request a part Send the manufacturer, part number (or type designation) and quantity via the contact page, by e-mail or by phone. KTB checks availability and alternatives and replies with an offer. - [Contact and inquiry](https://www.ktb-europe.com/en/contact/) - Phone: +49 40 766189 0 - E-mail: ktb@ktb-europe.com ## Key pages - [Home](https://www.ktb-europe.com/en/) - [About KTB](https://www.ktb-europe.com/en/about/) - [Locations](https://www.ktb-europe.com/en/locations/) - [Services](https://www.ktb-europe.com/en/services/) - [Glossary](https://www.ktb-europe.com/en/glossary/) - [Blog](https://www.ktb-europe.com/en/blog/) - [Frequently Asked Questions](https://www.ktb-europe.com/en/faq/) - [Product catalogue](https://www.ktb-europe.com/en/products/) - [Manufacturer index](https://www.ktb-europe.com/en/manufacturer/) ## Glossary 204 terms from procurement, maintenance, spare parts and foreign trade, each with a short definition. Overview: [Glossary](https://www.ktb-europe.com/en/glossary/) ### MRO & Maintenance #### CMMS (maintenance management software) URL: https://www.ktb-europe.com/en/glossary/cmms/ A CMMS (computerised maintenance management system) is maintenance software for planning and documenting servicing, repairs and spare parts. A CMMS maps a company's maintenance digitally. It replaces paper lists and spreadsheets with a central database of assets, work orders, plans and materials. It is to be distinguished from an EAM system, which covers the entire life cycle of physical assets including investment and finance, and from the maintenance module of an ERP system, which offers similar functions within the enterprise software. Typical functions are a hierarchical asset structure, fault reports and work orders, maintenance and inspection plans with automatic scheduling, spare parts and inventory management, time recording, document storage for manuals and drawings, and reports such as MTBF, MTTR and maintenance costs. Many solutions offer mobile interfaces for technicians and interfaces to ERP, purchasing and condition monitoring. For spare parts supply, the quality of the master data is decisive: if each asset component is assigned the correct manufacturer part number with a description, consumption can be analysed, reorder points maintained and purchase requisitions generated directly from the work order. Incomplete master data, on the other hand, reduce the benefit of any software. Maintaining master data is therefore an ongoing task. In practice: Before introducing a CMMS, it pays to clean up the asset structure, parts master data and manufacturer part numbers. A field for alternative and successor parts helps later with discontinuations and supply shortages. Also known as: computerised maintenance management system, maintenance management software, maintenance software, EAM, CMMS software Frequently asked questions: - **What is the difference between CMMS and EAM?** A CMMS focuses on operational maintenance, i.e. work orders, maintenance plans, spare parts and KPIs. An EAM system considers the entire life cycle of physical assets, from planning and procurement through operation and maintenance to decommissioning, and incorporates financial and investment data. The boundaries between the two categories are fluid. - **What functions should a CMMS have?** Important basic functions are asset management with a structure, work order management, maintenance planning with scheduling, spare parts and inventory management, documentation and reporting. Depending on the company, mobile use, interfaces to ERP and purchasing, test equipment management or connection to sensor data are added. What matters is that technicians actually use the system in their day-to-day work. - **How does a CMMS help with spare parts procurement?** A CMMS links spare parts to assets and work orders. As a result, when a fault occurs it is immediately clear which part is needed, whether it is in stock and what its manufacturer part number is. Consumption data show which parts are needed regularly, and reorder points trigger purchase requisitions in good time. - **What does the abbreviation CMMS stand for?** CMMS stands for computerised maintenance management system. In German-speaking countries, terms meaning maintenance software or IPS system, short for a maintenance planning and control system, are also common. In each case, this means software for organising maintenance. #### Condition-based maintenance URL: https://www.ktb-europe.com/en/glossary/condition-based-maintenance/ Condition-based maintenance is a strategy that monitors equipment using measured condition parameters and only intervenes when limit values are exceeded. Instead of replacing parts at fixed intervals, condition-based maintenance records the actual condition of a component. EN 13306 classifies it as preventive maintenance because it also intervenes before a failure. It is often abbreviated to CBM. The aim is to make the fullest possible use of the service life of components without risking a failure. Common methods are vibration measurement on rotating machines, which can detect bearing damage, imbalance or misalignment, for example; thermography to detect overheating at electrical connections or bearings; and oil analysis, which reveals wear particles, water or ageing in lubricating and hydraulic oil. Pressure, current and ultrasound measurements are also used. Measurements are taken on regular rounds or continuously via permanently installed sensors. Warning and alarm limits are set for each parameter. It must be distinguished from predictive maintenance, which analyses trends and forecasts the time of failure, whereas condition-based maintenance responds to limit values being exceeded. The boundaries are fluid. In practice: There is often only limited time between a warning and a failure. For monitored units, the lead times of the typically damaged parts, such as rolling bearings or seals, should therefore be known, and critical parts held in stock where appropriate. Also known as: CBM, condition monitoring, condition-dependent maintenance, on-condition maintenance Frequently asked questions: - **What is the difference between condition-based maintenance and predictive maintenance?** Condition-based maintenance triggers an action as soon as a measured value exceeds a defined limit. Predictive maintenance goes one step further: it analyses the trend of the measurement data and estimates when a failure is likely to occur. This allows interventions to be planned earlier. In practice, the two approaches often build on each other. - **Which measuring methods does condition-based maintenance use?** The most common are vibration measurement on motors, pumps, fans and gearboxes, thermography on switchgear and bearings, and the analysis of lubricating and hydraulic oils. In addition, ultrasound, current draw, pressure and flow are measured. Which methods make sense depends on the typical failure patterns of the equipment concerned. - **For which equipment is condition-based maintenance worthwhile?** It is worthwhile above all for equipment whose failure causes high consequential costs, and for components whose damage announces itself through measurable changes, such as rolling bearings in rotating machines. For inexpensive, easily replaceable parts with minor failure consequences, the effort of measurement and analysis is often greater than the benefit. #### Downtime costs URL: https://www.ktb-europe.com/en/glossary/downtime-costs/ Downtime costs are all costs a company incurs when a plant unexpectedly stops producing, from lost production to consequential damage. Downtime costs arise when a machine or line does not produce because of a breakdown, missing parts or other disruptions. A distinction is made between direct and indirect costs. Direct costs are lost contribution margin, personnel and fixed costs that continue to run, repair work, express surcharges for spare parts and external services, and scrap during restart. Indirect costs are contractual penalties, overtime to catch up, disrupted downstream processes, lost orders and damage to reputation with customers. A simple estimate starts with the cost per hour of downtime: lost contribution margin per hour plus personnel and fixed costs that continue without production. Multiplied by the expected duration of a failure and supplemented by repair and procurement costs, this gives a value per failure event. Whether a bottleneck is involved is decisive: a failure at the bottleneck machine affects the entire factory, whereas at a machine with a buffer it often has little effect. This figure is the basis for many maintenance and procurement decisions, for example whether an expensive spare part should be held in stock, a machine monitored or a second source of supply established. In practice: For stocking critical spare parts, the downtime costs during the replenishment lead time can be compared with the costs of stockholding. If the potential loss from a failure clearly exceeds the capital and storage costs, a part in stock is usually the more economical solution. Also known as: downtime cost, cost of downtime, cost of unplanned downtime, machine breakdown costs Frequently asked questions: - **How do you calculate downtime costs?** A practical approach: determine the cost per hour of downtime, i.e. lost contribution margin plus personnel and fixed costs that continue to run, and multiply it by the duration of the stoppage. Add repair costs, express surcharges, scrap during restart and any contractual penalties. The figures come jointly from controlling, production and maintenance. - **What indirect costs arise when a plant is down?** In addition to the directly measurable costs, there are consequential costs that are often underestimated: overtime to catch up on production, late deliveries and contractual penalties, disruptions in downstream processes, lost follow-up orders and a loss of customer confidence. These items are harder to quantify but should at least be included as a range in any estimate. - **When is it worth keeping a spare part in stock?** Stocking is worthwhile if downtime during the replenishment lead time costs more than the tied-up capital, storage and ageing risk of the part. This applies in particular to long lead times, bottleneck machines and parts with only one source of supply. For inexpensive parts that can be delivered quickly, a secured source of supply is often sufficient. #### Equipment availability URL: https://www.ktb-europe.com/en/glossary/equipment-availability/ Equipment availability is the proportion of planned time during which a plant is actually ready for operation and able to perform its required function. Equipment availability is a key metric in production and maintenance. It shows how much unplanned and planned downtime reduces the usable time of a machine or line. Different definitions are used depending on the purpose, which is why figures from different companies are only comparable if the basis of calculation is known. Technical or inherent availability is calculated from MTBF and MTTR: MTBF divided by the sum of MTBF and MTTR. Operational availability additionally takes account of waiting times, for example for personnel or spare parts, and planned maintenance. In the OEE metric, availability is the factor actual running time divided by planned production time. Example: 400 hours of running time out of 440 planned hours gives around 91 per cent. Availability increases when failures become less frequent or are remedied more quickly. Preventive and condition-based maintenance extend the time between failures, while well-thought-out spare parts stockholding shortens downtime. Particularly for bottleneck plants, the availability of critical components often determines the entire output. In practice: To make improvements, it helps to classify downtime by cause, for example fault, waiting for material, changeover and maintenance. If waiting times for spare parts account for a noticeable share, an analysis of critical parts with a stockholding decision is usually the quickest lever. Also known as: technical availability, machine availability, plant availability, asset availability Frequently asked questions: - **How is equipment availability calculated?** A widely used formula is: availability equals actual running time divided by planned production time. Alternatively, technical availability is calculated as MTBF divided by the sum of MTBF and MTTR. If, for example, MTBF is 190 hours and MTTR is 10 hours, the technical availability is 95 per cent. - **What is the difference between availability and OEE?** Availability only records how long a plant actually runs. OEE, overall equipment effectiveness, additionally multiplies availability by the performance rate and the quality rate. A plant can therefore be highly available and still have a low OEE if it runs slowly or produces a lot of scrap. - **How can equipment availability be increased?** Starting points are fewer failures through preventive and condition-based maintenance and shorter downtime through rapid diagnosis and well-organised spare parts supply. Changeover times and planned maintenance can often be shortened too. Which lever achieves the most is shown by an evaluation of downtime by duration and cause. - **Does planned maintenance count as unavailability?** That depends on the definition. In OEE analysis, planned maintenance is often booked outside planned production time and then does not reduce availability. In operational availability, by contrast, it is frequently included. It is important to define the rule consistently so that the figures remain comparable over time. #### Infrared thermography (maintenance) URL: https://www.ktb-europe.com/en/glossary/infrared-thermography/ Infrared thermography is a non-contact measuring method that uses a thermal imaging camera to visualise temperature distributions and detect overheating components early. In maintenance, thermography is one of the most important condition monitoring methods. An infrared camera captures the thermal radiation emitted by surfaces and displays it as a thermal image. As many faults are accompanied by heating, defects can be detected before they lead to failures, fires or downtime, and this during ongoing operation. Classic applications are electrical installations: loose or corroded terminal connections, overloaded cables, unevenly loaded phases and hot contactors, fuses and circuit breakers in control cabinets. On the mechanical side, it reveals bearings, couplings and gearboxes running hot; in process engineering, blocked pipes, defective steam traps, insulation damage and wear on furnace linings. Meaningful measurements require sufficient load, the correct emissivity setting, allowance for reflections and a comparison of similar components. Findings are documented with an image, temperature difference and urgency. This results in targeted measures and a plannable demand for spare parts, for example terminals, contactors or bearings. After replacement, a follow-up measurement confirms that the measure was successful. In practice: Thermographic findings should be documented with the exact component designation so that purchasing can procure the spare part without further queries. For electrical findings, the affected part can often be replaced during the next planned shutdown, provided it is available in time. Also known as: thermography, thermal imaging, IR thermography, thermal imaging inspection Frequently asked questions: - **What can thermography detect in maintenance?** Thermography mainly reveals unexpected heating: poor contacts and overload in electrical installations, bearings and couplings running hot, damage to insulation and refractory linings, blockages in pipework and defective steam traps. It indicates where the problem is located; the cause usually has to be clarified separately. - **What is emissivity in thermography?** Emissivity describes how strongly a surface emits thermal radiation compared with an ideal radiator. Matt, dark surfaces radiate a great deal, bright metals little, and instead reflect their surroundings. If the emissivity is set incorrectly, the camera shows incorrect temperatures. Remedies include correction values, markings or comparing similar components. - **When should control cabinets be inspected thermographically?** Measurements are taken under the highest possible typical load, because faults only heat up when current flows. Many companies set regular inspection intervals, sometimes based on insurance or internal requirements. Work on open control cabinets under voltage requires qualified personnel and appropriate protective measures; inspection windows can reduce the risk. - **Does thermography replace vibration analysis?** No. Thermography mainly detects heat build-up and is particularly suitable for electrical installations and thermal processes. Bearing damage often only shows up thermally at a late stage, whereas vibration analysis detects it much earlier. The two methods complement each other and are frequently combined in condition-based maintenance. #### Maintenance URL: https://www.ktb-europe.com/en/glossary/maintenance/ Under DIN 31051, maintenance covers all measures that retain or restore the functional condition of a plant or piece of equipment. DIN 31051 divides maintenance into four basic measures. Servicing slows down the depletion of the wear reserve, for example through lubricating, cleaning or adjusting. Inspection determines and assesses the actual condition. Repair returns a unit to a functional condition after a fault or damage. Improvement increases reliability or maintainability without changing the required function. In addition, DIN EN 13306 defines maintenance terminology at European level. Depending on when intervention takes place, a distinction is made between reactive (breakdown) maintenance, preventive (time- or usage-based) maintenance, condition-based maintenance and predictive maintenance. Which strategy fits depends on the consequences of failure, costs and plannability. Critical units are usually monitored on a condition basis, while non-critical components are often run to failure. Every strategy requires the necessary spare parts to be available in time. Maintenance and spare parts management are therefore closely intertwined: maintenance schedules determine the plannable demand, failure risks determine the safety stock. In practice: For planned shutdowns, parts lists should go to procurement early so that long lead times do not jeopardise the schedule. For breakdown repairs, fast and unambiguous identification of the defective part determines how long the downtime lasts. Also known as: plant maintenance, equipment maintenance, maintenance and repair Frequently asked questions: - **What is the difference between servicing, inspection and repair?** Servicing covers preventive tasks such as lubricating, cleaning or adjusting that slow down wear. Inspection determines and assesses the current condition, for example by visual check or measurement. Repair means restoring function after a fault or damage, usually by replacing or reconditioning parts. Together with improvement, these measures form the basic building blocks of maintenance. - **Which maintenance strategy is the right one?** There is no universally best strategy. The choice depends on the consequences of a failure, the predictability of wear and the effort required for monitoring. For non-critical, easily replaceable parts, running to failure can be economical. Bottleneck equipment, by contrast, tends to be managed with condition-based or predictive maintenance. In practice, companies combine several strategies, tailored to the individual units. - **Which KPIs are used in maintenance?** Common ones are mean time between failures (MTBF), mean time to repair (MTTR), technical availability and overall equipment effectiveness (OEE). In addition, maintenance costs relative to asset value, the share of planned versus unplanned work orders and spare parts availability are monitored. The figures only become meaningful when breakdowns and interventions are recorded consistently and uniformly. #### Maintenance plan (maintenance schedule) URL: https://www.ktb-europe.com/en/glossary/maintenance-plan/ A maintenance plan specifies for plants and assemblies which servicing and inspection tasks are carried out, at what interval, by whom and with which material. The maintenance plan is the central planning tool of preventive maintenance. It translates manufacturer specifications, statutory inspection obligations and in-house experience into specific, recurring tasks. This makes servicing plannable rather than leaving it to chance or to the memory of individual employees. A complete maintenance plan states for each plant the task, the interval, the responsible person or department, the time required, the tools needed, spare parts and consumables, and safety instructions. Intervals can be time-based, for example monthly, usage-based according to operating hours or switching cycles, or condition-based, when measured values trigger an action. The plan is kept in spreadsheets, checklists or a CMMS that generates dates automatically and documents completion. The maintenance plan results in a readily predictable demand for filters, lubricants, seals, belts and other wear parts. If this demand is pooled at an early stage, maintenance dates can be reliably met and rush orders avoided. Statutory inspections should be clearly marked in the plan so that they are not inadvertently dropped when dates are postponed. In practice: For each maintenance item, the required material should be recorded with its exact designation, manufacturer part number and quantity. Regularly comparing maintenance plans with actual failures shows whether intervals should be extended or shortened. Also known as: maintenance schedule, servicing schedule, preventive maintenance plan, maintenance calendar Frequently asked questions: - **What belongs in a maintenance plan?** A maintenance plan contains the plant or assembly, the specific task, the interval, the responsibility, the estimated time required, tools and material, and safety instructions. A field for confirming completion and space for findings are also helpful. The plan thus also serves as a record of the work carried out. - **How do you create a maintenance plan?** First, the plants are recorded and assessed according to criticality. Then manufacturer specifications, statutory inspection obligations and empirical values are combined into tasks with intervals. Responsibilities, material and time required are then added. After a few months, the plan should be reviewed and adjusted on the basis of failure and inspection data. - **What is the difference between a maintenance plan and an inspection plan?** The maintenance plan describes measures that delay wear, such as lubricating, cleaning or changing filters. The inspection plan describes checks used to determine and assess condition, for example visual checks, measurements or functional tests. In practice, the two are often kept in a single combined plan. - **Is there a template for a maintenance plan?** Templates are available as spreadsheets or in maintenance software, but they do not replace plant-specific preparation. The basic framework is usually a table with columns for plant, task, interval, responsibility, material, time required and completion note. The content should always be derived from the operating instructions and in-house experience. #### MRO (maintenance, repair and operations) URL: https://www.ktb-europe.com/en/glossary/mro/ MRO stands for maintenance, repair and operations and covers all goods and services that keep a plant running, serviced and repaired. The abbreviation MRO groups together materials and services that do not go into the end product but are needed for the ongoing operation of a plant. These include spare parts and wear parts such as bearings, seals, valves or sensors, as well as operating supplies, tools, personal protective equipment and maintenance services. In aviation the O often stands for overhaul, meaning a complete rebuild; in industry, operations is the usual reading. From a business perspective, MRO is part of indirect spend. It typically involves a very large number of items with low unit value, irregular consumption and numerous suppliers. The value of an MRO part is therefore rarely measured by its price, but by the consequences when it is missing: a bearing costing a few euros can bring a production line to a standstill. Key metrics in the MRO environment are availability, replenishment lead time, stock levels and process costs per order. Many companies therefore pool requirements, standardise item master data and define which parts are critical and must be kept in stock. In practice: In maintenance, MRO work starts with clean part identification: manufacturer part number, nameplate and installation situation. In procurement, it pays to rank MRO requirements by criticality rather than managing them like direct materials purely on unit price. Also known as: maintenance, repair and operations, maintenance, repair and overhaul (aviation), MRO supplies, MRO materials Frequently asked questions: - **What does MRO material include?** MRO material includes everything that keeps a plant running without becoming part of the product itself: bearings, seals, belts, filters, valves, sensors and drive components, as well as lubricants, cleaning agents, tools, measuring equipment and personal protective equipment. External maintenance and repair services are often included too. Each company defines the exact scope in its own category structure. - **What is the difference between MRO and direct materials?** Direct materials go straight into the manufactured product, such as raw materials or bought-in parts, and can usually be derived from production plans. MRO material, by contrast, keeps the equipment running. Demand for it arises from wear, servicing intervals or breakdowns and is therefore harder to plan. The control parameters differ accordingly: for direct materials, quantity and price; for MRO, above all availability and fast identification. - **Why is MRO so important for companies, even though the parts are often inexpensive?** The value of an MRO part only becomes apparent when it is missing. An inexpensive wear part can stop an entire line, and the downtime costs then exceed the price of the part many times over. On top of this come the process costs: many small orders with many suppliers cause considerable effort. A well-considered MRO strategy therefore aims at the availability of critical parts and lean processes, not just low unit prices. #### MTBF (mean time between failures) URL: https://www.ktb-europe.com/en/glossary/mtbf/ MTBF (mean time between failures) is the average operating time between two failures of a repairable system and a measure of its reliability. MTBF is calculated as the total operating time divided by the number of failures in the period under review. If, for example, ten identical pumps each run for 5,000 hours and fail five times in total, the MTBF is 10,000 hours. The term assumes that the system is repaired after a failure and continues to run. For non-repairable components, such as many electronic parts, MTTF (mean time to failure) is used instead, the average time to the first failure. MTTR (mean time to repair) describes the average time from the fault until the equipment is back in operation. Together, the two values give availability: MTBF divided by the sum of MTBF and MTTR. With an MTBF of 2,000 hours and an MTTR of 10 hours, availability is around 99.5 per cent. Manufacturers' MTBF figures are not a statement of service life or a warranty. They apply to defined operating conditions and are often based on calculation models with a constant failure rate. Under this assumption, more than half of the units will have failed at least once by the time the MTBF is reached. In practice: Spare parts logistics mainly affects MTTR: time spent waiting for a part counts in full towards the repair time. For components with a low MTBF and long lead times, a spare part held in stock often improves availability more than any other measure. Also known as: mean time between failures, mean operating time between failures, MTTF, MTTR Frequently asked questions: - **How do you calculate MTBF?** MTBF is the total operating time divided by the number of failures in that period. If several identical units are considered, their operating times are added together. Repair times do not count as operating time. The value only becomes meaningful with a sufficient number of failures and comparable operating conditions. - **What is the difference between MTBF, MTTF and MTTR?** MTBF is the average operating time between two failures of a repairable system. MTTF describes the average time to failure of a non-repairable component, which is then replaced. MTTR is the average duration of a repair, including troubleshooting and recommissioning. Together, MTBF and MTTR determine availability. - **Does an MTBF of 100,000 hours mean a device will last that long?** No. MTBF is a statistical average across many units, not a statement about the service life of an individual device. It only applies to the conditions defined by the manufacturer, such as temperature and load, and often excludes end-of-life wear. With a constant failure rate, a large proportion of devices fail well before the MTBF is reached. - **How do you calculate availability from MTBF and MTTR?** Availability is MTBF divided by the sum of MTBF and MTTR. An example: with an MTBF of 500 hours and an MTTR of 5 hours, the result is 500 divided by 505, i.e. around 99 per cent. Shorter repair times, for example thanks to spare parts held in stock, increase availability just as fewer failures do. #### MTTR (mean time to repair) URL: https://www.ktb-europe.com/en/glossary/mttr/ MTTR (mean time to repair) is the average time that elapses between the failure of a plant and the restoration of its functionality. MTTR is a key maintenance metric and describes how quickly a failed unit is ready for operation again. It is calculated as the sum of all downtime or repair times divided by the number of failures in a period. Together with MTBF, the mean operating time between failures, it determines the technical availability of a plant. Depending on the definition, MTTR covers only the actual repair time or the entire time from failure to restart, in which case it is often referred to as mean time to restore. This time is made up of fault reporting, travel, diagnosis, waiting for spare parts and personnel, the actual repair, functional testing and restart. For comparisons, it must therefore be clearly defined which elements are included. In many companies, the largest share is not the repair itself but the waiting time for spare parts. Good stockholding of critical components, unambiguous master data and prepared sources of supply therefore often reduce MTTR more than faster handling. In practice: Anyone wishing to reduce MTTR should split downtime into diagnosis, waiting time for material and repair, and record these separately. This makes it clear whether more stock, better parts documentation or training will have the greatest effect. Also known as: mean time to repair, mean time to restore, average repair time, mean time to recovery Frequently asked questions: - **How is MTTR calculated?** MTTR is the sum of all repair or downtime periods in a given period divided by the number of failures. Example: three failures with two, four and six hours of downtime give twelve hours divided by three, i.e. an MTTR of four hours. It is important always to use the same time definition. - **What is the difference between MTTR and MTBF?** MTBF describes the mean operating time between two failures and is therefore a measure of reliability. MTTR describes the mean time until a failed plant is running again and is a measure of maintainability and responsiveness. A high MTBF and a low MTTR together result in high availability. - **How can MTTR be reduced?** Effective levers are prompt fault reporting, good diagnostic capabilities, documented repair instructions and trained personnel. The availability of critical spare parts is particularly important: if the part and part number are known and the part is in stock or a source of supply has been prepared, the longest time element, waiting for material, often disappears. - **What does MTTR stand for?** MTTR is the abbreviation for mean time to repair, i.e. the average repair time. In some contexts it also stands for mean time to restore or mean time to recovery, meaning the entire time until operation is restored. Which reading applies should be explicitly defined in KPI definitions. #### Overall equipment effectiveness (OEE) URL: https://www.ktb-europe.com/en/glossary/oee/ Overall equipment effectiveness (OEE) is a KPI that multiplies a plant's availability, performance and quality to show its real productivity. OEE stands for overall equipment effectiveness. The KPI compares the quantity of good parts actually produced with what the equipment could theoretically have produced in the planned production time. It is closely linked to total productive maintenance and is expressed as a percentage. It is calculated as OEE = availability × performance × quality. An example: a machine is scheduled for 480 minutes, is down for 60 of them and runs for 420 minutes; availability is 87.5 per cent. With an ideal cycle time of one minute, 420 parts would be possible, but 378 are produced; performance is 90 per cent. Of these, 360 parts are good, so the quality rate is around 95.2 per cent. This results in an OEE of 75 per cent. The factors reflect typical types of loss: availability losses from breakdowns, changeovers and material shortages, performance losses from minor stoppages and reduced speed, and quality losses from scrap, rework and start-up losses. Missing spare parts show up directly as an availability loss. In practice: If the reasons for downtime are recorded properly, the OEE analysis shows what share of availability losses is due to waiting for spare parts. This figure is a solid basis for justifying stockholding or framework agreements for specific parts. Also known as: OEE, overall equipment efficiency, equipment effectiveness, plant effectiveness Frequently asked questions: - **How do you calculate OEE?** OEE is the product of three factors: availability (run time divided by planned production time), performance (actual output divided by the output theoretically possible in the run time) and quality (good parts divided by parts produced). A short formula is: good parts × ideal cycle time divided by planned production time. - **What is a good OEE value?** There is no universally valid target. The achievable OEE depends on the industry, product variety, batch sizes and type of equipment, and companies define planned production time differently. More meaningful than comparing with other companies' figures is the development of your own OEE over time and the question of which of the three factors is holding it back most. - **What is the difference between OEE and availability?** Availability is only one of the three OEE factors. It shows how long a machine actually runs during the planned time. A machine can have high availability and still a low OEE if it runs slower than possible or produces a lot of scrap. - **Which losses does OEE capture?** Losses are captured in three groups: availability losses such as breakdowns, changeover and waiting times, performance losses such as minor stoppages and reduced cycle speed, and quality losses from scrap, rework and start-up losses. In TPM these are often referred to as the six big losses. #### Predictive maintenance URL: https://www.ktb-europe.com/en/glossary/predictive-maintenance/ Predictive maintenance is a maintenance strategy that forecasts failures from condition and operating data and schedules intervention just beforehand. In predictive maintenance, machines are monitored continuously or at short intervals, for example using vibration, temperature, current or oil condition data. Statistical models or machine learning methods detect patterns that precede damage and estimate the remaining useful life of a component. Maintenance then intervenes not at a fixed interval, but when the condition requires it and the production schedule allows it. Predictive maintenance should be distinguished from condition-based maintenance: the latter reacts when limit values are exceeded, whereas the predictive approach forecasts when the failure will occur. In practice, the two approaches merge into one another. Prerequisites are suitable sensors, a reliable database containing historical failure cases and clear responsibilities for the analysis. The benefit depends heavily on whether the predicted spare part can actually be procured in the time remaining. In practice: A forecast is only worth as much as the replenishment lead time of the part concerned. For monitored units, lead times, sources of supply and possible alternatives should therefore be clarified in advance, especially for discontinued components. Also known as: PdM, forecast-based maintenance, data-driven maintenance Frequently asked questions: - **What data do you need for predictive maintenance?** The basis is condition data that indicates deterioration early, such as vibration, temperature, current draw, pressure or particles in the oil. Operating data such as load, speed and running time is just as important, along with a history of previous damage. Without documented failures, patterns can hardly be assigned reliably. Many projects therefore start with a few critical units and build up the database step by step. - **For which equipment is predictive maintenance worthwhile?** The approach brings the most benefit for units whose failure is expensive and whose damage announces itself measurably, such as large drives, pumps, compressors or gearboxes in bottleneck equipment. For inexpensive components that can be replaced quickly, the monitoring effort often exceeds the benefit. Random failures without warning signs, such as some electronic defects, can also only be predicted to a limited extent using condition data. - **What is the difference between preventive and predictive maintenance?** Preventive maintenance works with fixed intervals based on time, operating hours or quantities, regardless of actual condition. As a result, parts are sometimes replaced too early or too late. Predictive maintenance bases the intervention on the measured condition and a forecast of the time of failure. It makes better use of the wear reserve but requires measuring technology, data analysis and flexible provision of spare parts. #### Preventive maintenance URL: https://www.ktb-europe.com/en/glossary/preventive-maintenance/ Preventive maintenance is a strategy in which components are serviced or replaced at fixed time or usage intervals before they fail. With preventive maintenance, maintenance intervenes before damage occurs. In common usage, the term refers to the time-based or usage-based variant: parts are changed according to calendar time, operating hours, switching cycles or quantity produced, regardless of their actual condition. EN 13306 defines the term more broadly and also counts condition-based maintenance as preventive; fixed-interval maintenance is called predetermined maintenance there. The advantages lie in predictability: work can be scheduled during production breaks, staff and materials can be prepared, and unplanned breakdowns become less frequent. The disadvantage is that parts are often replaced even though they would last much longer. This increases material consumption and labour. In addition, rigid intervals do not prevent failures whose cause does not depend on age, and every intervention carries the risk of assembly errors. Preventive maintenance is particularly suitable for components with predictable, age-related wear and for components whose failure would have serious consequences but whose condition is difficult to measure. In practice: Because intervals and quantities are known, the parts required for preventive work can be secured well through annual quantities or call-off orders. It makes sense to review the intervals regularly based on the condition of the parts removed. Also known as: PM, planned preventive maintenance (PPM), predetermined maintenance, time-based maintenance, interval-based maintenance Frequently asked questions: - **What is the difference between preventive and condition-based maintenance?** Preventive maintenance in the narrower sense replaces or services parts at fixed intervals, regardless of their condition. Condition-based maintenance, by contrast, measures parameters such as vibration or temperature and only intervenes when limit values are exceeded. It makes better use of the parts' service life but requires measuring equipment and analysis. - **What are the advantages and disadvantages of preventive maintenance?** The advantages are good predictability, fewer unplanned stoppages and a foreseeable demand for spare parts. The disadvantages are the replacement of parts that are still intact, higher material and labour costs, and the risk of introducing new faults through frequent interventions. Failures that do not depend on a part's age are hardly prevented by fixed intervals. - **Is planned preventive maintenance the same as preventive maintenance?** Yes, the terms are used interchangeably. Under EN 13306, preventive maintenance covers all measures carried out before a failure, including condition-based maintenance. In everyday usage, it usually means the interval-based variant, which the standard calls predetermined maintenance. #### Reactive maintenance URL: https://www.ktb-europe.com/en/glossary/reactive-maintenance/ Reactive maintenance is a strategy in which action is only taken after a failure; components are deliberately run until they break down. With reactive or breakdown maintenance, no targeted measures are taken before damage occurs. Only when a component fails is it repaired or replaced. The approach is known as run-to-failure, and the action taken after the failure as corrective maintenance. EN 13306 also uses the term corrective maintenance. The strategy makes sense where a failure has minor consequences: for inexpensive parts that can be replaced quickly, for equipment with built-in redundancy, or for components whose condition can neither be measured nor sensibly planned in intervals. Typical examples are lamps, simple fuses or small parts held in stock. As an unplanned main strategy for important equipment, however, it is risky. Failures occur at inconvenient times, cause consequential damage to other components, tie up staff at short notice and lead to unplanned production interruptions. For procurement, reactive maintenance often means emergency purchasing: parts have to be found under time pressure, express surcharges accepted and quality checks shortened. The better part data and sources of supply are maintained in advance, the shorter the downtime. In practice: Anyone who deliberately runs certain components until they fail should keep their spare parts in stock or know sources that can supply at short notice. For the emergency enquiry, the manufacturer part number, photos and quantity should be ready to hand immediately. Also known as: breakdown maintenance, run-to-failure, corrective maintenance, firefighting maintenance Frequently asked questions: - **When does reactive maintenance make sense?** It makes sense when a failure causes only low costs and no safety risks, the part is inexpensive and quick to replace, or the equipment has built-in redundancy. In that case, preventive servicing or condition monitoring costs more than it saves. It is important that this decision is made deliberately and that the spare part is available. - **What are the risks of reactive maintenance?** Failures come without warning and often at the worst possible moment. A defective component can cause further damage, for example a seized bearing damaging the shaft and housing. On top of this come unplanned production losses, overtime and expensive rush purchases. For safety-relevant components, the approach is generally unsuitable. - **What is the difference between reactive and preventive maintenance?** Reactive maintenance only intervenes after a failure. Preventive maintenance acts beforehand by servicing or replacing parts at fixed intervals. Preventive measures are easier to plan but also incur costs for parts that would still work. Many companies combine both strategies depending on how important the equipment is. #### Reliability-centred maintenance (RCM) URL: https://www.ktb-europe.com/en/glossary/reliability-centred-maintenance/ Reliability-centred maintenance (RCM) is a method that determines the appropriate maintenance strategy for each plant function on the basis of its failure consequences. RCM was originally developed in civil aviation and later transferred to industrial plants. Instead of servicing all components at fixed intervals, RCM asks what function a plant is meant to perform, how it can fail and what consequences a failure has for safety, the environment, production and costs. The process follows a fixed sequence of questions: functions and performance standards, functional failures, failure modes, failure effects and consequences, possible preventive tasks and default actions where no suitable preventive task exists. This results in a strategy for each failure mode, such as condition monitoring, scheduled replacement, functional testing, design modification or deliberate run-to-failure. Criteria for RCM processes are described, for example, in the SAE JA1011 standard; FMEA is methodologically closely related. RCM provides valuable results for spare parts planning: where parts are replaced on schedule, demand is predictable; where equipment is run to failure, the part must be in stock or quickly obtainable if the consequences are critical. In practice: RCM analyses are particularly worthwhile for critical plants with high failure consequences. The results should be transferred directly into maintenance plans and stockholding decisions so that each strategy also has the right spare parts in stock. Also known as: RCM, reliability-centered maintenance, RCM analysis, reliability-based maintenance Frequently asked questions: - **What is the difference between RCM and TPM?** RCM is an analysis method that determines the technically and economically appropriate maintenance strategy for each failure mode. TPM is a comprehensive management concept that involves operators in maintenance and aims to reduce losses throughout production. The two are not mutually exclusive: RCM can be used within a TPM programme for critical plants. - **What questions does RCM ask?** RCM works with seven key questions: what are the functions of the plant, in what ways can it fail to fulfil them, what causes each functional failure, what happens when it occurs, what are its consequences, what can be done to prevent it and what should be done if no suitable preventive task is possible. The answers are documented for each failure mode. - **For which plants is RCM worthwhile?** RCM is laborious and requires expertise from operations, maintenance and engineering. It is particularly worthwhile for plants whose failure affects safety, the environment or large parts of production, such as bottleneck machines, utility plants or process plants. For simple, redundant or non-critical equipment, a simplified criticality assessment is often sufficient. - **What does run-to-failure mean in RCM?** Run-to-failure means deliberately operating a component until it fails, because prevention would be more expensive than the consequences of the failure. This only makes sense if the failure has no safety or environmental consequences. To keep the downtime short, the spare part and replacement procedure should nevertheless be prepared. #### Repair (maintenance) URL: https://www.ktb-europe.com/en/glossary/maintenance-repair/ Under DIN 31051, repair covers all measures that return a failed or damaged item to a functioning condition. Repair is one of the four basic maintenance measures defined in DIN 31051. It starts when a fault, damage or failure has occurred or becomes apparent during an inspection. The aim is to restore the required function. Measures that improve an item beyond its original condition, by contrast, are classed by the standard as improvement, not repair. Two approaches are common: with replacement, a defective component or an entire assembly is replaced by a new or reconditioned part. With repair in the narrower sense, the existing part itself is made usable again, for example by welding, reworking or rewinding a motor. Replacement usually shortens the downtime, while repairing the part saves material and is often the only option when a part is no longer available. Repairs can be planned, for instance following an inspection finding, or unplanned after a sudden breakdown. For procurement, unplanned repair means short-notice demand under time pressure. Knowing spare parts, exchange assemblies and repair service providers in advance shortens downtime considerably. In practice: For a quick spare parts enquiry after a breakdown, a photo of the nameplate, the manufacturer part number, the serial number of the machine and a brief description of the damage help. If the original part is no longer available, it is worth checking in parallel whether a repair or an alternative part is an option. Also known as: corrective maintenance, repair, breakdown repair, fault rectification Frequently asked questions: - **What is the difference between repair under DIN 31051 and repairing a part?** Repair is the standard term from DIN 31051 and covers all measures that make an item functional again. This includes both replacing components and repairing the existing part. Repairing a part is therefore one form of repair in the sense of the standard. In everyday language the terms are often used interchangeably. - **What is the difference between servicing and repair?** Servicing takes place before damage occurs and slows down wear, for example through lubrication or cleaning. Repair starts when a fault or damage is already present and restores the function. Servicing can usually be planned; repair often cannot. - **When is repairing a part worthwhile instead of replacing it?** Repairing is worthwhile if it is significantly cheaper than a new part, if the part has long lead times or is no longer manufactured. Replacement usually makes more sense if the machine has to be running again quickly and a spare part is immediately available. The two are often combined: an exchange part is fitted, and the defective part is then repaired and put into stock. - **What information is needed for a spare parts enquiry after a breakdown?** Important details are the manufacturer and manufacturer part number of the defective part, the type and serial number of the machine, photos of the part and the nameplate, and the quantity required. Technical data such as dimensions, material or rating are also helpful, along with the latest date by which the part is needed. #### Retrofit URL: https://www.ktb-europe.com/en/glossary/retrofit/ Retrofit refers to modernising existing machines with new controls, drives or safety technology instead of replacing them entirely. In a retrofit, the basic mechanical structure of a plant is retained while outdated or discontinued components are replaced with current technology. Typical triggers are controls and drives that are no longer available, higher demands on performance, energy efficiency or connectivity, and upgrades to safety technology. A retrofit is to be distinguished from an overhaul, which restores the original condition, and from a new purchase. A retrofit frequently covers replacing the controller and operator panel, inverters and motors, sensors, fieldbus systems and control cabinet components, sometimes also hydraulics or pneumatics. The existing installation, documentation and interfaces are surveyed beforehand. Where changes are extensive, it must be checked whether the machine has undergone a substantial modification, which may entail a new risk assessment and conformity assessment. The applicable legal framework is decisive; in case of doubt, expert advice should be sought. For spare parts supply, a retrofit is often the answer to obsolescence: instead of permanently searching for scarce legacy parts, the plant is converted to current, readily available components. In practice: A retrofit should begin with a list of all discontinued and hard-to-source parts, as this shows where the need for action is greatest. Until the conversion, a targeted stock of critical legacy parts helps keep the plant running safely. Also known as: machine modernisation Frequently asked questions: - **What is the difference between a retrofit and an overhaul?** An overhaul restores a machine to its original condition by replacing wear parts and reconditioning assemblies. A retrofit, by contrast, modernises the machine with new technology, such as a current controller or more efficient drives. In practice, the two are often combined: the mechanics are overhauled while the electrics and controls are renewed. - **When is a retrofit worthwhile?** A retrofit is usually worthwhile when the mechanics of a plant are still in good condition but the controls or drives are outdated or can no longer be sourced. The deciding factors are the comparison with a new purchase, the remaining service life, downtime risks due to missing spare parts and possible improvements in performance and energy consumption. - **Does a retrofit require new CE marking?** That depends on whether the changes count as a substantial modification. If, for example, function, performance or the safety concept are altered in such a way that new hazards arise, a renewed conformity assessment may be required. The classification is made case by case on the basis of the applicable regulations; this entry does not replace a legal review. - **Which components are typically replaced in a retrofit?** Most often, controllers, operator panels, frequency inverters, servo and induction motors, sensors and fieldbus components are replaced. Safety technology such as safety controllers and light curtains, as well as control cabinet components, are often added. Main mechanical assemblies such as the frame, guides and gearboxes are generally retained and overhauled if necessary. #### Root cause analysis (RCA) URL: https://www.ktb-europe.com/en/glossary/root-cause-analysis/ Root cause analysis (RCA) is a structured approach to finding the actual cause of a failure and preventing it from recurring. When faults occur, often only the symptom is eliminated: the defective bearing is replaced and the machine runs again. Root cause analysis goes further and asks why the bearing failed, for example due to misalignment, lack of lubricant or incorrect fitting. Only once this underlying cause has been eliminated does the failure frequency fall permanently. Common tools are the 5 Whys method, in which the question why is asked repeatedly, the Ishikawa or cause-and-effect diagram with categories such as man, machine, material, method, measurement and environment, fault tree analysis and the evaluation of damage patterns on removed parts. In structured problem-solving processes, root cause analysis is a fixed step. What matters are facts rather than assumptions: measurement data, operating logs, photos and the defective component itself. The result is corrective actions, such as changed maintenance intervals, better lubrication, training, design changes or the choice of a different material or spare part. For purchasing, the analysis may show that a cheaper part or one not meeting the specification was the actual cause. In practice: Removed damaged parts should be labelled and kept rather than disposed of immediately, as they are the most important piece of evidence. If a spare part turns out to be the cause, its origin, batch and inspection records belong in the complaint to the supplier. Also known as: RCA, failure cause analysis, root cause failure analysis (RCFA), failure analysis Frequently asked questions: - **What is the 5 Whys method?** With the 5 Whys method, starting from the problem, you ask why several times in succession until you reach a cause that can be specifically eliminated. The number five is a guideline; sometimes fewer steps suffice, sometimes more are needed. The method is simple but should be backed up by facts such as measured values or damage patterns. - **What root cause analysis methods are there?** Widely used are the 5 Whys method, the Ishikawa diagram, fault tree analysis, Pareto analysis for prioritising frequent causes and damage analysis on components. For complex cases, several methods are combined and embedded in a structured problem-solving process, such as a PDCA cycle. - **What is the difference between root cause analysis and FMEA?** Root cause analysis is carried out after a failure has occurred and looks back to find its cause. FMEA is forward-looking: it considers possible failures of a product or process before they occur and assesses their risks. Findings from root cause analyses are frequently fed into updates of existing FMEAs. - **When is root cause analysis worthwhile in maintenance?** It is useful for recurring failures, for faults with high downtime costs or safety consequences and for unexpectedly early failures of new parts. Many companies define triggers for it, such as a certain downtime duration or the same fault occurring several times within a given period. #### Servicing (maintenance) URL: https://www.ktb-europe.com/en/glossary/servicing/ Under DIN 31051, servicing covers all measures that slow down the depletion of a plant's wear reserve, such as cleaning, lubricating or adjusting. DIN 31051 classifies servicing as one of the four basic maintenance measures. Every technical item has a wear reserve that diminishes during operation through wear, corrosion or contamination. Servicing slows this depletion but does not restore the original condition. It must be distinguished from inspection, which determines and assesses the actual condition, from repair, which returns an item to a functioning condition after damage, and from improvement, which increases reliability or maintainability. Typical servicing tasks are lubricating, topping up operating fluids, cleaning, preserving, adjusting and the scheduled replacement of consumable parts such as filters or seals. They are recorded in a servicing schedule that describes the task, interval, responsibility and required materials for each machine. The intervals are based on manufacturer specifications, operating hours, calendar time or the company's own experience. Because servicing can be planned, its material requirements can also be forecast well. The servicing schedule gives quantities and dates for filters, lubricants, seal kits and other wear parts, which can be ordered in good time or called off under framework agreements. In practice: In the servicing schedule, each task should be linked to the exact part description with the manufacturer part number, not just “change filter”. This allows procurement to pool the annual requirement, and servicing dates do not fail because of missing material. Also known as: service, routine maintenance, servicing work, preventive servicing Frequently asked questions: - **What is the difference between servicing and maintenance?** Under DIN 31051, maintenance is the umbrella term and comprises four basic measures: servicing, inspection, repair and improvement. Servicing is therefore only one part of it. It slows down wear, while repair rectifies damage that has already occurred. In everyday usage the terms are often used interchangeably, but technically they are clearly distinct. - **What is the difference between servicing and inspection?** Inspection determines and assesses the condition of a machine, for example by visual check, measurement or function test. Servicing, by contrast, actively intervenes to slow down wear, for example by lubricating or cleaning. In practice, both are often carried out during the same appointment. - **What belongs in a servicing schedule?** A servicing schedule lists, for each machine or assembly, the servicing task, the interval, the responsible person or department, the time required, and the materials and tools. Notes on safety measures and a field for documenting completion are also useful. It is usually based on the manufacturer's specifications, supplemented by the company's own experience. - **How often should a machine be serviced?** The starting point is the servicing intervals in the manufacturer's operating manual. They are adjusted to the operating conditions: dust, heat, multi-shift operation or frequent load changes often shorten intervals, while gentle operation can extend them. Anyone who records condition data can set intervals more precisely than by calendar time alone. #### Total productive maintenance (TPM) URL: https://www.ktb-europe.com/en/glossary/total-productive-maintenance/ Total productive maintenance (TPM) is a concept from Japan that makes operators and maintenance jointly responsible for the availability of equipment. TPM originated in Japanese industry and was shaped largely by Seiichi Nakajima. The basic idea: maintenance is not solely the task of a specialist department but of all employees, from machine operators to top management. The aim is production without unplanned stoppages, without quality defects and without accidents. The concept is usually described in pillars. Central is autonomous maintenance: operators carry out simple tasks such as cleaning, lubricating, visual checks and retightening themselves and report abnormalities early. Further pillars are planned maintenance, the targeted elimination of sources of loss, quality maintenance, training, taking maintainability into account as early as equipment planning, TPM in administrative areas, and health, safety and environmental protection. The 5S method for order and cleanliness in the workplace is often regarded as the foundation. Overall equipment effectiveness (OEE) is used to measure success, combining availability, performance and quality losses in a single KPI. TPM also changes the demand for parts: operators need consumables directly at the machine, and early damage reports make spare parts requirements easier to plan. In practice: When introducing autonomous maintenance, it pays to store the consumable parts for operator tasks, such as lubricants, filters or seals, with unambiguous part numbers directly at the machine. A fixed replenishment procedure prevents the new routines from failing for lack of material. Also known as: TPM, total productive management, autonomous maintenance Frequently asked questions: - **What are the pillars of TPM?** A model with eight pillars is common: autonomous maintenance, planned maintenance, focused improvement, quality maintenance, education and training, early equipment management, TPM in administrative areas, and health, safety and environment. The number and names vary slightly depending on the source. The 5S method is usually regarded as the basis. - **What does autonomous maintenance mean?** Autonomous maintenance means that machine operators carry out simple maintenance tasks themselves: cleaning, lubricating, checking, retightening bolts and reporting abnormalities. This relieves the specialist maintenance team, which can concentrate on more demanding work. Prerequisites are training, clear standards and easily accessible materials. - **How are TPM and OEE related?** OEE is the central KPI in TPM. It shows how much of the theoretically possible production is actually achieved as good parts and makes visible whether losses stem from stoppages, reduced speed or scrap. This makes it possible to identify precisely where improvement measures should start. #### Vibration analysis URL: https://www.ktb-europe.com/en/glossary/vibration-analysis/ Vibration analysis is a condition monitoring method that measures machine vibrations in order to detect damage to rotating components early. Every rotating machine vibrates. If the level or composition of these vibrations changes, this indicates unbalance, misalignment, loose fastenings, bearing damage or gear tooth defects. Vibration analysis is therefore a core tool of condition-based and predictive maintenance of motors, pumps, fans, gearboxes and compressors. Measurements are usually taken with accelerometers at the bearing points, either with portable equipment on fixed measuring routes or permanently with online systems. The RMS value of vibration velocity in mm/s is used for general assessment; evaluation criteria for different machine classes are set out in the ISO 20816 series of standards, successor to ISO 10816. For diagnosis, the frequency spectrum is evaluated: certain patterns point to unbalance or misalignment, while envelope analysis reveals early rolling bearing damage on the basis of its defect frequencies. The greatest benefit lies in the time gained: bearing damage is often detected well before failure, so that spare parts can be procured as planned and repairs scheduled during a shutdown. This requires consistent measuring points and operating conditions so that trends remain comparable. In practice: For reliable bearing diagnosis, the exact bearing designations should be recorded for each measuring point, as the defect frequencies depend on the bearing geometry. If the analysis signals damage, procurement of the replacement bearing can begin immediately. Also known as: vibration monitoring, vibration measurement, vibration diagnostics, machine vibration analysis Frequently asked questions: - **What can vibration analysis detect?** Typical findings are unbalance, misalignment of shafts and couplings, mechanical looseness, rolling bearing damage, gear tooth defects in gearboxes, resonances and certain electrical faults in motors. Often it is possible not only to detect damage but also to estimate roughly how far it has progressed and how urgently action is needed. - **Which standard applies to the evaluation of machine vibration?** For evaluating vibration on machine housings and bearings, the ISO 20816 series of standards is used, which replaces the former ISO 10816. Depending on the type of machine, it contains zones ranging from good to unacceptable. The specific limit values depend on machine class, power and installation and are set out in the relevant part of the standard. - **What is the difference between vibration analysis and thermography?** Vibration analysis measures mechanical movements and is particularly suitable for rotating machines such as pumps, motors and gearboxes. Thermography measures surface temperatures without contact and mainly shows heating, for example at electrical connections or overloaded components. The two methods complement each other in condition-based maintenance. - **How often should vibration be measured?** The interval depends on the criticality of the machine and on the time a typical fault takes from the first signs to failure. Regular intervals are usual for route-based measurements and are shortened if values are conspicuous. Very critical machines are often monitored permanently online. ### Procurement & Purchasing #### Bid comparison (quotation comparison) URL: https://www.ktb-europe.com/en/glossary/bid-comparison/ A bid comparison sets several quotations for the same enquiry against each other in terms of price, scope and terms in order to select the most economical one. The bid comparison follows a request for quotation (RFQ) sent to several suppliers and forms the basis for the award decision. It makes quotations comparable, which are often structured differently, and documents why a supplier was selected. In many companies, it is an internal requirement above certain order values. At the same time, it supports traceability during internal audits. A distinction is made between the quantitative price comparison and the qualitative comparison. In the price comparison, all costs are brought to a common basis: unit price, quantity scales, discounts, surcharges, minimum quantities, delivery terms and payment terms. The qualitative comparison assesses criteria such as lead time, warranty, certificates, supplier evaluation results and technical conformity, often in a weighted scoring analysis. For spare parts, the technical check is particularly important. Quotations may relate to the original part, an alternative part or a different version without this being apparent at first glance. A price advantage loses its value if the part does not fit, arrives much later or is delivered without the required documents. In practice: For a fair comparison, the enquiry itself should be worded consistently: manufacturer part number, quantity, required delivery date, delivery terms and documents needed. In the comparison, it should be noted for each quotation whether the original or an alternative was offered and which lead time applies. Also known as: quotation comparison, bid tabulation, quote comparison, bid evaluation, price comparison sheet Frequently asked questions: - **How do you prepare a bid comparison?** First, all quotations are transferred to a uniform table, with line items, quantities, unit prices, surcharges, lead time, delivery terms and payment terms. Then the total costs per quotation are calculated and qualitative criteria assessed, such as technical conformity and supplier reliability. Finally, the decision is justified and documented. - **What is a price comparison sheet?** A price comparison sheet is a tabular comparison of the prices in several quotations, usually line by line. It is the quantitative core of a bid comparison. A price comparison sheet alone is rarely sufficient, however, because lead time, quality, terms and technical deviations often change the answer to the question of which quotation is the most economical. - **Which criteria belong in a bid comparison?** Besides price, the criteria include volume discounts, minimum order quantities, incidental costs, lead time, delivery terms, payment terms, warranty, accompanying documents such as certificates or declarations of conformity, and past experience with the supplier. For technical parts, it is crucial whether exactly the requested part or an alternative is being offered. #### C-parts management URL: https://www.ktb-europe.com/en/glossary/c-parts-management/ C-parts management optimises the procurement and supply of low-value, frequently needed items whose process costs often exceed their value. The term comes from ABC analysis. C-parts account for a large share of items but only a small share of procurement value. Typical examples are standard parts, screws, seals, cable ties, operating supplies or maintenance consumables. Yet each of these parts still involves an enquiry, purchase order, goods receipt, putaway and invoice verification. C-parts management therefore targets process costs, not the unit price. Common instruments are kanban systems with fixed bins, supplier-maintained shelves or vending machines at the point of use, vendor managed inventory, electronic catalogues and consolidated invoices. Often a system supplier takes over the entire range of a category. A clear distinction is important: a low-value part can still be critical if its absence stops a plant. Despite their C classification, such parts need safety stock and defined sources of supply. The economic benefit comes mainly from fewer ordering transactions, fewer suppliers and automated replenishment processes, not from lower unit prices. In practice: In maintenance, combining ABC analysis with a criticality assessment makes sense. This allows standard C-parts to be automated, while inexpensive but plant-critical parts are stocked in a targeted way. Also known as: C-parts procurement, C-class parts management, C-parts supply, small parts management Frequently asked questions: - **What are C-parts?** C-parts are items that account for a small share of purchasing value in an ABC analysis but make up a large proportion of the range in terms of numbers. Typical examples are standard parts, fasteners, small parts, consumables and simple wear parts. They are often needed frequently and are usually easy to procure. However, the classification says nothing about their technical importance for a machine. - **What systems are there for C-parts management?** Common are two-bin kanban systems, in which an empty bin automatically triggers replenishment. There are also supplier-managed shelves, vending machines at the point of use, vendor managed inventory and electronic catalogues with consolidated invoicing. Which model fits depends on the consumption pattern, the number of withdrawal points and the desired transparency about consumption. - **Can C-parts also be critical spare parts?** Yes. The ABC classification only assesses value, not the consequences of a part being missing. An inexpensive seal or sensor can stop a plant just as an expensive unit can. Despite their C classification, such parts should be flagged as critical, held with a safety stock and assigned a defined source of supply. A combination of value and criticality assessment prevents them from getting lost in automated processes. #### Call-off order URL: https://www.ktb-europe.com/en/glossary/call-off-order/ A call-off order is an order used to draw partial quantities from an existing framework agreement on the terms agreed there. A call-off order requires a framework agreement in which prices, terms and usually a total quantity or total value have already been set. With each call-off, the buyer only specifies the quantity, date and delivery address. Negotiation and supplier selection are no longer needed for each individual transaction. The basis is either a quantity contract, which sets a total quantity of an item, or a value contract, which provides for a total amount across several items. In ERP systems, the call-off is usually created as a release order referencing the contract, so that consumed and open quantities are visible at all times. Some agreements provide for fixed call-off dates or delivery schedules, others allow free call-offs within the term. The benefit lies above all in lower process costs: individual orders become simpler and faster and can in part be delegated to requesters. At the same time, the pooled volume of the framework agreement is retained. It is important to keep an eye on minimum purchase quantities, the end of the term and rules for quantities not called off, so that no unplanned obligations arise at the end of the term. In practice: In maintenance, call-off orders are suitable for regularly required wear parts and C-parts such as filters, seals or bearings. Regularly checking the call-off status shows early on whether the contract will run out prematurely or whether residual quantities are likely. Also known as: release order, call-off, scheduled release, blanket order release, delivery call-off Frequently asked questions: - **What is the difference between a framework agreement and a call-off order?** The framework agreement sets prices, terms and often a total quantity or total value for a period, but does not itself trigger a delivery. Only the call-off order specifies a partial quantity with a date and delivery address and turns it into an order that must be delivered. - **What is a quantity contract and what is a value contract?** In a quantity contract, a total quantity is agreed for a specific item and called off over the term. In a value contract, a total amount applies that can be used for several items or a category. Value contracts are more flexible when the exact items are difficult to determine in advance. - **What are the advantages of call-off orders for procurement?** Call-off orders reduce the effort per order because negotiation and supplier selection have already been completed. Orders are faster, can be partly automated or delegated to specialist departments, and the pooled terms of the framework agreement are retained. Consumption per contract also becomes transparent. - **What happens to quantities not called off at the end of the agreement?** That depends on the contractual arrangement. Some framework agreements include a purchase obligation, so that residual quantities must be paid for or taken; others only secure terms without any obligation. Purchase obligations, tolerances and extension options should therefore be agreed explicitly and the call-off status checked regularly. #### Category management (procurement) URL: https://www.ktb-europe.com/en/glossary/category-management/ Category management manages procurement by spend category, with its own strategies, suppliers and targets defined for each category. In category management, the entire procurement volume is divided into meaningful groups, for example drive technology, pneumatics, electrical components or services. Each category is the responsibility of a category manager who knows the market, demand and suppliers. In retail, category management additionally refers to range management on the sales side; in industrial procurement, it is about the buying side. The process usually follows fixed steps: analyse demand and spend, research the supply market, define the strategy, select and negotiate with suppliers, implement contracts and monitor results. Tools include spend analyses, portfolio matrices that classify categories by procurement volume and supply risk, and supplier evaluations. The aim is to achieve a balanced ratio of cost, quality and security of supply for each category. For MRO and spare parts, classification is often difficult because many items are bought only rarely and master data are inconsistent. Classification according to a uniform scheme provides the basis here. Strategies can then be differentiated, such as pooling for standard parts, framework agreements for wear parts and securing supply for critical components. Services such as repairs can also be managed as a separate category. In practice: A simple starting point is a spend analysis of recent years, broken down by category and supplier. It shows where many suppliers deliver small volumes and which categories carry a high supply risk. Also known as: category management, commodity management, category strategy, procurement category management Frequently asked questions: - **What does a category manager do in procurement?** A category manager is responsible for one or more categories across the entire procurement cycle. They analyse demand and spend, monitor the supplier market, develop a strategy for the category, run tenders and negotiations and manage the suppliers. In doing so, they work closely with engineering, maintenance and quality so that requirements and procurement objectives are aligned. - **What are the steps in category management?** The models differ in the number of steps but usually contain the same core phases: define the category, analyse demand and spend, research the supply market, develop the strategy, tender and select suppliers, implement contracts and monitor results. The cycle is repeated regularly because demand, prices and the supplier landscape change. - **What is the difference between category management in retail and in procurement?** In retail, category management refers to managing product ranges as independent business units, often together with manufacturers, in order to improve sales. In industrial procurement, it means organising purchasing by category with the aim of optimising cost, quality and security of supply for each category. #### Demand pooling URL: https://www.ktb-europe.com/en/glossary/demand-pooling/ Demand pooling combines similar requirements from several sites, departments or periods in order to improve terms and processes. With demand pooling, individual requirements that would otherwise be ordered separately are combined into larger volumes. This strengthens the negotiating position with suppliers and reduces the number of ordering and invoicing transactions. It is a key instrument of strategic procurement and often the basis for framework agreements. Pooling can take place across sites, for example when several plants need the same item; across categories, when one supplier covers several related ranges; and over time, when a year's requirements are combined in one contract. A prerequisite is transparency about actual consumption and uniform item descriptions. Pooling therefore often goes hand in hand with standardisation: variants of the same part are reduced so that larger quantities arise in the first place. Limits become apparent with critical and equipment-specific parts. Here, availability, originality and traceability count for more than price, and pooling with only one supplier can increase the risk of supply failure. It therefore makes sense to differentiate by criticality: standard and wear parts are pooled, while critical parts remain deliberately secured. In practice: A first step is to reconcile the material masters of several sites: the same part is often held under different numbers. Using the manufacturer part number, such duplicates can be identified and then included in a joint enquiry. Also known as: demand aggregation, volume bundling, volume pooling, spend aggregation Frequently asked questions: - **What types of demand pooling are there?** A distinction is usually made between geographical pooling across several sites, pooling by subject across categories or items, and pooling over time, in which the requirements of a longer period are combined in one contract. In practice, these forms are combined, for example in a cross-site annual contract for one category. - **What is the difference between demand pooling and supplier consolidation?** Demand pooling starts with the requirement: similar quantities are combined. Supplier consolidation starts with the supplier base and reduces the number of sources of supply. The two are closely linked, as pooled requirements are usually placed with fewer suppliers, but one is possible without the other. - **What does demand pooling require?** Reliable consumption data, unambiguous item master data and specifications that are as standardised as possible are needed. If identical parts are named differently at different sites, the pooling potential remains hidden. Internal coordination is also needed so that sites and specialist departments actually use the joint contracts. - **When does demand pooling not make sense?** For critical, equipment-specific or rarely needed parts, pooling can bring more risk than benefit, for example if only one supplier remains as a result. Even where standardisation would force technical compromises or quantities remain small despite pooling, the effort often outweighs the advantage. #### Dual sourcing and multiple sourcing URL: https://www.ktb-europe.com/en/glossary/dual-sourcing/ Dual sourcing and multiple sourcing refer to deliberately splitting a requirement between two or more qualified suppliers to reduce risk. With dual sourcing, an item or category is deliberately purchased from two suppliers; with multiple sourcing, from several. The opposite model is single sourcing, in which only one supplier is used even though alternatives exist. This must be distinguished from sole sourcing, where there genuinely is only one source of supply. The main advantage is security of supply: if one supplier fails, the other can take over at least part of the requirement. Competition is also maintained, which keeps prices and performance in check. On the other hand, there is greater effort for negotiation, quality assurance and supplier relationship management, as well as smaller volumes per supplier. The requirement is often split in fixed shares, or a main supplier is backed up by a qualified second source. A second source is only useful if it has been qualified before an emergency arises. This includes technical verification of equivalence, sample inspection, supplier evaluation and maintenance of master data, so that orders can be placed without delay when needed. A second source that exists only on paper, by contrast, offers little protection if it is only approached once a disruption occurs. In practice: For critical spare parts, it pays to use a second source with small quantities during normal operation so that processes and quality have been tried and tested. For parts supplied only by the original manufacturer, a verified alternative part can take on the role of the second source. Also known as: dual sourcing, multiple sourcing, multi-sourcing, second source, second sourcing Frequently asked questions: - **What is the difference between single, dual and multiple sourcing?** With single sourcing, a requirement is deliberately obtained from only one supplier, although alternatives would exist. Dual sourcing splits it between two suppliers, multiple sourcing between several. Each additional source increases security of supply, while at the same time coordination effort grows and volumes per supplier fall. - **When is dual sourcing worthwhile?** Dual sourcing is worthwhile above all for parts whose failure causes high downtime costs, for suppliers with an identifiable risk and in markets with fluctuating availability. For non-critical standard parts with many suppliers, on the other hand, the additional effort of a formally qualified second source is often not justified. - **How do you qualify a second supplier?** Usual steps are a supplier evaluation, verification of technical equivalence using data sheets and drawings, sample deliveries with incoming inspection and, if necessary, an audit. The second source should then be set up in the system and used regularly so that it is immediately ready in an emergency. - **What is sole sourcing?** Sole sourcing applies when there genuinely is only one source of supply, for example because a part is protected or manufactured exclusively by the original manufacturer. Unlike single sourcing, this is not a free choice. It can only be safeguarded through stockholding, contracts or the search for verified alternatives. #### E-procurement URL: https://www.ktb-europe.com/en/glossary/e-procurement/ E-procurement is the electronic handling of procurement processes, from supplier search and tendering to purchase order and invoice. E-procurement brings together the digital tools that companies use to buy. These include electronic catalogues, ordering platforms, tendering and auction portals, supplier portals and the electronic exchange of purchase orders and invoices. A distinction is often made between operational e-procurement for order processing and strategic e-sourcing for tendering and supplier selection. In catalogue-based systems, requesters order directly from approved ranges with stored prices; approvals run automatically according to defined rules. Electronic enquiries are used for requirements outside the catalogue. Master data, purchase orders and invoices are exchanged between the company's ERP system and the suppliers' systems via standardised data formats. In MRO procurement, e-procurement brings relief above all for frequent, low-value orders of C-parts. Its limits become apparent with technical spare parts that are rarely needed, are not catalogued or require technical clarification. For these, the structured enquiry with complete technical details remains an important part of the process. It helps if such enquiries are recorded in the same system, so that requirement, quotation and purchase order are documented end to end. In practice: Clean material and supplier master data are a prerequisite for functioning e-procurement. Before a catalogue is introduced, item descriptions, manufacturer part numbers and categories should be standardised; otherwise requesters cannot find the parts and resort to free-text orders. Also known as: electronic procurement, e-purchasing, e-sourcing, online procurement, digital procurement Frequently asked questions: - **What is the difference between e-procurement and e-sourcing?** E-sourcing covers the strategic steps before a contract is concluded, i.e. supplier search, electronic tenders, bid comparisons and auctions. E-procurement in the narrower sense refers to the operational handling afterwards: ordering from catalogues, approvals, order confirmations and invoices. In the broader sense, e-procurement also serves as an umbrella term for both. - **What are the advantages of e-procurement?** Typical advantages are lower process costs per order, shorter cycle times, fewer data entry errors, better compliance with framework agreements and a transparent data basis for spend analyses. Requesters order themselves within defined rules, so that purchasing can focus more on negotiation and supplier development. - **Is e-procurement suitable for spare parts?** Very much so for recurring standard parts such as filters, seals or standardised parts, because they can be catalogued. For rare, technically complex or discontinued spare parts, a catalogue reaches its limits. Here, electronic enquiries with the manufacturer part number, nameplate data and photos are used, enabling a technical review. #### Framework agreement URL: https://www.ktb-europe.com/en/glossary/framework-agreement/ A framework agreement sets prices and terms for future deliveries over a defined period; the individual quantities are called off later. A framework agreement governs the terms of a supply relationship in advance without already specifying every delivery. Typically agreed are the term, items or categories, prices or price formulas, lead times, payment and delivery terms, quality requirements, liability and termination rules. The actual orders are then placed as individual orders or call-off orders. A distinction is made between quantity contracts, in which a total quantity is agreed, and value contracts, in which a total value applies across various items. There are also agreements without a fixed purchase commitment that merely secure terms. Whether, and to what extent, there is an obligation to purchase should be expressly stipulated. For buyers, framework agreements reduce the effort per order, create planning certainty and improve the negotiating position through pooled volume. In return, suppliers receive forecasts with which they can plan capacity and stock. For long terms, price adjustment clauses, for example linked to raw material indices, as well as rules for quantity deviations and product changes are important so that the agreement remains viable even when market conditions change. In practice: For maintenance requirements, category-based framework agreements with agreed response times are suitable, because individual items are hard to predict. For critical parts, stock quantities held by the supplier can also be stipulated. Also known as: blanket order, blanket purchase agreement, master supply agreement, call-off contract Frequently asked questions: - **What is the difference between a framework agreement and a call-off order?** The framework agreement sets the overarching terms, such as prices, term, lead times and quality requirements. The call-off order is the specific order for a partial quantity based on this agreement, with quantity and delivery date. A framework agreement can therefore lead to many call-offs. As a rule, the binding obligation to deliver the respective quantity only arises with the call-off. - **Is there an obligation to purchase under a framework agreement?** That depends on how the contract is drafted. Some framework agreements contain fixed minimum purchase quantities or total quantities; others only secure terms without committing the buyer to a specific quantity. Rules on residual quantities at the end of the term are also common. Because the consequences can be significant, the purchase obligation should be worded unambiguously. If in doubt, a legal review clarifies the interpretation in the individual case. - **How long does a framework agreement usually run?** There is no fixed rule. Terms of one to several years are often agreed, sometimes with automatic renewal and defined notice periods. Short terms preserve flexibility in fluctuating markets, while long terms provide planning security and often better terms. For longer agreements, price adjustment clauses and regular review dates make sense so that the agreement matches requirements and market conditions. #### Global sourcing URL: https://www.ktb-europe.com/en/glossary/global-sourcing/ Global sourcing is the worldwide search for and use of sources of supply to improve costs, availability or access to technology. With global sourcing, a company extends its procurement market beyond national or regional borders. Reasons include lower purchase prices, a lack of capacity or technology at home, protection against shortages or proximity to the company's own plants abroad. For spare parts there is a further reason: components that are no longer available in one region may still be in stock elsewhere. This is offset by additional effort: remote supplier qualification, differences in language and law, customs duties and foreign trade documents, currency risks, longer transport routes and higher demands on quality inspection and communication. A price advantage in the quotation therefore says little about the actual total costs. Global sourcing is not synonymous with offshoring. It can equally mean nearshoring or a combination of regional and international sources. What matters is an assessment based on total cost of ownership and supply risk. In practice: For spare parts from abroad, proof of origin, inspection certificates and customs tariff numbers should be clarified as early as the enquiry stage. This avoids delays on import and queries from quality assurance. Also known as: international sourcing, international procurement, worldwide sourcing, global procurement Frequently asked questions: - **What are the advantages and risks of global sourcing?** Advantages are a larger supplier market, access to specialised manufacturers, possible cost advantages and additional sources of supply during shortages. These are offset by risks: more complex supplier qualification, language and legal differences, currency fluctuations, foreign trade formalities and political influences. Quality assurance also becomes more demanding when suppliers cannot easily be visited. A total cost assessment helps to weigh opportunities and risks realistically. - **What is the difference between global sourcing, offshoring and nearshoring?** Global sourcing describes the worldwide search for and use of sources of supply as a purchasing strategy. Offshoring usually means relocating a company's own activities or production to distant countries. Nearshoring refers to sourcing from or relocating to neighbouring regions, for example within Europe. Global sourcing can include both variants and explicitly does not rule out combining them with domestic suppliers. - **What should you look out for with international suppliers of spare parts?** Important are an unambiguous specification with the manufacturer part number, clear agreements on quality and inspection documents, and the question of whether the parts are original, equivalent or aftermarket parts. Origin details and customs tariff numbers should also be clarified early. For new sources, checking origin and traceability is recommended to reduce the risk of counterfeit or substandard components. #### Indirect procurement URL: https://www.ktb-europe.com/en/glossary/indirect-procurement/ Indirect procurement buys goods and services that do not go into the end product, such as MRO materials, services and operating equipment. Unlike direct procurement, which sources raw materials and components for production, indirect procurement covers the requirements of running the business. This includes spare and wear parts, tools, personal protective equipment, office and IT supplies, facility services, energy, logistics and consulting services as well as capital goods. Characteristic features are many requesters, heterogeneous categories, a large number of suppliers and often poorly standardised processes. A considerable proportion of orders are of low value but generate process costs similar to larger orders. In indirect procurement, process efficiency, demand pooling and supplier consolidation are therefore often more in focus than pure price negotiations. Typical instruments are catalogues and electronic ordering systems, framework agreements with call-offs, purchasing cards for small requirements and targeted tail spend management. For technical parts, specialist knowledge is also needed so that orders are clearly specified. Because requesters are spread across many departments, acceptance of the processes often determines success: ordering channels must be easier than bypassing procurement. In practice: In manufacturing companies, MRO materials often make up the most technically demanding part of indirect requirements. Close coordination between maintenance and procurement prevents incorrect orders and duplicate stock. Also known as: indirect purchasing, indirect spend, non-production materials (NPM), indirect sourcing Frequently asked questions: - **What is the difference between direct and indirect procurement?** Direct procurement buys material that goes straight into the product sold, such as raw materials, semi-finished products or bought-in parts. Indirect procurement covers everything else a company needs for its operations, from spare parts and tools to office supplies and services. Direct requirements can usually be derived from production plans, while indirect requirements arise in a scattered way across many departments. - **Which categories belong to indirect procurement?** Typical categories are MRO material such as spare and wear parts, operating supplies and consumables, tools and personal protective equipment, IT and office equipment, facility services, energy, consulting, staffing services and capital goods. The exact classification differs by company and industry. What these categories have in common is that they enable operations but do not become part of the end product. - **Why is indirect procurement considered difficult to control?** Requirements arise at many points in the company, often without central planning. The categories are very diverse, the number of suppliers is high and many orders are of low value. As a result, there is often a lack of transparency about spend and contracts. Part of the requirement is also ordered directly by specialist departments. Catalogues, clear ordering channels and pooling help to make this diversity manageable. #### Industrial distribution (technical trade) URL: https://www.ktb-europe.com/en/glossary/industrial-distribution/ Industrial distribution refers to the specialist and wholesale trade that supplies industrial companies with rolling bearings, drive technology, seals and fluid power. Industrial distribution sits between the manufacturers of technical components and the companies that use these components in production and maintenance. Typical ranges include rolling bearings and linear technology, drive elements such as belts, chains and couplings, seals, hoses and fittings, pneumatics and hydraulics, as well as tools and operating supplies. Unlike buying direct from the manufacturer, industrial distributors bundle the ranges of many manufacturers, hold stock and offer technical advice, for example on selecting equivalent parts or sizing components. Services are often added, such as kitting, hose assembly or managing stock on the customer's premises. Catalogue and online distributors of operating supplies, by contrast, rely more on a standardised range and self-service, with less application advice. For procurement, industrial distribution is relevant above all for broad, hard-to-plan maintenance requirements: a few suppliers cover many categories, which reduces orders, supplier accounts and invoices. Buying direct from the manufacturer can make more sense for large, plannable quantities or manufacturer-specific special parts. Which model fits therefore depends less on the part itself than on quantity, predictability and the need for advice. In practice: For spare parts enquiries to industrial distributors, the manufacturer part number, manufacturer, nameplate details and quantity are the most important information. Where requirements are broad, it is worth checking which categories a distributor can supply from its own stock and which it only sources on request. Also known as: technical wholesale, industrial supplies distribution, industrial distributor, MRO distribution, power transmission distribution Frequently asked questions: - **What is meant by industrial distribution?** It refers to the specialist and wholesale trade that carries technical products for industry and trades, such as rolling bearings, drive elements, seals, hoses, pneumatics and hydraulics. It buys from many manufacturers, holds stock and advises users on the selection and use of components. - **What is the difference between industrial distribution and buying direct from the manufacturer?** When buying direct, a company purchases straight from the manufacturer, which is particularly suitable for large, plannable quantities or custom-made products. Industrial distributors, by contrast, bundle the ranges of many manufacturers, also supply small quantities from stock and thus reduce the number of suppliers and ordering processes. - **How does industrial distribution differ from catalogue and online distributors?** Catalogue and online distributors of operating supplies usually work with a standardised range, fixed item data and self-service. Industrial distribution places more emphasis on application advice, sourcing unlisted parts and additional services such as kitting. In practice, the two models increasingly overlap. - **Which products typically belong to industrial distribution?** The core range includes rolling bearings, plain bearings and linear technology, drive technology such as belts, chains, couplings and gearboxes, sealing technology, hoses and fittings, and pneumatic and hydraulic components. Many distributors also carry tools, personal protective equipment and chemical-technical products such as lubricants, adhesives and cleaning agents. #### Make-or-buy decision URL: https://www.ktb-europe.com/en/glossary/make-or-buy-decision/ The make-or-buy decision determines whether a company produces a part or service itself or obtains it from an external supplier. Make or buy is a classic question in strategic procurement and controlling. It concerns components and assemblies as well as services, such as maintenance work, repairs or procurement itself. Intermediate forms include partnerships, contract manufacturing or outsourcing individual work steps. The decision is not taken once and for all but should be reviewed when costs, capacities or requirements change. The basis is a cost comparison: the costs of in-house production for material, personnel, machine time and a share of overheads are set against the purchase price and incidental costs of external sourcing. In the short term, with spare capacity, often only the variable costs count; in the long term, all costs do. In addition, there are qualitative criteria such as protection of know-how, quality, flexibility, dependence on suppliers, core competence and capacity utilisation. In maintenance, the question arises, for example, with the in-house repair of defective assemblies, the manufacture of simple spare parts in the company's own workshop or outsourcing spare parts procurement. For discontinued parts, remanufacture from drawings or by reverse engineering can be a make option that is weighed against buying a successor model. In practice: For a robust decision, hidden costs should also be recorded: inspection effort, documentation, stockholding and liability for defects. For safety-relevant parts, it must also be clarified whether in-house production affects the conformity of the machine. Also known as: make or buy, in-house production or external sourcing, insourcing or outsourcing, make-versus-buy analysis Frequently asked questions: - **What criteria apply to the make-or-buy decision?** Quantitatively, what counts above all are the costs of in-house production compared with the purchase price including incidental costs, as well as any investment required. Qualitatively, protection of know-how, quality requirements, flexibility, supply risks, available capacity and the strategic importance of the part are assessed. Both sides are often brought together in a weighted scoring matrix. - **How is make or buy calculated?** You determine the cost of in-house production per unit and compare it with the purchase price including incidental costs. With spare capacity, a comparison with the variable costs is sufficient in the short term, because fixed costs are incurred anyway. In the long term, full costs are decisive. The difference can also be used to derive a break-even quantity above which in-house production becomes cheaper. - **When is external sourcing worthwhile?** External sourcing is typically worthwhile when suppliers produce more cheaply or better through specialisation, in-house capacity is lacking, demand is low or fluctuating, or the part is not a core competence. For parts involving sensitive know-how or of great importance for product quality, by contrast, companies tend to opt for in-house production. #### Minimum order quantity (MOQ) URL: https://www.ktb-europe.com/en/glossary/minimum-order-quantity/ The minimum order quantity (MOQ) is the smallest quantity of an item that a supplier accepts per order or delivers on the stated terms. Suppliers set an MOQ because every order incurs fixed costs, for example for order processing, setting up production, packaging units or minimum lots from their own upstream supplier. It is to be distinguished from the minimum order value, which specifies a minimum amount per order rather than a quantity. Minimum quantities may relate to an item, a variant or an entire order. They frequently result from packaging units, such as bags of O-rings or reels of hose, or from production lots for custom parts. Some suppliers offer smaller quantities subject to a small-quantity surcharge. For the buyer, this creates a conflict of objectives: the MOQ may exceed actual demand and thus lead to excess stock and tied-up capital. In the spare parts business, minimum quantities often apply to small parts, seals or customer-specific components. If only one piece is needed, purchasing and maintenance face the choice of accepting the MOQ, pooling the demand of several sites or looking for a source of supply with smaller lot sizes. A comparison of total costs shows which solution is more economical. In practice: Enquiries should state the quantity actually required and explicitly ask about minimum quantities, packaging units and small-quantity surcharges. For recurring demand, a framework agreement with call-offs can mitigate a high MOQ. Also known as: MOQ, minimum purchase quantity, minimum quantity, minimum lot size Frequently asked questions: - **What does MOQ mean?** MOQ is the abbreviation for minimum order quantity. It indicates the minimum number of units a supplier sells or the volume from which a certain price applies. The information is usually found in the quotation, the catalogue or the supplier's terms of delivery and sale. - **What is the difference between minimum order quantity and minimum order value?** The minimum order quantity refers to the number of units of an item, the minimum order value to the total amount of an order. A supplier can specify both. Anyone ordering many different small parts from the same supplier often reaches a minimum order value more easily than the minimum quantity of a single item. - **Can a minimum order quantity be negotiated?** Often yes, especially if the MOQ derives from packaging units or handling costs. Options include small-quantity surcharges, partial deliveries from a larger order, framework agreements with call-offs or pooling the demand of several sites. For custom manufacturing, there is less scope, because set-up and material costs are largely independent of the quantity. #### MRO procurement URL: https://www.ktb-europe.com/en/glossary/mro-procurement/ MRO procurement is the purchasing of spare parts, wear parts, operating supplies and maintenance materials for ongoing plant operation. MRO procurement differs markedly from purchasing production material. Requirements often arise at short notice and irregularly, the variety of items is high, and many parts come from different manufacturers or are only available to a limited extent. An enquiry often starts with a manufacturer part number, a nameplate or even just a photo of the removed part. Core tasks are unambiguous identification, searching for sources of supply, comparing original and alternative parts, checking lead time and documents, and coordinating with maintenance. For urgent requirements, the replenishment lead time is decisive; for plannable requirements, the total cost comparison. Organisationally, MRO procurement is managed through framework agreements, catalogues, supplier pooling or outsourced procurement models. Metrics include the cycle time from requisition to delivery, first-time delivery rate, stock levels and number of active suppliers. Because many parts are needed only rarely, there is often no order history. This makes well-maintained master data all the more important, so that repeat requirements can be ordered without fresh research. In practice: The more complete an enquiry, the faster the procurement: manufacturer, part number, quantity, requested delivery date and required documents belong in every requisition. For recurring parts, a well-maintained item master with manufacturer details pays off. Also known as: MRO purchasing, MRO sourcing, maintenance procurement, MRO buying Frequently asked questions: - **What makes MRO procurement so demanding?** Requirements often arise at short notice, the variety of items is large and many parts are needed only rarely. Part numbers are often incomplete, manufacturers no longer on the market or parts discontinued. At the same time, the plant is at a standstill in the event of a breakdown, so speed matters more than the lowest price. This requires technical understanding, access to many sources of supply and well-maintained master data. - **What information do you need for an MRO enquiry?** Important are the manufacturer and manufacturer part number, the quantity required, the delivery date and the documents needed, such as inspection certificates or declarations of conformity. If the part number is missing, nameplate details, photos of the part and its installation situation, and dimensions help. Stating whether equivalent alternatives are also acceptable speeds up the search, especially for parts that are hard to obtain or discontinued. - **How can rush orders in MRO procurement be reduced?** Rush orders often arise because requirements are reported too late or critical parts are not held in stock. Remedies are parts lists for planned servicing passed on early, defined safety stocks for parts critical to operation and framework agreements with agreed response times. An analysis of past rush orders shows which parts are repeatedly affected and where stocking is worthwhile. #### Nearshoring URL: https://www.ktb-europe.com/en/glossary/nearshoring/ Nearshoring refers to relocating procurement, production or services to nearby countries rather than to distant low-wage regions. Nearshoring lies between onshoring, i.e. production in the home country, and offshoring to distant regions. It can concern a company's own production sites or its supplier base: instead of sourcing parts from distant markets, suppliers are developed in neighbouring countries, for Western European companies for example in Central, Eastern or Southern Europe. Reshoring, relocation back to the home country, is a related concept. Reasons for nearshoring are shorter replenishment lead times, less dependence on individual world regions, similar time zones and legal frameworks, easier supplier audits and simpler coordination of technical changes. These are often offset by higher unit prices than in low-wage regions, as well as the effort involved in finding and qualifying suppliers. The decision is therefore usually based on a total cost analysis rather than the purchase price alone. For spare parts and MRO material, nearshoring can increase security of supply, because nearby suppliers respond more flexibly to urgent requirements and remanufacturing is easier to coordinate. For manufacturer-specific original parts, however, the source of supply usually remains fixed; nearshoring tends to concern drawing parts, assemblies and standard components. In practice: When evaluating nearby suppliers, quality capability, inspection documentation, capacity and responsiveness should be checked as well as price. Before switching proven parts, a first article inspection is advisable before larger quantities are ordered. Also known as: near-shoring, near-sourcing, regionalisation of procurement, relocation to neighbouring countries Frequently asked questions: - **What is the difference between nearshoring, offshoring and reshoring?** Offshoring relocates production or procurement to distant countries, usually because of low costs. Nearshoring relocates to neighbouring or nearby countries. Reshoring refers to relocation back to the home country. All three terms describe location decisions and are not mutually exclusive: companies often combine them depending on the category. - **What are the advantages of nearshoring?** The main advantages cited are shorter and more predictable replenishment lead times, less dependence on individual regions, similar time zones, comparable standards and legal frameworks, and easier face-to-face coordination and audits. This makes it easier to respond quickly to design changes or urgent requirements, even if unit prices may be higher. - **What are the disadvantages of nearshoring?** Unit costs are often higher than in low-wage countries, and developing new suppliers involves effort for searching, qualification and first article inspection. In some regions, skilled workers and capacity are scarce. Whether nearshoring pays off is therefore only shown by an analysis of total costs, including risk and inventory costs. #### Operational purchasing URL: https://www.ktb-europe.com/en/glossary/operational-purchasing/ Operational purchasing covers the day-to-day processing of orders, from the purchase requisition through the order and goods receipt to invoice verification. Operational purchasing ensures that the materials and services required are available at the right time, in the right quantity and on the agreed terms. It works within the framework set by strategic procurement through supplier selection, category strategies and contracts. The typical process begins with a purchase requisition from a specialist department, such as maintenance. Purchasing checks it, obtains quotations if necessary or uses existing contracts, creates the purchase order and monitors the order confirmation and delivery date. After goods receipt comes invoice verification, usually as a match of purchase order, goods receipt and invoice. Expediting, complaints and master data maintenance are also part of the work. KPIs include cycle time per order, the share of orders placed via contracts or catalogues and process costs per ordering transaction. Many companies automate recurring processes so that operational purchasing can concentrate on exceptions. Maintenance in particular generates many of these exceptions, because requirements arise at short notice, in small quantities and for very different parts. Clear approval rules and good master data noticeably shorten cycle times here. In practice: For spare parts, a complete purchase requisition saves the most time: the manufacturer part number, manufacturer, quantity, urgency and place of use should already be captured in the requisition. For urgent cases, an agreed emergency process with clear approval limits helps. Also known as: order processing, transactional purchasing, operational procurement, purchase-to-pay (P2P), tactical purchasing Frequently asked questions: - **What is the difference between operational and strategic purchasing?** Strategic procurement plans for the long term: it analyses markets, selects suppliers, develops category strategies and negotiates framework agreements. Operational purchasing implements these guidelines in day-to-day business, processes individual orders, tracks dates and clarifies deviations. The two areas are closely intertwined. - **How does the ordering process work in operational purchasing?** It starts with a purchase requisition from a specialist department. After checking and approval, purchasing creates the purchase order, if necessary after obtaining quotations or as a call-off from a contract. This is followed by the order confirmation, expediting, goods receipt with inspection and finally invoice verification before payment is released. - **What does three-way matching mean in invoice verification?** In three-way matching, the purchase order, the goods receipt posting and the invoice are compared with one another. If quantity, price and terms match, the invoice can be approved. Discrepancies are clarified before payment is made. The procedure prevents payments for items that were not delivered or were invoiced incorrectly. - **What are the tasks of operational purchasing?** The tasks include processing purchase requisitions, obtaining quotations for one-off requirements, creating purchase orders and call-offs, expediting, clarifying delivery and quality deviations, supporting invoice verification and maintaining supplier and material master data. Recurring requirements are increasingly handled via catalogues or automated call-offs. #### Price adjustment clause URL: https://www.ktb-europe.com/en/glossary/price-adjustment-clause/ A price adjustment clause links a contractually agreed price to the development of defined cost factors such as material, energy or labour costs. Price adjustment clauses are used mainly in long-term contracts and with long lead times, when material or energy costs may change noticeably before delivery. Instead of building risk premiums into a fixed price, they share the price risk between both contracting parties according to a rule agreed in advance. They are to be distinguished from unilateral price reservations, under which one party can change the price without a defined benchmark. A common approach is a formula that divides the price into a fixed portion and variable portions for material, labour or energy. Each variable portion is linked to an index, often official price indices or published quotations for specific materials. The base date, the adjustment reference date, thresholds above which an adjustment is made and whether the clause works in both directions are also set out. In the procurement of components and spare parts, price adjustment clauses are found mainly in framework agreements and for parts with a high metal or plastic content. They should be transparent, traceable and reciprocal. Whether a clause is effective, particularly in general terms and conditions, depends on how it is drafted in the individual case; this entry does not constitute legal advice. In practice: Before concluding the contract, it should be checked whether the chosen index actually reflects the cost structure of the part and is published regularly. A worked example in the contract ensures that both parties later understand the adjustment in the same way. The wording itself should be reviewed by a legal expert. Also known as: price escalation clause, escalation clause, material price adjustment clause, price variation clause Frequently asked questions: - **How does a price adjustment clause work?** The price is broken down into a fixed portion and one or more variable portions, for example for material and labour. Each variable portion is linked to an index. If this index changes between an agreed base date and the reference date, the price changes proportionately. The calculation rule is set out in the contract in advance, so that both parties can follow the adjustment. - **What belongs in a price adjustment clause?** Important elements are the initial price, the breakdown into fixed and variable portions, the specifically named indices with their source, the base and adjustment dates, any thresholds or caps, and the rule that reductions are passed on in the same way as increases. Whether a particular wording is legally effective should be reviewed by an expert in the individual case. - **What is the difference between a fixed price and a price adjustment clause?** With a fixed price, the supplier bears the risk of rising costs and often includes a safety margin for this. With a price adjustment clause, the price follows the cost trend in a traceable way, both upwards and downwards. For the buyer, this usually means a lower risk premium but also less certainty when planning the budget. #### Procurement as a service URL: https://www.ktb-europe.com/en/glossary/procurement-as-a-service/ Procurement as a service refers to outsourcing purchasing tasks to an external service provider who takes them on as needed and often by category. Procurement as a service is a form of procurement outsourcing. An external provider takes on operational or strategic purchasing tasks, such as handling enquiries, supplier search, bid comparison, order processing or negotiations. Unlike the classic outsourcing of entire departments, the service is often called off flexibly and according to scope. The range extends from support with individual enquiries to taking over complete categories. Typical areas of use are indirect requirements, tail spend with many small suppliers, hard-to-source parts or categories for which there are no in-house specialists. Billing models range from fixed flat fees and fees per transaction to performance-based remuneration. The interfaces with the ERP system, approval process and invoice verification must be clearly defined. For maintenance and MRO, the model can offset capacity bottlenecks in purchasing and open up access to broader supplier networks. At the same time, the company remains responsible for defining requirements, technical approvals and supplier risks. Dependence on the service provider and the protection of sensitive data should be addressed in the contract. Regular reports show whether the agreed targets are being met. In practice: Before awarding the contract, it should be determined which categories, value limits and decisions lie with the service provider and which remain in-house. Clear KPIs such as processing time, delivery reliability and savings achieved make performance measurable. Also known as: procurement outsourcing, managed procurement, purchasing as a service, procurement services Frequently asked questions: - **What is the difference between procurement as a service and procurement outsourcing?** Procurement outsourcing is the umbrella term for outsourcing purchasing tasks, often on a long-term basis and on a large scale. Procurement as a service emphasises a flexible, service-based model in which services are called off and billed according to need, scope or category. In practice, the boundaries between the two models are fluid. - **Which companies is procurement as a service suitable for?** Particularly for companies with a small purchasing team, strongly fluctuating procurement workload or many low-value requirements spread across numerous suppliers. Those who need to source rarely required special parts without building up their own market knowledge can also benefit. What matters is that requirements and approvals remain clearly defined internally. - **What are the risks of procurement as a service?** Possible risks are dependence on the service provider, loss of in-house market knowledge, unclear responsibilities in the event of quality or delivery problems, and data security issues. They can be limited by a clear specification of services, measurable KPIs, reporting obligations and contractually defined exit options. #### Procurement management URL: https://www.ktb-europe.com/en/glossary/procurement-management/ Procurement management plans, steers and controls all processes through which a company obtains materials, goods and services externally. Procurement management is the overarching framework for purchasing and supply. It covers determining requirements, selecting and developing suppliers, negotiation and contract design, order processing and the control of costs, quality and delivery reliability. The aim is a supply that strikes a balance between cost, risk and availability. It is common to separate strategic and operational tasks. The strategic part defines category strategies, the supplier portfolio and contract models; the operational part processes orders, monitors deadlines and resolves deviations. In addition, there are cross-cutting topics such as compliance, sustainability in the supply chain and risk management. The focus differs considerably depending on the category. For direct materials, quantities, prices and quality are paramount. For spare parts and MRO requirements, availability, identification and lean processes count most, because many line items arise with low value and consumption that is hard to plan. In practice: For maintenance requirements, it is worth defining dedicated processes rather than channelling them through the workflows for production material. Clear approval limits, framework agreements and well-maintained item master data shorten the time between requirement and purchase order. Also known as: purchasing management, supply management, procurement Frequently asked questions: - **What is the difference between procurement management and purchasing?** In everyday use, purchasing often stands for processing orders and negotiating with suppliers. Procurement management is broader: it additionally covers demand planning, supplier strategy, contract design, risk management and performance monitoring across the entire supply process. In many companies, however, the terms are used inconsistently. What matters is that strategic and operational tasks are clearly assigned. - **Which KPIs are common in procurement management?** Frequently used are delivery reliability, quality rate at goods receipt, cycle time from requisition to purchase order, process costs per order and savings achieved. In addition, there is contract coverage, i.e. the share of spend via existing contracts, and the number of active suppliers. For spare parts, availability, replenishment lead times and the number of urgent rush orders are also meaningful. - **How can procurement management for maintenance requirements be improved?** A good approach starts with transparency: which parts are procured, how often, from which suppliers and with what effort? From this, framework agreements, catalogues for standard items and clear approval rules can be derived. Equally important are well-maintained master data with manufacturer details and close coordination with maintenance, so that requirements reach procurement early and in full. #### Procurement outsourcing URL: https://www.ktb-europe.com/en/glossary/procurement-outsourcing-definition/ In procurement outsourcing, a company permanently hands over purchasing tasks or entire categories to an external service provider. Procurement outsourcing ranges from individual process steps to full responsibility for a category. Tasks that are outsourced include supplier search and obtaining quotations, order processing, expediting, quality inspection or tail spend management. Strategic decisions and budget authority usually remain with the client company. Reasons include a lack of capacity in the company's own procurement team, high process costs with many small orders, access to market knowledge and supplier networks, and the pooling of volume. Closely related is the procurement as a service model, in which services are called off flexibly as needed. Prerequisites for good outsourcing are clearly defined scopes of service, KPIs such as cycle time, delivery reliability and savings, transparent remuneration models, and defined interfaces with maintenance, quality assurance and accounting. Exit planning is also important: data, supplier contacts and contract documents should be documented in such a way that switching service provider or bringing the work back in-house remains possible. It should also be clarified who holds the supplier contracts and who is liable towards suppliers. In practice: In the spare parts area, the part that is hardest to plan is often outsourced first: rare, discontinued or third-party parts that take a lot of time to research in-house. Standard requirements then remain in the company's own system via catalogues and framework agreements. Also known as: outsourced procurement, procurement as a service, purchasing outsourcing, procurement services Frequently asked questions: - **Which purchasing tasks can be outsourced?** Individual process steps such as supplier search, obtaining quotations, order processing, expediting or invoice matching can be outsourced, but so can entire categories. This most frequently concerns indirect requirements, small orders and hard-to-source parts. Strategic decisions, budget responsibility and the definition of requirements usually remain with the client company, which steers performance via KPIs. - **What is the difference between procurement outsourcing and procurement as a service?** With classic procurement outsourcing, a service provider takes over defined tasks or categories on a permanent basis, often with a fixed scope of services and a longer contract term. Procurement as a service relies more on flexible use: services are called off as needed and are often charged by volume or transaction. The boundaries are fluid, and many models combine fixed basic services with demand-based modules. - **What are the risks of outsourcing procurement?** Risks include the loss of in-house market knowledge, dependence on the service provider and unclear responsibilities at the interfaces. Data protection, confidentiality of supplier data and the question of liability towards suppliers must also be regulated. Countermeasures are clear service descriptions, measurable KPIs, regular reports and a documented handover arrangement in case of a change of provider. #### Purchase requisition URL: https://www.ktb-europe.com/en/glossary/purchase-requisition/ A purchase requisition (PR) is an internal request from a department to purchasing to procure a material or service. The purchase requisition is at the start of the operational procurement process. It documents who needs what, in what quantity and by when, and is not yet a purchase order: only after checking and approval does purchasing convert it into a binding order with the supplier. The abbreviation PR is particularly common in ERP environments. At the same time, it creates transparency about which requirements are open. Purchase requisitions are created manually by requesters, such as maintenance, or automatically by materials planning, for example when stock falls below the reorder point or from maintenance orders. Typical contents are the material number or description, quantity, required date, cost centre or order, delivery location and, where applicable, a suggested supplier. Depending on value and category, the requisition goes through an approval procedure. For spare parts, the quality of the purchase requisition often determines the speed of procurement. If the manufacturer part number, nameplate data or details of urgency are missing, a time-consuming round of queries begins. For emergencies, many companies provide simplified urgent procedures that are documented afterwards. A complete requisition therefore often saves more time than any acceleration later in the process. In practice: A purchase requisition for a spare part should contain the manufacturer, manufacturer part number, nameplate data, quantity, latest required date and the plant concerned; a photo helps in case of ambiguity. Permissible alternatives or the note “original only” should be stated at the same time. Also known as: PR, material requisition, purchase request, PReq Frequently asked questions: - **What is the difference between a purchase requisition and a purchase order?** The purchase requisition is an internal document used to report a requirement to purchasing. It is not binding on anyone outside the company. The purchase order, by contrast, is the binding declaration to the supplier to accept goods or services on certain terms. One or more purchase orders can result from a single purchase requisition. - **What must a purchase requisition contain?** Important are an unambiguous description of the material, ideally with a material or manufacturer part number, the quantity, the required date, the cost centre or order, the delivery location and the name of the requester. For technical parts, nameplate data, drawings or photos make procurement considerably easier and avoid queries. - **Who approves a purchase requisition?** Each company sets this out in its approval policy. The approval level usually depends on the order value, the cost centre and the category: smaller amounts are approved by the responsible manager, larger ones additionally by divisional or senior management. In ERP systems, these rules are often stored as a release strategy and run automatically. #### Purchase-to-pay (P2P) URL: https://www.ktb-europe.com/en/glossary/purchase-to-pay/ Purchase-to-pay (P2P) refers to the end-to-end procurement process from the requirement notification through ordering and goods receipt to payment of the invoice. The purchase-to-pay process links purchasing, warehousing and accounting. It begins with a purchase requisition, proceeds via approval, purchase order and order confirmation to goods receipt and ends with invoice verification and payment. The term procure-to-pay is usually used synonymously, but is sometimes defined more broadly to include supplier selection and contract management. A central control tool is three-way matching: the purchase order, goods receipt and invoice are checked for agreement on item, quantity and price before payment is released. KPIs such as cycle time per order, the share of orders placed via catalogues or framework agreements, process costs per order and the share of invoices with discrepancies show how efficiently the process is running. The more discrepancies have to be resolved manually, the longer payment takes and the higher the process costs. Especially in MRO, with many small orders, the process effort is often greater than the value of the goods. Automation via e-procurement, catalogues, call-off orders and electronic invoices reduces this effort. At the same time, a clean P2P process ensures that emergency orders remain traceable and are not handled by bypassing purchasing. In practice: Many invoice discrepancies arise from imprecise purchase orders. Unambiguous item descriptions with the manufacturer part number, agreed prices and clear delivery addresses in the order make subsequent matching easier and speed up approval. Also known as: P2P, procure-to-pay, purchase to pay, order-to-payment process Frequently asked questions: - **What is the difference between purchase-to-pay and procure-to-pay?** The two terms are often used synonymously. Where a distinction is made, purchase-to-pay describes the operational sequence from purchase order to payment, while procure-to-pay additionally includes upstream steps such as demand planning, supplier selection and contract negotiation. Which definition applies is usually set out by each company in its process description. - **Which steps does the P2P process comprise?** Typical steps are the requirement notification or purchase requisition, approval, purchase order to the supplier, order confirmation, goods receipt with inspection, receipt of the invoice, invoice verification against purchase order and goods receipt, and payment. Depending on the company, steps such as supplier selection or call-offs from framework agreements are added. - **What is three-way matching?** In three-way matching, accounting compares the purchase order, the goods receipt posting and the supplier invoice. If items, quantities and prices match, the invoice can be released. Discrepancies, such as partial deliveries or price differences, are resolved before payment. This prevents duplicate payments and payments for goods not delivered. #### Request for quotation (RFQ) URL: https://www.ktb-europe.com/en/glossary/request-for-quotation/ A request for quotation (RFQ) asks suppliers to submit a binding price offer for clearly specified items or services. The RFQ is the formal step before the order: procurement describes the requirement and asks one or more suppliers for a quotation covering price, lead time and terms. It must be distinguished from the RFI (request for information), which initially only gathers information about suppliers and solutions, and from the RFP (request for proposal), in which suppliers develop their own proposed solution for a more openly described problem. A good technical RFQ contains the manufacturer part number and the manufacturer, for spare parts ideally the nameplate details or a photo, the quantity, the required date, the delivery address and the documents required, such as inspection certificates or declarations of conformity. In addition, it states a deadline for quotations and whether equivalent alternatives are permitted. The more uniform the RFQ, the easier it is to compare quotations. Differences often lie not in the unit price but in lead time, minimum order quantities, certificates, warranty or whether the original part or an alternative part is actually being offered. A bid comparison should set these points out explicitly side by side, so that an apparently cheap but incomplete quotation does not win the contract. In practice: For spare parts, a fixed template with mandatory fields for manufacturer part number, nameplate, quantity, required date and certificates needed is recommended. Suppliers should state explicitly whether they are offering original or alternative parts and whether they deliver from stock or to order. Also known as: RFQ, request for quote, price enquiry, quotation request, invitation to tender (simplified) Frequently asked questions: - **What is the difference between an RFI, RFQ and RFP?** An RFI is used for market research and asks for general information about suppliers and solutions. An RFQ requests a specific price quotation for a requirement that has already been clearly specified. An RFP is used when the requirement is only described as an objective or problem and suppliers are to submit their own solution concepts including a price. - **What information belongs in an RFQ for spare parts?** Important details are the manufacturer and manufacturer part number, the nameplate details or a photo if the designation is unclear, the quantity required, the required date and the delivery address. Add the documents required, such as mill certificates or declarations of conformity, and a note on whether equivalent alternative parts are permitted. - **How do you compare quotations received for an RFQ correctly?** In addition to the unit price, lead time, minimum order quantities, surcharges, payment terms, warranty and the certificates supplied should be compared. It is also decisive whether exactly the part requested or an alternative is being offered. A uniform RFQ template and a side-by-side comparison table make the comparison considerably easier. - **How many suppliers should you ask for a quotation?** There is no fixed number; it depends on value, criticality and internal purchasing policy. For standard parts, a few comparative quotations are often sufficient; for high values, policies often require several. For parts made only by the original manufacturer, competition is limited anyway. #### Single sourcing URL: https://www.ktb-europe.com/en/glossary/single-sourcing/ Single sourcing is the deliberate decision to obtain a material or part from just one supplier, even though alternatives exist. Single sourcing pools the entire requirement for an item or category with one supplier. The advantages are higher volumes and thus better terms, less coordination effort, consistent quality and closer cooperation, for example in development or warehousing. The disadvantage is dependency: if the supplier fails, there is no short-term alternative. This must be distinguished from sole sourcing, where there genuinely is only one source of supply, for example because a part is patent-protected or only the original manufacturer produces it. With dual sourcing and multiple sourcing, by contrast, the requirement is deliberately spread across two or more suppliers in order to diversify risk and maintain competition. Whether single sourcing makes sense depends on criticality, market conditions and switching costs. A supplier risk assessment, contingency plans and contractually agreed minimum stock levels reduce the dependency. In practice: With spare parts, de facto sole sourcing often arises because only the original manufacturer supplies them. If such a part is discontinued, there is no alternative; checking for equivalent parts early on reduces this risk. Also known as: single source, single-source supply, single-supplier sourcing Frequently asked questions: - **What is the difference between single sourcing and sole sourcing?** With single sourcing, a company deliberately chooses only one supplier, even though others would be available, for example to pool volume. With sole sourcing, on the other hand, there genuinely is only one source of supply, for example because of intellectual property rights or exclusive manufacturing. The difference is important for risk management: single sourcing can be changed if necessary, sole sourcing only through technical alternatives. - **When does single sourcing make sense?** Single sourcing is suitable when pooling brings clear cost advantages, high consistency of quality is required or close technical collaboration is needed. Even with small quantities, a second supplier can cause more effort than it is worth. A prerequisite is a reliable, economically stable partner. For critical parts, contingency plans should nevertheless be in place, such as agreed safety stocks or a pre-qualified alternative source. - **How can the risk of single sourcing be limited?** Regular supplier evaluations and monitoring of the partner's financial position help. Contractually, minimum stocks at the supplier, response times and obligations to inform about product changes or discontinuations can be agreed. In addition, a second source can be technically pre-qualified without ordering from it permanently. This retains the pooling advantage while keeping a switch possible in an emergency. #### Spend analysis URL: https://www.ktb-europe.com/en/glossary/spend-analysis/ Spend analysis is the systematic evaluation of purchasing expenditure by supplier, category and business unit in order to identify potential and risks. Spend analysis creates transparency about what a company spends money on, with whom and through which channels. It is usually the first step towards demand pooling, supplier consolidation and category strategies in strategic procurement. Data sources are accounts payable, purchase orders from the ERP system, purchasing cards and, where applicable, travel and expense claims. The raw data is cleansed, supplier duplicates are merged and the expenditure is assigned to a uniform category structure. Questions such as these can then be answered: how many suppliers are there per category? What share of the volume falls on the tail spend, i.e. many small suppliers with low turnover? How high is the share of maverick buying, i.e. purchases that bypass the agreed purchasing process or existing contracts? For MRO, the analysis is particularly revealing because maintenance requirements are often spread across many suppliers, small orders and inconsistent descriptions. It shows which spare and wear parts are bought repeatedly from different distributors, where framework agreements are missing and which suppliers were only set up for one-off cases. A one-off analysis quickly becomes outdated; regular updates make sense. In practice: For MRO spend, an evaluation down to line-item level is worthwhile, as summary postings often obscure the actual content. A query for suppliers with few orders per year quickly shows where pooling potential lies in the tail spend. Also known as: spend analytics, expenditure analysis, purchasing volume analysis, spend cube Frequently asked questions: - **What data do you need for a spend analysis?** The basis is data from accounts payable and purchase orders from the ERP system, supplemented by purchasing card transactions and other payment channels. Line-item data with item description, quantity and price is helpful, as invoice totals alone say little about the content. Supplier master data is cleansed beforehand and duplicates are merged. - **What is maverick buying?** Maverick buying refers to purchases made outside the agreed procurement process, for example directly by specialist departments without a purchase order, from suppliers that have not been approved or outside existing framework agreements. The consequences are higher prices, a lack of transparency and compliance risks. Spend analysis makes such purchases visible. - **How do you classify expenditure in a spend analysis?** Expenditure is assigned to a uniform category structure, either a company-specific one or a classification standard common in the industry. The basis is item descriptions, the supplier's industry and general ledger accounts. Assignment is partly rule-based and partly manual and should be reviewed regularly so that analyses remain comparable. - **What are the benefits of a spend analysis for MRO?** It shows how many suppliers deliver maintenance requirements, which parts are bought repeatedly from different distributors and how high the share of small individual orders is. This gives starting points for pooling, framework agreements, supplier reduction and better master data quality for spare parts. #### Strategic procurement URL: https://www.ktb-europe.com/en/glossary/strategic-procurement/ Strategic procurement defines in the long term where, how and on what terms a company covers its requirements for materials and services. While operational purchasing handles individual orders, strategic procurement works at the level of categories and supplier relationships. It analyses requirements and spend, monitors supply markets, develops category strategies and decides on the number and selection of suppliers. Negotiations focus mainly on framework agreements, pricing mechanisms, quality agreements and delivery terms. Typical tools are spend analyses, portfolio matrices based on purchasing volume and supply risk, supplier evaluations and total cost of ownership calculations. In addition, there are make-or-buy decisions and safeguards against supply failures, for example through second sources. For indirect requirements and spare parts, strategic procurement is often understaffed because the individual volume appears small. Yet this is precisely where the levers lie: supplier pooling, standardised processes and clear rules for critical parts reduce process costs and failure risks. The result of the strategic work is documented category strategies with objectives, supplier selection, contract models and KPIs that are regularly reviewed and adapted to market changes. This creates a basis on which operational purchasing can order quickly and in compliance with the rules. In practice: For MRO categories, a classification by criticality and procurability rather than by turnover has proven effective. Critical parts that are hard to procure need different contracts and stock rules than catalogue items. Also known as: strategic sourcing, strategic purchasing, category management Frequently asked questions: - **What is the difference between strategic and operational purchasing?** Strategic procurement creates the framework: it analyses markets, selects suppliers, negotiates contracts and sets category strategies. Operational purchasing works within this framework and handles day-to-day requirements, i.e. purchase orders, expediting, clarifying deviations and approving invoices. The two areas depend on each other, because good contracts are of little use if they are not used in day-to-day ordering. - **Which methods does strategic procurement use?** Common methods are spend analyses for transparency on expenditure, portfolio matrices based on purchasing volume and supply risk, supplier evaluations and total cost assessments. Market analyses add competitor and cost structure analyses, while decisions draw on make-or-buy comparisons and tenders. The result is category strategies that define which suppliers and contract models will cover requirements in future and how success will be measured. - **What role does strategic procurement play for spare parts?** With spare parts, the issue is less about large volumes than about security of supply. Strategic procurement defines which parts are considered critical, how many sources of supply are needed and which agreements are made on stockholding or response times. It also examines how to deal with discontinuations and manufacturer-specific parts. This creates a framework that enables fast and compliant ordering in the event of a breakdown. #### Supplier consolidation URL: https://www.ktb-europe.com/en/glossary/supplier-consolidation/ Supplier consolidation deliberately reduces the number of suppliers in order to cut process costs, pool volumes and simplify management. Over the years, supplier bases often grow in an unplanned way: each department orders from its own sources, and new supplier accounts are created for one-off requirements. The result is high costs for master data maintenance, invoice verification, qualification and coordination. Supplier consolidation addresses this and concentrates demand on fewer, carefully selected partners. The process usually starts with a spend analysis: which categories are sourced from how many suppliers and with what volume? This leads to target pictures for each category, such as a system supplier for C-parts, a few qualified sources for critical components, or a service provider who pools many small suppliers. Framework agreements and catalogues secure the implementation. Consolidation has its limits. Too few suppliers increase dependency, especially for critical parts. The aim is therefore not the lowest number, but a supplier base that covers cost, risk and availability in a balanced way. In practice: In the spare parts area, many occasional suppliers can be pooled without losing access to specialist parts. It is important that the consolidated partner can also source parts outside its standard range. Also known as: supplier rationalisation, supplier base reduction, vendor consolidation Frequently asked questions: - **How do you go about supplier consolidation?** First, a spend analysis is used to determine which categories are sourced from how many suppliers. Then targets are defined for each category and suitable suppliers are selected on the basis of performance, range and risk. Framework agreements, catalogues and adapted ordering channels put the decision into practice. Finally, suppliers no longer needed are blocked and compliance with the new ordering channels is monitored. - **What are the benefits of supplier consolidation?** Fewer suppliers mean less master data maintenance, fewer invoices and less coordination effort. Pooled quantities improve the negotiating position, and the remaining suppliers can be managed and evaluated more closely. Transparency about spend and consumption often increases too. In addition, compliance risk falls because fewer unvetted occasional suppliers are active in the system. - **When does supplier consolidation become a risk?** It becomes critical when only one source remains for important parts and no fallback option has been prepared. The loss of specialist suppliers who were able to supply rare or older parts can also worsen supply. Every consolidation should therefore be differentiated by category and deliberately provide safeguards for parts critical to operation, for example through stockholding or a second qualified source. #### Supplier evaluation URL: https://www.ktb-europe.com/en/glossary/supplier-evaluation/ Supplier evaluation is the systematic assessment of suppliers against fixed criteria such as quality, delivery reliability, response time, price and compliance. Supplier evaluation provides a transparent basis for decisions on supplier selection, contract award, development or delisting. It is one building block of supplier management, which also covers strategy, contracts, collaboration and risk management. Without regular evaluation, such decisions often depend on the gut feeling of individual people. Typical criteria are quality, such as complaint rate and incoming inspection results; delivery reliability in terms of date and quantity; response time to enquiries and disruptions; price and cost development; and compliance topics such as sustainability, data protection and adherence to legal requirements. The criteria are weighted and combined in a points system from which supplier classes can be derived. KPIs from the ERP system are supplemented by subjective assessments from the specialist departments. In addition to ongoing evaluation, there is supplier selection before a business relationship begins and the supplier audit, in which the supplier's processes and quality management are checked on site or by questionnaire. For maintenance, response time, parts availability and the correctness of the parts supplied count in particular, as incorrect deliveries there directly prolong downtime. In practice: For MRO suppliers, it is advisable to measure not only delivery reliability but also the rate of correctly identified and delivered parts and the response time to spare parts enquiries. The results should be shared with suppliers regularly so that they can make targeted improvements. Also known as: supplier assessment, supplier rating, vendor evaluation, supplier scorecard, vendor rating Frequently asked questions: - **Which criteria belong in a supplier evaluation?** Common criteria are quality, delivery reliability by date and quantity, response time, price and cost development, flexibility, and compliance topics such as sustainability and adherence to legal obligations. Which criteria count and how strongly depends on the category. For spare parts, availability and parts accuracy play a greater role than for standard materials. - **How does scoring work in supplier evaluation?** Each criterion is given a weighting, for example as a percentage, and rated on a fixed scale. The weighted points produce an overall score, according to which suppliers are divided into classes, for example preferred, approved or to be developed. Clear measurement rules are important so that evaluations remain comparable. - **What is the difference between supplier evaluation and supplier management?** Supplier evaluation measures the performance of individual suppliers against criteria. Supplier management is the broader framework: it covers strategy, selection, contracts, development, risk management and the termination of supply relationships. Evaluation provides the data basis for this, for example for award decisions or development meetings with suppliers. - **What is a supplier audit?** In a supplier audit, the customer or an appointed auditor checks processes, quality management and, where relevant, sustainability aspects directly at the supplier, on site or by means of a structured questionnaire. Audits often take place before a business relationship begins, after quality problems or at fixed intervals for important suppliers. #### Supplier management URL: https://www.ktb-europe.com/en/glossary/supplier-management/ Supplier management covers the selection, evaluation, development and steering of suppliers throughout the entire business relationship. Supplier management, internationally also known as supplier relationship management (SRM), regards suppliers not merely as a source for individual orders but as long-term partners whose performance is measured and improved. The phases range from supplier search and qualification through contracts and ongoing evaluation to development or, if necessary, separation. Typical evaluation criteria are quality, delivery reliability, price, responsiveness, communication and, increasingly, sustainability and compliance, for example under the German Supply Chain Due Diligence Act (LkSG). Supplier audits, KPIs and regular reviews form the basis. This is complemented by risk management, which keeps an eye on financial, geographical and dependency risks. In the MRO area, the supplier base is often very large and fragmented. There, supplier management frequently aims first at transparency and consolidation: fewer, but better managed suppliers with clear agreements. Digital supplier portals and shared master data make it easier to exchange certificates, evaluations and complaints, and make the development of individual suppliers traceable over the years. In practice: For spare parts suppliers, response time to enquiries, on-time delivery and complete documentation are often more important than the unit price. These criteria should be explicitly weighted in supplier evaluation. Also known as: supplier relationship management (SRM), vendor management, supplier performance management Frequently asked questions: - **Which phases does supplier management comprise?** A typical cycle consists of supplier analysis and search, qualification and selection, contractual integration, ongoing evaluation and development. If a supplier shows persistent weaknesses, an orderly termination of the relationship can also be part of it. Risk management accompanies all phases. How intensively a supplier is managed usually depends on its importance for supply and on the purchasing volume. - **What is the difference between supplier management and supplier evaluation?** Supplier evaluation is a tool within supplier management. It measures a supplier's performance against defined criteria, such as quality, delivery reliability and response time, and often summarises the result in a score. Supplier management is the broader framework: it uses the evaluation results to select and develop suppliers, adjust contracts or restructure the supplier base. - **How can supplier risks be identified early?** Indications are declining delivery reliability, more frequent complaints, longer lead times or sluggish communication. In addition, financial indicators, dependencies on individual sites or sub-suppliers and changes of ownership are monitored. It helps to classify suppliers by their relevance to supply and to monitor the critical ones more closely. For parts with only one source of supply, fallback options should be examined before a shortage occurs. #### Supplier relationship management (SRM) URL: https://www.ktb-europe.com/en/glossary/supplier-relationship-management/ Supplier relationship management (SRM) is the systematic shaping of relationships with suppliers, from selection and evaluation to targeted development. SRM sees suppliers not merely as a source of goods but as partners of varying importance to the company. It covers supplier selection, classification, evaluation, development, risk management and the termination of supply relationships. The term overlaps strongly with supplier management; SRM places the emphasis on actively nurturing the relationship. SRM is also used as a name for corresponding software modules. A core element is segmentation: strategic suppliers receive regular meetings, shared objectives and development projects, while with standard suppliers the focus is on efficient handling. The basis is formed by KPIs such as delivery reliability, quality, response time and price development, which are discussed in supplier evaluations and annual reviews. It is important that the evaluation is also comprehensible to the supplier. In maintenance, SRM pays off particularly with suppliers of critical spare parts. A good relationship makes it easier to obtain early information about discontinuations, to be given consideration during shortages, to receive technical support with alternative parts and to resolve complaints quickly. Where there are very many small suppliers, supplier consolidation can reduce the effort of relationship management. In practice: For suppliers of critical parts, it is worth recording in writing the contacts for urgent cases, escalation paths and obligations to provide information on discontinuations. This makes it clear in the event of a breakdown who responds and how quickly. Also known as: SRM, supplier relationship management Frequently asked questions: - **What is the difference between SRM and supplier management?** The two terms are often used synonymously. Supplier management generally describes the selection, evaluation and management of suppliers. Supplier relationship management places greater emphasis on the long-term relationship, differentiation according to strategic importance and joint development with key suppliers. - **What are the objectives of supplier relationship management?** The aim is to derive the greatest possible lasting benefit from the supplier base: stable supply, good quality, competitive costs and access to innovation. At the same time, risks such as dependencies or supply failures should be identified early. To this end, suppliers are segmented, evaluated and managed with varying intensity depending on their importance. - **How are suppliers segmented in SRM?** Suppliers are often classified by procurement volume and supply risk or by their strategic importance, for example into strategic, important and standard suppliers. For each segment, it is defined how often evaluations and meetings take place, which KPIs apply and whether joint development projects make sense. #### Tail spend management URL: https://www.ktb-europe.com/en/glossary/tail-spend-management/ Tail spend management steers the share of procurement spend spread across many small, irregular orders with numerous suppliers. Tail spend refers to the long tail of the spend distribution: a large share of suppliers and orders accounts for only a small share of purchasing volume. Typical examples are one-off purchases, small orders without a contract, orders from occasional suppliers and requirements outside the established catalogues. Many of these transactions bypass strategic procurement. The problem lies less in the volume than in the process costs and lack of transparency. Every order generates effort for the enquiry, approval, supplier creation, goods receipt and invoice verification, regardless of the order value. On top of this come compliance risks if suppliers have not been vetted. Tail spend management relies on analysis, pooling and simplified processes: catalogues for standard requirements, framework agreements, purchasing cards, consolidation with a few partners or outsourcing to a service provider who takes over many individual requirements. Transparency is a prerequisite: only a cleansed analysis of suppliers and orders shows which requirements can be pooled and which individual cases remain. In practice: In manufacturing companies, a large part of tail spend consists of spare and wear parts from a wide range of manufacturers. Pooling is particularly worthwhile where maintenance technicians have so far ordered individually from many distributors themselves. Also known as: tail spend, long tail spend, low-value spend management Frequently asked questions: - **How do you identify tail spend in your own company?** The starting point is an analysis of all suppliers and purchase orders by volume. If suppliers are sorted in descending order of turnover, a long tail of many suppliers with small amounts each usually emerges. Further indications are one-off suppliers, orders without a contract or catalogue, and invoices without a prior purchase order. Cleansing duplicate supplier master data makes the picture considerably more meaningful. - **Why does tail spend cause high costs?** The costs arise less from the spend itself than from processing. Every small order goes through enquiry, approval, possibly supplier set-up, goods receipt and invoice verification, with similar effort to a large order. On top of this come unvetted suppliers, missing discounts and a lack of transparency. With many transactions, process costs can exceed the value of the goods. - **Which measures help with tail spend management?** Proven measures are catalogues for recurring standard items, framework agreements with a few preferred suppliers and simplified ordering channels for small requirements, such as purchasing cards with clear limits. Another lever is pooling many individual requirements with a partner who also sources rare items. It is important that the new channels are simpler for requesters than the previous direct orders. #### Total cost of ownership (TCO) URL: https://www.ktb-europe.com/en/glossary/total-cost-of-ownership/ Total cost of ownership (TCO) captures all costs of an asset over its life cycle, from purchase price through operation and failures to disposal. The TCO approach supplements a pure price comparison with all costs associated with a purchase. These include transaction costs such as enquiry, purchase order and invoice verification, transport, customs duties and import charges, inspection and quality costs, warehousing and tied-up capital, installation, operating and energy costs, maintenance, failure and downtime costs, and disposal or residual value. With technical components in particular, this shifts the assessment considerably. A cheaper part with a shorter service life, higher energy consumption or uncertain origin can be more expensive over its useful life than a higher-priced original. Conversely, an equivalent alternative with the same performance can save considerable costs. For supplier comparisons, TCO is often simplified: instead of a full life-cycle calculation, the main cost drivers of a category are weighted and combined with the quoted price. How meaningful the result is depends on the underlying data. Process, storage and failure costs are often only estimated; these assumptions should be documented openly so that comparisons remain traceable. In practice: For spare parts, lead time and potential downtime costs belong in every TCO assessment. A part that can be delivered faster at a higher price is often more economical than the cheapest offer with a long wait. Also known as: TCO, life cycle cost (LCC), whole-life cost, total cost of ownership analysis Frequently asked questions: - **How do you calculate total cost of ownership?** You add up all the costs associated with an item over its service life. A common breakdown is into costs before the purchase (such as enquiry and qualification), at the purchase (price, duties, inspection) and after the purchase (storage, operation, energy, maintenance, breakdowns, disposal). For comparisons, the values for each alternative are set side by side; assumptions and estimates should be documented openly. - **What is the difference between TCO and landed cost?** Landed cost comprises the purchase price plus direct procurement costs and minus discounts, i.e. the costs up to the point at which the item is available in the company. Total cost of ownership goes further and also takes into account follow-up costs during use, such as energy, maintenance, breakdowns, stockholding and disposal. A low landed cost can therefore go hand in hand with higher total costs. - **Which costs are often overlooked in the TCO of spare parts?** Frequently underestimated are downtime costs due to long lead times, the effort for identification and enquiry, tied-up capital and storage costs when stocking, and costs for inspection and documentation. A shorter service life of cheaper parts or additional installation effort for alternatives that do not fit exactly also add up. These factors can clearly outweigh the price difference between two quotations. ### Spare Parts & Obsolescence #### ABC analysis URL: https://www.ktb-europe.com/en/glossary/abc-analysis/ ABC analysis is a method that divides items into A, B and C classes according to their share of consumption value in order to target effort. ABC analysis is based on the Pareto principle: a small proportion of items accounts for a large proportion of consumption value. The basis is an item's annual consumption multiplied by its price. The items are sorted in descending order of this value and considered cumulatively. As a rule of thumb, around 70 to 80 per cent of consumption value is accounted for by A items, which make up only around 10 to 20 per cent of line items. B items are in the middle range, while C items make up the bulk of line items with a low share of value. The thresholds are not a standard but are set by each company. ABC analysis is often combined with XYZ analysis, which assesses how regular consumption is. For spare parts, the method has a clear limitation: consumption value says nothing about criticality. An inexpensive, rarely needed part can bring an entire line to a standstill. In spare parts management, ABC classification is therefore usually supplemented by a criticality assessment. Only both perspectives together provide a solid basis for stockholding and procurement. In practice: A items are suitable for framework agreements, price negotiations and close inventory control, C items for simplified ordering processes. Spare parts should additionally be classified by the consequences of failure, so that an inexpensive but critical part does not drop out of stock. Also known as: ABC classification, Pareto analysis, ABC inventory analysis, consumption value analysis Frequently asked questions: - **How do you carry out an ABC analysis?** The consumption value is calculated for each item, i.e. annual quantity times price. The items are then sorted in descending order, their share of the total value is accumulated and class thresholds are set. A typical classification has the few highest-value items forming the A class and the many low-value items forming the C class. - **What is the difference between ABC and XYZ analysis?** ABC analysis ranks items according to their share of total consumption value. XYZ analysis, by contrast, assesses how evenly or erratically an item is consumed. Combined, the two produce a matrix from which planning methods can be derived, for example consumption-based reordering for parts needed at a steady rate. - **Is ABC analysis sufficient for spare parts planning?** No. It only measures economic value, not the consequences of a missing part. Many critical spare parts are rarely consumed and therefore end up in the C class. An additional assessment based on the consequences of failure, replenishment lead time and the availability of sources of supply makes sense. #### Alternative part (equivalent part) URL: https://www.ktb-europe.com/en/glossary/alternative-part/ An alternative part is a component from another manufacturer or of another type that can replace an original part equivalently in form, fit and function. Alternative parts, also called equivalent parts, are used when the original part has been discontinued, is difficult to obtain or is disproportionately expensive. The benchmark is the form, fit, function principle: the replacement part must have the same dimensions, be installable without modifications and perform the same function under the same operating conditions. Suitability is checked technically, usually using data sheets, drawings and material specifications. Items to compare include dimensions, connections, performance data, materials, temperature and pressure ranges and electrical characteristics. For safety-relevant parts, it must also be checked whether the replacement affects the conformity of the machine, for example the CE marking, an approval or an explosion protection rating. For maintenance, proper approval is decisive. The alternative part is documented with the reason, test result and approval date and linked in master data and bills of materials. This keeps it traceable which part is installed where, and later purchases draw on the verified solution. It should also be recorded whether the alternative part is approved without restriction or only for certain machines. In practice: The most important basis for finding an alternative part is the manufacturer part number, nameplate details, data sheet and installation situation. Technical approval should be given before the first order, not only at installation. Also known as: equivalent part, substitute part, replacement type, form-fit-function replacement, cross-reference part Frequently asked questions: - **What does form, fit, function mean?** The formula describes three conditions for an equivalent replacement. Form stands for dimensions and shape, fit for the fit and installation without changes to the surroundings, and function for the same performance under the same operating conditions. Only when all three are met is a part considered directly interchangeable. - **May an alternative part be installed without consultation?** That depends on the application. For safety-relevant components or approved equipment, a replacement can affect conformity. A documented technical approval by the responsible department makes sense. If in doubt, it should be clarified whether the machine manufacturer or an inspection body needs to be involved. - **What documents are needed to check an alternative part?** Helpful are the manufacturer part number of the original, data sheets for both parts, drawings or dimensions, material specifications and the operating conditions at the installation location. For electrical components, characteristics such as voltage, current and IP rating are added. The more complete the information, the more reliable the assessment. #### Bill of materials (BOM) URL: https://www.ktb-europe.com/en/glossary/bill-of-materials/ A bill of materials (BOM) is a structured list of all assemblies, components and quantities that make up a product or a machine. The bill of materials (BOM) describes which parts a product is made of. Each line usually contains the part number, description, quantity and unit of measure. BOMs are the basis for design, manufacturing, material requirements planning and costing. Several types are distinguished according to structure. The summarised BOM lists all parts with their total quantity, without hierarchy. The indented (multi-level) BOM shows the complete structure across all production levels. The single-level BOM describes only one level at a time and refers to separate BOMs for the assemblies. In addition, there are variant and manufacturing BOMs for specific purposes. Which form is used depends on the purpose and on the system in place. For maintenance, the spare parts list, also called the spare parts BOM, is particularly important. It contains the parts that are usually replaced, often with item numbers and exploded drawings. An up-to-date BOM is often the quickest way to identify a spare part unambiguously, especially when nameplates are missing or illegible. Outdated lists, on the other hand, easily lead to wrong orders. In practice: Spare parts lists should be updated whenever equipment is modified or rebuilt or alternative parts are used. For a spare parts enquiry, the machine type, serial number, BOM item number and, if available, the manufacturer part number of the component are particularly helpful. Also known as: BOM, parts list, spare parts list, spare parts BOM, illustrated parts list Frequently asked questions: - **What types of bill of materials are there?** The most important are the summarised BOM, which lists all parts with total quantities and no structure, the indented BOM with the complete hierarchical structure, and the single-level BOM, which shows only one level. For spare parts, the spare parts list is also relevant; it contains replaceable parts with item numbers and drawings. - **What is the difference between a bill of materials and a spare parts list?** The bill of materials describes the complete structure of a product for design and manufacturing. The spare parts list is an extract for service and maintenance. It contains only the parts that can or should be replaced, usually supplemented by exploded drawings and order numbers. - **Who provides the spare parts list for a machine?** As a rule, the machine manufacturer supplies the spare parts list as part of the technical documentation. If it is missing or outdated, it is worth contacting the manufacturer, quoting the machine type and serial number. In addition, in-house lists can be built up on the basis of nameplates and maintenance experience. #### Consignment stock URL: https://www.ktb-europe.com/en/glossary/consignment-stock/ Consignment stock is held at the customer's site and remains the supplier's property until it is withdrawn, only then being invoiced. With consignment stock, the supplier provides goods on the customer's premises or close by. The customer withdraws items as needed, reports the withdrawals and is only invoiced for them. Until then, the supplier bears the tied-up capital while the customer has immediate access. The contract must in particular govern ownership, transfer of risk, insurance, stocktaking, reporting channels, minimum and maximum stock levels and the return of unused goods. This should be distinguished from vendor managed inventory: there the supplier manages the stock, but ownership generally passes on delivery. The two models can be combined. For cross-border consignment stock within the EU, VAT rules must be observed. Since 2020 there has been a simplification for this, implemented in Germany in Section 6b of the German VAT Act (UStG), which is tied to record-keeping and reporting obligations and should be reviewed from a tax perspective. In practice: For spare parts, the model is particularly suitable for expensive, critical parts with irregular consumption. The customer secures availability without having to pay for the parts in advance. Also known as: consignment inventory, consignment warehouse, call-off stock Frequently asked questions: - **What is the difference between consignment stock and vendor managed inventory?** The decisive factor is the transfer of ownership. In consignment stock, the goods remain the property of the supplier until the customer withdraws them and are only invoiced then. With vendor managed inventory, the supplier manages stock and replenishment, but ownership usually passes on delivery. Both models can be combined, for example as supplier-managed consignment stock. - **What are the advantages and disadvantages of consignment stock?** For the customer, tied-up capital and ordering effort fall while the parts are immediately available. In return, the supplier secures sales and close customer loyalty. Disadvantages are the administrative effort for withdrawal reports and stocktakes, the need for coordination in the event of shrinkage or damage, and questions of liability and insurance. For the supplier, the model also means tied-up capital and the risk of goods not being used. - **What needs to be covered in a consignment stock agreement?** Typical contents are items and quantities, minimum and maximum stock levels, retention of title, transfer of risk and insurance, reporting channels and deadlines for withdrawals, stocktaking rules, invoicing and the return of unused goods at the end of the agreement. For cross-border stock, VAT issues are added. The specific arrangement should be agreed with tax and legal advisers; this entry does not replace advice in the individual case. #### Critical spare parts URL: https://www.ktb-europe.com/en/glossary/critical-spare-parts/ Critical spare parts are parts whose absence causes plant downtime or a safety risk and which cannot be procured at short notice. Whether a part is critical is determined not by its price but by the consequences of a failure. Typical assessment criteria are the importance of the plant for production, safety and the environment, the probability of the part failing, the replenishment lead time, the number of available sources of supply and the possibility of temporarily bridging the failure. These criteria result in a criticality class. Critical parts are subject to their own rules. They are usually kept in stock even if they are rarely consumed. These include so-called insurance spares, i.e. expensive individual parts such as gearboxes, motors or pump shafts that are only needed in the event of damage, but then immediately. In addition, storage conditions, shelf life and regular functional checks are specified. The classification should be carried out jointly by maintenance, production and procurement and reviewed whenever plants or the supplier situation change. It is important to keep the list of critical parts up to date and to check stock regularly for condition and completeness. In practice: Critical parts with only one source of supply or a discontinuation notice deserve particular attention. Alternatives or stock quantities should be clarified for them before a failure occurs. Also known as: critical spares, insurance spares, strategic spares, capital spares Frequently asked questions: - **How do you determine which spare parts are critical?** A common tool is an assessment matrix: one axis shows the consequences of a failure for production, safety and the environment, the other the ease of procurement, i.e. replenishment lead time and number of sources. Parts with severe failure consequences and poor availability are considered critical. The assessment is best carried out per plant, because the same part can be of differing importance in different places. - **Do critical spare parts always have to be kept in your own store?** Not necessarily. Alternatives include a shared stock across several sites, a consignment stock at the user's premises or stock reserved contractually at a supplier. What matters is that the part is available quickly enough when needed. The shorter the tolerable downtime, the closer to the equipment the part should be stored. - **What should be considered when storing critical spare parts?** Many parts age even on the shelf. Elastomers need cool, dark and dry storage, electronic assemblies protection against moisture and electrostatic discharge. For large motors or pumps, it is often recommended to turn the shaft by hand at intervals so that the bearings do not suffer standstill damage. Regular visual inspections and documented shelf-life data prevent unpleasant surprises at installation. #### End of life (EOL) URL: https://www.ktb-europe.com/en/glossary/end-of-life/ End of life (EOL) refers to the final phase in a product's life cycle, in which the manufacturer gradually ends production, sales and support. A product reaches its end of life when the manufacturer decides to stop offering it permanently. Reasons include successor models, missing upstream materials, changed regulations or insufficient volumes. This is announced in an EOL notice, which usually states dates and, where applicable, a successor product. End of life often proceeds in stages. With end of sale, regular sales end, often combined with a last time buy date. After that, repairs, spare parts or technical support may still be offered for a while until end of service or end of support is also reached. The terms and periods are not uniformly regulated and differ from manufacturer to manufacturer. For operators of machines and plants, EOL is a key trigger in obsolescence management. Plants often run considerably longer than the life cycles of their components, especially controllers, drives and electronics. Anyone who records EOL notices early can assess requirements, secure stock or plan a changeover. In practice: EOL notices should be recorded centrally and matched against the affected equipment and bills of materials. For each affected item, a decision is recommended: stockholding, alternative part or modernisation. Also known as: EOL, end-of-life phase, product phase-out, end of sale, EOL notice Frequently asked questions: - **What is the difference between end of life, end of sale and end of service?** End of sale denotes the end of regular sales. End of service or end of support marks the point from which repairs, spare parts or technical support are also no longer available. End of life is used partly as an umbrella term for the entire phase-out and partly for a single date. The definitions in the respective manufacturer's notice are what count. - **What does an EOL notice contain?** Usual contents are the affected items with part numbers, the last order date, where applicable a last delivery date, information on continued service support and, if available, a recommended successor product. Scope and form are not uniformly regulated. If anything is unclear, it is worth asking the manufacturer. - **What should you do after an EOL notice?** First, check in which equipment the part is installed and how large the remaining requirement is until the planned end of operation. Then decide whether a last time buy, a verified alternative part or modernisation is the most sensible solution. It is important to meet the deadlines given in the notice. #### Form, fit and function (FFF) URL: https://www.ktb-europe.com/en/glossary/form-fit-function/ Form, fit and function (FFF) describes the interchangeability of a spare part that matches the original part in geometry, mounting interfaces and function. The FFF principle comes from configuration and spare parts management. A part is considered FFF-interchangeable if it can replace the original without changes to the surrounding design. Form stands for dimensions, geometry and weight, fit for interfaces such as fastening, connections, pin assignment and tolerances, and function for performance, ratings, signals and behaviour in operation. FFF is particularly important in the case of discontinuations and supply shortages. If a manufacturer offers a successor product as an FFF replacement, it can usually be installed directly. For alternative parts from other manufacturers, equivalence must be checked in all three dimensions. Approvals, material compliance, software and firmware versions or certificates are not automatically covered; these must be assessed separately. In maintenance, FFF approval speeds up procurement considerably, because no design change and no new acceptance is required. If full interchangeability is lacking, this is referred to as a restricted replacement, which requires adaptations and must be technically approved. Every approval should be documented in a traceable manner. In practice: In the event of discontinuations, the supplier should explicitly confirm whether a successor part is FFF-compatible or what deviations exist. This information, together with the approval note, belongs in the master data so that future orders are possible without a fresh review. Also known as: FFF, form fit function, drop-in replacement, FFF-compatible Frequently asked questions: - **What does form fit function mean?** Form fit function means that a spare part matches the original in three respects: in its external shape and dimensions, in its mounting and connection interfaces and in its function. A part that is interchangeable in this way can be installed without changes to the machine, wiring or software and is therefore also called a drop-in replacement. - **Is an FFF spare part identical to the original?** Not necessarily. An FFF replacement fulfils form, fit and function but may differ in material, internal design, manufacturer or components. For most applications, this is not critical. In regulated or safety-relevant areas, approvals, certificates and evidence of conformity must also be checked before the replacement is approved. - **How do you check whether an alternative part is FFF-compatible?** Data sheets and drawings of the original and the alternative are compared: dimensions, weight, fixing points, connections, pin assignment, electrical or mechanical ratings, ambient conditions and interfaces. Deviations are assessed and documented. In case of uncertainty, an installation and functional test follows before the part is generally approved. - **What is the difference between FFF and an alternative part?** An alternative part is any part that can be considered as a replacement for the original, even if adaptations are necessary. FFF is a quality characteristic of this interchangeability: an FFF-compatible alternative part fits without any change. If only function is matched, but not form or fit, modifications and a technical approval are required. #### Inventory management URL: https://www.ktb-europe.com/en/glossary/inventory-management/ Inventory management covers the planning, control and monitoring of stock in order to ensure availability and keep tied-up capital low. Inventory management operates within the conflict of objectives between service level and costs. Stock levels that are too high tie up capital, occupy storage space and become obsolete; levels that are too low lead to stock-outs and, in the case of spare parts, to plant downtime. The task is to hold the right quantity of each item at the right time. The requirements differ considerably depending on the type of item, for example between production material, consumables and spare parts. The tools include classifications such as ABC and XYZ analysis, planning parameters such as reorder point, safety stock and order quantity, and KPIs such as inventory turnover, service level and days of supply. Control is either consumption-based, according to historical values, or requirement-based, according to planned orders, for example from maintenance plans. Added to this are stocktaking, inventory valuation and the clean-up of items no longer needed. Spare parts follow their own rules. Many parts are rarely needed but are indispensable for operations. Here, criticality, the number of installed units, replenishment lead time and obsolescence risk determine stockholding more than consumption does. In addition, consignment stock, vendor managed inventory or framework agreements can keep stock at the supplier. The costs of a possible downtime also feed into this assessment. In practice: A clean master data basis is the prerequisite: duplicate items with different descriptions for the same part drive stock levels up unnoticed. Regularly comparing spare parts with the current asset base shows which parts are still needed and which can be run down. Also known as: stock management, inventory control, inventory planning Frequently asked questions: - **What is the aim of inventory management?** The aim is to keep the required materials available in sufficient quantities while limiting tied-up capital, storage costs and obsolescence risks. In practice, this means setting an appropriate service level for each item and choosing order quantities and order times so that this service level is achieved economically. - **Which KPIs are used in inventory management?** Commonly used are inventory turnover, average storage period, days of supply, service level or fill rate, stock-out rate and the share of items without movement over a longer period. For spare parts, it is also revealing how many downtimes or delays were caused by missing parts. - **What is the difference between inventory management and warehouse management?** Warehouse management deals with the physical side: putaway, storage locations, picking and stocktaking. Inventory management decides which items are held at all, in what quantity, and when to reorder. The two interlock but address different questions. #### Inventory turnover URL: https://www.ktb-europe.com/en/glossary/inventory-turnover/ Inventory turnover indicates how often the average stock is consumed and replaced within a period, usually a year. Inventory turnover is a key metric of inventory management. It relates the consumption or cost of materials in a period to the average stock. A high turnover rate means that little capital is tied up in stock; a low one indicates high stock levels or slow-moving items. The usual formula is: inventory turnover = consumption at cost price ÷ average stock. The average stock is calculated from opening and closing stock or, more precisely, from monthly values. From this, the average storage period is derived: 360 or 365 days divided by the turnover rate. Example: if the valued annual consumption is three times as high as the average stock, the result is a turnover of 3 and a storage period of around 120 days. For spare parts stores, the metric should be read with caution. Critical parts with infrequent demand naturally have a very low turnover but secure the availability of important plants. It therefore makes sense to look at part groups separately, for example consumables, wear parts and strategic spare parts. In practice: Before spare parts are run down because of low turnover, it should be checked which plants they safeguard and how long their replenishment lead time is. Genuine shelf warmers are often parts for machines that have already been decommissioned, which can be identified by comparing stock with the asset register. Also known as: stock turnover, inventory turns, stock turn rate, turnover rate Frequently asked questions: - **How is inventory turnover calculated?** You divide the consumption in a period, valued at cost price, by the average stock in the same period. If the valued annual consumption is three times as high as the average stock, inventory turnover is 3. For individual items, you can also calculate with quantities instead of values. - **What is a good inventory turnover?** There is no generally applicable target value. The metric depends heavily on the sector, product range and purpose of the store. Consumables turn over much faster than strategic spare parts held for rare failures. The comparison over time and between similar item groups within the company is what is most meaningful. - **How are inventory turnover and storage period related?** The average storage period is obtained by dividing the days of the period under review by the turnover rate. With an annual turnover of 4, an item is in stock for around 90 days on average. As turnover rises, the storage period falls, and with it the capital tied up. #### Last time buy (LTB) URL: https://www.ktb-europe.com/en/glossary/last-time-buy/ A last time buy is the final chance to order a discontinued product, buying the remaining demand for the rest of its service life. After a discontinuation, manufacturers set a date up to which the product can still be ordered. By then, customers must estimate how many units they will need for the rest of the plant's planned service life. This is often followed by a later date for the final delivery, the last time ship. Calculating the quantity is the real challenge. Historical consumption, the number of installed units, the expected failure rate, the remaining service life of the plant, planned modernisation and a buffer for uncertainties all need to be taken into account. Buying too few parts leads to shortages later; buying too many ties up capital and can lead to deterioration where shelf life is limited, for example with elastomers, batteries or electrolytic capacitors. A last time buy is a bridge, not a permanent solution. It buys time to prepare a modernisation or a qualified alternative part. In practice: For last-time-buy parts, storage conditions and shelf life should be documented. Anyone who misses the deadline is dependent on remaining stock at distributors or other users, which is often difficult to find. Also known as: LTB, lifetime buy, end-of-life buy, last order date (LOD) Frequently asked questions: - **How do you calculate the quantity for a last time buy?** A simple approach: expected annual consumption multiplied by the remaining years of use, plus a safety buffer, minus existing stock. Example: with 4 failures per year, 6 remaining years and a 20 % buffer, the requirement is around 29 units; if 5 are already in stock, about 24 are ordered. Rising failure rates in ageing equipment should be taken into account. - **What is the difference between last time buy and last time ship?** The last time buy date is the last day on which an order is accepted. The last time ship date is usually later and marks the manufacturer's final delivery. For planning, the order date is decisive: by then, quantity, budget and internal approvals must be settled, even if the goods only arrive months later. - **Who should be involved in the decision on a last time buy?** Maintenance knows consumption and failure behaviour, production the planned remaining life of the equipment, purchasing the deadlines and terms, and controlling the capital tied up. If the decision is made jointly and documented together with its assumptions, it can be traced later, for example if operating lives change or remaining stock has to be valued. #### Manufacturer part number (MPN) URL: https://www.ktb-europe.com/en/glossary/manufacturer-part-number/ The manufacturer part number (MPN) is the identifier assigned by the manufacturer that uniquely designates a component in a specific version. The manufacturer part number, MPN for short, is the most important piece of information for spare parts procurement. It distinguishes variants that look the same externally but differ in voltage, material, connection size or seal material, for example. It is often made up of a type code whose positions encode particular properties. Other identifiers must be distinguished from it: a distributor's order number or a company's internal material number is valid only within their own systems. The GTIN or EAN identifies a trade unit but does not describe the technical version. The customs tariff number assigns goods to a product group for customs purposes and says nothing about the specific version. Machine builders also use their own item numbers from spare parts lists, which first have to be translated into the supplier's manufacturer number. Manufacturer part numbers can change when products are modified. Successor numbers are not automatically compatible and should be checked against the data sheets. In practice: The MPN is usually found on the nameplate or directly on the component. If it is illegible, photos from several angles, dimensions and information from the machine documentation help with identification. Also known as: MPN, manufacturer's part number, OEM part number, type designation Frequently asked questions: - **Where can you find the manufacturer part number if the nameplate is missing?** Good sources are the machine's spare parts list and bill of materials, circuit diagrams, previous orders and invoices, and markings directly on the housing, circuit board or packaging. The machine builder can often name the installed components on the basis of the machine number. If the number remains unclear, parts can be narrowed down by dimensions, connections and technical data. - **Is the manufacturer part number alone sufficient for an order?** Usually yes, provided it is complete. Problems arise when suffixes, special characters or variant codes are omitted or a distributor shortens the number. For some parts, the revision status or firmware version is also important. In case of doubt, the number should be copied character for character and backed up with a photo of the nameplate. - **What does it mean if a manufacturer part number changes?** A new number may indicate a modified version, a successor type, a change to the type code or a takeover of the manufacturer. Only a comparison of the data sheets shows whether the new part is interchangeable. In the master data, the old and new numbers should be kept with a cross-reference and a note on compatibility so that both can still be found. #### Obsolescence URL: https://www.ktb-europe.com/en/glossary/obsolescence/ Obsolescence is the state in which a component, material or software is no longer offered by the manufacturer although it is still needed. In industry, obsolescence usually arises because manufacturers switch product lines to new technologies, consolidate production or withdraw from markets. Other causes are changed regulations, such as substance bans, the end of availability of raw materials or intermediate products, and a supplier's insolvency. Electronic components with short product cycles are particularly affected, but so are mechanical and hydraulic components from older series. The problem arises from differing life cycles: production plants often run for several decades, but many of their components are discontinued much earlier. If such a part fails, there is no original replacement and sometimes no documentation either. Technical obsolescence should be distinguished from functional obsolescence, in which a part is still available but no longer meets changed requirements, for example new communication interfaces. The concept of planned obsolescence from the consumer goods sector plays hardly any role in the capital goods industry. In practice: Typical triggers for a review are discontinuation notices, significantly longer lead times or price jumps for a part. For affected components, remaining stock, alternatives and conversion options should be assessed early. Also known as: component obsolescence, parts obsolescence, discontinued parts, end of life (EOL) Frequently asked questions: - **What is the difference between obsolescence and discontinuation?** Discontinuation is an event: the manufacturer announces that a product is being withdrawn. Obsolescence describes the resulting state in which the part is no longer regularly available but is still needed. Obsolescence can also occur without formal discontinuation, for example when a supplier disappears from the market or an upstream product is no longer available. - **Which components are particularly often affected by obsolescence?** The most affected are electronic components such as controllers, drive controllers, operator panels, power supplies and communication modules, because semiconductors and interfaces evolve rapidly. Software and operating systems also become outdated. With mechanical parts, obsolescence tends to affect special versions, parts from small manufacturers or older series, while standard parts usually remain available for a long time. - **What strategies are there to counter obsolescence?** A distinction is made between reactive and proactive measures. Reactive measures are searching for remaining stock, using alternative parts, repair or reproduction from drawings. Proactive measures are monitoring life cycle status, a timely last time buy, selecting components with several sources for new equipment and planned modernisation before shortages arise. #### Obsolescence management URL: https://www.ktb-europe.com/en/glossary/obsolescence-management/ Obsolescence management detects component discontinuations early and plans measures so that plants stay operational without original parts. The international standard IEC 62402, published in Germany as DIN EN IEC 62402, describes obsolescence management as a process across the entire life cycle of a product or plant. The basis is a complete list of installed components with manufacturers and part numbers. This is regularly compared with life-cycle information, such as discontinuation notices and availability data. A distinction is made between reactive and proactive strategies. Reactive action is taken when a discontinuation occurs: buying remaining stock, searching for alternative sources, qualifying alternative parts or repairing. Proactively, risks are already taken into account during design and procurement, for example through standard components, multiple sources of supply, stockholding agreements and planned modernisation. For each component at risk, a measure is chosen that takes into account cost, risk and the remaining service life of the plant. The result is an obsolescence plan that specifies when to stock up, when to retrofit and when to use an alternative. In practice: A pragmatic starting point is to assess a plant's critical components by supply status and consequence of failure. This list alone shows where a last time buy or a review of alternatives is urgent. Also known as: DMSMS (diminishing manufacturing sources and material shortages), end-of-life management, obsolescence risk management Frequently asked questions: - **What is the difference between proactive and reactive obsolescence management?** Reactive obsolescence management only acts when a discontinuation becomes known or a part is no longer available, for example by buying remaining stock or searching for alternatives. Proactive obsolescence management monitors life cycle data continuously, assesses risks in advance and plans measures before shortages arise. It takes obsolescence into account as early as design and procurement. The proactive approach involves more effort but prevents expensive emergency solutions. - **What measures are there for discontinued parts?** Common measures are a final stocking purchase (last time buy), searching for remaining stock through other sources of supply, qualifying equivalent alternative parts, repairing or reconditioning existing parts, and converting to new components. Which option fits depends on the remaining service life of the plant, the criticality of the part, the costs and the effort involved in a technical change. - **How do you get started with obsolescence management?** A good first step is a list of the components installed in important equipment, with manufacturer and part number. This is assessed by delivery status and consequences of failure, so that parts at risk become visible. Measures are defined and responsibilities assigned for the most critical items. The list should then be updated regularly and matched against manufacturers' discontinuation notices. #### OEM (original equipment manufacturer) URL: https://www.ktb-europe.com/en/glossary/oem/ OEM (original equipment manufacturer) refers to the original manufacturer of a machine, plant or component that sells the product under its own name. In mechanical and plant engineering, the OEM is usually the manufacturer of the complete machine. It develops the machine but installs many components from other manufacturers in it, such as bearings, drives, valves or controllers. These suppliers are in turn the original manufacturers of their respective components. The term is therefore used differently depending on the perspective. For spare parts procurement, three categories can be distinguished. The genuine spare part is obtained via the machine manufacturer, often under its own part number. The component manufacturer's OEM part is the same component, obtained directly under the part number of the actual manufacturer. An aftermarket part comes from a third-party supplier and is modelled on the original without being identical to it. This distinction is important for maintenance because availability, documentation and warranty can differ. Knowing the manufacturer part number of the installed component often gives more sourcing options than the machine manufacturer's part number alone. At the same time, it helps in deciding whether an aftermarket part is acceptable or whether the original should be used. In practice: In machine manufacturers' spare parts lists, it pays to determine the manufacturer part number of the actual component for each item, for example via the nameplate or data sheet. For warranty or maintenance contracts, it should be clarified in advance whether parts from other sources are permitted. Also known as: original equipment manufacturer, original manufacturer, machine builder, OEM part, genuine part Frequently asked questions: - **What is the difference between an OEM part and a genuine spare part?** A genuine spare part is obtained via the machine manufacturer under its part number. An OEM part is often the same component but procured directly from the component manufacturer or through its sales channels. Technically, both can be identical, but the part number, sourcing route and documentation differ. - **What is an aftermarket part?** An aftermarket part is made by a third-party supplier and is intended to replace an original part without coming from its manufacturer. Quality ranges from equivalent to significantly worse. Before use, dimensions, materials and performance data should be checked and suitability for the specific application approved. - **How do you find the actual manufacturer of a component?** Clues are provided by the component's nameplate, embossing or printing, the machine documentation and the machine manufacturer's spare parts list. The component's manufacturer part number can be used to find the data sheet and further sources of supply. If this information is missing, dimensions, photos and the installation situation help. #### Overhaul (refurbishment) URL: https://www.ktb-europe.com/en/glossary/overhaul/ An overhaul is the complete dismantling, inspection and reconditioning of a machine or assembly to an almost as-new condition. Overhauled means that a unit has not merely been repaired at the point of damage but completely dismantled, cleaned and measured. All wear parts such as bearings, seals and bushes are replaced, mating surfaces are reworked and damaged parts renewed. Finally, assembly and a test run follow. By contrast, a repair only remedies the specific damage, while a retrofit introduces new technology. Typical objects are gearboxes, pumps, hydraulic pumps and cylinders, electric motors, machine tool spindles, valves and compressors. The result is usually a test report with measured values, for example on clearance, leak tightness, performance or vibration. Terms such as reconditioned, refurbished or remanufactured are used differently on the market, which is why the agreed scope of work is decisive. For the spare parts strategy, an overhaul is an alternative to buying new, particularly for expensive or discontinued assemblies. The exchange principle is also widespread: an overhauled unit is installed, and the removed one is then reconditioned and stored as a spare. This keeps the plant ready for operation even if reconditioning takes a long time. In practice: Before awarding the work, it should be specified in writing which parts are always renewed, which tests are carried out and which report is supplied. For critical units, an overhauled spare unit in stock considerably shortens downtime. Also known as: refurbishment, general overhaul, major overhaul, reconditioning Frequently asked questions: - **What does overhauled mean?** Overhauled means that a machine or assembly has been completely dismantled, cleaned, inspected and rebuilt with new wear parts. The aim is a condition that comes as close as possible to new in terms of function and reliability. The exact scope is not standardised and should therefore be traceable from a specification of works and a test report. - **What is the difference between an overhaul and a repair?** A repair remedies a specific defect, for example by replacing a faulty bearing. In an overhaul, the entire unit is dismantled and all parts subject to wear are replaced, regardless of whether they have already failed. As a result, the effort is greater, but the expected running time afterwards is usually considerably longer. - **Is an overhaul worthwhile instead of buying new?** Often yes, if the housing and main parts are in good condition, the assembly fits the existing plant and a new part is expensive, difficult to obtain or discontinued. It makes less sense if the main parts are badly damaged or if a modern new part offers clear advantages in efficiency or spare parts supply. - **What should a test report after an overhaul contain?** A meaningful report lists the parts replaced, measured and test values such as bearing clearance, leak tightness, pressure or performance, results of the test run and, where applicable, vibration values. Findings on the cause of damage should also be documented. This information helps to assess the quality of the overhaul and to avoid repeat damage. #### Product discontinuation (PCN/PDN) URL: https://www.ktb-europe.com/en/glossary/product-discontinuation/ A product discontinuation is a manufacturer's notice that a product is being phased out, usually with dates for last orders and deliveries. Manufacturers usually inform their customers in writing about the end of a product. Common terms are product discontinuance notice (PDN), end-of-life notice or, for changes to the product, product change notification (PCN). The notice generally states the product concerned, the last order date, the last delivery date and, where available, a recommended successor. Between the discontinuation and the actual end of delivery there is often a window in which customers can make a last time buy. After that, some manufacturers still offer a repair or spare parts service for a limited period. Whether this applies, and for how long, is manufacturer-specific. A discontinuation becomes problematic if it does not reach the plant operator, for example because the part was procured via a machine builder or distributor. In addition, the successor type is not always compatible: dimensions, connections, software or approvals may differ. In practice: Discontinuation notices should be collected centrally and compared with the inventory of installed components. If a successor is recommended, a technical review is worthwhile before the last order date for the original passes. Also known as: product discontinuance notice (PDN), product change notification (PCN), end-of-life notice (EOL), discontinued part Frequently asked questions: - **What is the difference between a PCN and a PDN?** A product change notification announces a change to a product that remains available, for example to its material, production site, dimensions or firmware. A product discontinuance notice, by contrast, announces the end of the product. Both are relevant to maintenance: a change can affect interchangeability, while the end of a product requires a decision on stockpiling or replacement. - **How do you find out about discontinuations in good time?** Many manufacturers publish life cycle information on their websites or send notifications to registered customers. Anyone buying parts through distributors or machine builders should explicitly ask them to pass on such notices. Regular checks of the life cycle status of the most important components, for example once a year, and a central mailbox in which all notifications are collected also help. - **What should you do if a part has already been discontinued?** First, it should be clarified how many units are installed and how long they will still be needed. Several options are then possible: remaining stock at distributors or other users, a successor recommended by the manufacturer, a technically equivalent alternative part, repair of existing parts or modernisation of the affected assembly. A combination is often sensible. #### Reorder point URL: https://www.ktb-europe.com/en/glossary/reorder-point/ The reorder point is the stock level at which a replenishment order is triggered so that stock lasts until the goods are received. The reorder point links consumption and replenishment lead time. It is set so that the stock from the time of ordering is sufficient until the new delivery arrives, leaving the safety stock untouched. The common formula is: reorder point = average daily consumption × replenishment lead time in days + safety stock. Example: with a consumption of 4 units per day, a replenishment lead time of 15 days and a safety stock of 20 units, the reorder point is 80 units. With the reorder point method, the system continuously checks the stock and generates an order proposal as soon as it falls below this value. For spare parts, the formula reaches its limits. Many parts are only needed sporadically, so average consumption says little. For such items, fixed minimum quantities are often set, based on the number of units installed, criticality and replenishment lead time. Changes of supplier or new sources of supply also change the replenishment lead time and therefore the reorder point. In practice: Reorder points should be regularly compared with actual lead times, as longer replenishment lead times quickly make old values too low. For rarely needed, critical parts, a deliberately set minimum quantity usually makes more sense than a calculated value. Also known as: ROP, reorder level, order point, reorder threshold, trigger level Frequently asked questions: - **How do you calculate the reorder point?** Multiply the average daily consumption by the replenishment lead time in days and add the safety stock. If 10 units are consumed daily, replenishment takes 8 days and the safety stock is 30 units, the reorder point is 110 units. - **What is the difference between reorder point and safety stock?** Safety stock is a buffer that absorbs unforeseen fluctuations in consumption or lead time and is not normally touched. The reorder point is the trigger for an order. It contains the safety stock plus the expected consumption during the replenishment lead time. - **Does the reorder point also work for spare parts?** For regularly consumed parts such as filters or seals, yes. For parts with very rare, irregular demand, average consumption is not very meaningful. Here, stock is more likely to be controlled via fixed minimum quantities based on criticality, installed units and lead time. #### Replenishment lead time URL: https://www.ktb-europe.com/en/glossary/replenishment-lead-time/ Replenishment lead time is the period from identifying a requirement until the material is available in stock or at the point of use. Replenishment lead time covers more than the supplier's lead time. It begins when the requirement is identified and ends when the part has been inspected and stored ready for use. It is a key input for calculating the reorder point and safety stock. The longer and more uncertain it is, the larger the buffer in stock must be to avoid stock-outs. Typical components are the internal processing time for the requirement notification, purchase requisition and approval, transmission of the order, the supplier's lead time including production or procurement from the upstream supplier, inbound delivery, and goods receipt and inspection. Each of these phases can become shorter or longer; shortages at the manufacturer have a direct impact on the total duration. For spare parts, replenishment lead time often varies widely. Standard parts are sometimes available at short notice, while special versions or made-to-order parts can take considerably longer. Anyone planning with outdated values sets reorder points too low and risks downtime. The actual times from past orders should therefore be evaluated regularly and updated in the material master. In practice: In addition to the supplier's stated figure, the actually measured replenishment lead time should also be maintained in the material master. For critical parts with long lead times, it is worth considering framework agreements with reserved quantities or orders brought forward on the basis of the maintenance plan. Also known as: replenishment time, procurement lead time, total lead time Frequently asked questions: - **What is the difference between lead time and replenishment lead time?** Lead time is only the time the supplier needs from the order to delivery. Replenishment lead time is more comprehensive: it also includes internal steps such as determining requirements, approval and ordering, as well as goods receipt with inspection. For inventory planning, replenishment lead time is therefore decisive. - **How is replenishment lead time calculated?** You add up the duration of the individual phases: identification of the requirement and purchase requisition, approval and ordering, the supplier's lead time, inbound delivery, and goods receipt and inspection. The most reliable figure is an average from orders actually processed, supplemented by the observed variation, which feeds into the sizing of the safety stock. - **How can replenishment lead time be shortened?** Internally, lean approval processes, framework agreements with call-off orders and electronic order processing help. Externally, suppliers with their own stockholding, agreed reservations or consignment stock have an effect. For special parts, early demand planning from maintenance plans can bring the order forward so that long production times do not become a bottleneck. #### Reverse engineering (spare parts) URL: https://www.ktb-europe.com/en/glossary/reverse-engineering/ For spare parts, reverse engineering is the redesign of a component from an existing sample when the original is no longer available. If a manufacturer has discontinued a part, no longer exists or no documentation is available, reverse engineering can secure spare parts supply. All the information needed for new manufacture is obtained from an existing sample, ideally undamaged. Typical candidates are mechanical parts such as gears, shafts, bushes, impellers, seals and housing parts. The process comprises measurement with gauges, a coordinate measuring machine or 3D scanner, determination of material, hardness and surface treatment, derivation of fits and tolerances from the function, and preparation of a production drawing. This is followed by sample production, first article inspection and a functional test in the plant. With worn samples, the nominal dimensions have to be reconstructed, which requires a technical understanding of the assembly. Limits are set by intellectual property rights such as patents or registered designs, which must be checked before remanufacture, and by safety-relevant functions, for which a new assessment may be needed. Electronic assemblies with software can generally only be replicated to a limited extent. This entry does not replace a legal review in the individual case. In practice: For reverse engineering, the sample, any existing part drawings, installation position, mating parts, operating conditions and known damage patterns should be provided. The new drawing should then be archived as master data so that later reorders are possible without measuring again. Also known as: re-engineering, redesign from sample, backward engineering, part reverse engineering Frequently asked questions: - **When is reverse engineering worthwhile for spare parts?** Reverse engineering is worthwhile when a part is no longer available, no equivalent alternative part exists and the plant is to be operated for some time to come. Purely mechanical parts are particularly suitable. The effort for measurement, drawing and first article must be weighed against the costs of downtime or a retrofit. - **Is it permitted to replicate spare parts?** That depends on the individual case. If intellectual property rights such as patents, utility models or registered designs still apply, replication may be restricted. Contractual agreements with the manufacturer also play a role. The legal position should therefore be checked before remanufacture; the assessment of a qualified body is binding, not this entry. - **Which steps does reverse engineering comprise?** Usual steps are a survey and functional analysis, measurement of the sample, determination of material and hardness, reconstruction of nominal dimensions and tolerances, preparation of a drawing or 3D model, sample production, first article inspection and a functional test. Only after successful testing is the part released and documented as a spare part. - **What is the difference between reverse engineering and an alternative part?** An alternative part is a product from another manufacturer that is already available on the market and can technically replace the original. In reverse engineering, by contrast, a new part is drawn and manufactured on the basis of the original. It is usually used when no suitable alternative part can be found. #### Safety stock URL: https://www.ktb-europe.com/en/glossary/safety-stock/ Safety stock is an inventory buffer that absorbs fluctuations in consumption and replenishment lead time and is intended to prevent stockouts. Safety stock, also known as buffer stock or minimum stock, is not normally consumed. It only comes into play when more parts are needed than planned or a delivery takes longer than expected. It forms part of the reorder point and lies below it. There are simple and statistical approaches to calculating it. A simple method is a fixed daily requirement multiplied by a number of buffer days, or the difference between maximum and average consumption during the lead time. Statistical methods take into account the variability of consumption and lead time as well as a target service level, i.e. the probability with which a requirement can be met from stock. A higher service level requires disproportionately more stock. In spare parts management, safety stock is a trade-off between tied-up capital and the risk of failure. Storage costs, ageing and administrative effort are weighed against the costs of downtime. For critical parts with long lead times, the buffer is therefore set higher than for standard parts that can be sourced quickly. In practice: Safety stocks should be differentiated by criticality and replenishment lead time rather than set across the board. A regular review shows whether buffers need adjusting because of changed lead times or can be reduced because equipment has been retired. Also known as: buffer stock, minimum stock, reserve stock, safety inventory, iron stock Frequently asked questions: - **How do you calculate safety stock?** A simple approach multiplies average daily consumption by a fixed number of buffer days. Statistical methods use the standard deviation of consumption and lead time together with a safety factor derived from the target service level. Which approach fits depends on the available data and the consumption pattern. - **What does service level mean in relation to safety stock?** The service level indicates the probability or the proportion with which requirements are met directly from stock. A higher service level reduces the risk of stockouts but requires more stock. The last few percentage points are particularly expensive, because the buffer grows disproportionately. - **Is a high safety stock always a good idea?** No. Stock ties up capital, occupies storage space and can age, for example elastomers or electronics. A large buffer pays off above all for parts whose absence causes high downtime costs and which can only be procured with a long lead time. For readily available standard parts, a small buffer is usually sufficient. #### Second source URL: https://www.ktb-europe.com/en/glossary/second-source/ A second source is a second, equivalent source of supply for a component that secures supply if the main supplier fails or faces a shortage. A second source is an additional supplier or manufacturer that can supply a technically equivalent part. The term originally comes from electronics, where components were manufactured under licence by several manufacturers. It is to be distinguished from dual sourcing, in which two suppliers permanently receive volumes in parallel: a second source may merely be qualified and only activated when needed. A distinction is made between a second source for the same original part, such as another authorised distributor, and a second source for an alternative part from a different manufacturer. In the second case, equivalence must be demonstrated, usually by comparing form, fit and function, data sheets, materials and, where applicable, approvals. Only after this qualification is the source considered approved. In spare parts supply, a second source reduces the risk of supply shortages, discontinuations and price jumps at the single supplier. However, it involves effort for testing, master data maintenance and supplier evaluation. It is therefore worthwhile above all for critical spare parts and components with long replenishment lead times. In practice: To qualify a second source, the manufacturer part number, data sheet, drawing, material details and required certificates should be available. Approved alternatives belong in the master data with the approval date and any restrictions, so that they can be ordered in the event of a breakdown without a fresh review. Also known as: second sourcing, alternative source of supply, secondary supplier, backup supplier Frequently asked questions: - **What is the difference between a second source and dual sourcing?** In dual sourcing, a company permanently splits its ongoing demand between two suppliers. A second source, on the other hand, does not have to supply regularly: it can be qualified and approved but only come into use in the event of a failure, shortage or discontinuation at the main supplier. Dual sourcing is thus one way of actively using a second source. - **How do you qualify a second source for a spare part?** First, the technical requirements are defined: dimensions, connections, performance data, materials and necessary approvals. Then the data sheets and drawings of the alternative are compared, samples are checked at goods receipt or in trial use if necessary, and the supplier is evaluated. The result is documented so that the approval remains traceable. - **For which parts is a second source worthwhile?** It is particularly useful for parts whose failure brings a plant to a standstill, for long replenishment lead times, for parts offered by only a single manufacturer and for components facing foreseeable discontinuation. For inexpensive standard parts with many suppliers, on the other hand, the qualification effort is usually not justified. #### Spare parts list URL: https://www.ktb-europe.com/en/glossary/spare-parts-list/ A spare parts list records the replaceable parts of a machine with designation, part number and quantity and serves as the basis for ordering and stockholding. The spare parts list is usually supplied by the machine manufacturer as part of the technical documentation. It differs from the bill of materials: the latter describes the complete structure of a product for production, whereas the spare parts list covers only the parts that can or should be replaced during operation. It is often linked to exploded drawings in which each item bears a number. Typical details are the item number, designation, manufacturer part number or the machine manufacturer's article number, installed quantity, assembly and often a marking as a wear part, spare part or recommended stock part. Some manufacturers add a spare parts recommendation for initial stocking or for certain operating hours. For plants with many variants, the list often relates to the specific serial number. For maintenance, the spare parts list is the starting point for every order and for stock planning. It becomes problematic if it contains only the machine manufacturer's own numbers: it is then unclear which bought-in part, for example a standardised rolling bearing or a valve, lies behind them. A well-maintained list with the original manufacturer and type designation makes it easier to find second sources and reduces dependencies. In practice: When accepting new plants, a complete spare parts list with manufacturer part numbers for the bought-in parts should be contractually agreed. For existing plants, it is worth comparing the list with the nameplate data on site, as modifications and replacements have often not been recorded. Also known as: spare parts catalogue, recommended spare parts list (RSPL), parts list, illustrated parts catalogue Frequently asked questions: - **What is the difference between a bill of materials and a spare parts list?** A bill of materials describes all the components of a product with quantities and structure and is used mainly for design and production. The spare parts list contains only the parts that are replaceable during operation and is geared towards maintenance and ordering. It is therefore usually shorter and supplemented with notes on wear or stockholding. - **What should a spare parts list contain?** At a minimum, the item number, designation, part number, installed quantity and assignment to the assembly. Also helpful are the original manufacturer and type designation of bought-in parts, technical data, a marking as a wear or critical part and a recommended stock quantity. A reference to a drawing or exploded view makes unambiguous assignment easier. - **What should you do if the spare parts list only contains the machine manufacturer's numbers?** In that case, it is worth looking at the nameplate of the installed part, which often shows the original manufacturer and type designation. Data sheets, circuit diagrams or an enquiry to the machine manufacturer can also help. Once the original part has been identified, it can often also be procured via other sources of supply, provided it is not a special version. - **Who supplies the spare parts list for a machine?** Usually, the machine manufacturer provides it as part of the documentation. Scope, format and updates, however, depend mainly on what was agreed when the plant was ordered. Anyone who wants to be on the safe side specifies these points in the requirements specification or the purchase order. #### Spare parts management URL: https://www.ktb-europe.com/en/glossary/spare-parts-management-definition/ Spare parts management plans, procures, stores and controls spare parts so that plants stay available and stock levels remain economical. Spare parts management links maintenance, procurement and warehousing. It starts with recording the installed base: which plants and components are in use, which parts belong to them, and which of these typically fail? This results in a spare parts catalogue with unambiguous master data, manufacturer details and where-used records. On this basis, it is decided which parts are stocked, in what quantity and at which location. Criteria are criticality, consumption, replenishment lead time, price and shelf life. Methods such as ABC and XYZ analysis, reorder points and safety stock help with control. For rarely needed, expensive parts, consignment stock, pooling solutions or agreements with suppliers are options. An ongoing element is upkeep: reducing stock that is not used, identifying discontinuations, qualifying alternative parts and adjusting master data when plants change. KPIs such as service level, stock coverage, share of non-moving stock and replenishment lead times show whether spare parts management keeps availability and tied-up capital in balance. In practice: Many spare parts stores contain both excess stock and gaps at the same time. Reconciling the stock on hand with the components actually installed reveals both and is a sensible first step. Also known as: spares management, MRO inventory management, spare parts inventory management, service parts management Frequently asked questions: - **Which spare parts should you keep in stock?** Above all, parts are stocked whose failure stops a plant and whose replenishment takes longer than an acceptable downtime. Stock also makes sense for regularly consumed wear parts. Rarely needed parts that can be delivered quickly, on the other hand, are often not stocked. The decision is based on an assessment of criticality, consumption, replenishment lead time, price and shelf life. - **Which KPIs are important in spare parts management?** Key KPIs are the service level, i.e. the share of requests that can be met immediately, stock coverage, the share of stock without movement over a longer period and replenishment lead times. In addition, inventory value, turnover rate and the number of rush orders are monitored. Together, these values show whether availability and tied-up capital are in a sensible balance. - **What is the difference between spare parts management and spare parts procurement?** Spare parts procurement is the process of identifying a required part, finding a source of supply and ordering it. Spare parts management is more comprehensive: it determines which parts are needed at all, which are stocked, how master data is maintained and how discontinuations are handled. Procurement is thus one building block within spare parts management. #### Spare parts procurement URL: https://www.ktb-europe.com/en/glossary/spare-parts-procurement/ Spare parts procurement is the purchasing process for spare parts, from identifying the part through source and quotation to delivery. Spare parts procurement follows different rules from the procurement of series material. The requirement often arises unexpectedly, quantities are small and the part sought is not always clearly described. The process therefore starts with identification: manufacturer part number, nameplate, drawing, the machine's bill of materials or photos of the component. This is followed by the search for sources of supply. Besides the original manufacturer, authorised distributors, wholesalers, other users' stock, repaired parts or equivalent alternatives come into consideration. Quotations are compared by price, lead time, origin, condition and accompanying documents. For urgent requirements, lead time takes priority. Risks lie in confusing similar types, in counterfeits and in missing documentation. Incoming inspection, inspection certificates and traceable supply chains reduce these risks. For recurring requirements, it is worth recording the results of the research in the item master: verified sources of supply, alternative parts, lead times and required documents. This makes the next procurement of the same part much faster. In practice: An enquiry stating the manufacturer, complete part number, quantity, requested date and required documents saves follow-up questions. If the part number is missing, photos of the nameplate and the installation situation help. Also known as: spare parts purchasing, spare parts sourcing, spares procurement Frequently asked questions: - **What information belongs in a complete spare parts enquiry?** In addition to the manufacturer and complete part number, the quantity, required delivery date and necessary documents are important. Also helpful are the machine type and serial number, installation location, revision status and whether only new parts or also repaired or equivalent alternatives are acceptable. The clearer the enquiry, the easier it is to compare quotations from different sources. - **How does emergency procurement differ from planned purchasing?** When a plant is at a standstill, availability is what matters most and price takes a back seat. Several sources are contacted in parallel, approvals are shortened and in some cases repaired parts or alternatives are accepted. To ensure quality does not suffer, checks such as identity verification and document matching should be retained even in an emergency and documented afterwards. - **How can you recognise a reliable source of spare parts?** Important criteria are traceable origin of the goods, clear information on condition and manufacturer, available accompanying documents and a willingness to provide photos or test evidence before shipment. Transparent warranty terms and a contact person who can be reached also speak in favour of a source. Conspicuously low prices for otherwise hard-to-obtain parts, on the other hand, are a warning sign. #### Spare parts supply URL: https://www.ktb-europe.com/en/glossary/spare-parts-supply/ Spare parts supply means ensuring that required spare parts are available at the right time, in the right quality and in the right quantity. The term is used from two perspectives. From the plant operator's point of view, the aim is to be able to rectify failures quickly and carry out planned maintenance on schedule. From the manufacturer's point of view, spare parts supply describes the commitment to deliver parts for a certain period after the end of series production. In industry, such commitments are usually governed by contract and are not unlimited. Supply can be fed from various sources: in-house stock, the original manufacturer, distributors and wholesalers, third-party stock, the repair of defective parts or technically equivalent alternatives. The older a plant, the more important the alternative routes become, because manufacturers discontinue product lines or companies disappear from the market. Stable spare parts supply is based on complete master data, a criticality assessment, suitable stock rules and an overview of life-cycle notifications for the installed components. For plants built internationally in particular, supply is also a question of access to foreign sources of supply. In practice: For plants with a long service life, it is worth documenting manufacturers' supply commitments and deciding on stockholding or alternatives before they expire. This avoids shortages that only become apparent when a failure occurs. Also known as: spare parts availability, spares supply, spare parts provision, aftermarket parts supply Frequently asked questions: - **How long must manufacturers supply spare parts for industrial equipment?** For capital goods there is usually no general statutory obligation with a fixed duration. What counts are the commitments in the supply or service contract and the manufacturer's own statements. It is therefore worth recording in writing when purchasing equipment how long original or successor parts are to be available and how customers will be informed of an impending end of supply. - **How do you assess the spare parts supply for older equipment?** A proven approach is an inventory of the installed components with manufacturer part number, life cycle status, number of sources, stock level and replenishment lead time. From this, a simple traffic-light rating can be derived: uncritical, monitor or action required. Components with only one source, discontinued status and high importance for production are at the top of the list. - **What role does the repair of defective parts play in supply?** Repaired parts are an important additional source, especially for expensive or hard-to-obtain components such as motors, pumps, gearboxes or electronic assemblies. Removed parts are repaired, tested and returned to stock. What matters is whether repair is technically possible and economically sensible, and whether the repaired parts are documented with a test report and condition statement. #### Supply shortage URL: https://www.ktb-europe.com/en/glossary/supply-shortage/ A supply shortage exists when a material is not available in the required quantity or by the required date, putting supply at risk. A supply shortage is said to exist when demand for a part exceeds the available supply or delivery commitments cannot be met. It can affect a single component, an entire category or a raw material. Unlike a product discontinuation, the product is still being manufactured; it is only temporarily scarce. Causes include capacity limits at manufacturers, failures of upstream suppliers, raw material scarcity, sudden surges in demand, quality problems, political events or trade restrictions. A shortage is often recognisable from extended lead times, quotas imposed by the manufacturer (allocation), rising prices or postponed delivery dates. A shortage frequently affects several buyers at the same time, so that alternatives also quickly become scarce. For maintenance, a supply shortage is particularly critical if it affects a spare part without which a plant cannot continue running. Preventive measures include a deliberately sized safety stock for critical parts, approved second sources, framework agreements with call-off quantities and regular review of replenishment lead times. In acute cases, alternative parts, searching additional supply channels and repairing the defective part can help. In practice: When making enquiries during a shortage, the manufacturer part number, required quantity, latest required date and permissible alternatives should be clearly stated. Indicating early on whether partial quantities or equivalent parts from other manufacturers are acceptable considerably widens the search. Also known as: supply bottleneck, material shortage, component shortage, supply constraint Frequently asked questions: - **What should be done in the event of a supply shortage of spare parts?** First, it is clarified how long the existing stock will last and which plants are affected. Options can then be examined: approved alternative parts or second sources, additional authorised supply channels, transfers from other sites or repair of the defective part. Parts from unknown sources should be checked for authenticity and condition before installation. - **What is the difference between a supply shortage and a product discontinuation?** In a supply shortage, a product is still being manufactured but is temporarily not available in sufficient quantity or not in time. In a product discontinuation, the manufacturer permanently stops production. A shortage is therefore usually a timing problem, whereas a discontinuation requires a long-term solution such as a last time buy or a successor part. - **How can supply shortages be prevented?** Helpful measures are classifying parts by criticality, adequate safety stocks for critical items, qualified second sources, framework agreements with call-off quantities and ongoing monitoring of lead times and manufacturer notices. Reporting requirements to suppliers early also improves the chance of being given consideration when goods are scarce. #### Vendor managed inventory (VMI) URL: https://www.ktb-europe.com/en/glossary/vendor-managed-inventory/ Vendor managed inventory (VMI) is a model in which the supplier monitors stock at the customer's site and replenishes it independently. With vendor managed inventory, the supplier takes over the inventory planning for agreed items. It receives stock and consumption data from the customer, for example via electronic interfaces, scanners or regular stock counts, and triggers replenishment independently in order to maintain agreed minimum and maximum stock levels. The customer no longer has to initiate individual purchase orders for these items. Advantages are lower process costs, stable availability and often lower stock levels, because the supplier can smooth demand across several customers. Prerequisites are reliable data, clear KPIs such as service level and stock coverage, and trust, since the supplier gains insight into consumption. Unlike consignment stock, with VMI ownership usually passes on delivery and is then invoiced. Combinations of the two models are common. Access rights, data formats, response times and the handling of stock-outs must also be laid down in the contract so that responsibilities remain clear in day-to-day operations. In practice: VMI is particularly suitable for regularly consumed wear parts and C-parts. It is less suitable for rarely needed, critical individual parts, because consumption does not provide a reliable basis for planning. Also known as: VMI, supplier managed inventory (SMI), vendor-managed replenishment Frequently asked questions: - **How does vendor managed inventory work in practice?** Customer and supplier define items and minimum and maximum stock levels. The supplier regularly receives stock and consumption data, for example via an interface, scanners or on-site counts, and plans replenishments independently. The customer checks the deliveries at goods receipt and receives invoices, usually consolidated. KPIs such as service level and stock coverage are monitored jointly and discussed at regular intervals. - **What does vendor managed inventory require?** Unambiguous item master data, reliable stock recording and regular data exchange are needed. In addition, responsibilities, stock limits, response times and the handling of shortages must be set out in the contract. Trust is also important, as the supplier gains insight into consumption. The model works best for items with regular, readily predictable consumption. - **What are the benefits of VMI for customers?** Customers save effort for planning and individual orders because replenishment is triggered automatically. Availability of the agreed items becomes more stable, and stock can often be reduced, as the supplier plans quantities based on actual consumption. The number of ordering transactions and invoices also falls. However, the benefit depends on how well data and responsibilities work in day-to-day operations. #### Wear parts URL: https://www.ktb-europe.com/en/glossary/wear-parts/ Wear parts are components that wear out in normal operation through friction, load or ageing and are replaced at regular intervals. For these parts, wear is not a fault but a consequence of their function. Typical examples are seals, rolling bearings, filters, drive belts, carbon brushes, hoses, guide elements and cutting edges. Their service life depends on operating hours, load, temperature, lubrication and ambient conditions. Wear parts are a subset of spare parts. Spare parts in the broader sense also include parts that are only replaced after damage, such as shafts, housings or control modules. Wear parts, by contrast, are replaced in a plannable and recurring way, often at fixed intervals or based on condition. Contracts and manufacturers' terms often treat them separately, for example with regard to statutory warranty or guarantee. How this applies in an individual case depends on the contract; this entry does not constitute legal advice. For maintenance, wear parts are easy to plan. Consumption data can be used to derive maintenance intervals, order quantities and reorder points. Because they are needed regularly, they are well suited to being kept in stock permanently. Maintenance kits that bundle all the parts needed for a job also shorten downtime. In practice: Wear parts should be recorded in the master data with manufacturer part number, dimensions and material and bundled into maintenance kits. For elastomers such as seals and hoses, storage conditions and shelf life must be observed. Also known as: wearing parts, consumable parts, maintenance parts, fast-moving parts, wear and tear parts Frequently asked questions: - **What is the difference between wear parts and spare parts?** Spare parts is the umbrella term for all parts used to replace defective or worn components. Wear parts are the subset that wears out as planned in normal operation and is replaced regularly. Other spare parts, by contrast, are usually only needed after damage has occurred. - **Which parts typically count as wear parts?** These include above all seals, rolling bearings, filter elements, drive belts, carbon brushes, hoses, guides, coupling elements and cutting tools. Which parts count as wear parts in a given case is often specified by manufacturers in their operating instructions or spare parts list. Operating conditions and load are decisive. - **Does the statutory warranty also apply to wear parts?** Normal wear is generally not a defect. However, a wear part can be defective if it fails significantly earlier than would be expected under proper use. What applies in an individual case follows from the contract and the manufacturer's terms; legal advice provides a binding answer. - **How many wear parts should be kept in stock?** A guide value is derived from consumption per interval, the number of installed units and the replenishment lead time. For parts with regular consumption, the reorder point method with safety stock is suitable. For parts with limited shelf life, the quantity should be chosen so that it is used before the shelf life expires. #### XYZ analysis URL: https://www.ktb-europe.com/en/glossary/xyz-analysis/ XYZ analysis divides materials into three classes according to the regularity of their consumption: X for constant, Y for fluctuating and Z for irregular. XYZ analysis is a materials management method that classifies items according to the predictability of their demand. While ABC analysis looks at the share of value, XYZ analysis asks how evenly a part is consumed. The two are frequently combined into an ABC-XYZ matrix with nine fields. The basis is consumption figures over several periods, for example months. The measure usually used is the coefficient of variation, i.e. the standard deviation divided by the mean. A low value means even consumption (X), a medium value fluctuating consumption (Y), a high value sporadic consumption (Z). Each company sets the boundaries between the classes itself; there are no binding standard values. Spare parts fall strikingly often into the Z class, because they are only needed in the event of failures or planned repairs. Consumption-based ordering methods are poorly suited to them. Instead, stock levels are set according to criticality, the number of installed units and replenishment lead time. X parts such as filters or lubricants, by contrast, can be managed well via framework agreements, call-off orders or vendor managed inventory. In practice: For a meaningful XYZ analysis, consumption data over a sufficiently long period should be used and special effects such as major repairs considered separately. Z parts with high criticality do not automatically belong out of stock but require a deliberate stockholding decision. Also known as: XYZ classification, ABC-XYZ analysis, demand variability analysis Frequently asked questions: - **What is the difference between ABC and XYZ analysis?** ABC analysis classifies items according to their share of consumption value, i.e. how much money is tied up in them. XYZ analysis classifies them according to the regularity of consumption. Combined, the two produce a matrix from which ordering and stockholding strategies can be derived, such as tight control for AX parts and case-by-case decisions for CZ parts. - **How is XYZ analysis calculated?** For each item, consumption per period is recorded, the mean and standard deviation are calculated from this and the two are set in relation to each other. This coefficient of variation shows how strongly consumption fluctuates. The items are then assigned to classes X, Y or Z on the basis of self-selected thresholds. - **Why are many spare parts Z parts?** Spare parts are usually only needed when a component fails or is replaced during a planned repair. In between, there are often long periods without consumption. As a result, demand is hardly predictable statistically. For such parts, stock levels are better set according to criticality and replenishment lead time than according to a consumption forecast. ### Quality & Inspection #### AQL (acceptance quality limit) URL: https://www.ktb-europe.com/en/glossary/aql/ AQL (acceptance quality limit) is the quality level used in sampling inspection to decide whether a lot is accepted or rejected. The AQL value indicates what proportion of nonconforming units, as a process average, is still considered acceptable. It is at the core of sampling inspection to ISO 2859-1, which describes procedures for inspection by attributes: rather than checking every part, a sample drawn according to fixed rules is inspected. An important distinction: an AQL says nothing about individual parts and does not guarantee a defect-free lot. The lot size and inspection level give a code letter for the sample size. The general inspection levels I, II and III are common, along with special inspection levels for costly or destructive tests. For each AQL value, the table gives an acceptance number and a rejection number: if no more defects are found than the acceptance number, the lot is accepted; from the rejection number onwards it is rejected. Depending on supplier history, inspection switches between normal, tightened and reduced. In procurement, AQL is applied during incoming inspection and pre-shipment inspection. Separate AQL values are usually agreed for critical, major and minor defects. In practice: AQL values, inspection level and the classification of defects should be set out in writing in the purchase order or quality assurance agreement before inspection takes place. For safety-relevant spare parts, a sample is often not sufficient; here, 100 % inspection or inspection backed by an inspection document may be more appropriate. Also known as: acceptance quality limit, acceptable quality level, AQL sampling, ISO 2859-1, AQL inspection Frequently asked questions: - **What does AQL 2.5 mean?** AQL 2.5 means that a process average of 2.5 per cent nonconforming units is considered just acceptable. It does not follow that every lot may contain exactly that many defects. How many defects are permissible in the sample only follows from the lot size, the inspection level and the corresponding table in the standard. - **How do you determine the sample size according to AQL?** First, the code letter is determined from the lot size and the chosen inspection level. In the sampling plan of ISO 2859-1, this code letter leads to the sample size. Together with the agreed AQL value, the acceptance and rejection numbers are read off there. The usual starting point is general inspection level II with normal inspection. - **What is the difference between critical, major and minor defects?** Critical defects can lead to hazardous conditions or prevent functioning altogether; often no defect at all is tolerated for them. Major defects significantly impair fitness for use, minor defects hardly at all, for example small cosmetic flaws. As a rule, a separate AQL value is set for each defect class. - **Does an AQL inspection guarantee defect-free goods?** No. Sampling inspection works with probabilities: an accepted lot may still contain defective parts, and a good lot may occasionally be rejected. AQL inspection is an economical way of limiting risk, but it does not replace 100 % inspection where this is technically or safety-wise necessary. #### Calibration URL: https://www.ktb-europe.com/en/glossary/calibration/ Calibration is determining and documenting the deviation of a measuring instrument from a traceable reference standard under specified conditions. During calibration, a measuring instrument is compared with a more accurate reference instrument whose values are traced back to national or international standards through an unbroken chain. The result is the deviation found, together with the measurement uncertainty. An important distinction: calibration does not alter the instrument. The subsequent setting to reduce the deviation is called adjustment; legal metrological verification is a legally regulated inspection for certain measuring instruments, for example those used in trade. Typical items calibrated include pressure gauges, pressure transmitters, temperature sensors, flow meters, torque wrenches and quality assurance test equipment. The calibration interval is set by the operator, depending on manufacturer information, stress, criticality and previous stability. The calibration certificate documents measured values, deviations, measurement uncertainty and the reference standards used. Accredited laboratories work in accordance with ISO/IEC 17025 (DIN EN ISO/IEC 17025). In maintenance, calibration is part of test equipment management. Sensors that read incorrectly lead to control errors, quality deviations or unnecessary part replacement. When replacing a measuring instrument, it should be clarified whether it is supplied calibrated and whether a calibration certificate is required for in-house test equipment management. In practice: When ordering measuring and test equipment, state explicitly whether a factory calibration certificate or a certificate from an accredited laboratory is required, and for which measuring range. Calibration status and the next due date belong in the test equipment management system. Also known as: instrument calibration, factory calibration, accredited calibration, UKAS calibration, test equipment calibration Frequently asked questions: - **What is the difference between calibration, adjustment and legal verification?** Calibration determines and documents the deviation of a measuring instrument without altering it. Adjustment intervenes and sets the instrument so that the deviation is as small as possible. Legal verification is a mandatory inspection by weights and measures authorities or officially recognised bodies for measuring instruments whose use is governed by legal metrology law. - **How often does a measuring instrument need to be calibrated?** There is no universally valid interval. The operator sets it, taking into account manufacturer recommendations, operating conditions, required accuracy, criticality of the measurement and the results of previous calibrations. If an instrument shows stable values over several calibrations, the interval can be extended with justification; if deviations occur, it is shortened. - **What is an accredited calibration certificate?** It is issued by a calibration laboratory whose competence has been confirmed to ISO/IEC 17025 by an accreditation body, in Germany by DAkkS and in the UK by UKAS. The certificate states the metrological traceability and the measurement uncertainty. A manufacturer’s factory calibration certificate, by contrast, is not accredited but is sufficient for many applications. #### Complaint management (supplier claims) URL: https://www.ktb-europe.com/en/glossary/complaint-management/ Complaint management is the structured process by which companies record, assess, clarify with the supplier and eliminate defects in delivered goods. Complaint management covers every step from detecting a defect to eliminating it permanently. In purchasing, the focus is mainly on supplier complaints, that is, claims concerning delivered parts, such as the wrong version, dimensional deviations, damage, missing documents or functional faults. This is distinct from handling complaints from one’s own customers, even though both are structured in a similar way. A typical sequence: record and evidence the defect (photos, measured values, batch number), quarantine the affected parts, inform the supplier, agree on immediate actions, clarify the cause and follow up on corrective actions. For structured handling, the problem description, root cause analysis and actions are documented in a standardised report, which many companies request from the supplier. Between merchants, statutory obligations to inspect goods and give notice of defects also apply, the details of which are governed by the contract and commercial law; this entry does not constitute legal advice. In maintenance, rapid complaints are particularly important, because a defective spare part often only becomes apparent during installation, by which time a plant is already at a standstill. Analyses of complaints feed into supplier evaluation and supplier audits. In practice: Check spare parts at goods receipt at least for identity, quantity, damage and documents, so that defects can be reported early and with evidence. For every complaint, record the order number, manufacturer part number, batch or serial number and a precise description of the fault with photos. Also known as: supplier complaint, supplier claim, notice of defects, non-conformance report (NCR) Frequently asked questions: - **What should a supplier complaint include?** A complaint should include the order and delivery note numbers, item and manufacturer part numbers, the quantity of affected parts, the batch or serial number and a factual description of the fault. Photos, measurement records and details of when the defect was found make clarification easier. It should also state clearly what is expected, such as a replacement delivery, rework or a credit note, and by when. - **How can complaints be analysed meaningfully?** Complaints are collected by supplier, commodity group and type of fault and analysed regularly, for example as the share of rejected deliveries or the number of open cases. This makes recurring faults visible, such as wrong versions or missing documents. The results feed into supplier evaluation and provide a good basis for discussions about improvements or for a supplier audit. - **What is the difference between a complaint and a warranty?** Warranty refers to the buyer’s statutory rights in the event of a defect, such as subsequent performance or a price reduction. The complaint is the practical process by which the defect is notified to the supplier and resolved. Which rights apply in an individual case and which deadlines are relevant depends on the contract and the applicable law; legal advice should be sought where necessary. #### Counterfeit parts URL: https://www.ktb-europe.com/en/glossary/counterfeit-parts/ Counterfeit parts are parts with misrepresented origin, condition or specification, such as copies, relabelled parts or used parts sold as new. Components are considered counterfeit when they are offered with intent to deceive as something other than what they are. They must be distinguished from legitimate alternative parts that are openly sold as a compatible replacement by another manufacturer. Those most affected are electronic components, bearings, seals, control modules and high-value spare parts that have been discontinued or are in short supply. Typical forms are copies with imitated logos and labels, relabelled parts with altered type or performance data, and used, removed or refurbished parts sold as new. Counterfeits can be recognised, for example, by differing packaging, inconsistent markings, signs of rework, missing documents or conspicuously low prices. The risks range from premature failure and plant downtime to safety hazards and liability issues. The most effective prevention is sourcing through authorised or demonstrably qualified sources with full traceability back to the manufacturer. Clear document requirements in the purchase order and trained incoming inspection also help. For electronic components there are dedicated industry standards on counterfeit avoidance, for example from the aerospace sector. In practice: For discontinued parts from the open market, proof of origin, batch data and original packaging should be requested and specifically checked at goods receipt, where necessary with visual, dimensional or functional testing. Suspect parts are quarantined and not installed until their origin has been clarified. Also known as: counterfeit components, fake parts, product counterfeits, pirated parts, suspect counterfeit parts Frequently asked questions: - **How can you recognise counterfeit spare parts?** Indications include differing or damaged packaging, blurred or inconsistent markings, traces of sanding or paint on the surface, missing accompanying documents, implausible batch or date codes and a price well below market level. A reliable assessment often requires comparison with a reference part or a technical test. - **What is the difference between a counterfeit and an alternative part?** An alternative part is openly offered as a replacement by another manufacturer and bears that manufacturer's own marking; whether it is technically suitable must be checked. A counterfeit, by contrast, misrepresents the manufacturer, condition or specification. The decisive factor is therefore not the origin as such, but the false information. - **How can you protect yourself against counterfeit parts?** The most effective approach is sourcing through authorised distribution channels or qualified suppliers who can document the origin without gaps. This is complemented by clear document requirements in the purchase order, trained incoming inspection and a procedure for handling suspect parts, including quarantine and feedback to the supplier. - **Why do counterfeits occur especially with discontinued parts?** When a manufacturer no longer supplies a part, demand on the open market rises while supply falls. Counterfeiters exploit this gap with copies or refurbished used parts. Anyone who has to procure discontinued parts should therefore pay particular attention to proof of origin and inspections. #### EN 10204 (inspection documents) URL: https://www.ktb-europe.com/en/glossary/en-10204/ EN 10204 defines the types of inspection documents with which manufacturers of metallic products demonstrate compliance with the order. The standard EN 10204 (published in Germany as DIN EN 10204) specifies which inspection documents a manufacturer can provide to the purchaser and who confirms which information. It applies to metallic products, but in practice it is also agreed contractually for other products. It distinguishes in principle between non-specific inspection, carried out on products from the same production, and specific inspection on the product or lot actually delivered. There are four types. The declaration of compliance with the order 2.1 confirms compliance with the order without test results. The test report 2.2 additionally contains results of non-specific inspection. The inspection certificate 3.1 is based on specific inspection and is confirmed by the manufacturer's authorised inspection representative, who is independent of the manufacturing department. With the inspection certificate 3.2, a representative of the purchaser or an inspector designated by official regulations additionally confirms the results. The type of document is not supplied automatically; it must be specified in the purchase order. For spare parts for pressure equipment, valves or load-bearing components, it is often a prerequisite for use. In practice: The required type of inspection document should be stated explicitly in the spare parts enquiry, for example “inspection certificate 3.1 to EN 10204”. At goods receipt, a check is made that the certificate, material and marking on the part match. Also known as: DIN EN 10204, inspection documents to EN 10204, material certificate, mill test certificate (MTC), test report 2.2 Frequently asked questions: - **What is the difference between 2.2 and 3.1 to EN 10204?** The test report 2.2 contains test results from ongoing production that were not necessarily obtained on the product supplied. The inspection certificate 3.1 relates to specific inspection of the delivered lot and is confirmed by an authorised inspection representative independent of manufacturing. The 3.1 certificate can therefore be assigned more clearly to the material supplied. - **Who issues an inspection certificate 3.2?** A 3.2 certificate is confirmed jointly: by the manufacturer's authorised inspection representative and additionally by the purchaser's representative or an inspector named in official regulations. Because an external inspector is involved, the inspection must be planned early and agreed when the order is placed. - **Does a declaration of compliance with the order 2.1 contain test results?** No. With the declaration 2.1, the manufacturer merely confirms that the products supplied meet the requirements of the order. It contains no specific measured or test values. If values such as chemical composition or strength are required, at least a test report 2.2 or an inspection certificate must be ordered. - **Can an inspection document be requested afterwards?** Only to a limited extent. Specific certificates require inspection of the delivered lot and seamless traceability via the batch or heat number. If this data is not available or no inspection was carried out, the manufacturer often cannot issue the certificate retrospectively. The type of document therefore belongs in the purchase order. #### EU declaration of conformity URL: https://www.ktb-europe.com/en/glossary/eu-declaration-of-conformity/ The EU declaration of conformity is the manufacturer's declaration that its product meets all applicable EU harmonisation legislation. With the EU declaration of conformity, the manufacturer or its authorised representative takes responsibility for ensuring that a product meets the requirements of the relevant EU directives and regulations, for example on machinery, electrical equipment or electromagnetic compatibility. It is the basis for CE marking. Unlike a certificate, it is not confirmation by an independent body but a self-declaration by the manufacturer. Typical contents are the unambiguous identification of the product, the manufacturer's name and address, the legislation and harmonised standards applied, where applicable the notified body involved, and the place, date and signature. The exact mandatory information follows from the legislation concerned. For partly completed machinery intended for incorporation, EU machinery legislation requires not a declaration of conformity but a declaration of incorporation. For spare parts, whether a declaration of conformity is required at all depends on the product: a motor or valve with its own function may fall under it, a simple standard part usually does not. In practice: For spare parts bearing CE marking, the declaration of conformity should be requested with the quotation or at the latest with delivery and checked against the nameplate and item description. In the case of modifications or replacement with differing parts, it must be checked whether the plant's existing declaration remains valid. Also known as: EC declaration of conformity, declaration of conformity, DoC, CE declaration, EU DoC Frequently asked questions: - **Is an EU declaration of conformity a certificate?** No. The declaration of conformity is a declaration with which the manufacturer itself confirms that its product complies with EU law. A certificate, by contrast, is issued by an independent body, such as a notified body after type examination. Such a certificate may be part of the conformity assessment procedure, but it does not replace the manufacturer's declaration. - **Who issues the EU declaration of conformity?** It is issued by the manufacturer or by its authorised representative established in the EU. Anyone who places a product on the market under their own name or substantially modifies it may take on manufacturer obligations themselves. Distributors generally do not issue their own declaration, but must check that the required documents are available. - **What is the difference between a declaration of conformity and a declaration of incorporation?** The declaration of conformity applies to complete products that meet all requirements and bear the CE marking. The declaration of incorporation is issued for partly completed machinery that is to be incorporated into another machine. It states which requirements have already been met; the conformity of the complete machine is later declared by its manufacturer. - **What information does an EU declaration of conformity contain?** It usually contains the name and identification of the product, the manufacturer's name and address, the statement of sole responsibility, the EU legislation and standards applied, information on the notified body where applicable, and the place, date and signature. The specific mandatory information is laid down by the directive or regulation concerned. #### FMEA (failure mode and effects analysis) URL: https://www.ktb-europe.com/en/glossary/fmea/ FMEA (failure mode and effects analysis) is a preventive method for systematically assessing the potential failures of a product or process. FMEA analyses how a component, an assembly or a process step can fail, what consequences this has and which causes lie behind it. The aim is to identify risks before failures occur and to derive countermeasures. The general procedure is described in the international standard IEC 60812. The main distinction is between product or design FMEA and process FMEA. An interdisciplinary team considers the failure mode, failure effect and failure cause for each element. Traditionally, the severity of the effect, the probability of occurrence and the probability of detection are each rated on a scale; their product gives the risk priority number (RPN). Other approaches prioritise using rating tables, because the RPN can make very different risks numerically equal. The result is a set of actions for prevention or better detection, with owners and deadlines. In maintenance, FMEA is used to identify the critical components of a plant, for example as part of reliability-centred maintenance. This yields maintenance tasks, inspection intervals and the question of which spare parts should be held in stock. The FMECA variant extends the analysis with an explicit assessment of criticality. In practice: For spare parts planning, a cross-check is worthwhile: components with severe failure effects and long replacement lead times belong on the list of critical spare parts. Failure data from the maintenance history improves the rating of the probability of occurrence. Also known as: failure mode and effects analysis, FMECA, process FMEA (PFMEA), design FMEA (DFMEA) Frequently asked questions: - **What is the difference between product FMEA and process FMEA?** Product or design FMEA examines how a component or system can fail because of its design, for example due to unsuitable materials or tolerances. Process FMEA looks at the manufacturing or assembly steps and asks where failures can arise there. Both use the same methodology but start at different points. - **How is the risk priority number (RPN) calculated?** The RPN is the product of three ratings: severity of the failure effect, probability of occurrence and probability that the failure is detected before it has an effect. Each factor is usually rated on a scale of 1 to 10. A high RPN indicates a need for action but should not be the sole deciding factor, as severe effects always deserve attention. - **How is FMEA used in maintenance?** Maintenance teams use it to analyse which components of a plant can fail, in what way, and how serious the consequences are for safety, production and the environment. From this, servicing and inspection tasks, inspection intervals and stocking decisions for spare parts are derived. FMEA is often a building block of reliability-centred maintenance. #### Grey market (spare parts) URL: https://www.ktb-europe.com/en/glossary/grey-market/ The grey market is trade in genuine goods outside the distribution channels authorised by the manufacturer, for example through independent dealers or surplus stock. Grey market goods are essentially genuine manufacturer products that reach the market not through official distribution but through other channels: surplus stock from users, leftover stock from projects, goods from other countries or independent brokers. These must be clearly distinguished from counterfeits, that is, imitated or relabelled parts, which do, however, turn up more often on the grey market than in authorised distribution. Grey market trading is not automatically unlawful; whether trade mark or distribution law is affected in an individual case can only be assessed on the specific facts. For spare parts, the grey market is often the only source when a component has been discontinued and the manufacturer no longer supplies it. Risks include unclear origin, unknown storage duration and conditions, no manufacturer warranty, outdated firmware or build status, and counterfeit parts. Electronic components, controllers and drives are particularly affected. Professional procurement therefore assesses grey market sources like any other supplier, requires proof of origin and inspects the goods at goods receipt specifically for authenticity, completeness and condition before they are stored or installed. In practice: If you obtain a discontinued part from independent sources, ask about its origin, date code, original packaging and storage conditions, and request photos before delivery. Compare the nameplate and markings with a known genuine part and test critical components before installation. Also known as: grey market goods, gray market (US), parallel market, open market, broker market Frequently asked questions: - **Are grey market goods legal?** Grey market goods are generally genuine products, and trading them is not prohibited as a matter of principle. Depending on origin, trade mark law and distribution agreements, there may nevertheless be legal restrictions in individual cases, for example for goods originally intended for markets outside the EU. For a binding assessment, qualified legal advice should be sought; this entry does not constitute legal advice. - **What is the difference between the grey market and counterfeits?** Grey market goods come from the original manufacturer but are traded outside the authorised distribution channels. A counterfeit, by contrast, is an imitated, relabelled or refurbished part that is passed off as new. As both are offered through similar channels, the difference can often only be recognised through proof of origin and careful inspection of the goods. - **How can reputable suppliers of grey market spare parts be recognised?** Reputable suppliers state the origin of the goods, provide photos and date codes before delivery, offer their own warranty and have a transparent returns procedure. Documented inspection processes in the supplier’s goods receipt and references are helpful. Caution is advised with prices far below market level, a missing company address or payment in advance without security. #### Incoming inspection URL: https://www.ktb-europe.com/en/glossary/incoming-inspection/ Incoming inspection checks delivered goods for quantity, identity, external damage, documents and agreed quality characteristics. Inspection at goods receipt usually consists of two stages. First, the delivery is checked against the delivery note and purchase order: do the number of packages, items, quantities and labelling match, and is the packaging undamaged? Where required, a qualitative inspection follows, such as a visual check, dimensional check, functional test or comparison with inspection certificates and drawings. Scope and sampling are often specified in inspection plans. Legally, incoming inspection is significant in commercial sales between merchants. Under Section 377 of the German Commercial Code (HGB), the buyer must examine the goods without undue delay after delivery and notify recognisable defects without undue delay; if it fails to do so, the goods are deemed approved with regard to those defects. Different arrangements in quality assurance agreements are possible. For spare parts, there is also the identity check: does the delivered part correspond exactly to the version ordered, including manufacturer part number, revision level and marking? The inspection results should ideally feed into supplier evaluation. In practice: For critical spare parts, a documented inspection with photos of the nameplate and packaging is worthwhile. This allows discrepancies to be clarified quickly before the part is installed or put into stock. Also known as: goods receipt inspection, incoming goods inspection, receiving inspection, incoming quality control (IQC) Frequently asked questions: - **How quickly must defects be notified after goods receipt?** In commercial sales between merchants, the German Commercial Code (HGB) requires inspection and notification of defects without undue delay; the law does not specify a fixed period in days. What counts as without undue delay in an individual case depends on the goods and the circumstances, and quality assurance agreements may contain different rules. This note does not constitute legal advice; in case of doubt, the legal department should be consulted. - **What is the difference between incoming inspection and quality inspection?** Incoming inspection is a specific point in the process, namely the check carried out directly after delivery to the customer. Quality inspection is the umbrella term for all checks against a specification, regardless of where they take place. An incoming inspection can therefore include a quality inspection, but in many cases it is limited to quantity, identity, condition and documents. - **How should an incoming inspection be documented?** An inspection record should contain at least the date, inspector, purchase order and delivery note numbers, characteristics checked, findings and decision. Photos of the packaging, nameplate and any anomalies make later complaints easier. Goods with deviations are labelled and quarantined until a decision has been made on acceptance, rework or return. #### Inspection certificate 3.1 (EN 10204) URL: https://www.ktb-europe.com/en/glossary/inspection-certificate-3-1/ The inspection certificate 3.1 to DIN EN 10204 confirms test results on the delivered product, signed by an inspector independent of production. DIN EN 10204 defines types of inspection documents for metallic products; in practice it is also agreed for other components. It distinguishes between non-specific documents, which are based on tests on similar products, and specific documents, which relate to the lot actually delivered. The inspection certificate 3.1 is a specific document. In it, the manufacturer confirms that the products supplied meet the requirements of the order and states the test results, such as chemical composition, mechanical properties or dimensions. It is signed by the manufacturer's authorised inspection representative, who is independent of the manufacturing department. With the inspection certificate 3.2, a representative of the purchaser or an inspector designated by official regulations additionally confirms the results. By way of distinction: the declaration of compliance with the order 2.1 contains no test results, and the test report 2.2 contains non-specific results. A 3.1 certificate can only be clearly assigned to the component via its marking, such as the heat or batch number. In practice: The required type of inspection document must be stated in the purchase order; a 3.1 certificate requested afterwards is often no longer obtainable. At goods receipt, the batch number on the certificate should be checked against the marking on the part. Also known as: 3.1 certificate, EN 10204 3.1, mill test certificate (MTC), material certificate 3.1 Frequently asked questions: - **Who may issue an inspection certificate 3.1?** It is issued by the manufacturer of the product and signed by its authorised inspection representative, who is independent of manufacturing. Distributors and intermediaries do not issue their own 3.1 certificate but pass on the manufacturer's certificate unchanged. If material is processed further, for example cut to size, it is important that the marking is transferred so that the link to the original certificate is retained. - **When is an inspection certificate 3.2 required instead of 3.1?** A 3.2 certificate is required above all when regulations or the purchaser demand additional, independent confirmation, for example for safety-relevant components or certain pressure equipment. Because a representative of the purchaser or an independent expert takes part in the inspection, this must be agreed and scheduled in advance. As a rule, this costs time and additional money. - **Are 3.1 certificates also required for spare parts?** Often yes, especially in industries with high requirements for material traceability, for example in chemicals, pressure equipment, power plants or food processing. A spare part is usually subject to the same documentation requirements as the original part. Since certificates can hardly be obtained afterwards, it should be clarified before ordering goods from a distributor whether the manufacturer's certificate is available. #### Non-destructive testing (NDT) URL: https://www.ktb-europe.com/en/glossary/non-destructive-testing/ Non-destructive testing (NDT) covers methods used to examine components for defects such as cracks or porosity without damaging them. Non-destructive testing (NDT) methods examine materials and components without impairing their fitness for use. Unlike destructive testing, such as a tensile or notched-bar impact test on a specimen, the tested part can continue to be used afterwards. NDT is used in manufacturing, at goods receipt and in the periodic inspection of plant. Common methods include visual testing (VT), penetrant testing (PT) for surface cracks, magnetic particle testing (MT) for ferromagnetic materials, ultrasonic testing (UT) for internal defects and wall thicknesses, radiographic testing (RT) with X-rays or gamma rays, and eddy current testing (ET). Which method is suitable depends on material, geometry, type of defect and accessibility. Testing personnel are often qualified and certified to ISO 9712 (DIN EN ISO 9712). In maintenance, NDT is used to detect damage to shafts, welds, vessels or pipework at an early stage and to decide between repair and replacement. For spare parts, especially castings, forgings or welded parts, NDT can be part of acceptance and is then documented in the inspection certificate. In practice: If you require NDT for a spare part, specify the method, scope of testing, acceptance standard and required documentation in the enquiry. Without this information, quotations are hardly comparable, and the test report will later not match your acceptance requirement. Also known as: NDT, non-destructive examination (NDE), non-destructive evaluation, non-destructive inspection (NDI) Frequently asked questions: - **What non-destructive testing methods are there?** The most important methods are visual testing, penetrant testing, magnetic particle testing, ultrasonic testing, radiographic testing and eddy current testing. Surface methods such as penetrant and magnetic particle testing find open cracks, while volumetric methods such as ultrasonic and radiographic testing also find internal defects. Methods such as thermography or acoustic emission testing are used in addition, depending on the component and the question to be answered. - **What is the difference between destructive and non-destructive testing?** In destructive testing, a specimen is loaded until it fails, for example in a tensile, bend or notched-bar impact test. This yields material properties, but the specimen is then unusable. Non-destructive testing, by contrast, examines the component itself for defects without damaging it. The two approaches complement each other: material properties usually come from destructive tests, freedom from defects from NDT. - **When is ultrasonic testing used?** Ultrasonic testing is suitable for finding internal defects such as lack of fusion, shrinkage cavities or inclusions in welds, forgings and plates. It is also used to measure wall thicknesses, for example on vessels and pipework, in order to monitor corrosion loss. The method requires a couplant and well-prepared surfaces, and evaluation calls for qualified personnel. #### Pre-shipment inspection (PSI) URL: https://www.ktb-europe.com/en/glossary/pre-shipment-inspection/ Pre-shipment inspection (PSI) is an inspection of goods at the supplier's site before dispatch so that deviations are detected before delivery. In a pre-shipment inspection, the finished goods ready for dispatch are inspected at the supplier's location before they leave the factory. Typical inspection points are the quantity, identity and version of the items, marking and nameplates, workmanship and external condition, random dimensional and functional checks, packaging and the completeness of the accompanying documents. The advantage lies in the timing. Errors can be corrected with little effort before shipment; after arrival at the customer, by contrast, return and replacement delivery are lengthy and expensive, especially for deliveries from abroad. The inspection is frequently carried out by independent inspection bodies or by the buyer itself, often using sampling plans in accordance with ISO 2859-1. There is also officially mandated pre-shipment inspection: some importing countries require a conformity inspection before shipment for certain goods as a prerequisite for customs clearance. Which programmes apply depends on the destination country and the product category. In practice: For spare parts with long lead times, inspection before shipment prevents a wrong version from being discovered only weeks later. Inspection scope and acceptance criteria should already be specified in the purchase order. Also known as: PSI, pre-dispatch inspection, final random inspection (FRI), pre-shipment check Frequently asked questions: - **When is a pre-shipment inspection worthwhile?** It is particularly useful with new or little-known suppliers, high order values, custom-made items and parts with long replenishment lead times. Inspection on site also provides certainty when a defect would only become apparent during installation or a complaint over a long distance would be difficult. For low-value standard parts from known sources, the effort is often disproportionate. - **What does a pre-shipment inspection report contain?** An inspection report typically contains the order reference, inspection date and location, scope of inspection and sample size, the characteristics checked, deviations found with classification by severity, photos and an overall result such as pass or fail. On this basis, the buyer decides whether the goods are released, reworked or re-inspected. - **Does a pre-shipment inspection replace incoming inspection?** Not completely. The inspection at the supplier covers workmanship and condition at the time of inspection. At goods receipt, it still has to be checked whether the inspected goods have arrived complete and undamaged and match the documents. However, the scope of the incoming inspection can be reduced considerably after a passed pre-shipment inspection. #### Quality inspection URL: https://www.ktb-europe.com/en/glossary/quality-inspection/ A quality inspection determines whether a product meets the specified requirements for dimensions, material, function, marking and documentation. Quality inspections take place at various points in the supply chain: during the manufacturer's production, before shipment at the supplier's premises, at the customer's goods receipt or before installation. Inspection is carried out against a specification, for example a drawing, data sheet, standard or quality assurance agreement. Types of inspection range from visual inspection and dimensional and weight checks to functional tests, material testing and non-destructive methods such as ultrasonic or dye penetrant testing. Depending on the risk, every part is inspected or a sample is taken according to defined rules, for example under ISO 2859-1 with an agreed AQL value. The results are documented in inspection reports or inspection certificates in accordance with DIN EN 10204. It is important to separate inspection from assessment: the inspection provides measured values and findings, while the decision on acceptance, rework or return is made by the person responsible on the basis of the agreed criteria. In practice: For spare parts from unknown or new sources, the scope of inspection should be set higher than for established suppliers. Photos, dimensional reports and copies of the marking provide a sound basis for release. Also known as: quality control (QC), product inspection, goods inspection, QC inspection Frequently asked questions: - **What is the difference between 100 % inspection and sampling inspection?** In 100 % inspection, every single part is checked. This is laborious but customary for safety-relevant parts or small quantities. In sampling inspection, only part of the lot is examined and a decision is made on the whole lot on the basis of defined acceptance criteria. It saves effort but accepts an agreed residual risk that defective parts go undetected. - **What non-destructive testing methods are there?** Common methods include visual inspection, dye penetrant testing and magnetic particle testing for surface cracks, ultrasonic and radiographic testing for internal defects, and eddy current testing for conductive materials. Which method is suitable depends on the material, component shape and type of defect sought. The tested part remains undamaged and can be used afterwards. - **Who decides what is checked in a quality inspection?** As a rule, the purchaser, by setting out requirements in the purchase order, drawing, specification or quality assurance agreement. From this, an inspection plan is drawn up with characteristics, test methods, sample size and acceptance criteria. If there are no clear specifications, each party inspects at its own discretion, which can easily lead to disputes about deviations later. #### Supplier audit URL: https://www.ktb-europe.com/en/glossary/supplier-audit/ A supplier audit is a systematic on-site examination at a supplier, in which a customer assesses quality capability, processes and reliability. In a supplier audit, a buyer checks whether an existing or prospective supplier can meet its requirements on a lasting basis. Technically, it is a second-party audit: the customer audits the supplier itself or commissions a third party to do so. It is distinct from internal audits (first party) and from certification audits by independent bodies (third party). ISO 19011 (DIN EN ISO 19011) provides recognised guidelines for conducting audits. Three types are common: the system audit looks at the management system as a whole, the process audit at individual processes such as production, inspection or storage, and the product audit at whether finished parts conform to drawing and specification. Procedure: planning with a checklist, execution on site or as a remote audit, a report with findings and finally a corrective action plan whose implementation is followed up. The result often feeds into a classification of the supplier. In spare parts procurement, audits are particularly worthwhile for suppliers that deliver critical or safety-related parts, manufacture to drawing, or are to be qualified as a second source for discontinued components. The audit then examines, for example, incoming inspection, traceability, storage conditions and the handling of non-conforming parts. In practice: Plan audits on a risk basis: suppliers of critical spare parts and new sources first, rather than all suppliers across the board. Define in advance which evidence (inspection records, certificates, calibration records) is to be reviewed on site, and agree binding deadlines in the action plan for any findings. Also known as: supplier quality audit, second-party audit, on-site supplier assessment, supplier process audit Frequently asked questions: - **What is the difference between a supplier audit and supplier evaluation?** Supplier evaluation assesses a supplier continuously using key figures such as delivery reliability, quality and price, mostly from existing data. A supplier audit, by contrast, is a targeted examination on site or as a remote audit that looks directly at processes and evidence. Audits often provide the basis for an initial evaluation or clarify anomalies found in ongoing evaluation. - **What types of supplier audit are there?** A distinction is usually made between system audits, process audits and product audits. The system audit examines the management system as a whole, the process audit individual processes such as production or inspection, and the product audit whether parts conform to the specification. Depending on the reason, an audit can be announced, short-notice or remote, with document review and a video walk-through. - **How does a supplier audit work?** First, the scope, date and checklist are defined and communicated to the supplier. On site there is an opening meeting, a walk-through, interviews and a review of documents and records. Findings are discussed at the closing meeting. The audit team then prepares a report, the supplier submits a corrective action plan and its implementation is followed up, with a follow-up audit if necessary. - **When is a supplier audit worthwhile?** An audit is worthwhile above all when approving new suppliers, for parts with a high failure or safety risk, after repeated complaints, or when production is relocated to another site. For non-critical catalogue parts, a self-assessment with supporting evidence is often sufficient. The key is to align the effort with the risk of the part concerned. #### Traceability URL: https://www.ktb-europe.com/en/glossary/traceability/ Traceability is the ability to follow the origin, processing and whereabouts of a part or material completely by means of unique identification. Traceability answers two questions: where does a part come from, including its materials and preliminary products, and where was it installed or delivered to? A distinction is made between backward tracing to the origin and forward tracing to the user. Common quality management standards require organisations to identify outputs uniquely and to ensure traceability where it is required. The basis is unique identification, for example a batch or lot number, serial number, heat number for materials or date of manufacture. This identifier must appear on the part or its packaging and recur in documents such as the delivery note, inspection record or mill certificate to EN 10204 (DIN EN 10204). Depending on requirements, traceability extends to the batch or to the individual item. For maintenance and spare parts procurement, traceability is important in order to narrow down affected parts quickly in the event of a quality problem, carry out recalls in a targeted way and prove the authenticity of a component. For pressure-bearing, safety-related or food-contact components, it is often required by contract or regulation. In practice: When ordering critical parts, specify explicitly which identifier (batch, serial number, heat) and which documents must be supplied. Record this data at goods receipt and on installation in the maintenance system; otherwise the chain ends in your own warehouse. Also known as: tracking and tracing, batch traceability, lot traceability, product traceability Frequently asked questions: - **What is the difference between traceability and tracing?** Traceability describes the ability of a system to follow the origin and whereabouts of parts. Tracing is the actual process in which this ability is used, for example when all parts of a particular batch are searched for after a fault. Without identification and documentation set up in advance, rapid tracing is hardly possible in an emergency. - **What is the difference between a batch number and a serial number?** A batch number groups many parts that were made under the same conditions and from the same material. A serial number, by contrast, identifies each individual item. Batch traceability is often sufficient for standard parts, seals or materials. For devices such as drives, sensors or controllers, serial numbers are usual, because they also allow the build status and test data to be assigned. - **Which documents prove the traceability of a spare part?** Typical evidence includes the delivery note and invoice with batch or serial number, inspection documents to EN 10204, the manufacturer’s test records and, where needed, proof of origin along the supply chain. It is important that the identifier on the part, packaging and document matches. Discrepancies should be clarified at goods receipt before the part is stored or installed. ### Foreign Trade & Customs #### Certificate of origin URL: https://www.ktb-europe.com/en/glossary/certificate-of-origin/ A certificate of origin proves the country in which goods were produced under non-preferential origin rules; in Germany it is issued by the IHK. The certificate of origin proves the non-preferential origin of goods. The rules for this are laid down in the Union Customs Code: goods originate in the country in which they were wholly obtained or produced, or where they underwent their last substantial, economically justified processing or working. This origin is decisive for trade policy measures such as anti-dumping duties, import restrictions or embargoes. Many importing countries require a certificate of origin for customs clearance, and it is also frequently demanded under letters of credit. In Germany, the Chambers of Industry and Commerce (IHK) issue certificates of origin at the exporter's request, now predominantly electronically. They are based on information and evidence provided by the applicant, such as supplier's declarations or manufacturer information. This must be distinguished from preferential origin. It is evidenced by proofs of preferential origin such as the EUR.1 movement certificate or a statement on origin and enables reduced customs duties under free trade agreements. In practice: For spare parts sourced via distributors, the origin is often not immediately known. Origin details and, where applicable, supplier's declarations should therefore be requested with the quotation if the part is to be exported. Also known as: CO, non-preferential certificate of origin, proof of origin, origin certificate Frequently asked questions: - **Is “Made in …” on a part the same as a certificate of origin?** No. The “Made in …” label is the manufacturer's indication of origin. The certificate of origin is an officially issued document that certifies origin according to customs rules. The two often coincide, but need not, for example when a product has been assembled from components from different countries. For customs purposes, only the origin under customs law is decisive. - **What documents are needed for a certificate of origin?** Usually the completed application, the commercial invoice and evidence of the origin of the goods, such as supplier's declarations, manufacturer information or, for in-house production, documents on working or processing. The issuing body checks the information for plausibility. Applicants can find out which evidence is required in an individual case from the competent chamber of commerce (IHK). - **Can a distributor apply for a certificate of origin for goods made by another company?** Yes, in principle the exporter is entitled to apply, even if it did not manufacture the goods itself. However, it must be able to prove the origin, usually with information or declarations from its supplier. If these are missing, the certificate of origin cannot be issued. The competent chamber or the customs authorities provide binding information on the requirements. #### Customs tariff number (HS code) URL: https://www.ktb-europe.com/en/glossary/customs-tariff-number/ The customs tariff number assigns goods to a heading in the customs tariff and determines the duty rate, import charges and possible restrictions. The basis is the World Customs Organization's Harmonized System (HS), which classifies goods uniformly worldwide using six digits. The EU extends this to eight digits in the Combined Nomenclature; this commodity code is used, among other things, for exports and in foreign trade statistics. For imports into the EU, further digits are added in TARIC, and in Germany an eleven-digit code number is stated in the import declaration. Classification follows fixed rules of interpretation and is based on the nature and intended use of the goods. For machine parts it is not always clear-cut: a part may have to be classified as a specific machine part or as a general product, such as a bearing, valve or seal. Legal certainty is provided by binding tariff information (BTI) from the German customs administration. The customs tariff number determines the customs duty rate, import VAT, possible anti-dumping duties, licensing requirements and preferential treatment. Incorrect classification can lead to back payments and delays. In practice: The customs tariff number describes a product group, not a specific component, and does not replace a manufacturer part number. Both details should be kept separately in master data and quotations to avoid confusion. Also known as: HS code, commodity code, CN code, TARIC code, tariff code Frequently asked questions: - **How do you find the correct customs tariff number for a spare part?** One starting point is the German customs administration's electronic customs tariff, in which headings can be searched by keyword and chapter. Information from the manufacturer, who has often already determined the number for its own exports, is also helpful. Decisive, however, are the General Rules for the Interpretation of the Nomenclature. In case of doubt, the customs authorities provide binding information. - **What is binding tariff information?** Binding tariff information (BTI) is a decision by the customs authorities on the classification of a specific product. It is issued on application, binds the customs authorities throughout the EU in respect of the holder and is valid for a limited period. It is particularly useful for recurring imports where classification is disputed or relevant to duties. - **Do spare parts have the same customs tariff number as the machine?** Not necessarily. Parts that have their own heading in the customs tariff are classified there, even if they are intended for a particular machine. Rolling bearings, for example, fall under their own heading, as do many valves, motors and pumps. Only parts without their own heading are classified as parts of the machine concerned. In an individual case, the information provided by the customs authorities is binding. #### Dual-use goods URL: https://www.ktb-europe.com/en/glossary/dual-use-goods/ Dual-use goods are goods, software and technology that can be used for both civil and military purposes and are therefore subject to export control. The term describes items with a dual purpose. In the EU, Regulation (EU) 2021/821 governs the control of their export, brokering, technical assistance and transit. Its core is Annex I, the list of items subject to authorisation. Exporting listed items from the EU generally requires a licence, which in Germany is applied for from the Federal Office for Economic Affairs and Export Control (BAFA). Annex I is divided into ten categories, such as materials, materials processing, electronics, computers, telecommunications, sensors and aerospace. Each entry has a control list number and technical parameters. Common industrial goods may also be affected, for example certain machine tools, corrosion-resistant pumps and valves, measuring equipment or controllers, if they meet the stated performance characteristics. Whether an item is covered therefore depends on its technical data, not on the product name. The exporter is responsible for classification. Manufacturers often state an export control classification number or a declaration that the item is not listed. In an individual case, the information provided by BAFA is binding; this entry does not constitute legal advice. In practice: For spare parts for machines that are exported, the dual-use classification should be requested from the manufacturer and recorded in the item master. Spare parts and software for listed equipment may themselves be listed. Also known as: dual-use items, Dual-Use Regulation, export control classification number (ECCN), Annex I, goods with a dual purpose Frequently asked questions: - **How can you tell whether an item is dual-use?** The technical data of the item are compared with the entries in Annex I of the Dual-Use Regulation. Parameters such as accuracy, performance or material are decisive, not the product name. The manufacturer's information on the control list number often helps. In case of doubt, a ruling on the control list can be requested from BAFA. - **Who is responsible for classifying dual-use goods?** The exporter is responsible, i.e. the company exporting the goods. It may rely on information from the manufacturer but must check it for plausibility and document it. Incorrect classification can lead to unlicensed exports. In case of doubt, the information provided by the competent authority is binding. - **Are spare parts affected by dual-use rules?** Yes, this is possible. Spare parts, components and software may have their own list entries or be intended for listed equipment. Whether they require a licence depends on the specific part and the list entry. The classification should therefore also be checked for spare parts, not just for complete machines. - **What is the difference between dual-use goods and military goods?** Military goods are specially designed for military purposes and in Germany are covered mainly by Part I Section A of the national export list. Dual-use goods are essentially civil products that can also be used for military purposes. Licensing requirements apply to both, but on different legal bases. #### ECCN (Export Control Classification Number) URL: https://www.ktb-europe.com/en/glossary/eccn/ The ECCN (Export Control Classification Number) is the five-character US export control number that assigns an item to an entry on the Commerce Control List. The ECCN comes from the US Export Administration Regulations (EAR), which are administered by the Bureau of Industry and Security (BIS) within the US Department of Commerce. It assigns an item to an entry on the Commerce Control List (CCL). Goods that are subject to the EAR but not covered by any list entry are classified as EAR99. The number consists of five characters: the first digit (0 to 9) denotes the category, such as electronics or computers, the letter denotes the product group from A (systems and components) to E (technology), and the following digits identify the specific entry. The ECCN and the country of destination determine whether a US licence is required for export or re-export. The structure is similar to the EU dual-use list but does not match it completely. The ECCN is relevant for European companies because US law can also apply to the re-export of goods of US origin or with certain US content. Manufacturers of electronics, controllers and measuring equipment therefore often state the ECCN in their data sheets. For EU exports, the binding classification is the one under EU law, handled in Germany by the Federal Office for Economic Affairs and Export Control (BAFA); for US law, the US authority is decisive. This entry does not constitute legal advice. In practice: For electronic spare parts, ask the supplier for the ECCN and the EU export list number in addition to the customs tariff number, and store both in the item master. This makes it quick to check, before onward delivery abroad, whether a licence might be required. Also known as: Export Control Classification Number, US export control number, CCL number, EAR99 Frequently asked questions: - **What does EAR99 mean?** EAR99 is the classification for items that are subject to US export law but not listed in any entry on the Commerce Control List. This includes many ordinary industrial goods. EAR99 does not mean that every shipment is unrestricted: for certain countries of destination, listed recipients or critical end uses, a US licence may still be required. - **What is the difference between an ECCN and a customs tariff number?** The customs tariff number is used for tariff classification, that is, for determining duty rates and for statistics. The ECCN, by contrast, classifies an item for export control purposes under US law and shows whether an export may require a licence. Both numbers describe the same goods from different perspectives and cannot be converted into one another. - **Does the ECCN also apply to deliveries within the EU?** For exports from the EU, EU export control law applies first, with its own list of items. However, US law may apply in addition if goods are of US origin or contain US technology and are exported onwards. The ECCN helps to assess this risk. If in doubt, manufacturers, BAFA or specialist advisers should be consulted; this entry does not constitute legal advice. #### End-use certificate (end-user statement) URL: https://www.ktb-europe.com/en/glossary/end-use-certificate/ An end-use certificate is the recipient’s confirmation of the end user, intended use and final destination of goods, usually in the context of export control. With an end-use certificate, also known as an end-use statement or end-user certificate, the recipient of an export declares who will ultimately use the goods, what they will be used for and in which country they will remain. It often contains an undertaking not to pass the goods on without consent and not to use them for prohibited purposes. A distinction is made between official end-use documents, issued by an authority in the recipient country, and private end-use statements by the end user. In Germany, the Federal Office for Economic Affairs and Export Control (BAFA) requires an end-use certificate for many licence applications for listed goods and provides templates for this purpose. Even where no licence is required, companies use such statements to document their due diligence in checking the end use. For spare parts for plants abroad, such as controllers, drives or measuring instruments with a dual-use connection, an end-use certificate may be a prerequisite for delivery. The form and content required in an individual case are determined by the competent authority; its information is binding, and this entry does not constitute legal advice. In practice: When parts are needed abroad, clarify early whether an end-use certificate is required for the spare part, as obtaining the end user’s signature can take time. Make sure the details of the end user, the site and the plant in which the part will be used are complete. Also known as: end-user certificate (EUC), end-use statement, end-user undertaking, EUC Frequently asked questions: - **When is an end-use certificate needed?** An end-use certificate is needed above all when a licence is applied for to export listed goods and the authority wants proof of the end use. Companies also request one voluntarily when the goods or the destination country present an increased risk. Whether it is mandatory in a specific case follows from the requirements of the competent authority, in Germany usually BAFA. - **Who issues the end-use certificate?** The private end-use statement is signed by the end user of the goods, that is, the company that actually uses them, not an intermediate distributor. Official end-use documents, by contrast, are issued by a government body in the recipient country. Which variant is required and whether distributors must also provide a statement depends on the individual case and the authority’s requirements. - **What information does an end-use certificate contain?** Customary details are the name and address of the exporter and the end user, a precise description of the goods with quantity, the specific intended use, the place of use and an undertaking not to pass the goods on without consent or use them for impermissible purposes. Date, signature and, where applicable, company stamp are added. Authorities often provide templates with a binding structure. #### EORI number URL: https://www.ktb-europe.com/en/glossary/eori-number/ The EORI number is an EU-wide identification number that companies must state in all customs declarations and customs-related procedures. EORI stands for Economic Operators' Registration and Identification. Since 2009, economic operators in the European Union have needed this number to communicate with customs authorities, for example for import and export declarations, transit procedures or applications for authorisations. The number is assigned once by a member state and is then valid throughout the EU. It begins with the country code of the issuing state, followed by a national identifier. In Germany, the EORI number is applied for from the German customs administration; the competent authority is the Directorate General of Customs (Generalzolldirektion). Companies based outside the EU receive an EORI number in the member state in which they first carry out customs activities. Since the United Kingdom left the EU, companies trading with Great Britain also need a British EORI number. If the number is missing or stated incorrectly, customs clearance cannot be completed. In practice: Even companies that only occasionally source spare parts from outside the EU and act as the importer themselves need an EORI number. It should be stored in purchase order and master data so that suppliers and customs brokers can use it without having to ask. Also known as: EORI, Economic Operators' Registration and Identification number, EORI code, customs number (colloquial) Frequently asked questions: - **Is the EORI number the same as the VAT identification number?** No. The VAT identification number is used for VAT purposes in the single market, the EORI number for identification with the customs authorities. They are issued by different bodies and have different formats, even if they may begin with the same country code. The EORI number must be stated in customs declarations; the VAT identification number does not replace it there. - **Does every company need an EORI number?** Only companies that deal with customs themselves, for example as importer, exporter or declarant. Anyone who buys and sells exclusively within the EU generally does not need one. Whether your own company appears in customs terms in an import also depends on the agreed delivery terms. This can be clarified bindingly with the customs authorities. - **How do you check whether an EORI number is valid?** The European Commission offers a public online search that can be used to check the validity of an EORI number. Depending on the holder's consent, the name and address are also displayed. The check is helpful when setting up master data for new business partners or when a customs declaration has been rejected because of an incorrect number. #### Export control URL: https://www.ktb-europe.com/en/glossary/export-control/ Export control comprises government rules and in-house checks used to screen exports for licensing requirements, embargoes and sanctions. The aim of export control is to prevent goods, software or technology from falling into the wrong hands, for example for military purposes or weapons of mass destruction. In the EU, the legal bases are above all the Dual-Use Regulation and embargo and sanctions regulations, supplemented in Germany by the Foreign Trade and Payments Act and Ordinance (AWG/AWV) with the national export list. The competent licensing authority is the Federal Office for Economic Affairs and Export Control (BAFA). Essentially, four questions are checked: Is the item covered by a control list? Are there embargoes or restrictions for the country of destination? Are the consignee or other parties on sanctions lists? And what are the goods used for, i.e. what is the end use? Even unlisted goods can become subject to licensing if a critical end use is known. Companies organise these checks in an internal compliance programme with an export control officer from senior management, clear responsibilities, classification of goods, automated list screening and documentation. In an individual case, the information provided by BAFA is binding; this entry does not constitute legal advice. In practice: Spare parts can also be subject to export control, for example parts for listed machines or controllers. For exports, the control list number should be obtained from the manufacturer or supplier and the check documented before the order is accepted. Also known as: export controls, export compliance, trade compliance, internal compliance programme (ICP), ICP Frequently asked questions: - **Which authority is responsible for export control in Germany?** The Federal Office for Economic Affairs and Export Control (BAFA) is responsible for export licences. It decides on licences, provides rulings on the control list and makes information on embargoes available. The customs administration monitors compliance at export and checks whether the required licences are in place. - **What does end use mean in export control?** End use describes who ultimately receives the goods and what they are used for. For exports subject to licensing, authorities often require an end-use statement from the consignee. It is intended to ensure that the goods are not passed on or used for prohibited purposes. - **What is sanctions list screening?** In sanctions list screening, business partners are checked against the lists of sanctioned persons, companies and organisations. As a rule, no business may be done with listed persons and organisations and no funds may be made available to them. Many companies therefore screen customers, suppliers and consignees regularly with the help of software. - **Can unlisted goods also be subject to licensing?** Yes. So-called catch-all clauses can trigger a licensing requirement if the exporter knows, or has been informed by the authority, that the goods are intended for a critical end use. Looking at the control list alone is therefore not enough; the consignee and intended use must also be checked. #### Export declaration URL: https://www.ktb-europe.com/en/glossary/export-declaration/ The export declaration is the customs declaration with which goods are placed under the export procedure to leave the customs territory of the European Union. Anyone supplying goods from the EU to a non-EU country must in principle declare them for export to the customs authorities. In Germany this is done electronically via the ATLAS export system. The customs office checks the data, may order a physical examination and then releases the goods for export. On release, an export accompanying document with a unique movement reference number is generated, through which the declaration can be tracked until exit. The essential data include the exporter and consignee, the exporter's EORI number, description of the goods, customs tariff number, quantity, weight, value of the goods, country of destination and, where applicable, export control licences. Once the goods have left the customs territory of the EU, the customs authorities issue the exit confirmation electronically. The exit confirmation serves the exporter as proof that the goods have been exported, for example to the tax authorities for VAT purposes. Which procedures and simplifications apply in an individual case should be clarified with the competent customs office; this entry does not constitute legal or tax advice. In practice: For spare parts that are to be exported, the customs tariff number, origin information and, where applicable, the export control classification should already be requested from the supplier at the time of purchase. If this information is missing, the export declaration will be delayed. Also known as: export customs declaration, ATLAS export, export accompanying document (EAD), EAD, export entry Frequently asked questions: - **What is the exit confirmation?** The exit confirmation is the customs authorities' electronic confirmation that the declared goods have left the customs territory of the EU. It is transmitted to the declarant via the customs system and serves as proof of export. Companies therefore retain it as evidence for tax and customs purposes. - **What information is needed for an export declaration?** Required information includes details of the exporter and consignee, the EORI number, a commercial description of the goods, the customs tariff number, quantity and weight, the value of the goods, the country of destination and information on origin. If the goods are subject to licensing, the licence details must also be provided. - **What is ATLAS export?** ATLAS is the German customs administration's IT system for processing customs declarations electronically. In its export module, export declarations are transmitted and processed and the exit of the goods is confirmed. Companies use approved software or the customs administration's internet portal for this. - **What is the export accompanying document?** The export accompanying document is generated once the goods have been released for export and bears the movement reference number of the export declaration. Using this number, the customs office of exit can retrieve the declaration and confirm exit. For the procedure in an individual case, the information provided by the competent customs office is binding. #### Incoterms URL: https://www.ktb-europe.com/en/glossary/incoterms/ Incoterms are delivery terms issued by the International Chamber of Commerce that define obligations, costs and transfer of risk between seller and buyer. The International Commercial Terms are published by the International Chamber of Commerce (ICC) in Paris. The current version, Incoterms 2020, comprises eleven rules, each agreed as a three-letter code with a named place, for example FCA Hamburg. Seven rules apply to all modes of transport (EXW, FCA, CPT, CIP, DAP, DPU, DDP) and four only to sea and inland waterway transport (FAS, FOB, CFR, CIF). Each rule specifies where delivery is deemed to have taken place, when the risk of loss or damage passes to the buyer, who bears which costs and who handles export and import formalities. The range extends from EXW, under which the buyer assumes almost all obligations, to DDP, under which the seller is responsible up to the place of destination, including import duties. They do not govern the transfer of ownership, payment terms, liability for breach of contract or the applicable law. Incoterms only apply if they are expressly agreed, stating the version year. In practice: For buyers, the rule determines costing and responsibilities: who files the export declaration, who insures, and from when does one bear the risk? A quotation should always be compared with its rule, named place and version year. Also known as: International Commercial Terms, Incoterms 2020, Incoterms rules, international delivery terms Frequently asked questions: - **Which Incoterms rule is most favourable for buyers?** There is no rule that is cheapest across the board. A quotation on EXW terms often looks cheaper because the buyer takes on almost all costs, formalities and risks itself. With DDP, these are included in the price, but the seller's calculation is less transparent. For a fair comparison, quotations should be converted to the same rule and internal effort should also be taken into account. - **What does the named place mean in Incoterms?** Each rule is combined with a place, such as a city or an exact address. This place determines where delivery is deemed to take place and at which point costs and risk pass to the buyer. The more precisely it is specified, the less room there is for misunderstandings. Simply naming a country is generally not sufficient. - **May older versions of Incoterms still be agreed?** Yes. The International Chamber of Commerce does not declare earlier versions invalid, so contracting parties can still agree, for example, Incoterms 2010. It is important to state the version year explicitly, as the rules differ between versions. For specific contract drafting, expert advice should be sought in case of doubt; this entry does not constitute legal advice. #### Proof of preferential origin (EUR.1) URL: https://www.ktb-europe.com/en/glossary/proof-of-preferential-origin/ A proof of preferential origin certifies the preferential origin of goods and allows reduced or zero import duties under trade agreements. The EU has concluded free trade and preferential agreements with numerous countries. If goods meet the rules of origin of the agreement concerned, they can be imported into the importing country at a reduced rate of duty or duty-free. A proof of preferential origin is required for this. It must be distinguished from the certificate of origin, which certifies non-preferential origin and does not trigger any tariff preference. Which form is permitted is laid down in the agreement concerned. The classic form is the movement certificate EUR.1, which the exporter applies for and the customs authorities endorse; under pan-Euro-Mediterranean cumulation there is the EUR-MED. In addition, there is the statement on origin, which the exporter makes itself on the invoice or another commercial document. For some agreements and under the Generalised Scheme of Preferences, this requires registration as a registered exporter in the REX system. The proof is often based on supplier's declarations, with which upstream suppliers confirm the originating status of their goods. In an individual case, the information provided by the customs authorities is binding; this entry does not constitute legal advice. In practice: If spare parts are re-exported, supplier's declarations on preferential origin should be requested early and renewed regularly. Without them, a proof of preferential origin often cannot be issued for the exported goods. Also known as: movement certificate EUR.1, EUR-MED, statement on origin, origin declaration, preferential origin certificate Frequently asked questions: - **What is the difference between EUR.1 and a certificate of origin?** The EUR.1 certifies preferential origin under a trade agreement and can lead to lower duties in the importing country. The certificate of origin certifies non-preferential origin, for example for commercial policy measures, and does not bring any tariff preference. In Germany, certificates of origin are issued by the chambers of commerce (IHK), while the EUR.1 is endorsed by the customs authorities. - **What is a statement on origin on the invoice?** With a statement on origin, the exporter itself confirms preferential origin using prescribed wording on the invoice or another commercial document. Whether this is permitted and which conditions apply, such as authorisation as an approved exporter or REX registration, depends on the agreement concerned. - **What is REX?** REX stands for the Registered Exporter system. Registered exporters can certify preferential origin themselves with a statement on origin. The system is used under the EU's Generalised Scheme of Preferences and in some free trade agreements. In Germany, registration is carried out via the customs authorities. - **What is a supplier's declaration needed for?** With a supplier's declaration, a supplier within the EU confirms that its goods meet the preferential rules of origin. The exporter uses this information as the basis for its own proofs of preferential origin. There are single and long-term supplier's declarations; the latter cover recurring deliveries over a specified period. #### Sanctions list screening URL: https://www.ktb-europe.com/en/glossary/sanctions-list-screening/ Sanctions list screening is checking business partners against official sanctions lists in order to rule out prohibited transactions with listed persons. The EU and other states maintain lists of persons, companies and organisations against which financial and economic sanctions have been imposed. In the EU, a prohibition on making funds available applies to listed parties: no funds or economic resources may be made available to them, either directly or indirectly. This also covers ordinary deliveries of spare parts, regardless of whether the goods themselves are subject to export control. Customers, suppliers, consignees, parties involved in payment and often service providers are screened, both when they are first set up and regularly during the business relationship, because the lists change frequently. In the EU, the basis is the relevant sanctions regulations; consolidated lists are made publicly available. Depending on the transaction, lists of other states, such as the United States or the United Kingdom, may also be relevant. Many companies use software that finds names even when they are spelt differently. Sanctions list screening is one building block of export control, alongside item classification, country checks and end-use checks. In individual cases, the binding information is that of the competent authorities, such as the Federal Office for Economic Affairs and Export Control (BAFA), German customs or the Deutsche Bundesbank; this entry does not constitute legal advice. In practice: Document every screening with the date, the list used and the result, even if there is no match. In the event of a possible match, stop the transaction, verify the identity using further attributes and, if doubts remain, involve the competent authority. Also known as: sanctions screening, denied party screening, restricted party screening, embargo check, watchlist screening Frequently asked questions: - **Who has to carry out sanctions list screening?** EU sanctions prohibitions apply to all companies and persons within their scope, not only to exporters. Distributors, service providers and companies doing business purely within Europe are also not permitted to make economic resources available to listed persons. The law does not prescribe in detail how screening is to be organised; a documented, risk-based process is customary. - **How often should business partners be screened against sanctions lists?** At a minimum when a business partner is first set up and before every transaction with increased risk. Because sanctions lists are amended frequently, many companies additionally screen their entire partner base regularly or automatically whenever a list changes. The appropriate frequency depends on industry, destination countries and business volume and should be laid down in the internal compliance programme. - **What should be done in the event of a sanctions list match?** First, the transaction is put on hold. It is then checked whether it really is the same person or company, for example using address, date of birth or registration number. If the match is confirmed, the transaction must not be carried out. For the further procedure and any reporting obligations, the competent authorities or specialist advisers should be consulted. #### Supplier’s declaration (preferential origin) URL: https://www.ktb-europe.com/en/glossary/suppliers-declaration/ A supplier’s declaration is a statement by the supplier on the preferential or non-preferential origin of goods within the supply chain. With a supplier’s declaration, an upstream supplier confirms to its customer that the goods supplied meet certain rules of origin. The focus is usually on preferential origin: this is a prerequisite for an exporter being able to issue proof of preferential origin for its products, which is used to claim a reduced duty rate or duty exemption in the country of destination. The rules for supplier’s declarations within the EU are laid down in Union customs legislation, mainly in Implementing Regulation (EU) 2015/2447 from Article 61 onwards. A distinction is made between the single supplier’s declaration for a specific consignment and the long-term supplier’s declaration, which applies to deliveries of the same kind over a defined period of up to two years. There are also declarations of non-preferential origin, which are relevant, for example, for certificates of origin or trade policy measures. Important: origin is determined by the rules of origin of the agreement concerned, not simply by the country of manufacture. When purchasing spare and bought-in parts, supplier’s declarations are needed if one’s own company exports products under preferential arrangements. Incorrect declarations can lead to post-clearance demands for duty. In individual cases, the binding information is that of the customs administration; this entry does not constitute legal advice. In practice: Request long-term supplier’s declarations for regularly purchased parts in one batch and monitor their validity in the supplier master data. Check on a sample basis whether the description of goods and the customs tariff number in the declaration match the parts actually delivered. Also known as: supplier’s declaration, long-term supplier’s declaration (LTSD), supplier declaration of origin, LTSD Frequently asked questions: - **What is the difference between a supplier’s declaration and a certificate of origin?** The supplier’s declaration is an internal document within the supply chain with which an upstream supplier confirms the origin of goods to its customer. The certificate of origin, by contrast, is a foreign trade document that proves non-preferential origin to the authorities in the country of destination and is usually certified by a chamber of commerce and industry (IHK in Germany). The supplier’s declaration often serves as the basis for further proofs. - **What is a long-term supplier’s declaration?** A long-term supplier’s declaration covers all deliveries of goods of the same kind to the same customer over a defined period. It removes the need for individual declarations for each consignment. If the origin or manufacture changes, the supplier must inform the customer without delay. Period of validity and formal requirements are governed by Union customs legislation; the current legal position is decisive. - **Who is responsible for the accuracy of a supplier’s declaration?** The supplier who makes the declaration is responsible. It must be able to prove the originating status, for example through cost calculations or its own suppliers’ declarations. The customer should nevertheless check the declarations for plausibility, as it uses them for its own proofs of preferential origin. If in doubt, the customs administration can arrange for a verification at the supplier. ### Automation & Drive Technology #### Ball bearing URL: https://www.ktb-europe.com/en/glossary/ball-bearing/ A ball bearing is a rolling bearing in which balls roll between the inner and outer rings, supporting shafts so that they can rotate with low friction. Ball bearings belong to the rolling bearing family. Unlike in a plain bearing, the surfaces do not slide on one another; instead, balls roll in raceways between the inner and outer rings. A cage keeps the balls spaced apart. Because balls transmit the load only at points, ball bearings are suited above all to moderate loads and high speeds, whereas roller bearings carry higher loads. Important types are deep groove ball bearings, angular contact ball bearings, four-point contact bearings, self-aligning ball bearings and thrust ball bearings. They differ in whether they carry radial, axial or combined loads and whether they compensate for misalignment. Key parameters are bore and outside diameter, width, dynamic and static load rating, limiting speed, internal clearance, sealing and tolerance class. The boundary dimensions are internationally standardised, so bearings with the same designation from different manufacturers are generally dimensionally interchangeable. Ball bearings are found in electric motors, pumps, fans, gearboxes and conveyor systems and are among the most common spare parts in maintenance. Typical causes of failure are inadequate lubrication, contamination, overload, installation errors and current passage in inverter-fed motors. In practice: For a spare parts enquiry, the complete bearing designation including all suffixes, for example for sealing, internal clearance and cage, is usually sufficient. If it is missing, bore, outside diameter and width as well as details of speed, temperature and installation location will help. Also known as: ball bearing, radial ball bearing, ball race (colloquial), anti-friction bearing Frequently asked questions: - **What is the difference between a ball bearing and a roller bearing?** In a ball bearing, balls transmit the load via very small contact areas; in a roller bearing, cylindrical, tapered or spherical rollers do so along a line. Ball bearings therefore run with less friction and reach higher speeds. For the same size, roller bearings carry considerably higher loads and are therefore common in heavy machinery, rolls and large gearboxes. - **How do you read a ball bearing designation?** The basic designation states the bearing type, dimension series and bore code. From code 04 upwards, the code multiplied by five gives the bore diameter in millimetres; a bearing with code 05 therefore has a 25 mm bore. Suffixes describe seals or shields, internal clearance, cage material and special versions. These suffixes are coded differently by each manufacturer and should never be omitted when ordering. - **Why do ball bearings fail prematurely?** The most common causes are unsuitable or missing lubrication, ingress of dirt or moisture, installation with blows on the wrong ring, excessively tight fits and overload. In motors on a frequency inverter, current passage can also cause fluting in the raceways. A damage analysis of the removed bearing usually shows which cause was involved. - **Are ball bearings from different manufacturers interchangeable?** The boundary dimensions are standardised to ISO, so bearings with the same basic designation generally match dimensionally. Differences exist in suffixes, type of seal, grease fill, internal clearance and running accuracy. For critical applications, it should be checked whether all characteristics of the original are met before an equivalent bearing is used. #### Ball screw URL: https://www.ktb-europe.com/en/glossary/ball-screw/ A ball screw converts rotary motion into precise linear motion with low friction by means of recirculating balls between the screw shaft and nut. A ball screw consists of a threaded screw shaft, a nut and balls that roll in the thread grooves and recirculate via a return system in the nut. Compared with a trapezoidal lead screw with sliding friction, efficiency is considerably higher, wear is lower and positioning accuracy is better. Ball screws are not self-locking; on vertical axes, a brake on the drive is therefore usually required. Key ratings are nominal diameter, lead, length, accuracy class, load ratings and preload. Rolled screws are economical, while ground screws achieve higher accuracy. The nut is available as a single nut, preloaded single nut or double nut; preload eliminates axial play. Tolerance classes and terms are described in the ISO 3408 series of standards. The system includes the fixed and floating bearing supports of the screw and the coupling to the motor. Ball screws drive the axes of machine tools, presses, handling equipment and electromechanical cylinders. Wear shows up as increasing backlash, noise or positioning deviations; causes include contamination, insufficient lubrication, collisions and misalignment. In practice: For a replacement, nominal diameter, lead, total length, end machining according to drawing, nut type, preload and accuracy class are needed. It is often worth checking whether a repair by regrinding and fitting new balls is possible instead of manufacturing a completely new screw. Also known as: ball screw drive, ball screw spindle, recirculating ball screw, ball screw assembly Frequently asked questions: - **What is the difference between a ball screw and a trapezoidal lead screw?** The trapezoidal lead screw works with sliding friction between thread and nut, has lower efficiency and, depending on the lead, is self-locking. The ball screw uses rolling friction, achieves high efficiency, low heat generation and high accuracy, but is not self-locking and is more expensive. Trapezoidal screws are suitable for simple adjustments, ball screws for dynamic and precise axes. - **What does the lead of a ball screw mean?** The lead indicates how far the nut moves axially for one revolution of the screw, for example 5 or 10 millimetres. Small leads offer high resolution and force, large leads high traverse speed. When replacing, the lead must match exactly, otherwise the position measurement and controller parameters will no longer be correct. - **What information is needed to replace a ball screw?** Nominal diameter, lead, thread direction, total length and thread length, machining of the screw ends, nut type with flange dimensions, preload and accuracy class are required. The safest basis is a drawing or the machine manufacturer’s part number. Photos of the nut and screw ends help with identification. - **Can a ball screw be repaired?** Often, yes. Specialist workshops inspect the screw and nut, regrind worn raceways, fit new oversize balls and reset the preload. Whether this is worthwhile depends on the wear pattern, the accuracy requirement and a comparison with the price and lead time of a new part. #### Cable gland URL: https://www.ktb-europe.com/en/glossary/cable-gland/ A cable gland brings a cable into an enclosure with a seal and strain relief, protecting the entry against dust, water and the cable being pulled out. Cable glands are fitted wherever cables enter control cabinets, terminal boxes, motors or devices. When the dome cap nut is tightened, a sealing insert is pressed radially against the cable sheath. This creates the seal and at the same time a strain relief that protects the terminal points inside from mechanical stress. Key parameters are connection thread, clamping range, material, IP rating and temperature range. Today, metric threads such as M16x1.5, M20x1.5 or M25x1.5 dominate; older plants still have PG threads (steel conduit thread). Materials are polyamide, nickel-plated brass and stainless steel, for example for food or chemical areas. Special versions are available for EMC with shield contact, for potentially explosive atmospheres, with bend protection or as multiple-hole inserts for several cables. Failures are caused by embrittled sealing inserts, an incorrectly selected clamping range, missing locknuts or sealing rings, and UV or chemical exposure. A leaking entry can let moisture into terminal boxes and electronics. As a typical C-part, the cable gland is often underestimated in purchasing. A small, standardised selection of common thread sizes and clamping ranges in stock prevents a missing small part from delaying a repair in the control cabinet. In practice: For a replacement, the thread size and type, thread length, clamping range matching the cable outer diameter, material, degree of protection and, where applicable, EMC or Ex version are needed. The locknut and sealing ring should be ordered at the same time. Also known as: cable entry, metric cable gland, PG cable gland, EMC cable gland, cable connector gland Frequently asked questions: - **What is the difference between PG and metric cable glands?** PG stands for an older thread system originally developed for steel conduit, with its own flank angle and pitches. Metric cable glands use ISO fine threads with a 1.5 mm pitch and have largely replaced PG in new installations. The two systems are not directly compatible. Reducers or adapters are available for existing enclosure holes with PG threads. - **How is the right clamping range selected?** The clamping range states the minimum and maximum cable outer diameter for which the gland seals and provides strain relief. The actual diameter of the cable should be measured and should lie as close as possible to the middle of this range. If it is at the edge, sealing or strain relief suffers. - **What information is needed to order a cable gland?** Important are thread size and thread type, thread length to suit the wall thickness, clamping range, material, degree of protection and temperature range. Special requirements such as EMC shielding, suitability for potentially explosive atmospheres or food-grade design are added. Locknuts and sealing rings are often listed separately. A photo of the installation makes identification easier. - **When is an EMC cable gland needed?** An EMC cable gland is used when the shield of a shielded cable is to be connected to the enclosure over a large area. This is typical for motor cables on frequency inverters, servo drives or sensitive measuring equipment. Contact around the full circumference dissipates interference currents better than a single shield connection wire. #### Capacitive sensor URL: https://www.ktb-europe.com/en/glossary/capacitive-sensor/ A capacitive sensor detects objects and fill levels without contact by evaluating the change in an electric field between its electrodes. With its active face, a capacitive sensor forms an open capacitor. When an object enters the stray field, the capacitance changes because the material has a different dielectric constant from air. As a result, it detects not only metal but also plastic, glass, wood, powder, granules and liquids. Common applications are level detection on tanks, hoppers or silos and presence detection of non-metallic parts. Key ratings are sensing distance, housing style, mounting type, output type (PNP, NPN, normally closed, normally open), supply voltage, degree of protection and temperature range. On many units, sensitivity can be adjusted by potentiometer or teach-in. The actual sensing distance depends heavily on the material; substances with a low dielectric constant are only detected at a shorter distance. For liquids, there are designs with media-resistant housings that are screwed directly into a vessel. False switching is often caused by build-up, moisture or condensation on the sensor face and by sensitivity that has not been readjusted. After a replacement, the setting usually has to be made again. Modern units partly compensate for slight build-up themselves, but they do not replace regular cleaning of the active face. In practice: In addition to the manufacturer part number, housing style, output type and voltage, it should be stated which medium is detected and whether the sensor measures through a vessel wall. Note the sensitivity setting so that the replacement unit can be adjusted again quickly. Also known as: capacitive proximity switch, capacitive proximity sensor, capacitive level sensor, proximity sensor Frequently asked questions: - **Which materials does a capacitive sensor detect?** Capacitive sensors detect almost all substances whose dielectric constant differs from that of air, i.e. metals, plastics, glass, wood, paper, bulk materials and liquids. The higher the dielectric constant, the greater the achievable sensing distance. Water-based media are therefore usually detected more reliably than dry plastic granules. - **Can a capacitive sensor measure through a vessel wall?** Yes, if the wall is made of a non-conductive material such as plastic or glass and is not too thick. The sensor then detects the medium behind the wall, for example for level detection. The sensitivity must be set so that the wall itself is not detected as an object. - **What information is needed for a replacement capacitive sensor?** The manufacturer part number, housing style and size, sensing distance, mounting type, output type, normally closed or normally open function, supply voltage, connector type, degree of protection and temperature range are needed. It is also helpful to state the medium being detected and whether the sensor comes into contact with the product, for example in food applications. #### Circuit breaker URL: https://www.ktb-europe.com/en/glossary/circuit-breaker/ A circuit breaker is a switching device that switches operating currents and automatically and safely interrupts overload and short-circuit currents. Circuit breakers protect installations, distribution boards and cables and can interrupt even large short-circuit currents without being destroyed themselves. Unlike fuses, they can be switched on again after tripping. In low voltage, they are covered by the IEC/EN 60947 series of standards. In medium and high voltage, there are separate designs, for example with vacuum or gas quenching. In low-voltage installations, a distinction is made between moulded case circuit breakers and air circuit breakers for high currents, often in withdrawable design. Tripping is thermal-magnetic or electronic; electronic trip units offer adjustable protection functions against overload, short-time-delayed and instantaneous short circuit and, in some cases, earth fault. Key ratings are rated current, rated voltage, ultimate and service short-circuit breaking capacity, number of poles, trip unit type and accessories such as motor operator, auxiliary switches and shunt trip. Graded settings ensure selectivity between upstream and downstream protective devices. Circuit breakers are installed in main distribution boards, incoming feeders and large outgoing circuits. For older devices, spare parts such as trip units, operators and contacts have often been discontinued, which is relevant for spare parts planning. In practice: For a replacement, the rated current, breaking capacity, number of poles, trip unit type with settings, mounting type (fixed or withdrawable) and accessories must be known. A different device can change the selectivity of the installation; the selection should therefore be agreed with the responsible qualified electrician. Also known as: MCCB (moulded case circuit breaker), ACB (air circuit breaker), power circuit breaker, low-voltage circuit breaker Frequently asked questions: - **What is the difference between a circuit breaker and a miniature circuit breaker?** Miniature circuit breakers are small, usually non-adjustable devices for final circuits with limited breaking capacity. Circuit breakers cover higher currents, have greater breaking capacity and often adjustable trip units. They are used for incoming feeders, main distribution boards and large loads. The underlying standards are different. - **What do Icu and Ics mean for a circuit breaker?** Icu is the rated ultimate short-circuit breaking capacity, i.e. the highest short-circuit current the breaker can interrupt. Ics is the rated service short-circuit breaking capacity, after which the breaker remains fit for further operation. Both values must at least match the possible short-circuit current at the point of installation, which results from the installation calculation. - **What information is needed to replace a circuit breaker?** The type designation, rated current, rated voltage, breaking capacity, number of poles, trip unit with all settings, mounting type, connection type and accessories such as motor operator, auxiliary switches or shunt trip are needed. For withdrawable devices, the withdrawable chassis must also be stated. Photos of the nameplate and trip unit are very helpful. - **What should be done if a circuit breaker has been discontinued?** First, clarify whether replacement devices, exchange trip units or retrofit solutions are available that fit into existing panels. Many manufacturers offer successor types with adapters. If this is not possible, a repair or conversion of the panel may be considered. In any case, protection settings and selectivity must be reassessed. #### Contactor URL: https://www.ktb-europe.com/en/glossary/contactor/ A contactor is an electromagnetically operated switch that uses a small control voltage to switch large load currents on and off. A contactor consists of a magnet coil, a movable armature and contacts. When control voltage is applied to the coil, the armature pulls in and closes the main contacts; without voltage, springs open them again. The contactor thus galvanically separates the control circuit from the load circuit. It is designed for a very large number of operating cycles and is used for operational switching, not for short-circuit protection. It differs from a relay mainly in its higher switching capacity. Important parameters are the control voltage and type of current of the coil, the rated operational current or power in a utilisation category, and the number of main and auxiliary contacts. The utilisation category to IEC 60947-4-1 describes the load: AC-1 for virtually resistive loads, AC-3 for starting and switching off squirrel-cage motors. Contactor relays switch control currents only. Mirror contacts and mechanically linked contacts are used in safety circuits. Contactors are installed in almost every control cabinet, for example for motors, heaters and lighting. Wear parts are the main contacts, which erode through arcing, and coils, which fail due to incorrect voltage or overheating. In practice: For a replacement, state the coil voltage with type of current, the rated current in the appropriate utilisation category, the number of poles and the auxiliary contact configuration. For larger contactors, contact kits and coils are often available separately, which speeds up repair. Also known as: power contactor, motor contactor, contactor relay, magnetic contactor, AC contactor Frequently asked questions: - **What is the difference between a contactor and a relay?** Both work on the same principle: a coil actuates contacts. Contactors are designed for high load currents, often have arc-quenching devices and are used for motors and other loads. Relays switch smaller currents, mostly control and signal circuits. Contactor relays lie in between and are used for control, not for switching motor power. - **What does AC-3 mean on a contactor?** AC-3 is a utilisation category to IEC 60947-4-1 for starting and switching off squirrel-cage motors during operation. The associated rated current or motor power in kW shows which motor the contactor can switch reliably. AC-1 with higher permissible currents applies to resistive loads, while stricter categories apply to inching and plugging. - **What information is needed to replace a contactor?** Required are the coil voltage and type of current, that is, AC or DC, the rated current or motor power in AC-3, the number of main poles and the number and type of auxiliary contacts as normally open or normally closed. Frame size, mounting, type of connection such as screw or spring-loaded terminal, and fitted accessories are added. - **Why does a contactor hum?** AC contactors hum slightly when the pole faces of the armature and magnet core are dirty or worn, or when the shading ring in the core is damaged. Control voltage that is too low can also prevent the armature from pulling in cleanly. Loud humming is often accompanied by heating of the coil and should be checked. #### Control cabinet URL: https://www.ktb-europe.com/en/glossary/control-cabinet/ A control cabinet is an enclosure that houses and protects the electrical equipment of a machine or plant, such as controllers, drives and protective devices. In a control cabinet, components such as the incoming supply, circuit breakers, contactors, frequency inverters, controllers, power supplies and terminal blocks are grouped on mounting plates and DIN rails. The enclosure protects them against contact, dust, moisture and mechanical damage. The IEC 61439 series of standards applies to low-voltage switchgear and controlgear assemblies, and IEC 60204-1 to the electrical equipment of machines. National regulations and standards on electrical safety must also be observed during construction and modification. A distinction is made between wall-mounted enclosures, floor-standing cabinets, baying systems, console enclosures and terminal boxes, made of sheet steel, stainless steel or plastic. Key parameters are dimensions, degree of protection, material, load capacity and the climate control concept. Filter fans, heat exchangers or cooling units remove heat, while heaters and thermostats counter condensation. Cable glands and entry plates bring cables in without reducing the degree of protection. Inside, cable ducts, DIN rails and clear labelling of the equipment ensure a good overview. In maintenance, control cabinets mainly involve wear of fans, filter mats, cooling units and door seals, as well as ageing components inside. Up-to-date wiring diagram documentation is a prerequisite for rapid fault-finding and correct identification of spare parts. Thermographic images help to detect overloaded terminal points or protective devices at an early stage. In practice: Keep the bills of materials and wiring diagrams of every cabinet up to date and mark critical components. Filter mats, fans and cooling unit accessories are among the plannable wear parts whose replacement interval should be recorded in the maintenance plan. Also known as: electrical cabinet, switch cabinet, control panel, electrical enclosure, switchgear assembly Frequently asked questions: - **What goes into a control cabinet?** Typical contents are the incoming supply with main switch, protection by circuit breakers or motor protection circuit breakers, contactors, frequency inverters, a controller with input and output modules, power supplies, relays, terminal blocks for connection to the field and cable ducts. Components for climate control and lighting are added. The exact content is defined by the wiring diagram and the bill of materials. - **What degree of protection does a control cabinet need?** The degree of protection depends on the environment. In clean indoor areas, lower degrees of protection are often sufficient; in dusty or damp environments, for example in the food or paper industry, higher degrees of protection against dust and water jets are required. Note that fans, cable entries and cut-outs can reduce the degree of protection of the overall system. - **Why does a control cabinet need to be cooled?** Electronic components such as frequency inverters and power supplies generate heat losses. If the internal temperature rises above permissible values, components age faster or shut down. Filter fans, heat exchangers or cooling units remove the heat. Dirty filter mats are a common cause of overheating and should be replaced regularly. #### Cylindrical roller bearing URL: https://www.ktb-europe.com/en/glossary/cylindrical-roller-bearing/ A cylindrical roller bearing is a rolling bearing with cylindrical rollers that carries very high radial loads and permits high speeds. In a cylindrical roller bearing, cylindrical rollers roll in line contact between the inner and outer rings. As a result, they carry considerably higher radial loads than ball bearings of the same size. Most designs are separable: one ring with the roller set and cage can be separated from the other ring, which makes mounting and dismounting easier, for example with interference fits. The designs differ in the position of the ribs. In type NU, the outer ring has two ribs and the inner ring none, so the shaft can move axially. The bearing is therefore suitable as a floating bearing. Types such as NJ or NUP have additional ribs and can accommodate limited axial forces in one or both directions. There are also full-complement bearings without a cage for very high loads at low speeds, as well as double-row and multi-row versions, for example for rolling mills. Key ratings are dimensions, load ratings, rib arrangement, cage material and clearance. Typical applications are large electric motors, industrial gearboxes, machine tool spindles, rolls in paper and steel mills, and pumps. Damage is often caused by lack of lubricant, skidding under too light a load or edge running due to misalignment. In practice: In addition to the basic designation, the design, cage version and clearance are decisive, because an NU bearing cannot simply be replaced by an NJ bearing. For separable bearings, the inner and outer rings should be replaced together where possible, unless the manufacturer expressly identifies them as interchangeable. Also known as: CRB, NU roller bearing, cylindrical roller radial bearing, roller bearing NU/NJ/NUP Frequently asked questions: - **What do NU, NJ and NUP mean for cylindrical roller bearings?** The codes describe which ring has ribs. NU: two ribs on the outer ring, inner ring without ribs, freely displaceable axially. NJ: additionally one rib on the inner ring, axial guidance in one direction. NUP: inner ring with a fixed rib and a loose rib washer, axial guidance in both directions. This determines whether the bearing works as a floating or locating bearing. - **When is a cylindrical roller bearing used instead of a ball bearing?** When high radial forces have to be absorbed in a small installation space, for example on the drive end of large motors with belt or pinion drives, or in gearboxes. However, cylindrical roller bearings require a minimum load, otherwise the rollers can skid and damage the raceways. Under light loads, a ball bearing is often the better choice. - **What information is needed to replace a cylindrical roller bearing?** The full designation with design, i.e. NU, NJ, NUP or N, dimension series and bore code, as well as all suffixes for cage, clearance and accuracy, is required. The installation location, speed and operating temperature are also helpful. For bearings from machine tool spindles, the accuracy class is particularly important. - **Why does the cylindrical roller bearing have a brass cage?** Machined brass cages are robust against shocks, vibration and higher temperatures and are therefore preferred in heavy machinery. Polyamide cages are lighter and run with low friction but have temperature limits. Pressed steel cages are a common standard. A change of cage when procuring a replacement should only be made after checking the operating conditions. #### Deep groove ball bearing URL: https://www.ktb-europe.com/en/glossary/deep-groove-ball-bearing/ A deep groove ball bearing is the most widely used type of rolling bearing; it carries radial loads and limited axial loads in both directions. Deep groove ball bearings have deep, uninterrupted raceway grooves in the inner and outer rings, in which the balls roll. This geometry allows axial loads in both directions as well as radial loads. Deep groove ball bearings are non-separable, low-maintenance and suitable for high speeds. Compared with angular contact ball bearings, they carry lower axial loads; compared with roller bearings, lower radial loads. They are available open, with sheet steel shields or with contact or low-friction seals. Sealed bearings are greased at the factory and lubricated for life. Other variants are bearings with a snap ring groove, double-row designs and stainless steel bearings for damp or food-related environments. Important parameters are dimensions, load ratings, limiting speed, internal clearance, for example normal clearance or the larger C3 clearance, and the type of sealing. Deep groove ball bearings are standard in electric motors, fans, pumps, conveyor rollers and small gearboxes. They are therefore among the bearing items most frequently stocked by maintenance departments. Failures are mostly caused by aged grease, contamination, misalignment or improper installation. For motors on frequency inverters, electrically insulated versions are also used. In practice: When ordering, the complete designation counts: basic number plus suffixes for seal, internal clearance and, where applicable, high-temperature or food-grade grease. For electric motors on inverters, it should be checked whether electrically insulated bearings were originally fitted. Also known as: DGBB, radial deep groove ball bearing, 6000 series bearing, single-row deep groove ball bearing Frequently asked questions: - **What do 2RS and 2Z mean on deep groove ball bearings?** The suffixes indicate sealing on both sides. Usually, RS stands for an elastomer seal and Z for a sheet steel shield; the preceding 2 means on both sides. Seals give better protection against dirt and moisture, while shields cause less friction. The exact notation differs between manufacturers, so the suffix should be copied exactly. - **What does C3 mean on a deep groove ball bearing?** C3 denotes an internal clearance that is larger than normal clearance. It is chosen when the inner ring heats up more than the outer ring in operation or when tight fits reduce the clearance. This is the case, for example, in many electric motors. A bearing with normal clearance instead of C3 can run too hot there and fail early. - **What information is needed to replace a deep groove ball bearing?** The safest option is the complete designation from the bearing or from the spare parts list. Without it, the bore, outside diameter and width are needed, as well as sealing, internal clearance, operating temperature and speed. In special environments such as wet areas, food processing or high heat, details of material and grease are also important. - **Can deep groove ball bearings be relubricated?** Bearings sealed on both sides are greased for life and are not relubricated. Open bearings in housings with a grease nipple can be relubricated through the housing bore; the grease type, quantity and interval are specified by the machine or bearing manufacturer. Too much grease increases friction and temperature and is just as harmful as too little. #### Electric motor URL: https://www.ktb-europe.com/en/glossary/electric-motor/ An electric motor is an electrical machine that converts electrical energy into mechanical rotation via magnetic fields and drives machinery. At its core, an electric motor consists of a stationary part, the stator, and a rotating part, the rotor. The interaction of the magnetic fields of the two parts produces torque at the shaft. In industry, three-phase squirrel-cage induction motors predominate because they are robust and low-maintenance. There are also synchronous motors, for example with permanent magnets, DC motors and servo motors for precise positioning and control tasks. Energy efficiency is classified according to IEC 60034-30-1 into efficiency classes designated IE followed by a digit; a higher digit stands for higher efficiency. In the EU, the Ecodesign Regulation (EU) 2019/1781 sets minimum requirements for many electric motors and variable speed drives. Which class is required in an individual case depends, among other things, on power rating, number of poles and area of application. For replacement, the nameplate data are decisive: rated power, speed, voltage and connection, frequency, rated current, frame size, mounting arrangement according to the IM code (such as foot or flange mounting), degree of protection and thermal class. If frame size and mounting arrangement match, motors from different sources can often be swapped mechanically, but electrical and thermal data must be checked separately. In practice: For a spare parts enquiry, a legible photo of the nameplate and details of the mounting arrangement, shaft dimensions and flange are recommended. For older motors, it should be checked whether a new motor of the efficiency class required today fits in terms of frame size and mounting dimensions. Also known as: e-motor, three-phase motor, induction motor, asynchronous motor, AC motor Frequently asked questions: - **What is the difference between an induction motor and a synchronous motor?** In an induction (asynchronous) motor, the rotor turns slightly more slowly than the stator's rotating field; this slip is necessary to produce torque. In a synchronous motor, the rotor runs exactly in step with the rotating field, for example thanks to permanent magnets. Synchronous motors often achieve higher efficiencies but usually need an inverter to operate. Induction motors, by contrast, can run directly on the mains. - **What do the efficiency classes IE1, IE2 and IE3 mean?** The IE classes according to IEC 60034-30-1 describe how efficiently a motor converts electrical into mechanical energy. The higher the digit, the lower the losses. Which minimum class applies in the EU to a particular motor is governed by the Ecodesign Regulation (EU) 2019/1781, depending on power rating and design. In case of doubt, the current version of the regulation provides the answer. - **What information is needed to replace an electric motor?** Important are power, speed or number of poles, voltage, frequency, rated current, frame size, mounting arrangement according to the IM code, degree of protection and thermal class. In addition, shaft diameter, flange size and terminal box position are needed. For special versions, for example with a brake, separately driven fan or encoder, these components should also be described. - **What does the mounting arrangement IM B3 or IM B5 mean?** The IM code describes the mounting arrangement and type of fixing of a motor. IM B3 stands for a foot-mounted motor with a horizontal shaft, IM B5 for a flange-mounted motor with through holes in the flange. Combinations such as IM B35 denote motors with feet and flange. The correct mounting arrangement is essential so that a replacement motor can be fitted without modification. #### Fieldbus URL: https://www.ktb-europe.com/en/glossary/fieldbus/ A fieldbus is an industrial communication system that digitally connects sensors, actuators and drives to the controller via a shared cable. Before fieldbuses were introduced, every signal was wired individually from the field into the control cabinet. A fieldbus transmits many signals over a shared cable, reducing wiring effort and sources of error. Diagnostic and parameter data can also be transmitted. The protocols are described in the IEC 61158 series of standards. Instead of thick cable harnesses, a single bus cable is often sufficient, with distributed modules located close to the machine. Classic fieldbuses work over serial two-wire cables, for example to RS-485, and connect controllers, distributed inputs and outputs, frequency inverters or valve terminals. Today, Ethernet-based fieldbuses are increasingly prevalent, offering higher data rates, real-time capability and easy connection to IT networks. For sensors at the lowest level, there are also point-to-point interfaces. Key ratings are protocol, transmission medium, topology, data rate, cycle time and connector system. Faults are frequently caused by missing terminating resistors, damaged cables, poor shielding, incorrect addresses or defective bus interfaces. When replacing a bus node, the protocol, device description file and address must match. Replacement modules should therefore always be ordered in the correct bus variant. In practice: For every bus network, document the protocol, node addresses, device description files and firmware versions. In spare parts enquiries for bus modules, couplers or drives, always state the protocol used, as identical devices often exist in several bus variants. Also known as: field bus, industrial bus system, Industrial Ethernet, fieldbus system Frequently asked questions: - **What is the difference between fieldbus and Industrial Ethernet?** Classic fieldbuses use their own serial transmission technologies with comparatively low data rates. Industrial Ethernet is based on Ethernet technology, supplemented by real-time mechanisms for automation. It offers higher data rates and can be connected more easily to IT networks. In the broader sense, Ethernet-based systems are now also referred to as fieldbuses. - **What is a device description file?** A device description file describes the properties of a bus node, such as data volume, parameters and diagnostic messages, in a standardised format. The controller’s engineering software needs this file to integrate the device. When replacing with a different model or a new version, an updated file may be required. - **How can a fieldbus fault be recognised?** Typical signs are failed nodes, sporadic communication dropouts or error messages in the controller. Diagnostic LEDs on modules and the controller’s diagnostic functions help to narrow down the fault. Common causes are cable and connector damage, missing terminating resistors, shielding problems or duplicate addresses. #### Flow meter URL: https://www.ktb-europe.com/en/glossary/flow-meter/ A flow meter measures how much liquid, gas or steam flows through a pipe per unit of time, either as volume or as mass. Flow meters measure volume or mass flows in process plants, water supply, cooling circuits or dosing lines. Measurements are taken for process control, consumption metering or monitoring pumps and filters. Depending on the measuring principle, they are suited to particular media, temperatures and pressures. Many devices consist of a sensor in the pipe and a transmitter that is either mounted compactly on top or installed separately. Electromagnetic flow meters measure conductive liquids without any obstructions in the pipe. Coriolis meters measure mass flow and density directly. Ultrasonic meters work with transit time differences, some even clamped onto the outside of the pipe. Vortex meters are suitable for gases and steam, while variable area flow meters often display the flow purely mechanically. Key parameters are nominal size, measuring range, accuracy, pressure rating, process connection, liner and electrode materials, output signal and degree of protection. Typical problems are deposits, entrained air, abrasion of the liner and unfavourable inlet runs. For measurements relevant to billing or quality, regular calibration is also required. Straight, undisturbed inlet and outlet runs upstream and downstream of the device significantly improve the measuring accuracy of many methods. In practice: For a replacement, the measuring principle, nominal size, pressure rating, flange or connection standard, medium, temperature, measuring range, materials, output signal and power supply are needed. For a remote version, state whether the sensor, the transmitter or both are required. Also known as: flowmeter, flow sensor, magnetic flow meter (magmeter), flow measuring device, flow transmitter Frequently asked questions: - **What types of flow meter are there?** Common types are electromagnetic meters for conductive liquids, Coriolis meters for mass flow and density, ultrasonic flow meters, vortex meters for gases and steam, thermal mass flow meters for gases, and mechanical devices such as variable area, oval gear or turbine meters. The choice depends on the medium, the accuracy and the process conditions. - **What is the difference between volume flow and mass flow?** Volume flow states how much space the medium occupies per unit of time, for example in litres per minute. Mass flow states the weight per unit of time, for example in kilograms per hour. For gases and temperature-dependent liquids, mass flow is more meaningful, because volume changes with pressure and temperature. - **What information is needed to replace a flow meter?** Needed are the measuring principle, nominal size, pressure rating, connection standard, medium with temperature and conductivity, measuring range, liner and electrode materials, output signal, supply voltage and degree of protection. The nameplate usually contains an order code that encodes these features and makes identification easier. - **Does a flow meter need to be calibrated?** Whether and how often calibration is carried out depends on the application. For measurements used for billing, dosing or product quality, quality management or statutory requirements set the inspection intervals. Replacement devices are generally supplied factory-calibrated; a calibration certificate should be requested when ordering if it is needed. #### Frequency inverter (VFD) URL: https://www.ktb-europe.com/en/glossary/frequency-inverter/ A frequency inverter is an electronic device that converts the frequency and voltage of the mains supply to control the speed of three-phase motors steplessly. On the mains, three-phase motors run at a fixed speed that depends on the mains frequency and the number of poles. A frequency inverter makes the speed variable by supplying the motor with a voltage of adjustable frequency and amplitude. It enables soft starting, speed control, positioning tasks and braking operation. The usual design comprises three stages: a rectifier converts the AC mains voltage into DC voltage, the DC link with capacitors smooths and stores it, and an inverter with power semiconductors uses pulse width modulation to generate the required output voltage. Particularly with pumps and fans, considerable energy can be saved by adjusting the speed instead of throttling. Parameters are used to set motor data, ramps, limit values, control methods and communication interfaces. As an electronic component, the frequency inverter is subject to comparatively rapid obsolescence: device generations are discontinued, and successors differ in dimensions, connections and parameterisation. DC link capacitors and fans age and are among the typical causes of failure. For critical drives it is therefore advisable to record the installed device types and check their availability status regularly. In practice: The parameter settings should be backed up regularly and filed with the plant documentation; without them, a replacement is considerably more laborious. An enquiry requires nameplate data, power, mains voltage, communication interface and options used. For discontinued devices, it pays to look at successors and their differences early on. Also known as: variable frequency drive (VFD), VFD, inverter, AC drive, variable speed drive (VSD) Frequently asked questions: - **How does a frequency inverter save energy?** With pumps and fans, the power required falls much more sharply than the speed. If the flow rate is adjusted by lowering the speed instead of using throttle flaps or valves, power consumption falls accordingly. How large the saving is depends on the plant's load profile; with continuous full load, the effect is small. - **What is the difference between a frequency inverter and a soft starter?** A soft starter limits current and torque only during starting and stopping; after that, the motor runs at mains speed. A frequency inverter, by contrast, controls the speed throughout operation. Soft starters are simpler and less expensive but are not suitable for applications that require variable speed. - **What should be backed up before replacing a frequency inverter?** Before replacement, all parameters should be read out and saved using the relevant software or an operator panel. These include motor data, ramps, limit values, input and output assignments and communication settings. Photos of the wiring are also helpful. When changing to a successor device, the parameters often have to be transferred or reassigned. - **Why do frequency inverters sometimes fail after long storage?** The electrolytic capacitors in the DC link age even when not in use. After prolonged storage, it may be necessary to reform them gently before first commissioning, i.e. to apply voltage gradually. For stored spare devices, it is advisable to follow the manufacturer's instructions on storage time and reforming. #### Geared motor URL: https://www.ktb-europe.com/en/glossary/geared-motor/ A geared motor is a drive unit consisting of an electric motor and an attached gearbox that reduces speed and increases torque at the output shaft. In a geared motor, the motor and gearbox are combined into a compact unit. The gearbox reduces the high motor speed to the speed required at the machine, increasing the torque accordingly. Geared motors drive conveyor belts, agitators, lifting equipment, dosing units and many other machines. By type of gearbox, a distinction is made between, among others, helical geared motors with a coaxial output shaft, parallel shaft geared motors for shaft-mounted installation, bevel geared motors with right-angle output and good efficiency, and worm geared motors, which are compact and quiet-running but achieve lower efficiencies. Key parameters are the gear ratio, output speed, output torque, permissible overhung load and the service factor, which indicates how much reserve the gearbox has relative to the load in the particular application. The parts subject to wear are mainly shaft seals, bearings and the gear oil. In the event of a failure, the question arises whether the motor or gearbox can be repaired individually or the entire unit must be replaced. Output dimensions, fixing and mounting position determine whether an alternative make fits without modification. In practice: An enquiry requires the nameplate data of the motor and gearbox, plus the mounting position, output shaft (solid shaft or hollow shaft with dimensions), flange or foot mounting and any brake. A photo of the installation situation helps when checking alternatives. Also known as: gear motor, gearmotor, geared drive, drive unit, gear reducer motor Frequently asked questions: - **What is the difference between a helical and a bevel geared motor?** In a helical geared motor, the output shaft is in line with or parallel to the motor shaft. In a bevel geared motor, the rotary motion is deflected by 90 degrees, so that the motor lies at right angles to the driven shaft. The choice depends mainly on the installation space available and the layout of the machine; both designs achieve good efficiencies. - **What does the service factor indicate for geared motors?** The service factor describes the ratio between the permissible torque of the gearbox and the torque actually required. It takes into account influences such as shock loads, switching frequency and daily operating time. A factor above the minimum value recommended for the application means reserve; values that are too low shorten the service life of the gearing and bearings. - **What information is needed for a replacement geared motor?** Required are the motor's power, voltage and frequency, the output speed or ratio, output torque, gearbox type, mounting position and the type and dimensions of the output shaft. In addition, the mounting method, flange dimensions and additional equipment such as a brake or encoder are needed. If nameplate data are missing, dimensions and photos of the installation situation help. - **Why is the mounting position important for a geared motor?** The oil quantity, the position of the breather, oil level and drain plugs, and the lubrication of the gearing all depend on the mounting position. If a gearbox is operated in a position other than the one intended, parts may be insufficiently lubricated or oil may leak. The mounting position therefore belongs in every spare parts enquiry. #### Helical gearbox (spur gear unit) URL: https://www.ktb-europe.com/en/glossary/helical-gearbox/ A helical gearbox transmits torque via externally toothed gears on parallel shafts and is considered a robust, highly efficient type of gearbox. Cylindrical gears are toothed around their circumference. In a helical or spur gear unit, pairs of gears mesh on parallel shafts. Several stages in series produce higher ratios. This design has high efficiency per stage, a simple construction and is easy to maintain. Coaxial versions keep the output in line with the input, while shaft-mounted designs with parallel offset shafts save installation space in length. Straight-cut spur gears are easy to manufacture but run more noisily. Helical gears have more teeth in mesh at the same time, run more quietly and carry more load, but generate axial forces that have to be absorbed by the bearings. Key ratings are ratio, number of stages, rated torque, service factor, centre distance, mounting position and shaft design. In geared motors, the helical gearbox is connected directly to the electric motor. It is used in conveyor belts, pumps, agitators, hoists, mixers and many other machines. Wear parts are bearings, shaft seals and gaskets; damage to the gearing is mainly caused by overload, lack of lubricant or contaminated oil. In practice: For replacement or repair, nameplate data, ratio, mounting position and the shaft or flange design must be stated. Stocking seal kits and bearings for installed gearbox types shortens repairs, because the gearing itself fails less often than these components. Also known as: spur gearbox, helical gear unit, helical geared motor, gear reducer Frequently asked questions: - **What is the difference between straight and helical gearing?** With straight gearing, the teeth run parallel to the axis; with helical gearing, they run at an angle to it. Helical gears engage gradually, run more quietly and transmit more load for the same width. In return, an axial force acts on the bearings. Straight gearing is easier to manufacture and produces no axial force. - **When is a helical gearbox better than a worm gearbox?** When energy efficiency is important and the machine runs for long periods, because the helical gearbox has significantly lower friction losses. A worm gearbox makes sense when a right-angle output, a high ratio in a single stage or particularly quiet running is required. For right-angle drives with high efficiency, a helical-bevel gearbox is often chosen. - **What information is needed to replace a helical gearbox?** The manufacturer’s type designation, size, ratio, mounting position, shaft design and, where applicable, flange dimensions are important. If the gearbox is part of a geared motor, the motor data are also needed. If the nameplate is missing, photos, centre distance, shaft diameters and mounting dimensions help in the search for a dimensionally identical gearbox. - **How can damage to a helical gearbox be recognised?** Signs include changed noise, higher vibration, rising temperature, oil loss and metal particles in the oil. Vibration analysis and oil analysis often reveal gearing and bearing damage long before a failure. During inspections, the gearing can be checked for pitting and wear through the inspection opening or with an endoscope. #### HMI (human-machine interface) URL: https://www.ktb-europe.com/en/glossary/hmi/ An HMI (human-machine interface) is the operator interface of a machine, usually a touch panel, through which operators monitor and control processes. An HMI connects people and machines: it displays states, measured values, alarms and recipes and accepts inputs, such as setpoints or start and stop commands. In practice, the term is mostly used for operator panels connected to the PLC via a communication interface. Larger plants are additionally operated via control systems or visualisation software on PCs. Designs range from text displays with keys through touch panels with various screen sizes to panel PCs with a full operating system. Key parameters are display size and resolution, mode of operation, interfaces, supply voltage, mounting cut-out, front-side degree of protection and the configuration software used, including its version. Panels with a higher front-side degree of protection and stainless steel frames are used in areas subject to washdown. Typical faults are failed backlighting, unresponsive touch surfaces, damaged front membranes and memory errors. When replacing a panel, the project matters as much as the hardware: without a backed-up project file or compatible firmware, a new panel often cannot be commissioned. Discontinued panels frequently require migration of the visualisation. In practice: For every operator panel, back up the current project file, software version and firmware, ideally on a memory card as well. For an enquiry, the manufacturer part number, display size, interfaces and mounting cut-out are needed so that a successor model fits mechanically and electrically. Also known as: operator panel, human-machine interface, touch panel, operator interface terminal, HMI panel Frequently asked questions: - **What is the difference between an HMI and a PLC?** The PLC runs the control program and switches drives, valves and other actuators. The HMI is only the operator interface: it displays data from the PLC and transmits operator inputs to it. If the HMI fails, the machine may continue to run, depending on the programming, but can hardly be operated. - **What needs to be considered when replacing an operator panel?** Important are an up-to-date backup of the project, the matching version of the configuration software and compatible firmware on the replacement device. With a successor model, the mounting cut-out, interfaces and screen resolution must be checked, as otherwise screens may shift or communication with the controller may fail. - **What information is needed to replace an HMI?** Needed are the manufacturer part number from the nameplate, display size, mode of operation, interfaces to the controller, supply voltage, mounting cut-out and firmware version. It is also helpful to state which software and version were used to create the project, so that transfer of the visualisation can be checked. #### Induction motor (three-phase asynchronous motor) URL: https://www.ktb-europe.com/en/glossary/induction-motor/ An induction motor is a three-phase motor whose rotor turns slightly slower than the rotating field; it is the most widely used industrial drive. In the stator of an induction motor, the three-phase current generates a rotating magnetic field. This induces currents in the rotor, whose magnetic field produces torque. The rotor turns slightly slower than the rotating field; this difference is called slip. The most common design is the squirrel-cage rotor with short-circuited conductor bars. It is robust, brushless and low-maintenance. Slip-ring rotors are found in special applications. Key ratings are rated power, voltage and connection (star or delta), frequency, rated speed, number of poles, rated current, power factor and efficiency class to IEC 60034-30-1. Mechanically, shaft height or frame size, mounting arrangement (foot, flange or both), shaft dimensions, degree of protection, cooling method and insulation class all count. Speed is determined by the number of poles or by a frequency inverter. Induction motors drive pumps, fans, compressors, conveyor belts and agitators and are therefore present in every maintenance department. Common causes of failure are bearing damage, moisture in the winding, overload, phase loss and overheating due to dirty cooling fins. Vibration measurement, insulation resistance testing and thermography help to detect damage before the motor fails. Repairs usually involve replacing the bearings or rewinding. In practice: For a replacement, power, voltage, speed, frame size, mounting arrangement, degree of protection and shaft dimensions are needed from the nameplate; IEC standard motors of the same frame size are usually interchangeable in terms of mounting. It should also be checked whether a higher efficiency class is mandatory for the replacement motor and whether this changes the overall length or starting current. Also known as: three-phase induction motor, asynchronous motor, squirrel-cage motor, three-phase motor, IEC standard motor Frequently asked questions: - **What does slip mean in an induction motor?** Slip is the relative difference between the speed of the rotating field and the actual rotor speed. Without this difference, no voltage would be induced in the rotor and no torque would be produced. As the load increases, slip increases and speed drops slightly. This is why the rated speed is always somewhat below the synchronous speed. - **What is the difference between star and delta connection?** In star connection, each winding receives a lower voltage than in delta connection. Which connection is correct depends on the supply voltage and the voltage stated on the nameplate. Star-delta starting uses the changeover to limit the starting current. An incorrect connection leads to loss of power or overheating. - **What information is needed to replace an induction motor?** From the nameplate, power, voltage and connection, frequency, speed, current, frame size, mounting arrangement, degree of protection and efficiency class are needed. Shaft diameter and length, flange size, terminal box position and special versions such as forced ventilation, brake, encoder or explosion protection are also important. A photo of the nameplate is usually the quickest starting point. - **What do IE2, IE3 and IE4 mean?** These are efficiency classes to IEC 60034-30-1, rising from IE1 to IE4. A higher class means lower losses at the same output. In the EU, an ecodesign regulation sets minimum requirements for placing many motors on the market. Which class applies to a specific motor depends on power, number of poles and design and must be checked case by case. #### Inductive proximity sensor URL: https://www.ktb-europe.com/en/glossary/inductive-proximity-sensor/ An inductive proximity sensor is a non-contact proximity switch that detects metal objects by means of a high-frequency alternating electromagnetic field. An inductive sensor generates an alternating field at its active face. When a metal part approaches, eddy currents arise in it that draw energy from the oscillator; the electronics evaluate this damping and switch the output. Because it works without contact and without moving parts, it is resistant to dirt, oil and vibration and is suitable for position detection on machines, end positions or speed monitoring. Typical applications are end-position detection on cylinders, cam detection and counting metal parts on conveyors. Key ratings are the rated sensing distance, the housing style (cylindrical with thread or rectangular), flush or non-flush mounting, output type (PNP, NPN, normally closed or normally open, analogue), supply voltage, switching frequency and degree of protection. The real sensing distance depends on the material and is usually smaller for non-ferrous metals than for steel. Basic requirements for proximity switches are described in IEC 60947-5-2. Failures are often caused by mechanical damage, cable breakage or chips on the active face. Inductive sensors are typical wear parts and stock items that can be kept on hand with little effort. For welding applications, versions with a coating against weld spatter and immunity to magnetic fields are used. In practice: For a replacement, the manufacturer part number or housing style with thread size, sensing distance, mounting type, output type, contact function, voltage and connector are usually sufficient. Where many variants are in use, it is worth standardising on a few standard types. Also known as: inductive proximity switch, inductive sensor, proximity sensor, prox switch Frequently asked questions: - **What is the difference between an inductive and a capacitive sensor?** An inductive sensor only responds to metal, because it evaluates eddy currents in the object. A capacitive sensor, by contrast, detects changes in an electric field and therefore also responds to plastic, wood, liquids or bulk materials. For pure metal detection, the inductive sensor is usually less susceptible to interference. - **What do PNP and NPN mean for sensors?** PNP and NPN describe the type of transistor output. A PNP output switches the positive supply voltage to the output, an NPN output switches to ground. Which variant fits depends on the input card of the controller. When replacing, the output type must match, otherwise the signal will not be recognised. - **What information is needed to replace an inductive proximity sensor?** Housing style and size, sensing distance, flush or non-flush mounting, PNP or NPN output type, normally closed or normally open, supply voltage, connection type with connector type and degree of protection are needed. If the manufacturer part number is legible, this is usually sufficient to identify a suitable spare part. #### Industrial automation URL: https://www.ktb-europe.com/en/glossary/industrial-automation/ Industrial automation covers devices, software and methods used to control, regulate and monitor machines and processes automatically. The aim of industrial automation is to carry out recurring sequences reliably without constant human intervention. It combines electrical engineering, mechanical engineering and computer science. A broad distinction is made between factory automation, for example in machine tools and packaging lines, and process automation, for example in the chemical, paper or food industries. An automated system consists of sensors that detect states such as position, pressure or temperature, controllers such as PLCs or industrial PCs that make decisions according to a program, and actuators such as motors, valves and cylinders that intervene. Operator panels are used for interaction with personnel, while fieldbuses and Ethernet-based networks connect the levels. This is often shown as the automation pyramid, from the field level up to the enterprise level. For maintenance, automation means a large number of electronic components with short product life cycles. Discontinuation of controllers, drive controllers or operator panels affects plants that could mechanically run for decades more. Spare parts management in automation must therefore take account of software, firmware versions and compatibility as well as mechanics. Where successor products do not fit, stockholding, alternative parts or a retrofit of the control system are planned. In practice: An up-to-date register of all automation components with manufacturer part number, firmware and software version and backed-up programs is the basis for rapid replacement. For critical control components, a regular check of the life cycle status is worthwhile. Also known as: automation technology, factory automation, process automation, control engineering Frequently asked questions: - **What does industrial automation include?** It includes sensors and transmitters, controllers such as PLCs and industrial PCs, operator control and monitoring devices, drives with motors and inverters, valves and cylinders, and communication technology such as fieldbuses. This is supplemented by safety technology, control cabinet building and software for programming, visualisation and data acquisition. - **What is the difference between factory automation and process automation?** Factory automation controls discrete sequences in which individual items are machined, assembled or packaged. Process automation regulates continuous or batch processes involving liquids, gases or bulk materials, such as temperatures, pressures and flows. Both use similar components but place different emphasis on control and safety. - **Why are automation parts often difficult to source?** Electronic components have considerably shorter life cycles than the machines in which they are installed. Manufacturers discontinue product ranges, and successors are not always plug-compatible or software-compatible. Semiconductor shortages add to this. That is why inventory, life cycle monitoring and timely stockholding of critical parts are important. - **What is the automation pyramid?** The automation pyramid arranges the levels of a company hierarchically: at the bottom the field level with sensors and actuators, above it the control and process control levels, and above those the plant management and enterprise levels with production and planning systems. The model illustrates data flows but is becoming increasingly permeable in networked plants. #### Industrial connector URL: https://www.ktb-europe.com/en/glossary/industrial-connector/ An industrial connector is a robust, detachable electrical connection for power, signals or data in machines, plants and control cabinets. Industrial connectors differ from appliance plugs in their mechanical robustness, locking and protection against dust and water. They make it possible to connect sensors, drives or entire machine modules quickly and to disconnect them again during repair or conversion without rewiring individual cores. Common types are small circular connectors with M8 or M12 threads for sensors and data transmission, and rectangular connectors with housings and interchangeable contact inserts for power and signals. Important parameters are number of poles, rated voltage and current, coding, connection technology (crimp, screw or spring-loaded terminal), conductor cross-section, IP rating and temperature range. Coding prevents incorrect mating; with M12, for example, it separates sensor, power and Ethernet variants. Typical causes of failure are corroded or widened contacts, aged seals, broken locking mechanisms and tensile load at the cable outlet. Because housing, insert and contacts are often ordered separately, a complete designation of each component is decisive for a replacement. For procurement, it pays to standardise connectors across plants. Fewer designs and codings mean fewer stock items, less risk of mix-ups and faster replacement when faults occur at sensors or drives. In practice: For a replacement enquiry, the design, number of poles, coding, male or female side, connection technology, conductor cross-section and the manufacturer part numbers of housing and insert should be available. A photo of the mating face with the coding visible avoids mix-ups. Also known as: M12 connector, circular connector, rectangular connector, heavy-duty connector Frequently asked questions: - **What does the coding on M12 connectors mean?** The coding is a mechanical shape in the mating face that only accepts matching counterparts. There are several codings for M12, for example for sensors and actuators, for power supply and for Ethernet data lines. This prevents a data cable from being plugged into a power socket by mistake. When replacing, the coding must match exactly, otherwise the connector will not fit. - **What information is needed to replace an industrial connector?** Needed are design and size, number of poles, coding, male or female version, connection technology and conductor cross-section, as well as the required IP rating. For rectangular connectors, housing, contact insert and contacts must be specified separately. The manufacturer part number of each component and a photo of the mating face make unambiguous identification easier. - **What is the difference between crimp and screw connections?** With a crimp connection, the contact is permanently pressed onto the conductor with a special tool; this is fast, vibration-resistant and reproducible but requires the right tool. With a screw connection, the conductor is secured with a clamping screw and can be fitted without special tools. Spring-loaded connections are a third variant that requires few tools. - **What IP rating do connectors in production need?** That depends on the location. In the control cabinet, a low level of protection is often sufficient; on the machine, with coolant, dust or cleaning, IP65, IP67 or higher is usually required. The IP rating only applies when the connector is mated and locked; open sockets need protective caps. #### Industrial gearbox URL: https://www.ktb-europe.com/en/glossary/industrial-gearbox/ An industrial gearbox is a gearbox for machinery and plants that adapts the speed and torque of a drive to the needs of the driven machine. Industrial gearboxes reduce the usually high speed of an electric motor to a lower output speed while increasing torque. The term covers compact geared motors as well as large gearboxes with several megawatts of power for mills, rolling mills, extruders or conveyor systems. They are distinct from miniature gearboxes in devices and from precision gearboxes for measuring technology. By type of gearing, a distinction is made between helical, bevel, worm and planetary gearboxes as well as combinations such as helical-bevel gearboxes. Key ratings are ratio, rated torque, service factor, mounting position, shaft design (solid shaft, hollow shaft, flange) and type of lubrication. Larger gearboxes have oil cooling, circulating lubrication and monitoring of oil temperature, oil level or vibration. Sizing takes into account load type, switching frequency and daily operating time. Wear mainly affects bearings, shaft seals and gearing. Typical damage patterns are pitting, scuffing and tooth breakage. Oil analysis, vibration measurement and endoscopy help to detect damage early and to plan repairs before unplanned downtime occurs. For critical drives, a spare gearbox or a set of spare bearings is often kept in reserve, because new gearboxes in large sizes can have long lead times. In practice: For spare parts or an exchange gearbox, nameplate data such as type, ratio, size, mounting position and serial number are decisive. For large gearboxes, a repair with bearing and seal replacement is often available sooner than a new gearbox; spare bearings and seal kits should be stocked in good time for this purpose. Also known as: industrial gear unit, reduction gearbox, speed reducer, gear reducer Frequently asked questions: - **What types of industrial gearboxes are there?** The basic types are helical gearboxes, bevel gearboxes, worm gearboxes and planetary gearboxes. They differ in the axis arrangement of input and output, efficiency, achievable ratio and installation space. In practice, they are often combined, for example as a helical-bevel gearbox for a right-angle output with high efficiency. - **What is the service factor of a gearbox?** The service factor takes into account how much the actual load deviates from a uniform load. Shocks, frequent starts and long daily running times increase the required factor. The gearbox is selected so that its rated torque divided by the load torque at least reaches this value. When replacing, the service factor should not be lower than that of the original. - **What information is needed to replace an industrial gearbox?** Essential are the nameplate data with type, size, ratio, rated torque, mounting position and serial number. In addition, shaft and flange design, mounting dimensions, oil type and oil quantity as well as details of the motor and drive power are needed. For older gearboxes, photos of the installation situation and dimensional sketches help to identify a dimensionally identical replacement gearbox. - **When should the gear oil be changed?** The interval is stated in the operating instructions and usually depends on oil type, oil temperature and operating hours. Synthetic oils generally allow longer intervals than mineral oils. Regular oil analysis shows ageing, water and wear particles and helps to set the change according to need rather than purely by the calendar. #### Industrial PC URL: https://www.ktb-europe.com/en/glossary/industrial-pc/ An industrial PC is a computer designed for harsh production environments that handles control, visualisation and data tasks on machines. Industrial PCs differ from office PCs in their robust housings, extended temperature ranges, resistance to vibration and dust and the long-term availability of individual components. Many models are fanless and use flash storage instead of rotating hard disks. They are used for visualisation, software-based control, image processing, test benches and data acquisition. They frequently also run software controllers that replace a conventional PLC. Designs include DIN rail and box PCs, rack-mount PCs for control cabinets, panel PCs with an integrated touch display and computers in protective enclosures for use directly at the machine. Key ratings are processor, RAM, mass storage, interfaces (Ethernet, fieldbus, serial ports, expansion slots), supply voltage, operating system, temperature range and degree of protection. Many manufacturers offer configurations unchanged over a long period. Failures frequently affect storage media, power supplies, fans and displays. Because software, licences and drivers can be tied to the hardware, a replacement is more complex than for other components. In addition, there is obsolescence when processors, chipsets or operating systems are no longer supported. For long-lived plants, an early look at successor models and migration paths is therefore advisable. In practice: Create a complete image of the storage medium of every industrial PC and document licences, drivers and plug-in cards. In an enquiry, the manufacturer part number, configuration and operating system are important, because a successor model may require different drivers or licences. Also known as: IPC, industrial computer, panel PC, box PC, embedded PC Frequently asked questions: - **What is the difference between an industrial PC and a standard PC?** An industrial PC is designed for continuous operation, higher ambient temperatures, dust and vibration and often has no moving parts. In addition, components and configuration are offered unchanged for longer periods, which is important for machines with a long service life. Office PCs, by contrast, change their components frequently and are intended for clean, temperature-controlled rooms. - **What is a panel PC?** A panel PC combines an industrial PC with a built-in display, usually with touch operation, in one housing. It is installed in control cabinet doors or operator consoles and handles visualisation and computing tasks at the same time. Unlike a pure operator panel, it runs a fully fledged operating system. - **What information is needed to replace an industrial PC?** The manufacturer part number, design, processor, RAM, mass storage, interfaces and plug-in cards, supply voltage, operating system and, where applicable, display size are needed. It should also be clarified which software and licences run on the device and whether a storage image can be transferred. Without this clarification, a technically suitable device may still not be ready for immediate use. #### Linear guide URL: https://www.ktb-europe.com/en/glossary/linear-guide/ A linear guide is a machine element that guides moving assemblies precisely along a straight axis while absorbing forces and moments. Linear guides enable straight-line movements with low friction and high repeatability. The most widespread are profile rail guides: a carriage runs on a hardened rail, with balls or rollers circulating in its recirculation channels. There are also shaft guides with linear ball bushings, plain slideways, and roller and track roller guides for long travel and harsh environments. They largely determine the accuracy of a machine. Recirculating roller guides are stiffer and have a higher load capacity than recirculating ball guides and are preferred in machine tools. Important parameters are size, rail length, carriage type (flanged or narrow, short or long), load ratings, preload class and accuracy class. Preload determines stiffness, and the accuracy class the tolerances of height and parallelism. Wipers and seals protect the recirculation channels from chips and coolant. Linear guides are found in machine tools, handling equipment, packaging machines and measuring systems. Causes of failure are inadequate lubrication, contamination, damaged wipers, installation errors on the rail mounting surface and overload due to collisions. Repair is usually limited to replacing carriages, wipers or lubrication units; damaged rails, by contrast, must be replaced and realigned. In practice: To replace a carriage, the size, carriage type, preload, accuracy class and the associated rail must be known. Not every carriage fits every rail of the same system, so it should be checked whether carriage and rail are marked as interchangeable. Also known as: profile rail guide, linear motion guide, linear guideway, linear rail, linear bearing system Frequently asked questions: - **What is the difference between recirculating ball and recirculating roller guides?** In a recirculating ball guide, balls carry the load via point contact; in a recirculating roller guide, cylindrical rollers do so via line contact. Roller guides are stiffer, carry more and damp vibration better; they are common in metal-cutting machines. Ball guides run with less friction and more easily and are suited to fast, less heavily loaded axes, for example in handling and assembly. - **Can just the carriage be replaced?** Yes, if the system is designed for this and the rail is undamaged. Many manufacturers offer interchangeable carriages and rails in certain accuracy and preload classes. For high-precision or matched systems, however, carriage and rail are intended to be replaced together. Running marks or pitting on the rail require it to be replaced. - **What information is needed to replace a linear guide?** Needed are the complete type designation of carriage and rail, that is, size, carriage type, preload and accuracy class, rail length, hole spacing and type of fastening. Special features such as additional wipers, lubrication connections or corrosion protection are added. Without a designation, rail width, carriage height, flange dimensions and photos help. - **How often does a linear guide need to be lubricated?** The interval depends on load, speed, stroke and environment and is specified by the manufacturer as a travel distance or time period. Short-stroke applications and environments with coolant often require more frequent lubrication. Many machines have a central lubrication system whose function should be checked regularly, as inadequate lubrication is a common cause of failure. #### Motor protection circuit breaker URL: https://www.ktb-europe.com/en/glossary/motor-protection-circuit-breaker/ A motor protection circuit breaker is a switching device that disconnects motors on overload, phase failure and short circuit and can also be switched manually. The motor protection circuit breaker combines several functions: it switches a motor on and off, protects it against overheating with an adjustable thermal or electronic overload release and interrupts short-circuit currents with a magnetic instantaneous release. Many devices also detect phase failure. It therefore replaces the combination of fuse and overload relay in many motor feeders. The overload release is set to the rated current of the motor; each device has a limited setting range for this. The short-circuit release responds at a fixed multiple of the set current. Key parameters are setting range, rated voltage, short-circuit breaking capacity and trip class. Accessories such as auxiliary contacts, signalling contacts, undervoltage releases and shunt releases are mounted at the side or front. The motor protection circuit breaker is frequently combined with a contactor to form a load feeder. The requirements are described in the IEC/EN 60947 series of standards. The motor protection circuit breaker is standard in the control cabinets of pumps, fans and conveyor systems. Tripping usually points to a cause at the motor or the driven machine, such as stiff bearings, a blockage or phase failure. In practice: For a replacement, what matters is a setting range that matches the motor current, the short-circuit breaking capacity at the installation location, the frame size and existing accessories such as auxiliary contacts. If a motor protection circuit breaker trips repeatedly, the cause at the drive should be clarified before replacement. Also known as: MPCB, motor circuit breaker, manual motor starter, motor starter protector, motor protective switch Frequently asked questions: - **What is the difference between a motor protection circuit breaker and a miniature circuit breaker?** The miniature circuit breaker protects cables and wiring against overload and short circuit and has fixed tripping characteristics. The motor protection circuit breaker is designed for motors: its overload release is set precisely to the motor current, it tolerates starting currents and often detects phase failure. It is therefore the right choice for motor feeders. - **How is a motor protection circuit breaker set correctly?** The overload release is generally set to the rated current on the motor nameplate, matching the voltage and connection actually used. Deviations only make sense in accordance with the manufacturer’s instructions. Too high a value endangers the motor, too low a value leads to nuisance tripping. The motor current must lie within the setting range of the device. - **What information is needed to replace a motor protection circuit breaker?** Important are the type designation, setting range, rated voltage, required short-circuit breaking capacity and frame size for mounting. Also relevant are fitted accessories such as auxiliary contacts or undervoltage releases and any link modules to the contactor. A photo of the front usually provides all the data. - **Why does the motor protection circuit breaker keep tripping?** Possible reasons are overload from the driven machine, stiff bearings, starts that are too long or too frequent, phase failure, voltage imbalance, an incorrect setting or winding damage. High ambient temperatures in the control cabinet also affect thermal releases. Current measurement on all three phases and insulation testing of the motor help to find the cause. #### Photoelectric sensor URL: https://www.ktb-europe.com/en/glossary/photoelectric-sensor/ A photoelectric sensor is an optical sensor that detects objects as soon as they interrupt or reflect a light beam between emitter and receiver. Photoelectric sensors belong to the optoelectronic sensors and are used in automation for counting, positioning and presence detection, for example on conveyor lines, in packaging plants or on storage and retrieval machines. They usually work with red light, infrared or laser light. They should not be confused with safety light curtains, which are designed as protective devices for people. In a through-beam sensor, emitter and receiver face each other; it achieves long ranges. The retro-reflective sensor uses a reflector, often with a polarisation filter for shiny objects. The diffuse sensor evaluates the light reflected back by the object, and variants with background suppression ignore objects beyond a set distance. Key parameters are range, light type, output type, light-on or dark-on switching, response time, degree of protection and design. Laser light allows a very small light spot for detecting small parts. Faults are mostly caused by dirty optics, misaligned brackets, damaged reflectors or ambient light. Regular cleaning and stable mounting prevent many failures. Many devices use a stability indicator to show when the optics should be cleaned or realigned. In practice: For a spare parts enquiry, the manufacturer part number, operating principle, range, light type, output type, light-on or dark-on switching, voltage and connector are needed. For through-beam sensors, always state whether the emitter, the receiver or both are to be replaced. Also known as: photo eye, light barrier, through-beam sensor, retro-reflective sensor, diffuse sensor Frequently asked questions: - **What is the difference between a light barrier and a diffuse sensor?** A light barrier works with a separate receiver or reflector; the object is detected when it interrupts the beam. A diffuse sensor emits light and detects the object by the light reflected back, so no counterpart is needed. Diffuse sensors are easier to mount but usually have shorter ranges. - **What do light-on and dark-on switching mean?** With light-on switching, the output is active when light falls on the receiver. With dark-on switching, it is active when the light path is interrupted. Many devices can be switched between the two. When replacing, the switching logic must match, otherwise the controller works with inverted signals. - **May a standard photoelectric sensor be used to protect people?** No. To protect people at danger points, safety light barriers or safety light curtains are required, which are designed as safety components and monitor themselves. A standard photoelectric sensor can fail without this being detected and is therefore only suitable for process tasks. #### Plain bearing URL: https://www.ktb-europe.com/en/glossary/plain-bearing/ A plain bearing is a bearing in which the shaft and bearing surface slide on one another, separated by a lubricating film or a low-friction material. A plain bearing has no rolling elements. The shaft rotates or moves linearly in a bush or bearing shell. Depending on the design, a load-bearing lubricating film separates the surfaces, or the bearing material itself ensures low friction. Plain bearings are insensitive to shocks, run quietly, require little installation space and are also suitable for oscillating movements and slow rotation, where rolling bearings tend to develop false brinelling. Hydrodynamic plain bearings build up the lubricating film through the rotation itself; they are used in large turbomachinery, compressors and electric motors. Hydrostatic bearings receive oil pressure from an external pump. Maintenance-free or low-maintenance bushes are made of oil-impregnated sintered bronze, composite materials with a sliding layer or plastic. Key parameters are inner and outer diameter, width, material, permissible surface pressure, sliding speed and temperature range. Wear becomes apparent through increased bearing clearance, scoring or seizure marks. Common causes are lack of lubricant, dirt, edge loading due to misalignment and operation outside the permissible load. In practice: For a bush, state the inner and outer diameter, width, any flange dimensions, material and type of lubrication. For large bearing shells from turbomachinery, a drawing or the manufacturer part number is usually required, because the lining and tolerances are specific to the plant. Also known as: sleeve bearing, bushing, journal bearing, plain bush, slide bearing Frequently asked questions: - **What is the difference between a plain bearing and a rolling bearing?** In a rolling bearing, balls or rollers roll; in a plain bearing, surfaces slide on one another. Rolling bearings have low starting friction and are standardised. Plain bearings cope better with shocks and vibration, run more quietly and need less radial space. With correct lubrication, hydrodynamic plain bearings achieve very long service lives, but they are sensitive to oil starvation. - **What is a maintenance-free plain bearing?** This refers to bushes that do not need relubrication. They are made, for example, of composite materials with a low-friction sliding layer, oil-impregnated sintered bronze or engineering plastics. Their load capacity and sliding speed are limited, and service life depends on the wear of the sliding layer. They are widely used for slow oscillating and linear movements. - **What information is needed to replace a plain bearing bush?** Important are inner and outer diameter with tolerance, width, for flanged bushes the flange diameter and flange thickness, material and details of lubrication. Type of movement, load, temperature and medium are also helpful. Since the same dimensions are offered in different materials, the original material should be known if possible. - **How can a worn plain bearing be recognised?** Typical signs are noticeable shaft play, unusual noises, increased temperature, rising vibration levels or metal particles in the lubricant. With circulating oil bearings, bearing temperature and oil analysis indicate the condition at an early stage. Scoring, seizure marks or melted-out sliding layers are visible on removal. #### Planetary gearbox URL: https://www.ktb-europe.com/en/glossary/planetary-gearbox/ A planetary gearbox is an epicyclic gear unit with sun gear, planet gears, ring gear and carrier that transmits high torques in a small space. In a planetary gearbox, several planet gears mesh simultaneously with the central sun gear and the internally toothed ring gear. The planets are mounted on a planet carrier. Because the load is distributed over several tooth meshes, the gearbox is very compact and power-dense and has coaxial input and output shafts. Depending on which element is held stationary, different ratios result. Two groups are common in industry. Precision planetary gearboxes are used on servo motors; what matters there is low backlash in arc minutes, torsional stiffness and smooth running. Heavy-duty planetary gearboxes drive mills, conveyors, agitators, cranes and wind turbines. Key parameters are ratio, number of stages, nominal and peak torque, backlash, permissible radial and axial forces at the output, and connection dimensions for motor and machine. In maintenance, the focus is on bearing damage, gear tooth wear and leaks. In servo gearboxes, wear often shows up as increasing backlash, which causes positioning errors or oscillation in the control loop. In heavy-duty gearboxes, oil condition and bearing temperature are often monitored in order to detect damage to planet bearings at an early stage. In practice: For servo planetary gearboxes, besides type and ratio, the motor adapter, shaft version and backlash class in particular must be stated so that mounting fits without modification. For heavy-duty gearboxes, the nameplate, serial number and mounting position are the basis for spare parts. Also known as: planetary gear, epicyclic gearbox, planetary gear reducer, servo gearbox, planetary gearhead Frequently asked questions: - **How does a planetary gearbox work?** A sun gear in the centre drives several planet gears, which also mesh with an outer ring gear. If the ring gear is fixed, the planets travel around the sun gear and take the planet carrier with them, which forms the output. This produces a reduction with coaxial input and output. Several stages in series give higher ratios. - **What does backlash mean in planetary gearboxes?** Backlash is the small angle through which the output can be moved back and forth without load while the input is held. It is usually stated in arc minutes. For positioning tasks with servo motors, low backlash is important because it directly affects accuracy. Backlash increases as wear progresses. - **What information is needed to replace a planetary gearbox?** Important are type designation, ratio, frame size, number of stages and backlash class, as well as output type such as keyed shaft, smooth shaft or flange, and the motor adapter with shaft diameter and flange dimensions. For heavy-duty gearboxes, mounting position, oil grade and serial number are added. A photo of the nameplate makes identification easier. - **What is the difference between a planetary gearbox and a helical gearbox?** In a helical gearbox, one pair of gears meshes at a time, and the shafts are parallel offset or coaxial over several stages. In a planetary gearbox, several planets share the load, which allows smaller dimensions for the same torque. Helical gearboxes are simpler in design and usually less expensive; planetary gearboxes are more compact and stiffer. #### Pressure gauge (manometer) URL: https://www.ktb-europe.com/en/glossary/pressure-gauge/ A pressure gauge is an instrument that displays the pressure of gases or liquids, in industry usually as a mechanical local dial instrument. Pressure gauges display the pressure directly at the measuring point, for example on pumps, compressors, hydraulic power units, compressed air service units or vessels. The most widespread type is the Bourdon tube pressure gauge to EN 837-1: a curved Bourdon tube straightens under pressure, and a movement transmits this motion to the dial. Diaphragm and capsule pressure gauges are suitable for low pressures and for aggressive or viscous media. They need no auxiliary power and therefore remain readable even during a power failure. Key parameters are nominal size (case diameter), scale range, accuracy class, process connection with thread and position (bottom or back mount), materials of the measuring system and case, and any liquid filling, which damps pointer oscillation caused by pulsation and vibration. For special cases there are diaphragm seals, contact pressure gauges with a switching function and differential pressure gauges. Diaphragm seals separate the instrument from the medium by means of a diaphragm, for example with hot, crystallising or hygienically sensitive substances. The accuracy class states the permissible deviation as a percentage of the full-scale value. Pressure gauges fail due to overload, pressure surges, vibration, corrosion or blocked connections. A sticking pointer, or one that does not return to zero, is a clear signal for replacement. Pressure gauges at important measuring points are regularly compared with a reference instrument. In practice: For a replacement, the nominal size, scale range, unit, accuracy class, connection thread and position, materials and, where applicable, filling are needed. Choose the scale range so that the operating pressure lies as far as possible in the middle third of the scale; this protects the measuring system. Also known as: manometer, Bourdon tube pressure gauge, pressure indicator, dial pressure gauge Frequently asked questions: - **What is the difference between a pressure gauge and a pressure sensor?** A pressure gauge displays the pressure locally, usually mechanically and without auxiliary power. A pressure sensor converts the pressure into an electrical signal that is transmitted to a controller and evaluated there. Both are often combined at the same measuring point: the gauge for visual checks, the sensor for control and alarms. - **What is the glycerine filling in a pressure gauge for?** The liquid filling, often glycerine or silicone oil, damps pointer oscillation caused by pulsating pressure and vibration, for example on pumps or compressors. This makes the value easier to read and protects the movement. For certain media, such as oxygen, special fillings or unfilled instruments are mandatory. - **What information is needed to order a pressure gauge?** Needed are nominal size, scale range and unit, accuracy class, connection thread, connection position bottom or back, material of case and measuring system, medium, and whether a filling or a contact is required. If the old instrument is still legible, the dial contains most of this information. #### Pressure sensor (pressure transmitter) URL: https://www.ktb-europe.com/en/glossary/pressure-sensor/ A pressure sensor, also called a pressure transmitter, detects the pressure of gases or liquids and converts it into an electrical measuring signal. Pressure sensors measure pressure in hydraulic and pneumatic systems, pipelines, vessels or pump installations. A sensing element, such as a diaphragm with strain gauges, a piezoresistive chip or a ceramic measuring cell, deforms under pressure; the electronics convert this change into a signal. A pressure transmitter delivers a standardised signal such as 4–20 mA, while a pressure switch switches at a set value. It often replaces or supplements a pressure gauge when the reading needs to be sent to a control system. A distinction is made between gauge, absolute and differential pressure measurement. Key ratings are measuring range, overload and burst pressure, accuracy, output signal, process connection (thread or flange), materials of wetted parts, media and ambient temperature, electrical connection and degree of protection. For potentially explosive atmospheres there are versions with ATEX marking, and for food applications there are hygienic connections. Failures are frequently caused by pressure peaks, cavitation, aggressive media, vibration or moisture in the electronics. A replacement unit must match the measuring range, signal and process connection exactly. Pressure peaks can be reduced with restrictors or damping elements in the connection. For safety-relevant or quality-critical measuring points, regular calibration is part of maintenance. In practice: For an enquiry, the manufacturer part number, measuring range, pressure type, output signal, process connection, medium, temperature range and electrical connection are needed. In hazardous areas, the ignition protection marking must also match. Also known as: pressure transmitter, pressure transducer, pressure measuring transducer, pressure sensing element Frequently asked questions: - **What is the difference between a pressure sensor and a pressure transmitter?** In everyday usage, the two terms are often used interchangeably. Strictly speaking, the pressure sensor is the sensing element that converts pressure into an electrical quantity. The pressure transmitter also contains the electronics that turn this into a standardised, interference-resistant signal such as 4–20 mA and transmit it to the control system. - **What do gauge pressure, absolute pressure and differential pressure mean?** Gauge pressure is measured relative to the current ambient air pressure and is the most common in plants. Absolute pressure uses vacuum as its zero point. Differential pressure is the difference between two measuring points, for example upstream and downstream of a filter, to monitor how clogged it is. - **What information is needed to replace a pressure sensor?** The manufacturer part number, measuring range, pressure type, output signal, supply voltage, process connection with thread type, material of wetted parts, medium, temperature range, electrical connection and degree of protection are needed. For measurements in potentially explosive atmospheres, the Ex marking is mandatory; for food applications, details of the hygienic process connection are also required. #### Programmable logic controller (PLC) URL: https://www.ktb-europe.com/en/glossary/programmable-logic-controller/ A programmable logic controller (PLC) is a digital control device that controls machines and plants cyclically on the basis of a stored program. A programmable logic controller reads in signals from sensors and switches, processes them according to a user program and controls actuators such as motors, valves or displays. In industry it has largely replaced the hard-wired relay and contactor controls that used to be common, because the logic can be changed via software. A modular design is typical, consisting of a power supply, central processing unit (CPU), digital and analogue input and output modules, communication modules and, where needed, special modules, for example for counting or positioning tasks. The program is executed cyclically: read inputs, execute program, write outputs. The duration of one pass is called the cycle time. The programming languages are standardised in IEC 61131-3, including ladder diagram (LD), function block diagram (FBD), structured text (ST) and sequential function chart (SFC). Controllers often remain in service far longer than the respective device generation is available. Older series are discontinued, and replacement CPUs and modules are then only available to a limited extent. At the latest by then, the question arises of stockpiling or migrating to a current generation, which usually requires adjustments to the program, hardware and networking. In practice: The current user program should be backed up and version-controlled, together with the hardware configuration and the licences for the programming software. Spare parts enquiries require the complete item number, the hardware revision of the module and, where applicable, the firmware version, as these determine compatibility. Also known as: PLC, programmable controller, controller, PLC system, industrial controller Frequently asked questions: - **What programming languages are there for a PLC?** The standard IEC 61131-3 describes several languages: graphically, ladder diagram (LD), function block diagram (FBD) and sequential function chart (SFC); textually, structured text (ST). Instruction list (IL) is considered deprecated in newer editions of the standard. Which languages a controller actually supports depends on the programming environment. - **What is the cycle time of a PLC?** The cycle time is the time a controller needs for one complete pass: reading inputs, executing the program and setting outputs. It depends on program size, processing power and communication load. For time-critical tasks, a short and consistent cycle time is important; many controllers monitor it and go into a fault state if it is exceeded. - **What should you do if a PLC has been discontinued?** First, the installed modules, their condition and existing reserves should be recorded. In the short term, stockpiling or a last time buy secures operation; in the medium term, migration to a current controller generation should be planned. This includes program conversion, checking the peripherals and planned commissioning. A backed-up, commented program version makes each of these steps easier. - **What information is needed to replace a PLC module?** Required are the complete item number, the hardware revision and, for CPUs, the firmware version. Information on slot assignment, the bus system and the programming software used is also helpful. A different hardware revision can mean that a module is not recognised without adjusting the hardware configuration. #### Relay URL: https://www.ktb-europe.com/en/glossary/relay/ A relay is an electrically operated switch in which a small control current, via a coil or electronics, switches a separate circuit. In an electromechanical relay, an energised coil attracts an armature that actuates one or more contacts. The control circuit and load circuit are galvanically isolated. Relays are used to amplify or multiply signals, to separate voltage levels or to create interlocks. Solid-state relays switch via semiconductors without moving parts; they are wear-free and silent but generate heat losses and have leakage currents. Important types are interface relays for coupling between controller and field devices, timing relays with on-delay or off-delay, monitoring relays for voltage, phases or level, and safety relays. Key parameters are coil voltage and type of current, contact type (normally open, normally closed, changeover), number of contacts, switching current and switching voltage, contact material, mechanical and electrical service life, and design, for example plug-in with socket or for printed circuit boards. Relays are installed in large numbers in control cabinets. Contacts wear through arcing erosion, particularly with inductive loads without suppression circuitry. Typical faults are welded or contaminated contacts and defective coils. Plug-in relays can be replaced quickly if the socket fits. In practice: When sourcing a replacement, coil voltage, contact configuration, switching capacity and design or socket are decisive. For applications with frequent switching, a solid-state relay may be appropriate; in that case heat dissipation and type of load must be checked. Also known as: interface relay, control relay, solid-state relay (SSR), plug-in relay, SSR Frequently asked questions: - **What is the difference between a relay and a contactor?** Relays and contactors work on the same principle but differ in switching capacity. Relays switch smaller currents, mainly in control and signal circuits. Contactors are built for large load currents such as motor power, with more robust contacts and arc quenching. In practice, relays are often used to drive the coil of a contactor from the controller. - **What do normally open, normally closed and changeover mean?** A normally open contact is open in the rest state and closes when the relay picks up. A normally closed contact is closed in the rest state and opens on pick-up. A changeover contact combines both with a common terminal and switches between two contacts. The contact configuration, for example two changeover contacts, belongs in every spare parts enquiry. - **What information is needed to replace a relay?** Needed are coil voltage with type of current, number and type of contacts, maximum switching current and switching voltage, design with pin assignment or socket, and additional functions such as LED, freewheeling diode or test button. For timing relays, the time range and function are added. The complete type designation from the housing makes identification easier. - **When should a solid-state relay be used instead of a mechanical relay?** Solid-state relays are suitable for very frequent or fast switching, for example in heating control, because they have no contact wear and operate silently. However, they generate heat losses, often need a heat sink and have a small leakage current in the off state. For safe isolation or infrequent switching, the mechanical relay often remains the better choice. #### Rolling bearing URL: https://www.ktb-europe.com/en/glossary/rolling-bearing/ Rolling bearings are bearings in which balls or rollers roll between inner and outer rings, guiding and supporting shafts with low friction. A rolling bearing usually consists of an inner ring, an outer ring, rolling elements and a cage that keeps the rolling elements apart. Unlike a plain bearing, motion is produced by rolling instead of sliding, which reduces friction and starting torque. According to the shape of the rolling elements, a distinction is made between ball bearings and roller bearings, the latter including cylindrical roller, tapered roller, spherical roller and needle roller bearings. According to the direction of load, there are radial and thrust bearings. The designation of rolling bearings is largely standardised internationally, for example in accordance with DIN 623-1. A basic designation describes the type and dimensions, while prefixes and suffixes identify versions such as sealing, internal clearance, cage material or accuracy. The basic rating life is calculated in accordance with ISO 281. Common causes of failure are inadequate lubrication, contamination, mounting errors, overload and misalignment. Vibration monitoring is a widely used method for detecting bearing damage at an early stage. Suitable lubrication, clean mounting with the right tools and correct fits extend service life considerably. In practice: For replacement, the complete designation including suffixes is what counts. Two bearings with the same basic designation may differ in sealing or internal clearance and are then not readily interchangeable. Also known as: rolling-element bearing, anti-friction bearing, ball bearing (subtype), roller bearing (subtype) Frequently asked questions: - **What do suffixes such as 2RS, 2Z or C3 mean?** Suffixes describe design details. 2RS usually stands for contact seals made of elastomer on both sides, 2Z for sheet steel shields on both sides. C3 means a larger internal clearance than normal, as chosen for example for higher operating temperatures or tight fits. Some suffixes are manufacturer-specific, so their meaning should be checked in the relevant catalogue. - **How can bearing damage be detected early?** Typical signs are changed running noise, increasing vibration, higher bearing temperature and discoloured or contaminated lubricant. Vibration analysis can often detect damage to raceways or rolling elements weeks before failure. Temperature measurement and ultrasonic methods are also used. It is important to compare measured values over time rather than looking only at individual readings. - **Are rolling bearings from different manufacturers interchangeable?** For standardised designs, the boundary dimensions are defined internationally, so bearings with the same basic designation are generally dimensionally interchangeable. Differences can exist in load ratings, cage design, sealing, internal clearance and grease fill, and some suffixes are used differently by different manufacturers. The data sheets of both bearings should therefore be compared before switching. #### Rotary encoder URL: https://www.ktb-europe.com/en/glossary/rotary-encoder/ A rotary encoder is a sensor that converts the rotation of a shaft into electrical signals for position, angle or speed. Rotary encoders detect how far and how fast a shaft rotates. They provide controllers and drive controllers with feedback for positioning, synchronisation or speed control, for example on machine tools, conveyor belts or printing machines. A distinction is made between incremental encoders, which output pulses per revolution, and absolute encoders, which assign a unique value to each angular position. Absolute encoders are available as single-turn for one revolution and as multi-turn, which also counts complete revolutions. Scanning is optical or magnetic. Key ratings are resolution (pulses or steps per revolution), interface (such as TTL, HTL, sine/cosine, SSI or fieldbus), supply voltage, shaft design (solid shaft or hollow shaft), flange type and degree of protection. There are also bearingless encoders and versions for potentially explosive atmospheres. In servo drives, the encoder is often integrated into the motor and matched to the relevant drive controller. Failures are frequently caused by bearing wear, shaft misalignment, vibration, moisture or damaged cables. A replacement unit must fit both electrically and mechanically; with absolute encoders, the axis often has to be referenced after replacement. A flexible shaft coupling or torque arm prevents shaft misalignment from overloading the bearings. In practice: For an enquiry, the manufacturer part number, resolution, interface, supply voltage, shaft or hollow shaft diameter, flange type and connector pin assignment are needed. Allow time after the replacement for setting the zero point or reference. Also known as: encoder, incremental encoder, absolute encoder, shaft encoder, angle encoder Frequently asked questions: - **What is the difference between an incremental encoder and an absolute encoder?** An incremental encoder outputs pulses when it rotates, from which the controller calculates distance and speed. After a power failure, the position is unknown and must be referenced again. An absolute encoder provides a unique value for every position, so the position is known immediately after switching on. - **What information is needed to replace a rotary encoder?** Important are the manufacturer part number, encoder type, resolution, output or interface signal, supply voltage, shaft design with diameter, flange or mounting type, connector type and degree of protection. For multi-turn absolute encoders, the number of detectable revolutions also counts. If the nameplate is missing, photos of the mechanics and the connection help. - **What does the resolution of a rotary encoder mean?** The resolution indicates how many pulses or measuring steps an encoder delivers per revolution. The higher it is, the more finely position or speed can be detected. When replacing, the resolution must match the parameter settings of the controller or inverter, otherwise distances and speeds will no longer be correct. #### Safety controller (safety PLC) URL: https://www.ktb-europe.com/en/glossary/safety-controller/ A safety controller is a programmable controller that processes a machine’s safety functions in a fail-safe manner and shuts down in the event of faults. A safety controller evaluates signals from emergency stop buttons, light curtains, guard door switches or enabling switches and controls safe outputs. Unlike a standard PLC, it has an internally multi-channel design, monitors itself and continuously tests its inputs and outputs. Compared with individual safety relays, many functions can be linked in one device by software. If the machine or the safety concept changes, the logic can be adapted without rewiring. There are compact, freely configurable safety modules, modular systems with expansion cards, and controllers that combine standard and safety logic in one CPU. They often communicate via safe protocols on Ethernet-based fieldbuses with distributed inputs and outputs or drives. Key ratings are the number and type of safe inputs and outputs, communication interfaces and the achievable performance level to EN ISO 13849-1 or SIL to IEC 62061. For maintenance, the safety program counts as well as the hardware. Without a backed-up project file and matching firmware, a defective device often cannot be replaced in a meaningful way. Many systems store the configuration on a removable memory module that can be transferred to the replacement device. In practice: For every safety controller, keep the manufacturer part number, firmware version, project file with checksum and storage medium documented and ready. In a spare parts enquiry, it should be mentioned whether an identical device with compatible firmware is required, because a successor model may require the safety functions to be validated again. Also known as: safety PLC, fail-safe controller, safety CPU, programmable safety controller Frequently asked questions: - **What is the difference between a PLC and a safety controller?** A standard PLC controls the production process but is not designed to reliably detect its own faults. A safety controller works redundantly, tests its inputs and outputs and switches to the safe state in the event of an internal fault. Only it may execute safety functions such as emergency stop or guard door monitoring. Some devices combine both tasks in separate program sections. - **What must be considered when replacing a safety controller?** In addition to the right device, you need the valid safety program, ideally with a documented checksum, and a compatible firmware version. After the replacement, the safety functions are usually tested. If the replacement device differs in type or firmware, validation may have to be repeated. Responsibility lies with the person in charge of the safety of the machine. - **Which standards apply to safety controllers?** For assessing safety functions on machinery, EN ISO 13849-1 with the performance level and IEC 62061 with the safety integrity level are mainly used. IEC 61508 is fundamental for the functional safety of electronic systems. Which requirements apply in an individual case results from the risk assessment of the machine. #### Safety light curtain URL: https://www.ktb-europe.com/en/glossary/safety-light-curtain/ A safety light curtain is an electro-sensitive protective device that safeguards a hazardous area with parallel light beams. A safety light curtain consists of a transmitter and a receiver, between which a field of infrared beams is created. If a beam is interrupted, the safety outputs switch off and the hazardous movement is stopped. Light curtains replace fixed guards where material is frequently loaded or removed, for example on presses, packaging machines or palletisers. The most important rating is the resolution: fine resolutions are used for finger or hand protection, coarser ones for body protection; multi-beam safety light barriers safeguard access points. Further characteristics are protective field height, range, response time, type to IEC 61496 and functions such as muting or blanking. The required safety distance to the danger point is calculated to EN ISO 13855 from the response time, the machine’s stopping time and the resolution. Muting temporarily bridges the protective field so that material can pass while people continue to be detected; blanking deliberately masks individual beams, for example for fixed machine parts in the protective field. Typical causes of failure are mechanical damage, dirty front screens, misalignment and defective connecting cables. Because resolution and response time feed directly into the safety distance, a light curtain may only be replaced by a device with equivalent ratings. In practice: For a replacement, the manufacturer part number, protective field height, resolution, range, response time, type and connection type are needed, as well as details of muting or blanking. If an alternative device differs in response time, the safety distance must be checked again. Also known as: light curtain, safety light grid, ESPE, AOPD (active opto-electronic protective device) Frequently asked questions: - **What is the difference between a light curtain and a photoelectric sensor?** A simple photoelectric sensor works with a single beam and is mostly used for object detection in the process. A safety light curtain creates many parallel beams, monitors itself and is approved as a protective device for people. Only devices designed as safety components may be used for personal protection. - **How is the safety distance of a light curtain calculated?** The basis is EN ISO 13855. In simplified terms, the distance results from the approach speed of a person multiplied by the total stopping time, i.e. the response time of the light curtain and evaluation unit plus the stopping time of the machine, plus an allowance that depends on the resolution. The exact formulae and values are to be taken from the text of the standard. - **What information is needed to replace a safety light curtain?** The manufacturer part numbers of transmitter and receiver, protective field height, resolution, range, response time, type to IEC 61496, connector type and activated additional functions such as muting or blanking are needed. With these data, it can be checked whether a replacement device maintains the existing safety distance. #### Safety relay URL: https://www.ktb-europe.com/en/glossary/safety-relay/ A safety relay is a switching device that evaluates safety functions such as emergency stop or guard door monitoring redundantly and safely shuts down hazards. A safety relay monitors signals from safety devices, such as emergency stop buttons, guard door switches or light curtains, and shuts down the hazardous movement when required. Unlike a standard relay, it has an internally redundant design, usually with force-guided contacts, and detects its own faults such as welded contacts or cross-circuits in the wiring. Typical ratings are the number of enabling contacts, single- or dual-channel connection, the start mode (automatic or monitored start), feedback circuit, supply voltage and switching capacity. In addition to versions with instantaneous opening contacts, there are devices with off-delay for stop category 1 and variants for two-hand control or standstill monitoring. The achievable level of safety is stated as a performance level to EN ISO 13849-1 or as a SIL claim limit to IEC 62061. Safety relays are safety-relevant components: when replacing one, the new device must achieve at least the same safety function, category and performance level. A different model can affect the validation of the machine. Because the devices often remain installed for decades, product discontinuations and the search for functionally equivalent alternatives play an important role. Replacement devices should therefore be stocked in good time. In practice: For a spare parts enquiry, the manufacturer part number, supply voltage, contact configuration, start mode and required performance level are needed; a photo of the nameplate and terminal assignment helps. Replacement with a different model should always be agreed with the person responsible for machine safety and documented. Also known as: safety relay module, emergency stop relay, E-stop relay, safety switching device Frequently asked questions: - **What is the difference between a safety relay and a standard relay?** A standard relay simply switches a contact without monitoring itself. A safety relay works with two channels, uses force-guided contacts and checks in every switching cycle whether all contacts have opened correctly. If it detects a fault, it prevents a restart. This is why only a safety relay may evaluate a safety function such as an emergency stop. - **What information is needed to replace a safety relay?** Important are the manufacturer part number from the nameplate, the supply voltage, the number of enabling and signalling contacts, single- or dual-channel wiring, automatic or monitored start and any delay times. It should also be known which performance level or SIL is required for the safety function, so that an alternative device can be assessed correctly. - **When is a safety controller better than a safety relay?** Safety relays are suitable for a few simple safety functions, such as an emergency stop circuit or a guard door. As soon as many sensors, several zones or logic operations are added, wiring with individual relays becomes confusing. A programmable safety controller is then usually more economical and easier to extend and diagnose. #### Safety switch (interlock switch) URL: https://www.ktb-europe.com/en/glossary/safety-switch/ A safety switch monitors the position of guard doors or covers and positively signals any opening to the machine’s safety evaluation unit. Safety switches, technically interlocking devices, ensure that a machine only performs hazardous movements when the guard is closed. If someone opens the door, the safety circuit is interrupted. Guard locking devices additionally keep the door locked until any run-down movement has come to a standstill. The term should be distinguished from the maintenance or main isolator switch, which is also colloquially called a safety switch. Designs include mechanical switches with a separate actuator, hinge switches, position switches with positive opening and non-contact switches with a coded transponder or magnet. Requirements for design and protection against defeat are set out in EN ISO 14119. Key ratings are contact configuration, locking force, coding level, degree of protection, connection type and the achievable performance level in combination with the evaluation unit. Non-contact versions are less sensitive to tolerances in the door guide and are easy to clean, which is an advantage in hygienic areas. Frequent failures are caused by bent actuators, door misalignment, contamination and cable breakage. Because tampering is a known problem, a faulty switch should be replaced promptly and not bypassed. Actuators and switches are often matched to each other and are best procured as a pair. In practice: For an enquiry, the manufacturer part numbers of switch and actuator, contact configuration, locking principle, supply voltage, connector type and, for transponder switches, the coding level are relevant. With high-coded switches, the replacement part may need to be taught in again. Also known as: interlock switch, safety interlock, guard door switch, safety position switch, guard locking device Frequently asked questions: - **What is the difference between a safety switch and a guard locking device?** A safety switch only detects whether a guard door is closed. A guard locking device additionally locks the door mechanically and only releases it when a controller signals that the condition is safe. Guard locking devices are used when machine parts run down and immediate opening would be dangerous. - **What information is needed to replace a safety switch?** The manufacturer part numbers of switch and actuator, the type of contacts or outputs, the supply voltage for electronic devices, the connection type, the degree of protection and, for guard locking devices, the principle, i.e. spring-applied or power-to-lock, are needed. For non-contact switches, the coding level is also important. - **Why must safety switches not be bypassed?** A bypassed switch permanently signals a closed door to the controller, even though it may be open. This disables the protective function, and people can reach into running movements. Operators are obliged to prevent tampering; EN ISO 14119 describes measures that make defeating more difficult. #### Servo motor URL: https://www.ktb-europe.com/en/glossary/servo-motor/ A servo motor is a closed-loop controlled electric motor that uses a feedback system and servo drive to set position, speed and torque precisely. A servo motor always operates in a closed control loop. An encoder in the motor reports position and speed to the servo drive, which adjusts the current so that the setpoints from the controller are maintained precisely. Servo drives thus achieve high dynamics, good positioning accuracy and high short-term overload capacity. In industry, permanent magnet synchronous servo motors are the most widespread; there are also asynchronous servo motors for higher power ratings. Important parameters are standstill torque, rated and maximum speed, peak torque, moment of inertia, voltage level, encoder type and resolution, and degree of protection. Features include a holding brake, shaft design with or without key, flange size, cooling and connector version. Motor, encoder and servo drive are matched to one another; the drive must be able to evaluate the encoder type and must know the motor data. Servo motors drive axes in machine tools, robots and packaging, printing and assembly equipment. Failures frequently involve the encoder, bearings, holding brake and cables. Connectors and cables in drag chains are under particular stress. Cooling and contamination also play a role. A repair is often available faster than a new motor, especially for discontinued product ranges. In practice: For a replacement, the complete type designation from the nameplate and the servo drive used should be stated, as an electrically different motor may require new commissioning or parameterisation. It is also worth asking about a repair, such as replacing bearings, brake or encoder. Also known as: servomotor, servo drive motor, synchronous servo motor, AC servo motor, servo Frequently asked questions: - **What is the difference between a servo motor and a stepper motor?** A servo motor always works in a closed control loop with an encoder and actively corrects deviations. A stepper motor moves in fixed angular steps and is usually controlled without feedback. Servo drives are more dynamic, maintain torque even at high speeds and can handle overloads, while stepper motors are simpler and less expensive for smaller positioning tasks. - **What information is needed to replace a servo motor?** Most important is the complete type designation, which encodes options such as encoder type, brake, shaft design and degree of protection. In addition, standstill torque, rated speed, voltage and the servo drive used are needed. A photo of the nameplate and the connectors prevents confusion between similarly named variants. - **Can a servo motor be repaired?** Often, yes. Bearings, shaft seal, holding brake and connectors can be replaced, and defective encoders are also exchanged. After an encoder replacement, the commutation, that is, the assignment of encoder position to rotor position, usually has to be set again. In the case of damage to the winding or magnets, a new motor is often the better option. - **What does standstill torque mean for a servo motor?** Standstill torque indicates the torque the motor can deliver continuously at zero speed without overheating. It is an important reference value for selection. For short periods, servo motors can deliver a considerably higher peak torque, for example for acceleration. Both values are given in the data sheet. #### Soft starter URL: https://www.ktb-europe.com/en/glossary/soft-starter/ A soft starter limits starting current and torque surge when a three-phase motor is switched on by increasing the voltage gradually. An induction motor switched on direct-on-line draws a multiple of its rated current during starting and produces a torque surge. A soft starter controls the motor voltage via anti-parallel thyristors using phase-angle control and ramps it up over an adjustable ramp. This reduces current peaks, the load on the supply network and the mechanical stress on couplings, belts, gearboxes and conveyed goods. Many units also offer a soft stop, for example to prevent pressure surges in pump lines. The soft starter must be distinguished from the frequency inverter: it changes only the voltage, not the frequency, and is therefore not suitable for speed control during operation. Compared with star-delta starting, the start is stepless. After run-up, an internal or external bypass contact often bridges the thyristors to save heat losses. Key ratings are rated current, supply voltage, control voltage, number of controlled phases, starting frequency and integrated protection functions. It is used for pumps, fans, compressors, conveyor belts and mills running at fixed speeds. Failures are often caused by overheating, excessive switching frequency or defective thyristors after a short circuit. In practice: For replacement or conversion, motor power and current, supply and control voltage, starting duty (normal or heavy) and starts per hour must be stated. The set parameters such as starting voltage, ramp time and current limit should be noted before replacement. Also known as: softstarter, soft start unit, motor soft starter, reduced voltage soft starter Frequently asked questions: - **What is the difference between a soft starter and a frequency inverter?** The soft starter only reduces the voltage during starting and then lets the motor run at mains frequency and fixed speed. The frequency inverter changes voltage and frequency and can control the speed throughout operation. Soft starters are smaller, simpler and less expensive. Where speed adjustment is needed to save energy, the frequency inverter is the appropriate choice. - **When is a soft starter worthwhile instead of star-delta starting?** When current and torque jumps that occur when switching from star to delta are to be avoided, or when a soft stop is needed, for example with pumps. A soft starter also requires only three motor cables instead of six. Star-delta circuits, on the other hand, are very simple and built without power electronics. - **What information is needed to replace a soft starter?** Important are the type designation, rated current, supply voltage, control voltage, number of controlled phases, integrated bypass, interfaces and protection functions. Motor data, load type and starting frequency are also needed. The current parameter settings should be documented so that the replacement unit can be set up straight away. The ambient temperature in the control cabinet is also relevant. - **Can a soft starter protect the motor?** Many units include protection functions such as electronic overload protection, phase loss or stall detection. Whether these functions may replace separate motor protection depends on the device, the requirements of the standards and the installation design. Short-circuit protection is generally provided by upstream fuses or circuit breakers, which are specified in the manufacturer’s documentation. #### Spherical roller bearing URL: https://www.ktb-europe.com/en/glossary/spherical-roller-bearing/ A spherical roller bearing is a double-row, self-aligning rolling bearing with barrel-shaped rollers for very high loads and shaft misalignment. Spherical roller bearings have two rows of barrel-shaped rollers that roll on a common sphered raceway in the outer ring. This allows the inner ring to tilt relative to the outer ring. The bearing thus compensates for misalignment and shaft deflection without creating additional edge stresses. At the same time, it carries very high radial loads and axial forces in both directions. Versions with a cylindrical and with a tapered bore are available. Bearings with a tapered bore are mounted on a tapered seat or, using an adapter or withdrawal sleeve, on a cylindrical shaft; the bearing clearance is deliberately reduced as the bearing is driven up. Key ratings are dimension series, bore type, clearance, cage design and, where applicable, a lubrication groove with holes in the outer ring. Sealed variants are also available. For housed bearing arrangements, spherical roller bearings are frequently installed in plummer block or flanged housings with their own seals. Typical applications are vibrating screens, crushers, fans, conveyor systems, paper machines, continuous casting plants and large gearboxes. Causes of failure are mainly lack of lubricant, contamination, insufficient residual clearance after mounting and false brinelling caused by vibration at standstill. Vibration monitoring often detects damage early. In practice: For bearings with a tapered bore, the matching adapter or withdrawal sleeve together with nut and locking device belongs in the enquiry. Clearance class, cage type and any special versions, for example for vibratory applications, must also be stated. Also known as: SRB, self-aligning roller bearing, spherical roller radial bearing, barrel roller bearing Frequently asked questions: - **What is the difference between a spherical roller bearing and a barrel roller bearing?** Strictly speaking, a barrel roller bearing is a single-row bearing with barrel-shaped rollers that mainly carries radial loads. The spherical roller bearing is double-row and additionally carries considerable axial forces in both directions. In everyday usage the two terms are sometimes used interchangeably, but for a replacement the exact design must be correct. - **What does the K in the designation of a spherical roller bearing mean?** The suffix K usually stands for a tapered bore. Such bearings are mounted on the shaft with an adapter sleeve or withdrawal sleeve, or directly on a tapered seat. A bearing with K cannot be replaced by one with a cylindrical bore without changing the fastening. The taper must match the existing sleeve. - **What information is needed to replace a spherical roller bearing?** Important are the full designation with dimension series and bore code, the bore type, the clearance, the cage and any suffixes for a lubrication groove or suitability for vibration. For sleeve mounting, the sleeve, nut and lock washer are included. For housed bearings, the housing designation is also helpful. - **How is a spherical roller bearing mounted with an adapter sleeve?** The bearing is placed on the shaft with the sleeve and driven up using the nut until the specified clearance reduction is reached. The residual clearance is measured with a feeler gauge or via the axial drive-up distance. Driving it up too far removes the operating clearance, while too little allows the inner ring to creep. The target values are provided by the bearing manufacturer. #### Stepper motor URL: https://www.ktb-europe.com/en/glossary/stepper-motor/ A stepper motor is an electric motor whose rotor turns in fixed angular steps driven by controlled current pulses, positioning without an encoder. In a stepper motor, driver electronics generate a magnetic field in the windings that advances step by step, and the rotor follows it. Each pulse moves the rotor through a fixed angle. The number of pulses gives the position, and the pulse frequency gives the speed. A stepper motor can therefore be operated in open loop without feedback, as long as it is not overloaded and does not lose steps. Hybrid stepper motors are widespread, often with 200 steps per revolution, i.e. 1.8 degrees per step. Half-step and microstep operation of the driver makes the motion finer and smoother. Key ratings are step angle, holding torque, phase current, winding resistance, number of phases, flange size and shaft design. The available torque drops significantly as speed increases. Versions with an encoder or closed-loop control detect lost steps and correct them. Stepper motors are found in dosing and labelling machines, laboratory equipment, format adjustment systems, valve drives and small positioning axes. Typical problems are lost steps due to overload or resonance, heating, bearing wear and cable breakage. Bearing noise often gives early warning of wear. In practice: For a replacement, flange size, overall length, shaft diameter and length, holding torque, phase current and winding connection matter, so that the existing driver still fits. A motor with a different phase current can only be used if the driver is set accordingly. Also known as: stepping motor, step motor, hybrid stepper motor Frequently asked questions: - **How does a stepper motor work?** The driver energises the windings in a fixed sequence. Each time, the magnetic field jumps on a little, and the rotor aligns itself with it. Each pulse corresponds to one step. The controller counts the pulses and thus knows the position without measuring it. The prerequisite is that the load torque stays below the available motor torque. - **What is microstep operation?** In microstep operation, the driver divides each full step into many small intermediate steps by varying the currents in the windings in fine increments. This makes the motor run more smoothly, reduces resonance and increases resolution. However, the actual positioning accuracy still depends on the motor, load and mechanics. - **What information is needed to replace a stepper motor?** The type designation or, failing that, flange size, overall length, step angle, holding torque, phase current, winding resistance or inductance, number of connecting leads and shaft dimensions are needed. It is also important whether a brake, encoder or gearbox is fitted and which driver controls the motor. - **Why does a stepper motor lose steps?** Lost steps occur when the load torque exceeds the available motor torque, when acceleration is too fast or when mechanical resonance occurs. A current set too low on the driver or a supply voltage that is too low at high speeds are also possible causes. Without an encoder, the controller does not notice the position error. #### Tapered roller bearing URL: https://www.ktb-europe.com/en/glossary/tapered-roller-bearing/ A tapered roller bearing is a rolling bearing with conical rollers that can carry high radial loads and axial loads in one direction at the same time. In a tapered roller bearing, the raceways and rollers are conical, and their imaginary extensions meet at a point on the bearing axis. The bearing can therefore carry combined loads: high radial forces together with axial forces in one direction. The larger the contact angle, the higher the axial load capacity. The bearing is separable; the inner ring with rollers and cage is called the cone, and the outer ring the cup. Because a single tapered roller bearing only carries axial load in one direction, two bearings are usually adjusted against each other, in a back-to-back (O) or face-to-face (X) arrangement. Clearance or preload is only created during mounting and is set using nuts, spacers or shims. Besides single-row designs, there are matched, double-row and four-row versions. Metric and inch series exist and are not interchangeable with each other. Tapered roller bearings are found in gearboxes, rope sheaves, rolling mills, cranes and pumps. Common sources of failure are incorrectly set clearance, lack of lubricant and mixing cones and cups from different sources. In practice: In an enquiry, the cone and cup should each be stated with their full designation, especially for inch bearings, which have separate part numbers. After replacement, the specified clearance or preload must be set according to the manufacturer’s instructions. Also known as: TRB, taper roller bearing, tapered roller radial bearing, cone and cup Frequently asked questions: - **What is the difference between back-to-back (O) and face-to-face (X) arrangement?** In the back-to-back (O) arrangement, the load lines of the two bearings diverge outwards, the support base is wide and the bearing arrangement is rigid against tilting. In the face-to-face (X) arrangement, the load lines converge inwards and the base is narrower, but the arrangement is less sensitive to misalignment and easier to adjust. Which arrangement is fitted is determined by the design and should be retained when replacing. - **Can cones and cups from different manufacturers be combined?** Dimensionally, standardised parts often fit together. Nevertheless, many manufacturers recommend using cone and cup as a set from one source, because raceway geometry and tolerances are matched to each other. Mixing is ruled out for matched or preloaded sets. If in doubt, the complete set should be replaced. - **What information is needed to replace a tapered roller bearing?** The designations of cone and cup or the set designation are needed, along with whether it is a metric or inch version and, for matched bearings, the type of pairing. If designations are missing, bore, outside diameter, total width, width of cone and cup and a photo of the markings help. - **Why does a tapered roller bearing have to be adjusted?** Because the bearing clearance only results from the axial position of the two bearings relative to each other. Too much clearance leads to knocking and uneven load distribution, too much preload to heating and early failure. The machine manufacturer usually specifies a setting dimension, frictional torque or axial displacement to which the bearing is adjusted. #### Temperature sensor (Pt100) URL: https://www.ktb-europe.com/en/glossary/temperature-sensor/ A temperature sensor detects the temperature of media or components; in industry, the Pt100 resistance thermometer is the most widely used type. Temperature sensors convert temperature into an electrical signal. Besides thermocouples and semiconductor sensors, industrial plants mainly use platinum resistance thermometers. In a Pt100, the resistance at 0 °C is exactly 100 ohms and rises almost linearly with temperature; the characteristic curve and tolerance classes are defined in IEC 60751. A Pt1000 has 1000 ohms at 0 °C. The measuring insert is usually housed in a protective tube or thermometer stem, which is installed directly in the medium or in a thermowell in the pipeline. It is connected using two-, three- or four-wire technology; more wires compensate better for lead resistance. Key ratings are sensor type, tolerance class, measuring range, insertion length, protective tube diameter, process connection, connection head and any integrated transmitter. At high temperatures or with strong vibration, thermocouples are used instead. Failures are caused by vibration, moisture in the connection head, mechanical stress on the protective tube or drift after long service. It is often sufficient to replace only the measuring insert while the protective tube remains in the plant. Measuring points with high accuracy requirements are calibrated at fixed intervals. In practice: For a replacement, sensor type, tolerance class, wiring configuration, insertion length, diameter, process connection and head form are needed. Clarify in advance whether the complete probe or only the measuring insert is to be ordered – this reduces downtime because the protective tube does not have to be removed. Also known as: Pt100, resistance thermometer, temperature probe, RTD, Pt1000 Frequently asked questions: - **What is the difference between Pt100 and Pt1000?** Both are platinum resistance thermometers with the same shape of characteristic curve. The Pt100 has a resistance of 100 ohms at 0 °C, the Pt1000 of 1000 ohms. With a Pt1000, lead resistance has less effect, which is why it is often used with two-wire connection. The evaluation unit or transmitter must be set to the relevant type. - **Which is better: Pt100 or thermocouple?** A Pt100 measures more accurately and stably in the medium temperature range. Thermocouples cover higher temperatures, respond faster and are mechanically more robust, but less accurate. The choice depends on temperature range, required accuracy and installation conditions. For measurements up to medium temperature ranges with high accuracy, the Pt100 is usually preferred. - **What do two-, three- or four-wire connections mean?** The connection describes how many conductors link the sensor to the evaluation unit. With a two-wire connection, lead resistance enters the measurement and distorts it. A three-wire connection largely compensates for this effect, and a four-wire connection almost completely. For accurate measurements, three or four wires are therefore used. #### Terminal block URL: https://www.ktb-europe.com/en/glossary/terminal-block/ A terminal block is a connecting element mounted on a DIN rail that securely and detachably connects conductors in a control cabinet. Terminal blocks form the interface between the internal wiring of the control cabinet and the cables to sensors, actuators and motors. They are snapped onto DIN rails side by side, linked with jumpers and identified with markers. Requirements for terminal blocks for copper conductors are described in IEC 60947-7-1, and for protective conductor terminal blocks in IEC 60947-7-2. They make testing, fault-finding and replacing cables easier. By connection technology, a distinction is made between screw terminals, spring-cage terminals and push-in terminals, into which solid conductors can be inserted without tools. By function, there are feed-through, protective earth, multi-level, fuse, disconnect, test and sensor terminal blocks as well as terminal blocks with components such as diodes. Key ratings are rated cross-section, rated current and voltage, number of connection points, rail type and colour. Multi-level terminal blocks save space on the rail, while disconnect terminal blocks allow measurements without disconnecting the conductors. Terminal blocks are inexpensive, but their failure can bring a plant to a standstill. Causes are loosened screw connections, overheated contact points, incorrect conductor cross-sections or damaged terminal housings. Accessories such as jumpers, end plates and markers must match the terminal system. With screw terminals, the specified tightening torque should be observed. In practice: For replacement or extension, the manufacturer part number, connection technology, cross-section, function and colour as well as matching accessories are needed. It pays to standardise on a few terminal systems across the plant so that jumpers, end plates and markers remain interchangeable. Also known as: DIN rail terminal, feed-through terminal block, connection terminal, modular terminal block Frequently asked questions: - **What is the difference between screw, spring-cage and push-in terminals?** With screw terminals, the conductor is clamped with a screw that can be retightened regularly. Spring-cage terminals hold the conductor by spring force; the spring is opened with a tool to insert it. With push-in terminals, solid conductors or conductors with ferrules can be inserted directly. Spring technologies are largely maintenance-free and vibration-resistant. - **Which terminal block for which cross-section?** Each terminal block is designed for a specific rated cross-section and can accept conductors within a defined range around it. The cross-section depends on current, cable length and installation method. The terminal should match the conductor used; terminals that are too small can overheat, while terminals that are too large do not hold thin conductors securely. - **What information is needed to reorder terminal blocks?** The manufacturer part number, connection technology, rated cross-section, terminal function, number of levels and connections, colour and rail type are needed. Matching accessories such as cross-connectors, end covers, end brackets and markers should also be stated, as these are usually system-specific. If terminals from different systems are mixed, jumpers and covers often do not fit. #### Thermocouple URL: https://www.ktb-europe.com/en/glossary/thermocouple/ A thermocouple is a temperature sensor made of two joined metals that generates a temperature-dependent thermoelectric voltage through the Seebeck effect. A thermocouple consists of two wires of different metals joined at the measuring point. If there is a temperature difference between the measuring junction and the reference junction, a small voltage is produced, from which the evaluation unit calculates the temperature. Thermocouples need no auxiliary power, respond quickly and are suitable for high temperatures, for example in furnaces, hardening shops, glassworks or steelworks. What is measured is always the temperature difference; the temperature of the reference junction is therefore recorded and compensated in the evaluation. The pairings are standardised as types designated by letters, with reference values and tolerances governed by IEC 60584. Common types are type K (nickel-chromium/nickel), type J (iron/copper-nickel), type N and precious metal types such as S, R or B for very high temperatures. Designs include mineral-insulated thermocouples, screw-in sensors with thermowell and versions with ceramic protection tubes. Suitable thermocouple or compensating cables are used for the connection to the evaluation unit. Thermocouples age, especially at high temperatures, and drift as a result. Other sources of error are incorrect compensating cables, reversed polarity and damaged protection tubes. In high-temperature processes they are therefore regarded as wear parts. The achievable service life depends heavily on temperature, atmosphere and protection tube. In practice: For an order, the thermocouple type, tolerance class, design, diameter, insertion length, protection tube material, process connection and type of connection are needed. Where replacements are frequent, keeping a stock of measuring inserts of the same length is worthwhile. Also known as: TC, type K thermocouple, mineral-insulated thermocouple, MI thermocouple, thermocouple probe Frequently asked questions: - **What types of thermocouple are there?** Several types are standardised and designated by letters. Type K is the most widely used general-purpose type, type J is often used at lower temperatures, and type N is regarded as more stable at higher temperatures. Precious metal thermocouples such as type S, R or B are used at very high temperatures. - **What is a compensating cable for a thermocouple?** A compensating cable connects the thermocouple to the evaluation unit and has thermoelectric properties similar to those of the thermocouple itself within the relevant temperature range. A normal copper cable would generate additional voltages at the junctions and distort the measurement. Cable type and thermocouple type must match. - **What information is needed to replace a thermocouple?** Needed are type, tolerance class, sheath or protection tube diameter, insertion length, protection tube material, process connection, terminal head or connector type and details of the measuring junction, such as insulated or grounded. The maximum operating temperature is also important, as it determines material and design. If the nameplate is missing, the colour of the connecting cable often helps to identify the type. #### Transmitter (signal converter) URL: https://www.ktb-europe.com/en/glossary/measuring-transmitter/ A transmitter converts a sensor signal into a standardised, interference-resistant output signal such as 4–20 mA that control systems can process directly. Many sensors only deliver weak or non-linear raw signals, such as the millivolts of a thermocouple or the resistance of a Pt100. A transmitter amplifies, linearises and scales this signal and outputs it as a standard signal. It can sit directly in the sensor head, be installed as a field device or be mounted on a DIN rail in the control cabinet. This also allows longer cable runs to the control system to be bridged without significant signal loss. Common outputs are 4–20 mA, 0–10 V and digital protocols; some devices transmit additional digital information superimposed on the current signal. The current signal is insensitive to lead resistance, and the live zero at 4 mA makes it possible to detect wire breaks. Key ratings are input type, measuring range, output signal, accuracy, galvanic isolation, supply in two- or four-wire technology and Ex approval. Isolating amplifiers additionally separate circuits galvanically. A faulty transmitter shows up as frozen, jumping or out-of-range values. For a replacement, it is crucial that measuring range and configuration are set again exactly. Many devices are configured via software, operating buttons or a programming adapter; without these tools, a replacement unit can hardly be adapted. In practice: Keep the parameter settings ready for every transmitter: input type, measuring range, output signal, damping and behaviour on sensor break. In an enquiry, state whether a head-mounted, DIN rail or field device is required and whether it should be supplied preconfigured. Also known as: measuring transmitter, signal converter, signal conditioner, measuring amplifier, 4–20 mA transmitter Frequently asked questions: - **Why is 4–20 mA used instead of 0–20 mA?** With a 4–20 mA signal, the start of the measuring range corresponds to 4 mA instead of zero. If the current falls below this value, the control system detects a fault such as a wire break or loss of supply. With 0–20 mA, a cable break could not be distinguished from a genuine measured value of zero. In addition, the base current can power a two-wire device. - **What is a two-wire transmitter?** A two-wire transmitter draws its power via the same two wires over which it outputs the 4–20 mA signal. This saves wiring and is very common in the field. Four-wire devices have separate supply and signal lines and are used when the electronics require more energy. - **What information is needed to replace a transmitter?** The manufacturer part number, input type such as Pt100, thermocouple type or voltage, measuring range, output signal, supply, design, Ex approval and, where applicable, communication protocol are needed. So that the replacement unit is ready for use immediately, the current parameters should be documented and passed on. Otherwise the device has to be reset on site. #### Ultrasonic sensor URL: https://www.ktb-europe.com/en/glossary/ultrasonic-sensor/ An ultrasonic sensor measures distances or detects objects by emitting sound pulses above the audible range and evaluating the travel time of the echo. An ultrasonic sensor emits short sound pulses and receives the echo reflected by the object. From the travel time and the speed of sound, the electronics calculate the distance. Because the principle works independently of colour, transparency and surface gloss, the sensor is suitable for glass, films, liquids and bulk materials, for example for level measurement, roll diameter detection or presence detection. The method also works more reliably than many optical sensors in dusty or misty environments. There are ultrasonic proximity sensors with a switching output, sensors with an analogue output for continuous distance measurement, and through-beam and retro-reflective systems. Key ratings are measuring range with a blind zone directly in front of the sensor, sound cone shape, resolution, output type (switching output, current or voltage, digital interface), response time, temperature compensation and degree of protection. Because the speed of sound depends on the air temperature, many sensors compensate for this effect internally. Several sensors next to each other can interfere with one another if they are not synchronised. Measurement errors are caused by inclined or sound-absorbing surfaces, strong air movement, temperature fluctuations and deposits on the transducer face. After a replacement, switching points or measuring range usually have to be set again. In practice: For a replacement, the manufacturer part number, measuring range, output type, housing style, voltage, connector and degree of protection are needed. Document the set switching points or scaling before removal so that the replacement unit can be commissioned without lengthy trial and error. Also known as: ultrasonic proximity sensor, ultrasonic distance sensor, ultrasonic level sensor, ultrasonic transducer Frequently asked questions: - **What is the blind zone of an ultrasonic sensor?** The blind zone is the area directly in front of the sensor in which no reliable measurement is possible, because the transducer first has to stop oscillating after transmitting. Objects in this zone are not detected or are detected incorrectly. When installing, the sensor must therefore be positioned so that the object is always outside this range. - **When is an ultrasonic sensor better than a photoelectric sensor?** Ultrasonic sensors have the advantage with transparent or highly reflective objects, changing colours and in dusty or misty environments where optical sensors reach their limits. Photoelectric sensors, on the other hand, respond faster and have a narrower detection range, which is better for small objects or high cycle rates. - **What information is needed to replace an ultrasonic sensor?** The manufacturer part number, measuring range, output type such as switching output, 4–20 mA or 0–10 V, housing style and thread size, supply voltage, connector type and degree of protection are needed. It should also be known which medium is being detected, as foam or soft surfaces influence the selection. #### Worm gearbox URL: https://www.ktb-europe.com/en/glossary/worm-gearbox/ A worm gearbox is a right-angle gearbox in which a worm shaft drives a worm wheel, achieving high ratios in a single stage. In a worm gearbox, the input and output shafts are usually at right angles to each other without intersecting. The worm resembles a threaded spindle and meshes with the worm wheel. High reduction ratios are possible with just one stage. The tooth flanks slide on one another, so worm gearboxes run very quietly and absorb shocks, but they have a lower efficiency than helical or bevel gearboxes. A common pairing is a hardened steel worm with a bronze worm wheel, optimised for sliding properties. At high ratios, the gearbox can be statically self-locking; however, this does not count as a reliable brake or protection against back-driving, because vibration can cancel the self-locking effect. Key parameters are ratio, centre distance, output torque, efficiency, mounting position and shaft design, often with a hollow shaft. Worm gearboxes are widely used in conveyor systems, lifting tables, agitators, packaging machines and dosing equipment. Typical damage is wear of the bronze wheel, leaks at shaft seals and overheating due to incorrect or aged oil. Wear of the wheel often shows up as bronze particles in the oil and increasing play at the output. In practice: When sourcing a replacement, the ratio, centre distance, mounting position and shaft design are important, as the oil quantity depends on the mounting position. The lubricating oil must be suitable for the bronze pairing; oil changes should only be carried out with the oil type approved by the manufacturer. Also known as: worm gear, worm gear reducer, worm drive, right-angle gearbox, wormwheel gearbox Frequently asked questions: - **Is a worm gearbox self-locking?** That depends on the ratio, the lead angle of the worm, friction and the operating state. At high ratios, a worm gearbox can be self-locking at standstill. During operation or under vibration, however, this self-locking can be cancelled. Where back-driving would be dangerous, for example in lifting equipment, an additional brake must therefore be provided. - **Why does a worm gearbox have lower efficiency?** The tooth flanks of the worm and worm wheel slide on one another to a large extent instead of mainly rolling. This generates frictional heat. The higher the ratio, the lower the efficiency as a rule. For long operating times, a bevel-helical gearbox may therefore be more energy-efficient, even if it costs more to buy. - **What information is needed to replace a worm gearbox?** Needed are type designation, size or centre distance, ratio, mounting position, input and output design such as hollow shaft, solid shaft or flange, and also motor power and motor mounting. For installation compatibility, the fixing dimensions and housing shape are important. The nameplate contains most of this information. - **What oil does a worm gearbox need?** Worm gearboxes with a bronze wheel need oils suitable for this material pairing. Synthetic polyglycol oils are often used, but they are not miscible with all other oils. The lubricant specification of the gearbox manufacturer is decisive. Changing to a different oil base usually requires thorough flushing. ### Hydraulics, Pneumatics & Sealing #### Air preparation unit (FRL) URL: https://www.ktb-europe.com/en/glossary/air-preparation-unit/ An air preparation unit treats compressed air upstream of consumers, usually by filtering, regulating and, if required, lubricating it, protecting pneumatic components. Compressed air from the network contains particles, water and often oil residues. An air preparation unit, frequently mounted directly on the machine, removes these contaminants and sets the appropriate working pressure. This allows valves, cylinders and valve terminals to work more reliably and for longer. The classic combination consists of filter, pressure regulator and lubricator; filter and regulator are often combined in a filter regulator. The filter separates particles and condensate, which is drained manually, semi-automatically or automatically. Fine and activated carbon filters further improve purity. Lubricators add oil to the air but are no longer needed for many modern components. The unit is often supplemented by a shut-off valve for exhausting the system, a soft-start valve for gradual pressure build-up and a pressure switch. The purity of compressed air is described in classes in accordance with ISO 8573-1. Full filter bowls, clogged filter elements and defective condensate drains are among the most common faults. A pressure drop downstream of the unit leads to incomplete cylinder strokes and lost cycles. Regular visual inspection of bowls and condensate drains therefore belongs in every maintenance plan for pneumatic machines and systems. In practice: For a replacement, the series, port size, filter rating, adjustment range and type of condensate drain are needed. Filter elements and bowl seals should be kept in stock as maintenance materials and listed with their part numbers in the maintenance plan. Also known as: FRL unit (filter, regulator, lubricator), compressed air treatment unit, filter regulator, service unit, air service unit Frequently asked questions: - **What does an air preparation unit consist of?** Typical components are a filter, a pressure regulator with pressure gauge and, where required, a lubricator. The unit is often extended with a shut-off valve for isolating and exhausting, a soft-start valve for gradual pressure build-up, fine or activated carbon filters, a pressure switch and a distributor block. The modules are assembled into one unit using connecting elements. - **Does an air preparation unit need a lubricator?** Many modern pneumatic components are designed for unlubricated compressed air and are lubricated for life. A lubricator is then superfluous. However, once oil has been added, lubrication must generally continue permanently, because the oil washes out the initial lubrication. The specifications of the component manufacturers are decisive. - **What information is needed to replace an air preparation unit?** Required are the series and size, connection thread, flow rate, filter rating, adjustment range, type of condensate drain, pressure gauge version and additional modules such as shut-off or soft-start valves. For filter elements and bowls, the spare part numbers from the operating manual are often sufficient. A photo of the entire unit helps with identification. - **How often is the filter element of an air preparation unit changed?** Fixed intervals are given in the manufacturer’s specifications but depend heavily on air quality. A differential pressure indicator shows when the filter is clogged. If the pressure downstream of the unit drops noticeably under load or the element becomes discoloured, a change is due. #### Axial piston pump URL: https://www.ktb-europe.com/en/glossary/axial-piston-pump/ An axial piston pump is a positive displacement pump in which pistons arranged parallel to the drive shaft deliver hydraulic oil at high pressure. Several pistons are arranged in a circle around the shaft in a rotating cylinder block. A tilted plate or an angled axis makes them move back and forth with each revolution, drawing in oil and pushing it into the pressure line. Axial piston pumps achieve high pressures and efficiencies and are widely used in high-performance systems such as presses, rolling mills and injection moulding machines. A distinction is made between swashplate and bent-axis designs. Changing the swivel angle changes the displacement; such variable displacement pumps can be adapted to demand via controllers, for example pressure, flow, load-sensing or power controllers. Fixed displacement pumps have a fixed angle. Key parameters are maximum displacement, rated and peak pressure, speed, direction of rotation, controller version, shaft end and mounting flange. Typical damage is caused by contaminated oil, cavitation, inadequate case pressure relief via the case drain line and overheating. Wear on slippers, valve plate and pistons increases the leakage flow. Given the high replacement values, it is often weighed up whether a repair with new rotating group parts or a replacement is more economical. Oil cleanliness after the repair is decisive for the remaining service life. In practice: For a replacement, the complete type designation is crucial because it encodes displacement, controller, direction of rotation, shaft and ports. Before commissioning, the housing must be filled with oil via the case drain port. Also known as: variable displacement pump, swashplate pump, bent-axis pump, piston pump Frequently asked questions: - **What is the difference between swashplate and bent-axis designs?** In the swashplate design, the cylinder block is coaxial with the shaft and the pistons are supported via slippers on an inclined plate. In the bent-axis design, the entire cylinder block is angled relative to the shaft. Swashplate pumps are compact and well suited as variable displacement pumps, while bent-axis units achieve larger swivel angles. - **What does a load-sensing controller do?** A load-sensing controller adapts the pump’s pressure and displacement to the actual demand of the consumer. It measures the load pressure and maintains a constant pressure differential across the control valve. As a result, the pump delivers only as much oil and pressure as necessary, which significantly reduces energy losses and heat generation compared with fixed displacement systems. - **What information is needed to replace an axial piston pump?** Required are the complete type designation from the nameplate, displacement, rated pressure, speed, direction of rotation, controller type with settings, shaft end, mounting flange, port sizes and, where applicable, a through-drive for a second pump. The serial number helps to identify special versions. Controller settings should be documented before removal. - **Why is the case drain line important for axial piston pumps?** The case drain line returns oil from the pump housing to the tank without pressure. If it is too small, kinked or blocked, the case pressure rises and can destroy the shaft seal or cause the slippers to lift. The drain oil also carries heat away. The line must therefore be free and adequately sized. #### Ball valve URL: https://www.ktb-europe.com/en/glossary/ball-valve/ A ball valve is a shut-off valve whose bored ball fully opens or tightly closes the flow with a quarter turn. The body houses a ball with a bore, supported between two seat rings. When the bore is aligned with the pipe, the medium flows almost unhindered; after a 90-degree turn, the passage is closed. Ball valves switch quickly, seal reliably and are widely used in water, compressed air, gas, oil and chemical lines. A distinction is made between full-bore and reduced-bore ball valves, one-, two- or three-piece bodies, and two-way and multi-way valves with L- or T-port. In smaller nominal sizes, the ball is usually floating; in large sizes and at high pressures, it is trunnion-mounted. Key ratings are nominal size (DN), nominal pressure (PN), connection type such as thread, flange or weld ends, body material, seal material and temperature range. For actuators, a top flange geometry to ISO 5211 is common. Ball valves are designed as shut-off valves, not control valves; partial opening damages the seats. Failures are caused by worn seals, deposits and leakage at the stem. For automated valves, valve and actuator should be considered together, as torque and connection geometry must match. In practice: For a replacement, DN, PN, connection type, face-to-face length, materials of body, ball and seals, medium and temperature are needed. For automated valves, the top flange, square drive and actuator data must also be stated. Also known as: ball cock, three-way ball valve, shut-off ball valve, quarter-turn valve Frequently asked questions: - **What is the difference between a ball valve and a butterfly valve?** A ball valve shuts off with a bored ball and, when full-bore, offers almost no flow resistance and high tightness. A butterfly valve uses a rotating disc that remains in the flow even when open. Butterfly valves are lighter and less expensive in large nominal sizes, while ball valves are preferred for small and medium nominal sizes and high tightness requirements. - **Can a ball valve be used for control?** Standard ball valves are built for the open and closed positions. In intermediate positions, the medium flows past the seat edges at high velocity and damages them. For control tasks, there are special control ball valves with a V-shaped ball opening or segmented ball. Otherwise, control valves are the appropriate choice. - **What information is needed to replace a ball valve?** The nominal size, nominal pressure, connection type and thread or flange standard, face-to-face length, full or reduced bore, body and seal materials, medium, temperature and operation by lever or actuator are needed. For automated ball valves, the top flange, square drive size, torque and actuator type are added. - **What do full bore and reduced bore mean?** With full bore, the ball bore corresponds to the inside diameter of the pipe; flow resistance and pressure loss are minimal, and the line can, for example, be pigged. With reduced bore, the bore is smaller. This makes the valve more compact and less expensive, but it causes a higher pressure loss. #### Butterfly valve URL: https://www.ktb-europe.com/en/glossary/butterfly-valve/ A butterfly valve is a pipeline valve that opens or shuts off the flow with a rotatable disc by means of a quarter turn. The butterfly valve belongs to the quarter-turn valves: a disc sits on a shaft in the middle of the flow path and is rotated through 90 degrees between the open and closed positions. Compared with gate valves or ball valves, it is short, light and inexpensive in large nominal sizes. It is used in water, wastewater, cooling and process lines, sometimes also for coarse throttling. A distinction is made between concentric valves with a soft-sealing elastomer liner and double and triple offset valves, which handle higher pressures and temperatures and can also be metal-seated. For installation, there are wafer versions, lug versions with threaded lugs that are also suitable as end-of-line valves, and double-flanged valves. Important parameters are nominal size (DN), nominal pressure (PN), face-to-face dimension, materials of the body, disc and liner, and operation by hand lever, gearbox or valve actuator. Typical causes of failure are worn or swollen liners, deposits on the disc, cavitation during continuous throttling and leaking shaft passages. The valve can often be repaired by replacing the liner or shaft seals, provided these are available as spare parts. In practice: A spare parts enquiry requires the nominal size, nominal pressure, design (concentric or offset), installation type, materials, medium and temperature, as well as the actuator connection. A photo of the nameplate and the flange connection often saves several follow-up questions. Also known as: wafer butterfly valve, lug butterfly valve, throttle valve, high-performance butterfly valve Frequently asked questions: - **What is the difference between a butterfly valve and a ball valve?** Both valves are operated with a quarter turn. In the open position, a ball valve usually provides an almost unobstructed passage and seals very reliably, but it is heavy and expensive in large nominal sizes. The butterfly valve is shorter and lighter, but the disc remains in the flow path even in the open position and causes a certain pressure loss. - **What do concentric and offset mean for butterfly valves?** In a concentric valve, the shaft is centred in the disc and seal, and the disc seals against an elastomer liner. In offset (eccentric) valves, the shaft is positioned off-centre so that the disc lifts quickly away from the sealing surface when opening. This reduces friction and wear and allows higher pressures and temperatures as well as metal seals. - **What information is needed to replace a butterfly valve?** Required are the nominal size, nominal pressure, face-to-face dimension and installation type (wafer, lug or double-flanged), as well as the materials of the body, disc and seal, medium, operating temperature and type of operation. For actuated valves, the flange pattern and shaft connection for the actuator are also needed. The data from the nameplate is the most important basis for this. - **Can a butterfly valve be used for control?** To a limited extent, yes. Many butterfly valves are suitable for coarse throttling, but their characteristic is not designed for fine control tasks. At small opening angles, high flow velocities, cavitation and rapid wear of the disc and liner are likely. For precise control, special control butterfly valves or control valves are used. #### Centrifugal pump URL: https://www.ktb-europe.com/en/glossary/centrifugal-pump/ A centrifugal pump is a rotodynamic machine that accelerates liquids with a rotating impeller, thereby generating pressure and flow. Centrifugal pumps are the most widely used type of pump in industry and building services. An impeller transfers energy to the liquid, which is converted into pressure in the casing, for example a volute. Unlike positive displacement pumps, the flow rate depends heavily on the back pressure of the system. Depending on impeller shape, a distinction is made between radial, mixed-flow and axial pumps; multistage pumps achieve higher heads. Characteristic values are flow rate, head, power input and efficiency, which are summarised in the pump curve. The duty point results from the intersection of the pump curve and the system curve. If the pressure at the impeller inlet drops too far, vapour bubbles form and collapse abruptly; this cavitation destroys impellers. To avoid it, the NPSH available in the system must be sufficiently above the NPSH required by the pump. Standardised pumps, for example to EN 733 or ISO 2858, have standardised main and connection dimensions, which makes replacement easier. Typical wear parts are the mechanical seal or gland packing, bearings, wear rings and the impeller. In practice: For spare parts or a replacement pump, the nameplate data, pumped medium, temperature, duty point, impeller diameter and the materials of casing, impeller and mechanical seal are required. Leaking mechanical seals should be replaced promptly, before escaping medium damages the bearings or motor. Also known as: rotodynamic pump, standardised pump, radial pump, volute pump, end-suction pump Frequently asked questions: - **What is the difference between a centrifugal pump and a positive displacement pump?** A centrifugal pump transfers energy via a rotating impeller; its flow rate changes significantly with back pressure. A positive displacement pump, such as a piston, gear or screw pump, encloses volumes of liquid and pushes them onward; its flow rate remains largely independent of pressure. Centrifugal pumps are suited to large volumes of low-viscosity media, positive displacement pumps to high pressures or viscous media. - **What is cavitation in centrifugal pumps?** Cavitation occurs when the pressure at the impeller inlet falls below the vapour pressure of the liquid. Vapour bubbles form, which collapse in areas of higher pressure and erode material from the impeller. Signs include crackling noises, vibration and loss of performance. Remedies include sufficient inlet pressure, shorter suction lines or an adjusted duty point. - **What does NPSH mean?** NPSH stands for net positive suction head. The NPSHr value indicates the minimum suction head the pump needs at the inlet; it is taken from the pump curve. The NPSHa value describes what the system actually provides. To prevent cavitation, NPSHa must be above NPSHr with a sufficient safety margin. - **What information is needed for a replacement centrifugal pump?** Required are the flow rate and head at the duty point, the pumped medium with temperature and density, connection nominal sizes, installation type and motor data. Materials and seal design are also needed. With standardised pumps, standardised dimensions make replacement easier; nevertheless, the pump curve and connection dimensions should be compared. #### Check valve (non-return valve) URL: https://www.ktb-europe.com/en/glossary/check-valve/ A check valve is a self-acting valve that lets a medium pass in one direction only and prevents backflow by closing. Check valves operate without external energy: the pressure of the flowing medium opens the closing element, and when flow stops or reverses, back pressure, a spring or the element’s own weight pushes it back onto the seat. They protect pumps against reverse rotation, prevent pipes from draining and separate circuits in hydraulics, pneumatics and process engineering. Common designs are swing check valves, ball, disc and cone check valves, dual-plate wafer check valves and spring-loaded nozzle check valves, which close particularly quickly. In hydraulics, pilot-operated check valves and screw-in cartridges are also used. Important for selection are cracking pressure, nominal size or connection thread, nominal pressure, flow direction, permissible installation position, materials and type of seal. Failures are frequently caused by dirt on the seat, broken or fatigued springs, wear from chattering at too low a flow rate and pressure surges when a slow-closing valve is slammed shut by the backflow. A leaking check valve is often only noticed indirectly, for example by pumps turning backwards or pressure loss at standstill. Regular checks when pumps stop help to detect such damage early. In practice: In a spare parts enquiry, the design, connection type and size, nominal pressure, cracking pressure, medium, temperature and installation position should be stated. If the design is changed during replacement, for example from a swing check valve to a spring-loaded valve, pressure loss and closing behaviour change. Also known as: non-return valve, NRV, swing check valve, backflow preventer Frequently asked questions: - **How does a check valve work?** When the medium flows in the direction of flow, it pushes the closing element, such as a ball, disc or flap, away from the seat. When the flow decreases or reverses, the element closes by itself through spring force, its own weight or the back pressure. No controller or auxiliary energy is needed for this. - **What is the cracking pressure of a check valve?** The cracking pressure is the pressure differential at which the closing element lifts off the seat and flow becomes possible. It depends mainly on the spring force. Too high a cracking pressure increases the pressure loss in the system, while too low a value can lead to leakage or chattering in certain installation positions. When replacing, the value should match. - **Does the installation position of a check valve matter?** Yes. Gravity-operated designs such as some swing or ball check valves only work in certain positions, for example in horizontal pipes or with flow from bottom to top. Spring-loaded valves are usually independent of position. The permissible installation position is given in the manufacturer’s documentation and should be checked when replacing. - **Why does a check valve slam when the pump is switched off?** Slamming occurs when the closing element reacts too slowly and the column of liquid already flowing back forces it abruptly onto the seat. This creates pressure surges that stress pipes and valves. The usual remedy is fast-closing, spring-loaded designs or damped swing check valves, whose suitability must be checked case by case. #### Control valve URL: https://www.ktb-europe.com/en/glossary/control-valve/ A control valve is a final control element that continuously influences flow, pressure or temperature in a plant by means of a variable opening area. Unlike isolating valves, which know only open or closed, a control valve can take up any intermediate position. It consists of the valve body with seat and plug or rotary element, a valve actuator and usually a positioner, which converts the signal from the process controller into a precise stroke position. Control valves are found in steam, water, gas and process lines as well as in heating and cooling circuits. Globe valves in straight-through or three-way form are common, alongside rotary plug valves, segmented ball valves and control butterfly valves. The central parameter is the Kvs value, which describes the flow when the valve is fully open at a defined differential pressure. Further sizing parameters are the valve characteristic (for example linear or equal percentage), rangeability, nominal size, nominal pressure, seat leakage, materials and the type of stem sealing. Typical damage includes seats and plugs washed out by cavitation or erosion, leaking stuffing boxes and faults in the positioner. Many control valves can be repaired with trim sets consisting of seat, plug and seals, provided the Kvs value and characteristic of the original trim are known. In practice: Replacement trims or a replacement valve require the Kvs value, characteristic, nominal size, nominal pressure, materials, medium, pressures and temperature as well as the data of the actuator and positioner. Without the Kvs value and characteristic, it cannot be ensured that the control loop will work in the same way after the replacement. Also known as: regulating valve, modulating valve, final control element, globe control valve Frequently asked questions: - **What is the Kvs value of a control valve?** The Kvs value indicates how much water in cubic metres per hour flows through the valve when it is fully open at a differential pressure of one bar. It is used for sizing and comparing valves. An excessively large Kvs value means that the valve works almost exclusively in the lower stroke range and controls poorly. - **What is the difference between a control valve and an isolating valve?** An isolating valve is intended to open a line fully or close it tightly. A control valve changes the flow continuously and works permanently in intermediate positions. For this purpose, it is equipped with a defined characteristic, a sensitive actuator and usually a positioner. Some control valves also perform an isolating function, but do not always achieve the same tightness. - **What information is needed for a replacement control valve?** Required are the Kvs value, valve characteristic, nominal size, nominal pressure, connection type and face-to-face dimension, materials of the body and trim, medium, inlet and outlet pressure and temperature. In addition, the actuator type, fail-safe position on loss of power and the positioner signal are needed. The nameplates of the valve and actuator contain most of this data. - **What does equal percentage characteristic mean?** With an equal percentage characteristic, each equal change in stroke produces the same percentage change in flow relative to the current value. In the lower stroke range, the flow therefore changes little, and in the upper range it changes a lot. This characteristic is often chosen when the pressure drop across the valve varies considerably with the load. #### Diaphragm pump URL: https://www.ktb-europe.com/en/glossary/diaphragm-pump/ A diaphragm pump is a positive displacement pump in which an oscillating diaphragm separates the pumped medium from the drive and draws it in and expels it via valves. The diaphragm moves back and forth, enlarging and reducing a pumping chamber. Check valves on the suction and discharge sides determine the direction of flow. Because no shaft seal comes into contact with the medium, diaphragm pumps are suitable for aggressive, toxic, abrasive or solids-laden liquids in chemicals, electroplating, food production and wastewater treatment. Air-operated double diaphragm pumps are widespread: they need no electric motor, can run dry safely and can be controlled via the air pressure. Mechanically or hydraulically driven diaphragm pumps work with a motor and eccentric and are also used as metering pumps. Key parameters are flow rate, discharge pressure, suction lift, connection size and the materials of the housing, diaphragms and valves, such as polypropylene, stainless steel, PTFE or EPDM. Diaphragms are wear parts that fatigue as a result of load cycles, chemicals or solids. A ruptured diaphragm can allow the medium into the air side or the drive, so regular inspection and spare part kits make sense. For pumps available in several material variants, the spare parts order must match the installed version exactly. A wrongly selected diaphragm can swell or tear and quickly lead to another failure. In practice: Replacement diaphragms and valves require the pump type, size and material combination from the type designation. For new media, the chemical resistance of the materials should be checked before use. Also known as: double diaphragm pump, AODD pump (air-operated double diaphragm), air-operated diaphragm pump, membrane pump Frequently asked questions: - **How does an air-operated double diaphragm pump work?** Two diaphragms are connected by a rod. An air control valve alternately pressurises the back of one diaphragm with compressed air, which pushes the medium out of its chamber while the opposite diaphragm draws medium in. Ball or flap valves determine the direction. The flow rate can be adjusted via air pressure and air volume. - **What information is needed for diaphragm pump spare parts?** Required are the pump type and size, drive type and the materials of the housing, diaphragms, valve balls and valve seats. This information is usually encoded in the type designation. The serial number should be to hand for diaphragm kits. If the medium changes, the resistance of the materials must be checked. - **Can a diaphragm pump run dry?** Air-operated double diaphragm pumps are considered safe to run dry because there are no sliding seals or rotating parts rubbing in the medium. Prolonged dry running nevertheless increases wear on diaphragms and valves. For other designs, the manufacturer’s specifications apply. The valves should also be checked after periods of dry running. - **When is a diaphragm pump better than a centrifugal pump?** Diaphragm pumps are advantageous for viscous, abrasive or solids-laden media, for aggressive chemicals without the risk of leakage at shaft seals, for self-priming operation and, with an air drive, in potentially explosive atmospheres. Centrifugal pumps are usually more efficient for large volumes of low-viscosity media and continuous operation. #### Flat gasket URL: https://www.ktb-europe.com/en/glossary/flat-gasket/ A flat gasket is a flat, static seal that is compressed between two flat surfaces, such as pipe flanges or housing covers. Flat gaskets seal stationary joints in which the components do not move relative to each other during operation. The bolt force compresses the gasket so strongly that it fills irregularities in the sealing surfaces and the medium cannot pass through. The main applications are pipe flanges, pump and valve housings, vessel covers and gearbox housings. Depending on pressure, temperature and medium, bonded fibre materials, expanded graphite, PTFE, elastomers or semi-metallic gaskets such as kammprofile and spiral wound gaskets are used. For non-metallic flat gaskets on PN-designated flanges, EN 1514-1 specifies the dimensions. Key parameters are inside and outside diameter, thickness, bolt pattern, material, permissible surface pressure and temperature and media resistance. Leaks are usually caused by insufficient or uneven surface pressure, gasket relaxation, reused gaskets, damaged sealing surfaces or a material unsuitable for the medium and temperature. Flange gaskets are therefore replaced every time the joint is dismantled. For joints with higher requirements, assembly is often carried out and documented with a defined tightening torque and a specified tightening sequence so that the gasket is compressed evenly. In practice: For flange gaskets, nominal size, nominal pressure, gasket type and material are usually sufficient; for special shapes, a drawing or template with all dimensions is required. Medium, pressure and temperature should always be stated so that the material can be checked; the bolt tightening torque belongs in the assembly instructions. Also known as: flange gasket, sealing washer, static seal Frequently asked questions: - **What information is needed for a flange gasket?** For standard flanges, the nominal size, nominal pressure or pressure class, flange type and gasket material are sufficient, for example DN 100 PN 16 with a ring or full-face gasket. For special parts, the inside and outside diameter, thickness, pitch circle and the number and diameter of the holes are needed. Medium, pressure and temperature should also be stated. - **Can a flat gasket be reused?** As a rule, no. A flat gasket is permanently deformed when tightened and adapts to the sealing surfaces. Once loosened, it lacks the recovery needed to seal again when retightened. A new gasket is therefore fitted every time the joint is dismantled, even if the old one still looks undamaged. - **What is the difference between a ring gasket and a full-face gasket?** A ring gasket lies only inside the bolt circle between the flange faces, with the bolts running outside it. A full-face gasket covers the entire flange face and has holes for the bolts. Which type is needed depends on the flange design and the construction; the two must not be interchanged without checking. - **Which material is suitable for flat gaskets at high temperatures?** At high temperatures, graphite gaskets, mica materials or semi-metallic gaskets such as kammprofile and spiral wound gaskets are often used. Which variant is suitable also depends on pressure, medium and flange design. The limit values are specific to the material and manufacturer and should be checked against the data sheets. #### Fluid power URL: https://www.ktb-europe.com/en/glossary/fluid-power/ Fluid power is the umbrella term for hydraulics and pneumatics, i.e. the transmission of energy and signals by means of pressurised liquids or gases. Fluid power covers all methods in which a pressurised medium transmits forces and movements. In hydraulics the medium is usually a mineral oil or another hydraulic fluid, in pneumatics compressed air. Hydraulics is suited to large forces in a compact design, pneumatics to fast, comparatively light movements and simple automation tasks. A fluid power system consists of energy generation (pump or compressor), conditioning (filters, coolers, air service unit), control (directional, pressure and flow control valves) and actuation (cylinders, motors). Pipes, fittings and hoses connect the components, and accumulators and reservoirs complete the system. The graphical symbols for circuit diagrams are standardised in ISO 1219-1, so that diagrams can be read internationally. For maintenance, cleanliness of the medium, leak-tightness and the condition of seals and hoses are decisive. Many failures are due to contamination, leakage or ageing. Replacement requires precise information on pressure rating, connection type and medium, because seemingly identical components can differ in these respects. In practice: For spare parts enquiries in fluid power, the operating pressure, nominal size, connection thread, seal material and medium should be stated in addition to the part number. An up-to-date circuit diagram helps to determine the function of a component unambiguously. Also known as: hydraulics and pneumatics, fluid technology, fluidics, fluid power systems Frequently asked questions: - **What is the difference between hydraulics and pneumatics?** Hydraulics works with virtually incompressible liquids and high pressures; it generates large forces and allows precise, smooth movements. Pneumatics uses compressible compressed air at much lower pressures; it is fast, clean and simple, but less rigid and less suitable for large forces. Both belong to fluid power. - **What does ISO 1219 cover?** ISO 1219-1 specifies graphical symbols for fluid power components and systems, for example for pumps, valves, cylinders and filters. Further parts of the standard deal with the layout of circuit diagrams. As a result, hydraulic and pneumatic diagrams can be read regardless of language and manufacturer, which makes troubleshooting and spare part identification easier. - **Which components make up a hydraulic system?** A hydraulic system comprises a reservoir, a pump with drive, filters, valves for controlling direction, pressure and flow, and cylinders or hydraulic motors as actuators. These are supplemented by pipes, hoses, accumulators, coolers and measuring instruments. Reliability depends heavily on the cleanliness of the hydraulic fluid. #### Gear pump URL: https://www.ktb-europe.com/en/glossary/gear-pump/ A gear pump is a positive displacement pump in which two meshing gears carry liquid in the tooth gaps from the suction side to the discharge side. As the gears rotate, tooth gaps open on the suction side, fill with liquid and carry it along the housing wall to the discharge side, where the meshing of the teeth displaces it. Gear pumps are simple, robust and inexpensive and are used as fixed displacement pumps in hydraulic power units, as lubricating oil pumps and as transfer pumps for viscous media such as oils, resins or adhesives. In the external gear pump, two externally toothed gears mesh; in the internal gear pump, an externally toothed pinion runs inside an internally toothed ring gear, which is quieter and produces less pulsation. Key parameters are displacement per revolution, speed range, maximum pressure, direction of rotation, shaft end and mounting flange. Because the displacement is fixed by design, the flow rate is varied via the speed. Wear on tooth flanks, bearings and side plates enlarges the internal clearances, so efficiency drops. Causes are dirt particles, cavitation due to excessive suction resistance and dry running. Because of their simple design, gear pumps are often replaced completely rather than repaired when worn. For critical hydraulic power units, it is worth keeping a suitable pump in reserve. In practice: For a replacement, the displacement, direction of rotation, shaft end, flange, connection type and maximum pressure are needed. With gear pumps in particular, the direction of rotation is crucial, because many versions may only be operated in one direction. Also known as: external gear pump, internal gear pump, fixed displacement pump, gear-type pump Frequently asked questions: - **What is the difference between an external and an internal gear pump?** In an external gear pump, two externally toothed gears mesh; it is simple and inexpensive but comparatively noisy. In an internal gear pump, a pinion rotates inside an internally toothed ring gear, separated by a crescent-shaped filler piece. It runs more quietly and with less pulsation and is therefore often chosen for noise-sensitive applications. - **How do you identify the direction of rotation of a gear pump?** The direction of rotation is stated looking at the shaft end, i.e. clockwise or anticlockwise. It is given in the type designation or marked by an arrow on the housing. Different-sized ports often also reveal the suction and discharge sides. A pump installed the wrong way round will not deliver or will be damaged. - **What information is needed to replace a gear pump?** Required are the displacement in cubic centimetres per revolution, maximum operating pressure, direction of rotation, shaft form, mounting flange, position and type of ports and speed range. For process pumps, the pumped medium, viscosity, temperature, materials and shaft seal are also needed. The nameplate and manufacturer part number speed up identification. - **Why is a gear pump getting noisy?** Increased noise often indicates cavitation due to excessive suction resistance, oil that is too viscous when cold, or air being drawn in through leaking suction lines. Worn bearings and tooth flanks or incorrect alignment with the drive shaft also generate noise. Checking the suction side is often the first step. #### Hydraulic cylinder URL: https://www.ktb-europe.com/en/glossary/hydraulic-cylinder-definition/ A hydraulic cylinder is an actuator that converts hydraulic pressure into linear motion with high force, for example in presses or rolling mills. Inside the cylinder tube, a piston with piston rod moves, displaced by oil pressure on one or both sides. The force is the product of pressure and effective piston area. Hydraulic cylinders generate considerably higher forces than pneumatic cylinders in a compact design and can be positioned sensitively. Single-acting cylinders work in one direction only and retract by load or spring, while double-acting cylinders are pressurised in both directions. There are also double-rod cylinders with a through rod, telescopic and plunger cylinders. In terms of construction, a distinction is made between tie-rod, round-body and welded cylinders. Key ratings are piston and rod diameter, stroke, nominal pressure, mounting style, end-position cushioning and seal system. For certain series, mounting dimensions are standardised in ISO 6020 and ISO 6022. Common causes of failure are worn seals, scoring on the piston rod, contaminated oil, side loads due to misalignment and corrosion. In steelworks or on injection moulding machines, heat and scale are added. A seal kit is often sufficient; if the rod is damaged, a repair is necessary. For cylinders without documentation, a replacement can be reproduced on the basis of measurements, installation situation and operating data. In practice: For replacement or repair, nameplate data, piston and rod diameter, stroke, operating pressure, mounting style, port thread and medium are needed. For special cylinders without documentation, a dimensioned drawing helps; seal kits should be stocked for critical cylinders. Also known as: hydraulic ram, hydraulic actuator, differential cylinder, plunger cylinder, double-acting cylinder Frequently asked questions: - **What is the difference between a single-acting and a double-acting hydraulic cylinder?** A single-acting cylinder is pressurised with oil on one side of the piston only; it retracts by the weight of the load or by a spring. A double-acting cylinder has two ports and is moved hydraulically in both directions. Double-acting cylinders are common in presses, hoists and conveying equipment because they deliver force in both directions. - **How is the force of a hydraulic cylinder calculated?** The force is the product of pressure and effective area. When extending, the full piston area acts; when retracting, only the annular area, i.e. piston area minus rod cross-section. A cylinder therefore produces less force when retracting. In practice, friction and pressure losses reduce the theoretical value. - **What information is needed to replace a hydraulic cylinder?** Piston diameter, rod diameter, stroke, maximum operating pressure, mounting style at base and rod, port type and size, installation length as well as medium and temperature are needed. Details of end-position cushioning and any position measuring system are also important. The nameplate and manufacturer part number shorten clarification considerably. - **Why does a hydraulic cylinder leak oil or drift down?** External leakage at the rod usually indicates a worn rod seal or a damaged rod surface. If a cylinder drifts down under load, a defective piston seal or a leaking valve in the circuit may be the cause. A test should distinguish between the two before parts are replaced. #### Hydraulic filter URL: https://www.ktb-europe.com/en/glossary/hydraulic-filter/ A hydraulic filter retains particles from the hydraulic fluid, protecting pumps, valves and cylinders against wear and malfunctions. Contamination of the hydraulic fluid is considered one of the most common causes of failure in hydraulic systems. Particles from manufacturing, abrasion or the environment accelerate wear in the narrow clearances of pumps and valves and can cause spools to stick. Hydraulic filters retain these particles and thus safeguard the service life of the components. By installation location, a distinction is made between suction filters upstream of the pump, pressure filters downstream of the pump to protect sensitive valves, and return line filters, which clean the oil flowing back to the reservoir. There are also breather filters on the reservoir and offline (bypass) filters. Characteristic values are filter rating, filtration efficiency, dirt-holding capacity and permissible differential pressure. Fluid cleanliness is specified according to ISO 4406 with a code of three numbers describing the particle count in three size classes. A clogging indicator signals visually or electrically when the differential pressure across the element becomes too high. Many filters have a bypass valve that lets unfiltered oil through when the element is clogged; this protects the element, but not the system. Timely element replacement is therefore a key maintenance task. In practice: For replacement elements, the element designation, filter rating, filter media material, seal material and permissible differential pressure are required. An element with a different rating may fail to achieve the required oil cleanliness or clog too quickly; replacement elements should therefore be specified as equivalent. Also known as: hydraulic filter element, hydraulic oil filter, filter element, return line filter, pressure filter Frequently asked questions: - **What is the difference between suction, pressure and return line filters?** Suction filters sit upstream of the pump and keep out coarse particles; they are usually coarse to avoid cavitation. Pressure filters are located downstream of the pump and protect sensitive components such as servo or proportional valves. Return line filters clean the oil before it flows back into the reservoir, thus maintaining the overall cleanliness of the system. - **What does a cleanliness code such as 18/16/13 to ISO 4406 mean?** The three numbers stand for particle counts in three size classes per millilitre of fluid, measured at 4, 6 and 14 micrometres and above. Each number corresponds to a range in a standardised table; a value one step higher means roughly twice the number of particles. The required cleanliness is specified by the manufacturers of the most sensitive components in the system. - **When does a hydraulic filter need to be changed?** The primary criterion is the clogging indicator, which responds when the differential pressure is too high. In addition, change intervals according to the operating instructions apply, for example after commissioning or after repairs. If an element is changed too late, the bypass valve may open and unfiltered oil may enter the system. #### Hydraulic hose URL: https://www.ktb-europe.com/en/glossary/hydraulic-hose/ A hydraulic hose is a flexible pressure line consisting of inner tube, reinforcement and cover that carries hydraulic fluid between moving components. Hydraulic hoses connect components that move or vibrate relative to each other, such as cylinders on presses, slewing drives in conveying equipment or tools on injection moulding machines. An oil-resistant inner tube carries the medium, a reinforcement of steel wire braid or spiral absorbs the pressure, and the cover protects against abrasion, ozone and weathering. With crimped fittings, this becomes a hose assembly. Key ratings are nominal size, maximum operating pressure, temperature range, minimum bend radius and media compatibility. Common types are described in EN 853 (braid-reinforced), EN 856 (spiral-reinforced) and EN 857 (compact braided hoses); SAE types are also widespread. Fittings differ in connection form, for example sealing cone with O-ring or thread with sealing cone. Hoses age even without visible damage. Causes of failure are falling below the bend radius, torsion, chafing, heat and pressure peaks. A burst can endanger people through escaping oil; regular inspection and timely replacement are therefore mandatory. For maintenance, it pays to keep a register of all hose assemblies with installation location, type, length and installation date. Inspection dates and replacement needs can then be planned from it. In practice: The layline printed on the hose and the fitting designation contain the most important data for reproduction. In addition, the overall length, connection forms at both ends, offset angle for elbow fittings and the manufacturing date of the hose assembly are needed. Also known as: hydraulic hose assembly, high-pressure hose, hose assembly, 2SN hose Frequently asked questions: - **What information is needed for a new hydraulic hose?** The hose type or standard, nominal size, operating pressure, overall length including fittings, connection form and thread at both ends, the offset angle for elbow fittings, as well as medium and temperature are needed. The layline on the hose and the stamping on the fitting provide most of the data. Photos of both ends avoid misunderstandings. - **How long may a hydraulic hose be used?** Hydraulic hose assemblies are subject to ageing and may not be used indefinitely. Rules of the German statutory accident insurance institutions and manufacturer information contain recommendations on the period of use, which are adjusted according to the stress involved. The decisive factor is the operator’s risk assessment; visible damage requires immediate replacement, regardless of age. - **What do 1SN, 2SN or 4SH mean for hydraulic hoses?** The codes designate hose types from European standards. SN types are reinforced with one or two layers of steel wire braid and are intended for medium pressures. SP and SH types have several layers of steel wire spiral and withstand higher pressures and pressure impulses. The permissible pressure also depends on the nominal size. - **How can a damaged hydraulic hose be recognised?** Warning signs are cracks or blisters in the cover, exposed braid, kinks, deformation, damp patches and leakage at the fitting. A displaced or corroded fitting also indicates a problem. Such hose assemblies should be replaced immediately. #### Hydraulic motor URL: https://www.ktb-europe.com/en/glossary/hydraulic-motor-definition/ A hydraulic motor converts the pressure and flow of a hydraulic fluid into a rotary motion with high torque, often at low speed. The hydraulic motor is the rotating counterpart to the hydraulic cylinder. Its design resembles a hydraulic pump, but it works in the opposite direction: the pressurised incoming oil drives the displacement elements and generates torque at the shaft. Hydraulic motors are compact, overload-proof and infinitely variable in speed. Depending on the design, a distinction is made between gear, vane, axial piston and radial piston motors as well as orbital motors based on the gerotor principle. High-speed motors operate at high speeds and are often combined with a gearbox, while low-speed motors deliver high torque directly, for example for screw conveyors, agitators, winding or roller drives. The central parameter is displacement per revolution; torque is proportional to displacement and pressure differential, and speed is proportional to flow rate. Wear on running surfaces and seals leads to increasing leakage flow and falling torque. Contaminated oil, inadequate case drain and pressure peaks are among the most common causes of damage. In procurement, it should be noted that motors of the same size can differ considerably in shaft, flange and ports. The complete type designation from the nameplate is therefore more important than the size alone. In practice: For a replacement, the design, displacement, maximum pressure, speed range, shaft end, flange type, port sizes and direction of rotation are needed. Whether a case drain port is present and how it is routed should be clarified before replacement. Also known as: hydromotor, orbital motor, radial piston motor, oil motor, hydraulic drive motor Frequently asked questions: - **What is the difference between a hydraulic motor and a hydraulic pump?** The pump converts mechanical energy from a drive into hydraulic energy, while the motor converts hydraulic energy back into rotary motion. Many designs are similar in construction but are optimised for their function, for example in terms of bearings, seals and direction of rotation. Not every pump can simply be operated as a motor. - **How do you calculate the torque of a hydraulic motor?** The theoretical torque is the displacement multiplied by the pressure differential between inlet and outlet, divided by two pi. With the displacement in cubic centimetres and the pressure in bar, conversion gives the torque in newton metres. The mechanical efficiency reduces the actual value. - **What information is needed to replace a hydraulic motor?** Important are the design, displacement, maximum operating pressure, speed range, direction of rotation or reversibility, shaft form and diameter, mounting flange and port type and size. Information on the case drain port and, where applicable, integrated brakes or valves is also needed. Nameplate data and the manufacturer part number are the quickest route to identification. - **Why is a hydraulic motor losing power?** The most common cause is internal wear, which increases the leakage flow so that less oil does useful work. Low system pressure, an incorrectly set pressure relief valve, clogged filters or oil that is too hot and thin also reduce torque and speed. Measuring the case drain flow helps to identify the motor as the cause. #### Hydraulic power unit URL: https://www.ktb-europe.com/en/glossary/hydraulic-power-unit/ A hydraulic power unit is a compact assembly of tank, pump, drive motor and valves that supplies a machine with pressurised hydraulic oil. The hydraulic power unit is the energy source of a hydraulic system. An electric motor drives the pump, which draws oil from the tank and delivers it into the system under pressure. Valves control direction, pressure and flow before the oil reaches cylinders or motors and then flows back into the tank after filtering. In addition to the pump and motor, a unit usually includes a pressure relief valve, suction, pressure or return filters, a cooler, level and temperature indicators, a breather filter and a pressure gauge or pressure sensor. Depending on the application, accumulators, heating and a control block are added. Key parameters are tank volume, flow rate, operating pressure, motor power and oil type. Units are built as standard assemblies for low power ratings or as custom-designed systems, for example for presses and rolling stands. Many failures are caused by contaminated or overheated oil. Clogged filters, defective coolers and air in the system damage the pump and valves. Oil analysis and temperature monitoring are therefore key maintenance measures. Because many units are configured individually, the replacement of individual components depends heavily on complete documentation. If the circuit diagram or bill of materials is missing, components must be recorded on site from their nameplates. In practice: Spare parts require the hydraulic circuit diagram, bill of materials and the nameplates of the pump, motor and valves. Filter elements, seals and breather filters should be kept in stock as maintenance materials with their exact designations. Also known as: HPU, hydraulic power pack, hydraulic station, hydraulic unit, power pack Frequently asked questions: - **What does a hydraulic power unit consist of?** The basic components are the tank, pump, electric motor with coupling and bell housing, and a pressure relief valve. These are complemented by filters, a cooler, level and temperature indicators, a breather filter and a pressure gauge. Larger units have control blocks with directional valves, accumulators, heating and sensors for monitoring. - **Why does the oil in the hydraulic power unit get too hot?** Heat is generated wherever pressure is reduced without doing work, for example across throttles or a pressure relief valve that responds constantly. Other causes are a dirty or undersized cooler, a low oil level or internal leakage in the pump and cylinders. Oil that is too hot ages faster and damages seals. - **What information is needed for hydraulic power unit spare parts?** The most important documents are the hydraulic circuit diagram and the bill of materials. Nameplate data is needed for each component: for the pump, the design, displacement and shaft end; for the motor, power, speed and frame size; for valves, nominal size and actuation. For filters, the filter rating, design and element designation count. - **How often does the oil in the hydraulic power unit need changing?** Fixed intervals from the operating manual are a starting point. More meaningful is regular oil analysis for contamination, water content and ageing. Clean systems operated at low temperatures allow longer service lives than hot or heavily loaded ones. Filter elements should also be renewed when changing the oil. #### Hydraulic pump URL: https://www.ktb-europe.com/en/glossary/hydraulic-pump/ A hydraulic pump converts mechanical drive energy into hydraulic energy by delivering pressurised fluid into a hydraulic circuit. Hydraulic pumps work on the displacement principle: chambers that expand and contract draw in hydraulic fluid and force it into the system. Pressure is only created by the resistance of the consumers, such as cylinders or motors. Important types are gear pumps, vane pumps, axial piston pumps and radial piston pumps. They differ in pressure range, efficiency, noise behaviour and cost. With fixed displacement pumps, the delivery volume per revolution is fixed; with variable displacement pumps, it can be adjusted to demand via controllers, for example pressure-controlled or power-controlled. Key parameters are displacement in cubic centimetres per revolution, maximum operating pressure, speed range, direction of rotation and shaft and flange design. Many pump failures have their cause outside the pump: contaminated oil, air in the system, incorrect viscosity or cavitation on the suction side. Effective filtration, regular oil analyses and monitoring of case drain flow and noise help to detect pump damage early and prevent consequential damage in the rest of the system. In practice: For replacement, the type code, direction of rotation, shaft end, flange and controller version are decisive. Before installing a replacement pump, the cause of failure should be clarified and the hydraulic oil checked. Also known as: hydraulic power pump, positive displacement pump (generic term), hydro pump Frequently asked questions: - **How do you calculate the flow rate of a hydraulic pump?** The theoretical flow rate is displacement multiplied by speed. A pump with 28 cm³ per revolution theoretically delivers 42 litres per minute at 1,500 revolutions per minute. Because of internal leakage, the actual value is lower; with a volumetric efficiency of 0.95, it is around 40 litres per minute. As wear increases, this efficiency falls. - **How can you recognise a worn hydraulic pump?** Typical signs are louder or changed running noise, slower movement of the actuators, system pressure no longer being reached, an increasing case drain flow and higher oil temperatures. Because similar symptoms can also be caused by valves, filters or cylinders, pressure, flow rate and case drain flow should be measured systematically before the pump is replaced. - **What is cavitation and why does it damage the pump?** Cavitation occurs when the pressure on the suction side falls so far that vapour or air bubbles form in the oil. These collapse abruptly in the high-pressure area and erode material from surfaces. It can often be heard as a crackling noise. Causes include clogged suction filters, suction lines that are too narrow, oil that is too cold and therefore too viscous, or excessive speeds. #### Mechanical seal URL: https://www.ktb-europe.com/en/glossary/mechanical-seal/ A mechanical seal seals rotating shafts, for example in pumps and agitators, by means of two sealing faces that slide axially against each other. The mechanical seal, also known as an axial mechanical face seal, consists of a rotating seal ring that turns with the shaft and a stationary mating ring. Springs press the rings together, and a thin lubricating film forms between the very flat sealing faces. Secondary seals such as O-rings or bellows seal the rings against the shaft and housing. Typical material pairings are carbon graphite, silicon carbide, tungsten carbide or ceramic. A distinction is made between single and double seals, unbalanced and balanced designs, and cartridge seals, which are installed as a pre-assembled unit. Installation dimensions for common designs are standardised in EN 12756; for pumps in refineries, petrochemicals and chemicals, API 682 often applies. Selection depends on the medium, pressure, temperature, speed and shaft diameter. Common causes of damage are dry running, solids in the medium, unsuitable materials and installation errors. Leakage at the seal is often the first visible sign of a problem and should be investigated early. In practice: For a suitable replacement, the pump manufacturer and type, shaft diameter, design and the seal's material code are required. The material code is often stated on the seal or in the pump data sheet. Also known as: mechanical face seal, end face seal, cartridge seal (design), shaft seal (generic term) Frequently asked questions: - **Is slight leakage at the mechanical seal normal?** Yes, to a small extent. The lubricating film between the seal faces causes minimal leakage, which with many media escapes as vapour and is barely visible. Noticeable dripping, crystal deposits or an increasing leakage rate, on the other hand, indicate wear, damage or unfavourable operating conditions. Permissible values depend on the seal and application and are given in the manufacturer's specifications. - **What is a cartridge seal and what are its advantages?** A cartridge seal is a pre-assembled unit consisting of seal ring, mating ring, springs, secondary seals and shaft sleeve. It is slid onto the shaft and fixed as a whole. This reduces assembly errors, because the fitting dimension and preload are already set, and shortens downtime. In return, it is usually more expensive to buy than a component seal. - **What is the difference between a single and a double seal?** A single seal has one pair of seal faces and is sufficient for many non-critical media. A double seal has two pairs, between which a barrier or flush fluid circulates. It is used for toxic, flammable, abrasive or crystallising media, because the product does not escape directly into the environment. A supply system for the barrier fluid is required for this. #### Metering pump URL: https://www.ktb-europe.com/en/glossary/metering-pump/ A metering pump delivers a precisely adjustable volume of liquid per stroke or unit of time and is used to add chemicals and additives to processes accurately. Metering pumps are usually reciprocating positive displacement pumps. With each stroke, a piston or diaphragm draws in a defined volume and pushes it into the line via check valves. They are used in water treatment, chemicals, food and paper production, for example to add acids, alkalis, flocculants, biocides or dyes. Diaphragm metering pumps separate the medium completely from the drive, while piston metering pumps achieve higher pressures. In terms of drive, a distinction is made between solenoid metering pumps for small volumes and motor-driven pumps for higher capacities. The dosing rate is set via stroke length and stroke frequency and can be controlled by analogue or pulse signals. Key parameters are capacity, back pressure, metering accuracy and the materials of the dosing head, valves and seals. Peristaltic and gear pumps are also used for metering. Inaccurate dosing is often caused by worn or dirty valves, gas bubbles in the dosing head or a fatigued diaphragm. Crystallising media clog valves. Because dosing errors directly affect product quality or water treatment, metering pumps are considered critical in many processes. Redundant pumps or spare parts held in stock secure supply there. In practice: Spare parts require the pump type, dosing head size and material combination from the type designation. Keeping the diaphragm, valves and seals in stock as a spare part kit shortens downtime in the dosing process. Also known as: dosing pump, diaphragm metering pump, solenoid metering pump, chemical dosing pump, proportioning pump Frequently asked questions: - **How is the delivery rate of a metering pump set?** The delivery rate results from the volume per stroke and the number of strokes per unit of time. Many metering pumps allow both to be set: the stroke length mechanically or electronically, the stroke frequency via the controller or an external signal. For accurate results, the actual volume should be calibrated against the real back pressure using a measuring cylinder. - **What is the difference between a solenoid and a motor-driven metering pump?** In a solenoid metering pump, an electromagnet moves the diaphragm in pulses; it is compact and suitable for small volumes. Motor-driven metering pumps drive the diaphragm or piston via an electric motor and eccentric and achieve higher capacities and pressures. The choice depends on volume, back pressure and the required controllability. - **What information is needed for metering pump spare parts?** Required are the pump type and full type designation, dosing head size, materials of the dosing head, valves and seals, and the connection design. For motor-driven metering pumps, the gear ratio and motor data are also needed. The serial number helps with older series. Materials should suit the medium, especially for acids and solvents. - **Why is a metering pump dosing too little?** Common causes are dirty or worn suction and discharge valves, air or gas bubbles in the dosing head, a leaking suction line, a fatigued diaphragm or excessive back pressure. Outgassing media often require automatic venting. A systematic check of the suction side and valves resolves many cases. #### O-ring URL: https://www.ktb-europe.com/en/glossary/o-ring/ An O-ring is an annular sealing element with a round cross-section that is compressed in a groove and seals static or dynamic joints. The O-ring is the most widely used seal in mechanical and plant engineering. When installed, it is preloaded radially or axially in a groove; the system pressure additionally presses it against the sealing surfaces and thus increases the sealing effect. It is used in hydraulics and pneumatics, in pumps, valves, fittings and housings, mainly in static applications but also with slow movements. An O-ring is designated by its inside diameter and cross-section, for example 20 x 2.5 mm; dimensions and tolerances are set out in the ISO 3601 series of standards. The material is decisive: NBR for mineral oil-based media, FKM for higher temperatures and many chemicals, EPDM for water and steam but not for mineral oil, plus VMQ, HNBR and FFKM for special cases. Further ratings are hardness in Shore A, colour, temperature range and, where applicable, approvals, for example for food or drinking water. Typical causes of failure are gap extrusion at high pressure, compression set after long service, swelling or embrittlement due to incompatible media, damage during installation on edges and threads, and ageing due to incorrect storage. In practice: For reordering, inside diameter, cross-section, material, hardness, medium, temperature and any required approvals are needed. Measuring a removed O-ring is unreliable, because it may have swollen or been compressed; groove dimensions or bill of materials data are better. Also known as: O-ring seal, toric joint, round sealing ring, packing ring Frequently asked questions: - **How is an O-ring measured correctly?** The inside diameter and cross-section are measured. With removed rings, the values are often distorted because the material has swollen, shrunk or been flattened. It is more reliable to measure the groove diameter, groove depth and groove width or to use the data from the bill of materials and drawing and derive the correct ring size from them. - **Which O-ring material is the right one?** The material depends on medium, temperature and pressure. NBR is the standard for hydraulic oils and greases, FKM is suitable for higher temperatures and many oils and chemicals, EPDM for hot water, steam and many aqueous media, but not for mineral oils. If in doubt, a chemical resistance chart from the seal manufacturer should be checked. - **What is the difference between an O-ring and a quad ring?** The O-ring has a round cross-section, the quad ring an approximately square cross-section with four sealing lips. Under dynamic loads, quad rings are less prone to twisting and have somewhat lower breakaway friction. They often fit into the same grooves, but the manufacturers’ installation recommendations should be checked before switching. - **How long can O-rings be stored?** Shelf life depends heavily on the elastomer. Recommendations on storage conditions and storage periods can be found in standards and manufacturer information; cool, dry and dark storage without ozone and without deformation is essential. Older stock should be checked for cracks, hardening and tackiness before installation. #### Pneumatic cylinder URL: https://www.ktb-europe.com/en/glossary/pneumatic-cylinder/ A pneumatic cylinder converts the energy of compressed air into linear motion and serves as an actuator in automation and mechanical engineering. Inside the cylinder barrel, compressed air moves a piston whose piston rod transmits the force to the outside. In single-acting cylinders, compressed air works in only one direction and a spring provides the return stroke. Double-acting cylinders are pressurised with compressed air in both directions. There are also special designs such as rodless cylinders, compact cylinders, guided cylinders and rotary actuators. Key parameters are piston diameter, stroke, operating pressure, cushioning and port thread; together they determine force and speed. For common designs, standards specify the mounting dimensions, for example ISO 15552 for standard cylinders, ISO 6432 for small-bore round cylinders and ISO 21287 for compact cylinders. As a result, cylinders from different manufacturers are often mechanically interchangeable, even if details such as sensor slots or cushioning differ. Wear parts are mainly piston and rod seals as well as guide bands, which can be replaced as seal kits. End-position cushioning and sensing of the piston position are important features. In practice: For replacement, the design, piston diameter, stroke, mounting and sensors are required. With standard cylinders, it is worth checking whether a part from another manufacturer with the same mounting dimensions is available more quickly. Also known as: air cylinder, pneumatic actuator, compressed air cylinder, pneumatic ram Frequently asked questions: - **How do you calculate the force of a pneumatic cylinder?** The theoretical force is pressure multiplied by piston area. A cylinder with a 50 mm piston diameter has an area of around 1,963 mm²; at 6 bar, i.e. 0.6 N/mm², this gives approximately 1,180 N on extension. Friction losses reduce this value. On retraction the force is smaller, because the piston rod occupies part of the area. - **When is it worth replacing the seals rather than the whole cylinder?** A seal kit makes sense if the cylinder barrel and piston rod are undamaged and only leaks or declining force occur. If the piston rod shows scoring, corrosion or bending, replacing the cylinder is usually the better choice. For small standard cylinders, a new part is often more economical; for large or custom-made cylinders, repair is more likely to pay off. - **What does end-position cushioning do?** End-position cushioning slows the piston down shortly before it reaches the end position so that it does not strike hard. Elastic cushioning works with buffers made of plastic or elastomer, pneumatic cushioning with a trapped air cushion that can often be adjusted via a throttle screw. A suitable setting protects the cylinder, mountings and moving parts and reduces noise. #### Pressure regulator URL: https://www.ktb-europe.com/en/glossary/pressure-regulator/ A pressure regulator, also called a pressure reducing valve, lowers a fluctuating inlet pressure to an adjustable outlet pressure that is kept as constant as possible. Pressure regulators ensure that consumers are supplied at the pressure appropriate for them, regardless of fluctuations in the network. In compressed air systems they supply cylinders, tools and valve terminals; in process engineering they regulate gases, water or steam. A lower working pressure saves energy and protects components. In the common spring-loaded design, the set spring force acts against the outlet pressure on a diaphragm or piston. If the outlet pressure falls, the valve opens further; if it rises, the valve closes. Relieving regulators automatically vent excessive outlet pressure. Precision regulators work with minimal deviation, while electronic proportional pressure regulators set the pressure via an electrical setpoint signal. Key parameters are inlet pressure, adjustment range, flow rate, connection size, medium and materials. Faults show up as fluctuating outlet pressure or outlet pressure that creeps upwards. Causes include dirty valve seats, aged diaphragms and seals or a regulator that is too small for the flow rate. In maintenance, it pays to document set pressures and secure them against unauthorised adjustment. A regulator set too high increases energy consumption and wear; one set too low leads to malfunctions. In practice: For a replacement, the medium, inlet pressure, adjustment range, flow rate, connection thread and required functions such as relieving or a gauge port must be known. Regulators in gas or steam systems are also subject to the requirements of the respective installation. Also known as: pressure reducer, pressure reducing valve (PRV), pressure reducing regulator, air regulator Frequently asked questions: - **What is the difference between a pressure regulator and a pressure relief valve?** A pressure regulator lowers a higher inlet pressure to a lower, constant outlet pressure and is open during operation. A pressure relief valve is closed in normal operation and only opens when the pressure reaches a limit, in order to reduce it. The regulator therefore supplies consumers, while the relief valve protects the system. - **What does relieving mean for a pressure regulator?** A relieving regulator can itself reduce excess pressure on the outlet side, for example when the setpoint is lowered or a reaction from the consumer increases the pressure. The air escapes via a vent port. Without this function, the higher pressure remains until a consumer draws off air. - **What information is needed to replace a pressure regulator?** Important are the medium, maximum inlet pressure, required adjustment range, required flow rate, connection thread, materials, temperature range and additional functions such as relieving, a pressure gauge or a lockable adjusting knob. For electronic regulators, the setpoint signal and supply voltage are also needed. The nameplate and type designation provide most of the data. - **Why does the outlet pressure at the pressure regulator rise slowly?** A creeping rise in pressure usually indicates that the valve no longer closes tightly, for example due to dirt on the valve seat or a worn valve disc. A damaged diaphragm can also cause this behaviour. Cleaning or a repair kit often solves the problem; upstream filters help prevent it. #### Pressure relief valve URL: https://www.ktb-europe.com/en/glossary/pressure-relief-valve/ A pressure relief valve opens as soon as the system pressure reaches a set value, thereby protecting pumps, lines and consumers against overload. The pressure relief valve is one of the pressure control valves and is present in almost every hydraulic circuit, usually directly downstream of the pump. When the set pressure is reached, a valve element lifts against a spring and diverts the excess flow to the tank. This keeps the pressure limited, even when a cylinder is at its end stop or a line is blocked. Direct-acting valves are simple in design and respond quickly, but are better suited to smaller flow rates. Pilot-operated valves use a small pilot valve that opens the main spool; they operate with a stable characteristic even at high flow rates and can be remotely controlled or electrically unloaded. Key parameters are nominal size, pressure stage or adjustment range, maximum flow rate and design as a cartridge, subplate or in-line valve. It should be distinguished from the safety valve for pressure vessels, which has its own inspection and approval requirements. Wear on the seat, broken springs or dirt lead to leakage or an incorrect opening pressure. Frequent operation generates heat. As a central protective element, the pressure relief valve should be checked for leakage and cracking pressure during inspections. In the worst case, a sticking valve can overload the pump, hoses and cylinders. In practice: For a replacement, the nominal size, design, adjustment range and set pressure must be known; the set pressure should be documented before removal. Adjustments to the valve must only be made by qualified personnel and with a pressure gauge check. Also known as: relief valve, PRV, overpressure valve, pressure limiting valve Frequently asked questions: - **What is the difference between a pressure relief valve and a pressure reducing valve?** The pressure relief valve limits the pressure at its inlet by opening when the set value is reached and diverting oil to the tank; in normal operation it is closed. The pressure reducing valve, by contrast, reduces a higher inlet pressure to a lower, constant outlet pressure for a sub-circuit; it is open in normal operation. - **What is the difference between a direct-acting and a pilot-operated pressure relief valve?** In a direct-acting valve, the system pressure acts directly against the spring of the valve element. This is simple and fast, but the characteristic rises noticeably as the flow rate increases. In a pilot-operated valve, a small pilot valve opens first and relieves the main spool. As a result, the pressure remains stable even at high flow rates. - **What information is needed to replace a pressure relief valve?** Important are the design as a cartridge, subplate or in-line valve, nominal size, mounting pattern or thread, pressure adjustment range, set pressure, maximum flow rate and type of adjustment. For pilot-operated valves, remote control or electrical unloading must also be specified. The nameplate or the marking stamped on the valve body provides the exact designation. - **Is a pressure relief valve the same as a safety valve?** Not quite. Pressure relief valves in hydraulic systems are functional components that limit the working pressure. Safety valves on pressure vessels and steam systems are safety accessories and are subject to their own standards as well as inspection and marking obligations. Which requirements apply depends on the plant and the relevant regulations. #### Progressive cavity pump URL: https://www.ktb-europe.com/en/glossary/progressive-cavity-pump/ A progressive cavity pump is a positive displacement pump in which a helical rotor turning in an elastic stator forms cavities that travel along the pump. The metal rotor turns eccentrically in the stator, which is usually made of an elastomer. Sealed cavities form between the two and move continuously from the suction side to the discharge side. As a result, the pump delivers almost pulsation-free and gently. It is suitable for viscous, abrasive, solids-laden or shear-sensitive media such as sludges, pastes, adhesives, paints and food masses. The drive is via a joint, such as a cardan or pin joint, which compensates for the eccentric movement. The number of stages determines the achievable pressure, while speed and geometry determine the flow rate. Key parameters are flow rate, pressure, viscosity, solids content, temperature, rotor and stator material and the shaft seal. Versions with a hopper and feed screw handle very viscous masses, for example in paper mills and sewage treatment plants. The stator and rotor wear as a result of abrasion, swelling or dry running. Even brief dry running can destroy the stator, which is why dry-running protection is often used. For maintenance, it is worth monitoring the delivery rate and current consumption. Falling output at the same speed indicates stator wear early on, so the replacement can be planned rather than carried out after a breakdown. In practice: A replacement stator and rotor require the size, number of stages, rotor geometry, materials and, where applicable, undersize or oversize version. The stator, rotor and joint parts are classic items to keep in stock for critical pumps. Also known as: PC pump, eccentric screw pump, progressing cavity pump, helical rotor pump, single-screw pump Frequently asked questions: - **What is a progressive cavity pump used for?** It pumps media that are too viscous, abrasive or rich in solids for centrifugal pumps, such as sludges in sewage treatment plants, coating colours in paper production, adhesives, resins and food masses. Thanks to the even, low-shear delivery, sensitive substances remain intact. It is also suitable for metering, because the flow rate is proportional to the speed. - **Why is dry running dangerous for progressive cavity pumps?** The elastomer stator is lubricated and cooled by the pumped medium. If the pump runs dry, the stator heats up very quickly due to friction and can burn or stick. Even short periods of dry running cause damage. Dry-running protection with temperature or level monitoring switches the pump off in good time. - **What information is needed for the stator and rotor of a progressive cavity pump?** Required are the pump type and size, number of stages, rotor material and any coating, stator elastomer, geometry and, where applicable, fit variant. This data is usually found in the type code or the order confirmation. The serial number helps with special versions. If the medium or temperature changes, the stator material must be reassessed. - **How can you tell that a stator is worn?** Signs are a falling flow rate at the same speed, declining pressure build-up, rough running and rising current consumption. On dismantling, scoring, washed-out areas, swelling or hardening of the elastomer become visible. The rotor should then also be checked for wear and coating damage. #### Proportional valve URL: https://www.ktb-europe.com/en/glossary/proportional-valve/ A proportional valve adjusts pressure, flow or direction continuously and in proportion to an electrical setpoint, usually by means of a proportional solenoid. Whereas a switching valve knows only open or closed, a proportional valve can take up any intermediate position. This allows speeds, forces and pressures in hydraulics and pneumatics to be finely metered, for example when a press starts smoothly, for positioning in materials handling or on injection moulding machines with varying injection profiles. There are proportional directional valves, proportional pressure valves and proportional flow valves. A proportional solenoid generates a force corresponding to the coil current; amplifier electronics convert the setpoint, for example 0–10 V or 4–20 mA, into this current. These electronics are either external or mounted on the valve as on-board electronics. Valves with a position transducer and closed-loop position control achieve higher accuracy and lower hysteresis. They should be distinguished from servo valves, which are even more dynamic and precise but also more sensitive to dirt. Failures are caused mainly by contaminated oil that jams spools, by defective coils or connectors and by faults in the amplifier electronics. As proportional valves often work in closed control loops, a replacement affects the behaviour of the entire axis. After installation, adjustment of the zero point, gain and ramps is therefore usually required. In practice: For a replacement, not only the nominal size, function and nominal flow but also the setpoint signal, supply voltage, connector pin assignment and electronics variant must match. Amplifier electronics parameters should be backed up before the replacement. Also known as: proportional directional valve, proportional pressure valve, continuous valve, proportional solenoid valve Frequently asked questions: - **What is the difference between a proportional valve and a servo valve?** Both are continuous valves that adjust infinitely. Proportional valves are usually operated directly or pilot-operated via proportional solenoids and are sufficient for many positioning and pressure tasks. Servo valves work with very high dynamics and accuracy, often via nozzle-flapper systems, and place higher demands on oil cleanliness. In practice, the boundary is fluid. - **What does on-board electronics mean for proportional valves?** In valves with on-board electronics, the amplifier is integrated directly on the valve. The valve receives only the supply voltage and setpoint, and the built-in electronics handle the control of the solenoid. Valves without integrated electronics require a separate amplifier card in the control cabinet. For a replacement, it must be clear which variant is installed. - **What information is needed to replace a proportional valve?** Required are the valve function, nominal size and mounting pattern, nominal flow or pressure stage, direct or pilot operation, setpoint signal, supply voltage, connector type and electronics variant. The complete type designation from the nameplate is particularly important, because small characters in the designation encode significant differences between versions. - **Why does a proportional valve respond inaccurately or jerkily?** Common causes are contaminated oil that makes the valve spool stiff, an incorrectly set amplifier with unsuitable ramps or characteristics, interference in the setpoint signal or a damaged coil. Air in the system can also impair behaviour. Before replacing the valve, it is worth checking oil cleanliness and the signal curve. #### Radial shaft seal URL: https://www.ktb-europe.com/en/glossary/radial-shaft-seal/ A radial shaft seal is a seal for rotating shafts whose spring-loaded lip runs radially on the shaft and keeps lubricant inside the housing. Radial shaft seals seal shaft passages in gearboxes, electric motors, pumps and bearing arrangements. They keep oil or grease inside the housing and prevent dust and splash water from entering. A thin lubricating film under the sealing lip ensures low friction and wear. A radial shaft seal consists of a metal reinforcing ring, a sealing lip made of elastomer or PTFE and a garter spring. Dimensions and designs are described in DIN 3760 and ISO 6194; common designs have a rubber-covered or metal outer case, with or without an additional dust lip. A radial shaft seal is designated by shaft diameter, bore diameter and width, for example 40 x 62 x 8. Further parameters are material, permissible surface speed, temperature and pressure differential. Common causes of failure are grooved or damaged shaft surfaces, dry running, lips hardened by overheating, ingress of dirt and overpressure in the housing, for which standard radial shaft seals are not designed. Assembly errors such as pressing the seal in at an angle or damaging it on shaft edges also lead to early leakage. In practice: In addition to the three dimensions, an enquiry should state the design, material, medium, speed and temperature. If the shaft shows a wear groove, offset installation or a shaft repair sleeve helps; otherwise the new seal will also soon leak. Also known as: rotary shaft seal, oil seal, lip seal, shaft seal, RWDR Frequently asked questions: - **How do you read the designation of a radial shaft seal?** The numbers indicate the shaft diameter, housing bore and width in millimetres, for example 35 x 52 x 7. These are supplemented by the design, for example with or without a dust lip, and the material of the sealing lip, such as NBR or FKM. Some designations also contain information on the helix direction or on pumping features on the lip. - **What is the difference between a radial shaft seal and a mechanical seal?** A radial shaft seal seals with a lip radially on the shaft surface and is suitable for lubricants at low pressure differentials. A mechanical seal seals axially between two precisely lapped rings and is used mainly in pumps and agitators for process media and higher pressures. It is more complex and more expensive than a radial shaft seal. - **What requirements does a radial shaft seal place on the shaft?** The running surface must be sufficiently hard, round and smooth and should be machined free of lead so that no oil is pumped out and no dirt is pumped in. A lead-in chamfer on the shaft edge makes assembly easier. If the shaft is grooved at the sealing point, a thin shaft repair sleeve can create a new running surface without replacing the shaft. - **Why does a new shaft seal soon start leaking?** Common reasons are a grooved shaft, damage to the lip when pushing it over edges or keyways, installation at an angle, dry running on start-up or the wrong material for the medium and temperature. Increased internal pressure in the housing, for example due to a blocked breather, can also lift the lip. #### Safety valve URL: https://www.ktb-europe.com/en/glossary/safety-valve/ A safety valve is a self-acting valve that opens when a set pressure is exceeded and protects vessels or pipelines against overpressure. Safety valves are the last line of protection against impermissible overpressure in steam boilers, pressure vessels, compressed air and process plants. When the pressure reaches the set pressure, the valve opens without auxiliary energy and discharges medium until the pressure falls again and it closes. It should be distinguished from the hydraulic pressure relief valve, which limits system pressure during normal operation. Most safety valves are spring-loaded; there are also pilot-operated and weight-loaded designs. Basic requirements are described in the EN ISO 4126 series of standards (DIN EN ISO 4126). Key parameters are set pressure, blowdown, discharge capacity or discharge coefficient, minimum flow area, inlet and outlet connection sizes, materials and the medium. Within the EU, safety valves are classed as safety accessories within the meaning of the Pressure Equipment Directive. Causes of failure include deposits and corrosion that prevent the valve from lifting, damaged sealing surfaces after frequent discharge and unsuitable settings. Selection, setting and periodic inspection are governed by the plant documentation and the applicable regulations; in individual cases, the assessment by competent persons or the responsible inspection body is binding. In practice: A safety valve is only replaced with a valve that has the same set pressure, sufficient discharge capacity, suitable connections and the required marking. An enquiry requires the nameplate data, medium, operating and set pressure, temperature and the required capacity; the seal and inspection records should be documented when replacing the valve. Also known as: pressure safety valve (PSV), safety relief valve, overpressure valve, SV Frequently asked questions: - **What is the difference between a safety valve and a pressure relief valve?** A safety valve is a protective device that only responds in the event of a fault and protects a vessel or plant from dangerous overpressure. A pressure relief valve, by contrast, is part of normal operation, especially in hydraulics, and limits the system pressure during operation. The requirements for design, marking and inspection differ accordingly. - **What does set pressure mean for a safety valve?** The set pressure is the pressure at which the valve begins to open under operating conditions. It is set and secured at the factory or by an authorised body, usually with a seal. The set pressure must not exceed the permissible pressure of the protected plant and is stated on the nameplate. - **What information is needed to replace a safety valve?** Required are the set pressure, medium and its physical state, operating temperature, required discharge capacity, nominal sizes of inlet and outlet, connection type, materials and the data from the nameplate. It is also important to know which marking and documentation are required for the plant. Replacing a safety valve on the basis of thread size alone is not permissible. - **How often does a safety valve need to be inspected?** Inspection intervals depend on the type of plant, the medium and the applicable national law and are specified for each plant. They often include a function test by lifting the valve and an inspection as part of periodic plant inspections. The operating manual and the requirements of the responsible inspection body are decisive; this entry does not replace a legal assessment. #### Solenoid valve URL: https://www.ktb-europe.com/en/glossary/solenoid-valve/ A solenoid valve is a valve actuated by an electric coil that opens, closes or switches the flow of liquids or gases. In a solenoid valve, a current-carrying coil generates a magnetic field that attracts a movable armature (plunger). The armature opens or closes the valve seat directly or indirectly. Solenoid valves link electrical control with media circuits, for example for water, compressed air, oil, steam or technical gases, and are used in automation, fluid power and building services. Direct-acting solenoid valves switch the seat by magnetic force alone and also work without a pressure differential, but are limited to smaller nominal sizes. Pilot-operated valves use the media pressure to assist and therefore usually require a minimum pressure differential. By number of ports and switching positions, a distinction is made, for example, between 2/2-way valves for opening and closing and 3/2-way valves for switching or venting. The normal position is normally closed (NC) or normally open (NO). Also important for operation are coil voltage and type of current, power consumption, duty cycle, degree of protection of the coil and the materials of the body and seal. Common faults are burnt-out coils, worn seals and deposits on the seat. In practice: For a replacement, the valve function, normal position, nominal size, connection thread, pressure range, medium and temperature as well as coil voltage and type of current should be stated. Often, replacing the coil or a seal kit is sufficient; this requires the exact designation of the existing part. Also known as: solenoid-operated valve, electromagnetic valve, solenoid valve NC/NO, directional valve (solenoid-operated) Frequently asked questions: - **What is the difference between a direct-acting and a pilot-operated solenoid valve?** In a direct-acting valve, the magnetic force opens the seat directly; it also works without a pressure differential but is limited to smaller nominal sizes or pressures. A pilot-operated valve uses the media pressure to move the main seat via a diaphragm or piston. It switches large flows with a small coil but generally requires a minimum pressure differential. - **What do normally closed (NC) and normally open (NO) mean?** Normally closed means that the valve is shut when there is no voltage at the coil and only opens when energised. Normally open means, conversely, that the valve allows flow in its rest state and closes when energised. The choice depends on which state is safe in the event of a power failure. - **What does the designation 3/2-way valve mean?** The first number indicates the number of ports, the second the number of switching positions. A 3/2-way valve therefore has three ports, usually pressure, working line and exhaust, and two switching positions. It is used, for example, to pressurise and then vent a single-acting cylinder. A 5/2-way valve, by contrast, typically controls double-acting cylinders. - **What information is needed to replace a solenoid valve?** Important are valve function, normal position, nominal size, connection size, permissible pressure range, medium, media and ambient temperature, and seal material. For the coil, voltage, type of current, power, connector type and degree of protection are needed. In potentially explosive atmospheres, the appropriate Ex marking is also required. A photo of the nameplate and coil makes unambiguous identification easier. #### Vacuum pump URL: https://www.ktb-europe.com/en/glossary/vacuum-pump/ A vacuum pump draws gases or vapours out of an enclosed space and creates a pressure there below atmospheric pressure. In industry, vacuum pumps are used for clamping, lifting and gripping, vacuum packaging, drying and degassing, plastics processing, paper machines and laboratories. Depending on the achievable pressure, a distinction is made between rough, fine and high vacuum; for higher vacuum levels, several pumps are often combined. Common designs are rotary vane pumps in oil-lubricated or dry-running versions, liquid ring pumps for humid or vapour-laden gases, claw and screw vacuum pumps for oil-free operation, and Roots pumps to increase pumping speed. For high vacuum, turbomolecular and other special pumps are added. Key ratings are pumping speed, achievable ultimate pressure, drive power, tolerance of vapours and particles, and type of lubrication. Depending on the design, wear affects vanes, bearings, shaft seals, separator elements and filters. Oil-lubricated pumps require regular oil changes; vapours or particles drawn in shorten service life considerably. In processes that come to a standstill without vacuum, such as packaging or drying, vacuum pumps are considered critical spare parts. A standby pump or a stocked service kit shortens downtime considerably. Before replacement, it should be clarified whether the extracted medium contains vapours, particles or aggressive components. In practice: For replacement and maintenance, the design, pumping speed, ultimate pressure, motor data, oil type and designations of inlet and exhaust filters are needed. Oil separator and filter elements as well as vanes should be stocked as maintenance material. Also known as: rotary vane pump, liquid ring pump, vacuum generator, vacuum compressor Frequently asked questions: - **What types of vacuum pumps are there?** For rough and fine vacuum, rotary vane, liquid ring, claw, screw, diaphragm and Roots pumps are common. For high vacuum, turbomolecular and other special pumps are usually combined with a backing pump. The choice depends on the required pressure, the pumping speed and whether the extracted gas contains moisture, vapours or particles. - **What is the difference between an oil-lubricated and a dry-running vacuum pump?** Oil-lubricated pumps use oil for sealing, lubrication and cooling and achieve a low ultimate pressure, but require oil changes and separators. Dry-running pumps work without oil in the pumping chamber, avoid oil mist and contamination and need less maintenance, but depending on the design reach different pressure ranges. Oil-free pumps are often chosen for food and cleanroom applications. - **What information is needed to replace a vacuum pump?** The design, pumping speed in cubic metres per hour, achievable ultimate pressure, motor power, voltage and frequency, connection sizes and the type of extracted medium with its moisture and vapour content are needed. The nameplate and serial number help to identify the right model or spare parts such as vanes, filters and seals unambiguously. - **Why does a vacuum pump no longer reach its ultimate pressure?** Possible causes are leaks in pipes and connections, clogged inlet filters, worn vanes or seals, contaminated or insufficient oil and vapours drawn in that condense in the oil. A test with the inlet port shut off shows whether the pump itself or the system is the cause. #### Valve actuator URL: https://www.ktb-europe.com/en/glossary/valve-actuator/ A valve actuator is an electric, pneumatic or hydraulic drive that automatically operates valves such as butterfly valves, ball valves or globe valves. Valve actuators convert a control signal into a rotary or linear movement. They make isolating and control valves remotely operable and are thus the link between the control system and the pipeline. A distinction is made between quarter-turn actuators for quarter-turn valves, linear actuators for globe valves and multi-turn actuators for gate valves. Pneumatic actuators work as diaphragm or piston actuators, for example with rack and pinion or scotch yoke, and are single-acting with spring return or double-acting. Electric actuators use a motor with gearbox and offer limit switches, torque cut-off and position feedback. Important parameters are torque or thrust, operating time, fail-safe position on loss of power, control pressure or voltage, degree of protection, explosion protection where applicable, and the valve interface, for quarter-turn actuators often to ISO 5211. Failures affect the seals and springs of pneumatic actuators, the motors, gearboxes and limit switches of electric actuators, and accessories such as solenoid valves and positioners. Seal kits and accessories are often available separately, so the complete actuator does not have to be replaced. For valves with a safety function, the fail-safe position should be checked after every replacement. In practice: For a replacement actuator, the actuator type, required torque with a safety margin, fail-safe position, control pressure or voltage, flange pattern and shaft connection of the valve and the accessories needed are specified. If the flange and square drive do not match, an adapter is possible, but it changes the overall height. Also known as: quarter-turn actuator, rotary actuator, valve drive Frequently asked questions: - **What is the difference between a single-acting and a double-acting valve actuator?** A double-acting pneumatic actuator is moved in both directions by compressed air and usually stays in position if the air supply fails. A single-acting actuator is operated by compressed air in one direction only, with springs providing the return. If the compressed air fails, it automatically moves to a defined fail-safe position, i.e. open or closed. - **What information is needed to replace a valve actuator?** Required are the actuator type, torque or thrust, angle of rotation or stroke, operating time, fail-safe position, control pressure or supply voltage, degree of protection and, where applicable, explosion protection. For mounting, the flange pattern and shaft connection of the valve matter. It should also be stated which accessories, such as limit switches, positioners or solenoid valves, are fitted. - **How is a valve actuator sized?** The basis is the torque or thrust that the valve requires under unfavourable conditions, for example on breakaway after a long period at standstill. A safety margin is added to this. For spring-return actuators, the torque must be sufficient at both the spring end and the air end. Valve manufacturers state the required torques in their documentation. - **What does ISO 5211 mean for valve actuators?** ISO 5211 specifies the connection dimensions for attaching part-turn actuators, i.e. actuators with a quarter turn, to the valve. These include flange sizes with pitch circle and holes. If the flange and shaft connection match, actuators from different sources can be interchanged more easily. The exact shaft form must nevertheless be checked separately. #### Valve terminal (valve manifold) URL: https://www.ktb-europe.com/en/glossary/valve-terminal/ A valve terminal combines several pneumatic valves on a common base plate with a central compressed air supply and grouped electrical control. Instead of piping and wiring each valve individually, many valves are mounted side by side on a valve terminal. Supply pressure and exhaust run through common channels, and control is centralised. This saves space, assembly time and wiring and is widespread in packaging machines, assembly systems and process engineering. The stations hold valves with different functions, for example 5/2-way valves with spring or pulse return, 5/3-way valves or two 3/2-way valves in one housing. The electrical connection is via a multi-pin plug or a fieldbus or Ethernet module; some terminals integrate input and output modules. Key parameters are pitch, number of valve stations, flow rate, pressure range, voltage, port sizes and degree of protection. Pressure zones allow different pressures on one terminal. Failures usually affect individual valves, solenoid coils, seals between valve and base plate or the electronics. Contaminated or oily compressed air shortens service life. Because valve terminals are configured for specific projects, ordering an identical new unit is hardly possible without the complete code. For critical machines, individual valves and coils from the installed series are therefore often kept in stock as spares. In practice: The order designation of a valve terminal is often a long configuration code that defines the valve functions and modules for each station. To replace individual valves, their own type designation is usually sufficient; for the complete terminal, the full code from the nameplate should be available. Also known as: valve manifold, valve island, pneumatic valve terminal, manifold valve block Frequently asked questions: - **What are the advantages of a valve terminal over individual valves?** A valve terminal combines compressed air supply, exhaust and electrical control. This reduces hoses, cables and assembly work, saves space in the control cabinet or on the machine and simplifies troubleshooting. Via a fieldbus or Ethernet connection, diagnostic data can also be reported to the controller. - **Can individual valves on a valve terminal be replaced?** On most valve terminals, individual valves or solenoid coils can be replaced without removing the entire terminal. The compressed air must first be shut off and the system exhausted. It is important that the replacement valve corresponds exactly to the function and series; the seals to the base plate should be renewed at the same time. - **What information is needed to replace a valve terminal?** Required is the complete order or configuration code from the nameplate, which defines the series, number of stations, valve functions, port sizes, electrical connection and, where applicable, pressure zones. Photos and the assignment of each station are also helpful. For fieldbus modules, the protocol and firmware version must be stated. - **Why does a valve on the valve terminal not switch?** Causes may be a missing electrical signal, a defective solenoid coil, a dirty pilot stage, insufficient supply pressure or a jammed valve spool. The manual override shows whether the valve switches mechanically. LED indicators and diagnostic data help to distinguish electrical from pneumatic faults. #### Vane pump URL: https://www.ktb-europe.com/en/glossary/vane-pump/ A vane pump is a positive displacement pump in which radially movable vanes in an eccentric cam ring form pumping chambers of varying size. A slotted rotor turns eccentrically in a cam ring. Vanes sit in the slots and are pressed outwards against the ring by centrifugal force or pressure. Chambers form between each pair of vanes, enlarging on the suction side and shrinking on the discharge side. Vane pumps run quietly and smoothly and are valued in machine tools, plastics machinery and presses. In fixed displacement pumps, the displacement is fixed; double-stroke versions with an oval ring balance the bearing forces. In variable displacement pumps, the eccentricity of the ring is changed, often via a pressure compensator, so that once the pressure is reached the pump only covers leakage losses. Key parameters are displacement, pressure, speed, direction of rotation, controller version and mounting. Rotary vane vacuum pumps work on the same principle. Vane pumps are sensitive to contamination and to viscosity that is too low. Wear on vanes, ring and side plates reduces output; spare part kits with rotor, vanes and ring are common. Before installing a replacement pump, the cause of the wear should be clarified, usually contamination or the wrong type of oil. In practice: For replacement or repair, the displacement, pressure range, direction of rotation, controller type, shaft end, flange and ports are needed. For worn pumps, it should be checked whether a cartridge kit is sufficient or the complete pump has to be replaced. Also known as: rotary vane pump, variable displacement vane pump, sliding vane pump, vane-type pump Frequently asked questions: - **What is the advantage of a vane pump?** Vane pumps work with low pulsation and a low noise level. As variable displacement pumps, they automatically adapt their displacement to demand, reducing energy consumption and heating, for example in clamping hydraulics on machine tools. In addition, many series can be repaired by replacing an inner cartridge. - **What is the difference between a vane pump and a gear pump?** Both are positive displacement pumps. Gear pumps are simpler, more tolerant of contamination and mostly designed as fixed displacement pumps. Vane pumps run more quietly and can be built as variable displacement pumps, but are more sensitive to dirt and viscosity. The choice depends on pressure, noise requirements and control needs. - **What information is needed to replace a vane pump?** Important are the displacement, maximum pressure, fixed or variable version with controller type and setting, direction of rotation, shaft end, mounting flange and ports. The complete type designation from the nameplate usually contains these features in coded form. For multiple pumps, each stage must be specified individually. A photo of the shaft and ports is also helpful. ### Standards & Marking #### ATEX (explosion protection) URL: https://www.ktb-europe.com/en/glossary/atex/ ATEX refers to the EU explosion protection rules governing equipment for potentially explosive atmospheres and the protection of workers there. The term ATEX derives from the French “Atmosphères Explosibles” and covers two EU directives. Directive 2014/34/EU is addressed to manufacturers and covers equipment and protective systems intended for use in potentially explosive atmospheres. Directive 1999/92/EC is addressed to employers and concerns the safety and health protection of workers potentially at risk from explosive atmospheres. Employers classify hazardous areas into zones: zones 0, 1 and 2 for gases, vapours and mists, and zones 20, 21 and 22 for combustible dusts, graded according to the frequency and duration of occurrence. Equipment is divided into equipment group I for mining and equipment group II for other areas, with group II subdivided into categories 1, 2 and 3. The category determines in which zone a piece of equipment may be used. The marking includes, among other things, the Ex symbol, equipment group and category, the atmosphere (G or D) and, depending on the equipment, type of protection, explosion group and temperature class. Replacement equipment and safety-relevant parts must meet the approval required for the zone at least to an equivalent level. In practice: When replacing equipment for hazardous areas, the complete Ex marking of the existing equipment should be available and checked against the plant's explosion protection document. Responsibility for the assignment lies with the operator; this entry is for guidance only and does not replace legal advice or inspection by a competent person. Also known as: explosion protection, Ex protection, ATEX Directive, ATEX 2014/34/EU, hazardous area equipment Frequently asked questions: - **What is the difference between ATEX 2014/34/EU and 1999/92/EC?** Directive 2014/34/EU, often called the product directive, requires manufacturers to design, assess and mark equipment for potentially explosive atmospheres safely. Directive 1999/92/EC, the workplace directive, requires employers to assess risks, define zones and use suitable equipment. In Germany, the employer side is implemented mainly in the Hazardous Substances Ordinance and the Industrial Safety Regulation (GefStoffV, BetrSichV). - **Which equipment may be used in zone 1?** In zone 1 for gases, vapours and mists, equipment of equipment group II with category 2G or 1G is permitted. Category 3 equipment is not sufficient there; it is intended only for zone 2. The explosion group and temperature class, which must match the substances present, are also decisive. The zone classification in the operator's explosion protection document is binding. - **How do you read an ATEX marking?** The Ex symbol in a hexagon is followed by the equipment group and category, for example II 2G for equipment group II, category 2, gas atmosphere. For electrical and non-electrical equipment, this is usually followed by the type of protection, explosion group such as IIB and temperature class such as T4. This information shows the conditions under which the equipment may be used. - **May ATEX equipment be replaced with equipment without Ex approval?** No. In a designated Ex zone, the replacement equipment must have at least the category required there as well as a suitable explosion group and temperature class. The requirements for maintaining explosion protection must also be observed during repairs. In case of doubt, competent persons or the responsible supervisory authority provide binding information. #### CE marking URL: https://www.ktb-europe.com/en/glossary/ce-marking/ With CE marking, the manufacturer declares that a product meets all applicable EU harmonisation legislation; it is not a quality seal. CE marking is a prerequisite for certain products to be placed on the market in the European Economic Area. It is intended only for products covered by at least one directive or regulation that requires it, such as machinery, low-voltage equipment, pressure equipment, products for potentially explosive atmospheres or equipment subject to electromagnetic compatibility requirements. The general principles are laid down in Regulation (EC) No 765/2008. Before affixing it, the manufacturer carries out a conformity assessment procedure, draws up the technical documentation and issues an EU declaration of conformity. Depending on the product and risk, a notified body must be involved, whose identification number then appears next to the CE mark. For machinery, the Machinery Regulation (EU) 2023/1230 applies from 20 January 2027 in place of the Machinery Directive. Importers of products from third countries have their own verification obligations: they must ensure that the conformity assessment, documentation and marking are in place. In practice: For spare parts, the marking obligation depends on whether the part itself falls under harmonisation legislation. For parts from third countries, CE marking and the declaration of conformity should be clarified before ordering. Also known as: CE mark, CE certification (colloquial), CE label, EU declaration of conformity Frequently asked questions: - **Who checks whether CE marking has been affixed correctly?** Responsibility lies with the manufacturer, who assesses and declares conformity itself. There is no general prior government approval; only for certain products must a notified body be involved. Checks are carried out afterwards by the market surveillance authorities of the member states, which can request documents, test products and, in the event of infringements, take measures up to and including a sales ban. - **Do spare parts need their own CE marking?** That depends on the part. Components that themselves fall under harmonisation legislation, such as many items of electrical equipment, safety components or equipment for potentially explosive atmospheres, bear their own marking. Pure components such as seals or bearings generally do not. In an individual case, the information provided by the competent market surveillance authority is binding; this entry does not constitute legal advice. - **How can you recognise questionable CE marking?** Warning signs are incorrect proportions or a mark that is too small, as it must generally be at least 5 mm high, a missing or incomplete EU declaration of conformity and notified body identification numbers that do not match the product. Identification numbers can be checked in the European Commission's public database. In case of doubt, the declaration of conformity should be requested before ordering. #### Conformity assessment URL: https://www.ktb-europe.com/en/glossary/conformity-assessment/ Conformity assessment is the procedure used to demonstrate that a product meets the requirements of the EU legislation applicable to it. Before a product covered by EU harmonisation legislation is placed on the market, the manufacturer must demonstrate its conformity with the applicable requirements. This is done in the conformity assessment. Its result is the technical documentation, the EU declaration of conformity and, as a rule, the CE marking. Responsibility always remains with the manufacturer, even when third parties are involved. The possible procedures are described in modules based on Decision No 768/2008/EC. Module A is internal production control without an external body; other modules provide for type examination, monitoring of production or full quality assurance with the involvement of a notified body. Which modules are permissible is laid down by the respective directive or regulation depending on the risk, for example the Low Voltage Directive, the Pressure Equipment Directive or the Machinery Regulation. Notified bodies are listed in a public database of the European Commission. For procurement, it is important that the declaration of conformity matches the product supplied and names the relevant legislation. In the case of conversions, the party carrying out the conversion may itself be required to carry out a new assessment. The respective legal acts are authoritative; this entry does not constitute legal advice. In practice: For spare parts subject to CE marking, check whether the manufacturer, type and directives named in the declaration of conformity match the part supplied. If a notified body is involved, its identification number next to the CE mark can be verified in the EU’s public database. Also known as: conformity assessment procedure, proof of conformity, Module A (internal production control), CE conformity assessment Frequently asked questions: - **Who carries out the conformity assessment?** Responsibility always lies with the manufacturer, even if it is based outside the EU. Importers do not carry out the assessment themselves but must ensure that the manufacturer has done so; anyone who places a product on the market under their own name or modifies it takes on manufacturer obligations themselves. For many lower-risk products, the manufacturer carries out the assessment itself. For higher risks, the applicable law requires the involvement of a notified body, which, for example, carries out a type examination or monitors the quality assurance system. - **What is a notified body?** A notified body is an independent testing organisation that has been notified by a Member State for specific conformity assessment procedures. It receives a four-digit identification number, which is shown next to the CE mark when it is involved. Whether a body is competent for a particular directive and procedure can be checked in the European Commission’s public database. - **What is the difference between conformity assessment and the declaration of conformity?** Conformity assessment is the procedure by which the manufacturer checks and demonstrates that its product meets the requirements. The EU declaration of conformity is the document with which, at the end of this procedure, it declares in a legally binding manner that the requirements are met. The declaration is therefore the result, and the assessment is the route to it. #### EMC Directive URL: https://www.ktb-europe.com/en/glossary/emc-directive/ The EMC Directive 2014/30/EU ensures that electrical equipment does not cause undue interference to other equipment and is itself sufficiently immune to interference. EMC stands for electromagnetic compatibility. Directive 2014/30/EU requires two things: equipment may only emit so much electromagnetic disturbance that other equipment and radio services can operate as intended (emission), and it must be sufficiently insensitive to the disturbances usual in its environment (immunity). In Germany, it is transposed by the Electromagnetic Compatibility Act (EMVG). The directive distinguishes between apparatus and fixed installations. Apparatus requires a conformity assessment, technical documentation, an EU declaration of conformity and CE marking. Fixed installations, such as a permanently installed production line, must be built in accordance with good engineering practice but do not receive CE marking as a whole. For industrial environments, there are harmonised generic standards on immunity and emission, for example from the EN 61000-6 series. In maintenance, EMC issues play a role with frequency inverters, power supplies, controllers and sensors. A replacement device with a different EMC design or incorrectly implemented shielding can cause interference. The text of the directive is authoritative; this entry does not constitute legal advice. In practice: When replacing inverters or power supplies, make sure the replacement device is designed for industrial environments, and adopt filters, shielding and earthing as in the original. Many faults after a replacement are due to changed cabling rather than the device itself. Also known as: EMC, Directive 2014/30/EU, electromagnetic compatibility Frequently asked questions: - **What do emission and immunity mean?** Emission describes how much electromagnetic energy a device releases into its environment, either conducted or radiated. Immunity describes how well a device withstands such disturbances without its function being impaired. The EMC Directive requires both. The relevant standards specify how measurements are made and which requirements apply to residential or industrial environments. - **Does a fixed installation need CE marking under the EMC Directive?** No. Fixed installations, i.e. permanently installed combinations of equipment at a specific location, do not receive CE marking as a whole under the EMC Directive. They must be built and documented in accordance with good engineering practice. The individual devices within them, by contrast, generally require their own CE marking. Other legislation, for example for machinery, may also apply. - **What is the difference between the EMC Directive and the Low Voltage Directive?** The Low Voltage Directive protects against electrical hazards such as electric shock or fire from equipment in the low voltage range. The EMC Directive, by contrast, governs the mutual influence of electrical equipment through electromagnetic fields, regardless of voltage. Many industrial components must comply with both directives, which is stated in the EU declaration of conformity. #### IP rating (IP code) URL: https://www.ktb-europe.com/en/glossary/ip-rating/ The IP rating to IEC/EN 60529 indicates how well an enclosure is protected against contact, ingress of foreign objects and water. IP stands for International Protection and is also commonly read as Ingress Protection. The IP code is defined in the standard IEC 60529, in Europe EN 60529 (DIN EN 60529 in Germany), and describes the degree of protection provided by enclosures of electrical equipment. It can be found on motors, control cabinets, sensors, luminaires, valve coils and many other devices. The code consists of the letters IP and two characteristic numerals. The first numeral, from 0 to 6, describes protection against access to hazardous parts and the ingress of solid foreign objects, up to dust-tightness. The second numeral, from 0 to 9, describes protection against water, from vertically falling drops through splashing and jetting water to immersion and high-pressure or steam-jet cleaning. If a requirement is not specified, an X takes its place. Additional letters can provide further information. Typical examples: IP54 means dust-protected and protected against splashing water, IP65 dust-tight and protected against water jets, IP67 dust-tight and protected against temporary immersion. Up to numeral 6, a higher level of water protection includes the lower levels; levels 7 to 9, however, only cover their own test. This is why some devices carry several ratings, such as IP65/IP67. In practice: When replacing equipment, the IP rating should be at least that of the original and suit the installation situation, for example with water-jet cleaning or outdoor installation. The rating only applies if seals, cable glands and covers are correctly fitted. Also known as: IP code, ingress protection, degree of protection, IP protection class, enclosure rating Frequently asked questions: - **What do the two digits of the IP rating mean?** The first digit indicates protection against contact and solid foreign objects, from 0 for unprotected to 6 for dust-tight. The second digit describes protection against water, from 0 for unprotected through dripping, splashing and jetting water to immersion. For the first digit, and for the water digit up to 6, a higher level includes the lower ones; water levels 7 to 9 (immersion, high-pressure cleaning) only cover their own test. - **What is the difference between IP65 and IP67?** Both ratings mean dust-tight. IP65 additionally protects against water jets from any direction, IP67 against temporary immersion under specified test conditions. An IP67 device is therefore not automatically tested against water jets; anyone who needs both should look for a dual rating such as IP65/IP67. - **What does IP54 mean?** IP54 stands for dust-protected and protected against splashing water from all directions. Dust may enter in limited quantities, but not in an amount that impairs operation. This rating is common for many industrial devices in dry to moderately humid indoor areas, but is often not sufficient for wet cleaning or outdoor installation. - **What does an X in the IP rating mean, for example IPX4?** The X replaces a numeral that has not been specified or tested. IPX4 therefore means that only protection against splashing water is specified, not protection against foreign objects. It cannot be concluded from this that there is no protection against foreign objects; it is simply not classified. #### Low Voltage Directive (LVD) URL: https://www.ktb-europe.com/en/glossary/low-voltage-directive/ The Low Voltage Directive 2014/35/EU governs the safety of electrical equipment rated at 50 to 1000 V AC or 75 to 1500 V DC. The Low Voltage Directive 2014/35/EU applies to electrical equipment with a rated voltage between 50 and 1000 volts alternating current or between 75 and 1500 volts direct current. It is intended to protect persons, domestic animals and property against electrical and other hazards arising from such equipment. In Germany, it is transposed via an ordinance under the Product Safety Act (ProdSG). It covers, for example, motors, power supplies, switchgear, luminaires, controllers or measuring instruments with a mains connection. The manufacturer generally carries out the conformity assessment itself, using the internal production control procedure. A notified body is not required. The presumption of conformity usually derives from harmonised standards, for example on the electrical equipment of machines. The result is technical documentation, an EU declaration of conformity and CE marking. For spare parts procurement, this means: electrical equipment within the scope of the directive that is placed on the market in the EU must bear CE marking, and the declaration of conformity should name the Low Voltage Directive. For parts from non-EU countries, it is worth taking a close look at these documents. The text of the directive is authoritative; this entry does not constitute legal advice. In practice: For electrical spare parts from new sources, ask for the EU declaration of conformity and check whether the Low Voltage Directive and the EMC Directive are listed. Compare the rated voltage and degree of protection on the nameplate with the original part. Also known as: LVD, Directive 2014/35/EU, LV Directive Frequently asked questions: - **Which products does the Low Voltage Directive apply to?** It applies to electrical equipment with a rated voltage between 50 and 1000 volts alternating current or 75 and 1500 volts direct current. This includes many industrial components such as motors, power supplies, contactors or control units. Exclusions include certain specialised areas listed in an annex to the directive. Equipment with a lower voltage is not covered but may be subject to other regulations. - **Is a notified body required for the Low Voltage Directive?** No, as a rule it is not. The manufacturer assesses the conformity of its products itself using the internal production control procedure, prepares the technical documentation and the EU declaration of conformity and affixes the CE marking. Voluntary testing by independent test laboratories is possible and frequently used, but does not replace the manufacturer’s responsibility. - **What is the difference between the Low Voltage Directive and the Machinery Directive?** The Low Voltage Directive concerns electrical hazards from equipment in the specified voltage range. The Machinery Directive and, in future, the Machinery Regulation cover all hazards of a machine, including mechanical ones. For machinery, the electrical safety objectives of the Low Voltage Directive are covered by the machinery legislation. Individual electrical components, by contrast, fall directly under the Low Voltage Directive. #### Machinery Regulation (EU) 2023/1230 URL: https://www.ktb-europe.com/en/glossary/machinery-regulation/ The Machinery Regulation (EU) 2023/1230 governs the safety of machinery in the EU single market and applies from 20 January 2027 in place of the Machinery Directive. The Machinery Regulation (EU) 2023/1230 replaces the Machinery Directive 2006/42/EC and applies from 20 January 2027. As a regulation, it is directly applicable in all Member States without national transposition. It sets out essential health and safety requirements for machinery, related products such as safety components and partly completed machinery, as well as conformity assessment, documentation and CE marking. New features include requirements for protection against corruption and for the cybersecurity of safety-related control systems, rules for systems with self-evolving behaviour, the option of providing the instructions for use digitally and an explicit provision on substantial modification. Anyone who substantially modifies a machine may thereby assume manufacturer obligations. For certain categories of machinery, a conformity assessment involving a notified body is required. For maintenance and spare parts procurement, the regulation is relevant above all for conversions, retrofits and the replacement of safety components: an equivalent replacement is generally not critical, whereas a change in function or performance must be assessed. The text of the regulation is authoritative; this entry does not constitute legal advice. In practice: When replacing safety components, document that the replacement and the original match in function and safety parameters. Plan retrofits that will be commissioned after 2027 with the new requirements in mind now, for example regarding the protection of control systems against tampering. Also known as: EU Machinery Regulation, MR 2023/1230, Regulation (EU) 2023/1230, new Machinery Directive Frequently asked questions: - **When does the Machinery Regulation apply?** The Machinery Regulation (EU) 2023/1230 applies from 20 January 2027. From that date, it replaces the previous Machinery Directive 2006/42/EC. Individual provisions, for example on notified bodies, already apply earlier according to the text of the regulation. Transitional arrangements apply to machinery placed on the market before the cut-off date; the exact wording of the regulation is authoritative. - **What is the difference between the Machinery Directive and the Machinery Regulation?** The Machinery Directive had to be transposed into national law, in Germany via the Machinery Ordinance under the Product Safety Act (ProdSG). The new EU Machinery Regulation, by contrast, applies directly in all Member States. In terms of content, it introduces new features such as cybersecurity requirements, rules on substantial modifications, requirements for self-evolving systems and the permission of digital instructions for use. - **What does substantial modification mean under the Machinery Regulation?** A substantial modification exists when a machine is modified after being placed on the market in such a way that new hazards arise or existing risks increase and new protective measures become necessary. Anyone who carries out such a modification may be treated as a manufacturer. Whether a conversion falls under this must be checked in each individual case on the basis of the text of the regulation; this entry does not constitute legal advice. - **Does the Machinery Regulation affect the replacement of spare parts?** Replacement with an equivalent spare part that does not change the function or safety level of the machine is generally not considered a substantial modification. The situation may be different if a spare part changes performance, control function or safety characteristics, for example in a retrofit. For safety components, equivalence should therefore be documented. #### Nameplate (rating plate) URL: https://www.ktb-europe.com/en/glossary/nameplate/ The nameplate is a plate permanently attached to a product, showing the manufacturer, type designation, serial number and the most important technical rating data. A nameplate, also called a rating plate or manufacturer’s plate, uniquely identifies a device or machine and states the data needed for operation, inspection and replacement. For machinery, the Machinery Directive and, in future, the Machinery Regulation prescribe minimum information, such as the name and address of the manufacturer, designation, series or type, serial number, year of construction and the CE marking. Depending on the product, technical information is added. For electric motors, this includes rated power, voltage, current, speed, frequency, power factor, degree of protection and thermal class. Pumps show flow rate, head and material; valves show nominal size, nominal pressure and medium; pressure equipment shows the maximum allowable pressure and temperature. The manufacturer’s article or order number is often given as well. For spare parts procurement, the nameplate is the most important source of information. If it is illegible, lost or painted over, identifying the right replacement becomes considerably more difficult and must be done using dimensions, drawings, bills of materials or the plant documentation. In practice: Photograph the nameplates of critical components as a precaution and store the images in the maintenance system. When sending a spare parts enquiry, include a sharp photo of the complete plate, as the serial number and year of construction often determine the correct version. Also known as: rating plate, type plate, data plate, manufacturer’s plate, identification plate Frequently asked questions: - **What information must a nameplate contain?** For machinery, EU law requires at least the name and address of the manufacturer, the designation of the machine, series or type, serial number if any, year of construction and the CE marking. Product-specific standards add technical information, for motors, for example, power, voltage, current and speed. Which information is mandatory in an individual case depends on the respective regulation and product standard. - **How do you read the nameplate of an electric motor?** Important are the rated power in kilowatts, the voltage with connection (star or delta), the rated current, the frequency, the speed and the power factor. In addition, there are the degree of protection, thermal class of the insulation, duty type, mounting arrangement and, where applicable, efficiency class. For a replacement, the frame size, mounting arrangement and shaft dimensions are also decisive, and these are not always on the plate. - **What should you do if the nameplate is missing or illegible?** First, it is worth looking at the plant documentation, bills of materials and spare parts lists from the machine manufacturer. Sometimes markings are also stamped or cast into housing parts. Otherwise, dimensions, photos from several angles, connection diagrams and technical data from operation help. With this information, a part can often be identified or a suitable replacement determined. #### Performance level (EN ISO 13849) URL: https://www.ktb-europe.com/en/glossary/performance-level/ The performance level (PL) under EN ISO 13849-1 describes, in five levels from a to e, how reliably a control system performs a safety function. The performance level is the central parameter of EN ISO 13849-1 for safety-related parts of control systems on machinery. It ranges from PL a to PL e, with PL e denoting the highest reliability. The standard applies regardless of technology, i.e. to electrical, electronic, pneumatic, hydraulic and mechanical control systems. First, the required performance level (PLr) is determined for each safety function, usually by means of a risk graph with the parameters severity of injury, frequency and duration of exposure to the hazard, and possibility of avoidance. The PL achieved results from the category of the control architecture (B, 1, 2, 3 or 4), the mean time to dangerous failure (MTTFd) of the channels, the diagnostic coverage (DC) and measures against common cause failures (CCF). For wearing components such as valves or contactors, the B10d value is taken into account. For maintenance and procurement, this means: safety components such as emergency stop buttons, safety switches, safety relays or valves may only be replaced by parts whose parameters continue to satisfy the assessment. The text of the standard and the manufacturer’s specifications are authoritative. In practice: For safety components, ask not only for the order number but also for parameters such as PL, category, MTTFd or B10d, and compare them with the safety assessment of the machine. A different model may require recalculation; after the replacement, the safety function must be tested. Also known as: PL, PLr (required performance level), EN ISO 13849-1, ISO 13849 Frequently asked questions: - **What is the difference between PL and PLr?** PLr is the required performance level, i.e. the target that results from the risk assessment for a safety function. PL is the performance level actually achieved by the implemented control system. The safety function is adequately designed if the PL achieved is at least as high as the PLr. Both are stated on the same scale from a to e. - **How is the performance level determined?** For the implemented safety function, the category of the architecture, the MTTFd of the components involved, the diagnostic coverage and measures against common cause failures are determined. The standard contains a simplified procedure from which the PL can be read off. In practice, calculation software and the parameter libraries of component manufacturers are often used for this. - **What does the B10d value mean?** The B10d value indicates the number of switching cycles after which, statistically, ten per cent of the components have failed dangerously. It is used for components subject to wear, such as contactors, relays, valves or position switches. Together with the switching frequency in operation, it can be used to calculate the MTTFd, which feeds into the assessment of the performance level. #### Pressure Equipment Directive (PED) URL: https://www.ktb-europe.com/en/glossary/pressure-equipment-directive/ The Pressure Equipment Directive 2014/68/EU governs the design, manufacture and conformity assessment of pressure equipment above 0.5 bar maximum allowable pressure. The Pressure Equipment Directive 2014/68/EU (PED) applies to pressure equipment and assemblies with a maximum allowable pressure PS above 0.5 bar. This includes vessels, piping, steam and hot-water generators, pressure accessories such as valves, and safety accessories such as safety valves. In Germany, it is transposed via the Pressure Equipment Ordinance under the Product Safety Act (ProdSG). Pressure equipment is classified into categories I to IV according to its hazard potential. Decisive factors are pressure, volume or nominal size and the fluid group: group 1 comprises dangerous fluids, group 2 all other fluids. The higher the category, the stricter the conformity assessment procedure and the more likely it is that a notified body is involved. Equipment below category I is manufactured in accordance with sound engineering practice and does not bear CE marking under this directive. When replacing valves, safety valves or vessels, the category of the original is decisive. The spare part must be suitable for the pressure, temperature and medium and be marked accordingly. The operation of pressure installations is also subject to separate operator obligations. The text of the directive is authoritative; this entry does not constitute legal advice. In practice: When requesting pressure-bearing spare parts, state the medium, maximum allowable pressure, temperature range, nominal size and material, and ask for the EU declaration of conformity and material certificates. A different material or a lower pressure rating is not an equivalent replacement. Also known as: PED, Directive 2014/68/EU, PED 2014/68/EU Frequently asked questions: - **Which equipment does the Pressure Equipment Directive apply to?** It applies to pressure equipment and assemblies with a maximum allowable pressure above 0.5 bar. This includes vessels, piping, pressure accessories such as valves, and safety accessories such as safety valves or bursting discs. Certain products are excluded because they are covered by other rules; the exclusions are listed in the directive itself. - **How is the category of pressure equipment determined?** The category is derived from charts in an annex to the directive. Input variables are the type of equipment, the physical state and fluid group of the medium, the maximum allowable pressure and the volume for vessels or the nominal size for piping. The category determines the possible conformity assessment modules and whether a notified body is involved. - **What does sound engineering practice mean in the Pressure Equipment Directive?** Pressure equipment whose hazard potential is below category I must be designed and manufactured in accordance with sound engineering practice. No conformity assessment procedures under the directive apply to it, and it must not bear CE marking under the Pressure Equipment Directive. However, it must be safe, be supplied with adequate instructions for use and allow the manufacturer to be identified. #### REACH Regulation URL: https://www.ktb-europe.com/en/glossary/reach/ The REACH Regulation (EC) No 1907/2006 governs the registration, evaluation, authorisation and restriction of chemical substances in the European Union. REACH stands for Registration, Evaluation, Authorisation and Restriction of Chemicals. Regulation (EC) No 1907/2006 requires manufacturers and importers to register substances above certain quantities with the European Chemicals Agency (ECHA) and to assess their risks. Substances of very high concern (SVHC) are included in a Candidate List that is extended regularly; some are subject to authorisation, others to restrictions. REACH concerns not only chemicals but also articles, i.e. objects such as seals, cables, bearings or electronic assemblies. If an article contains a Candidate List substance in a concentration above 0.1 per cent by weight, suppliers must inform their professional customers under Article 33 and state at least the name of the substance. Additional obligations regarding safety data sheets apply to mixtures and substances. In spare parts procurement, REACH mainly shows up in requests for SVHC information, in safety data sheets for lubricants and operating materials and in restrictions on certain substances in plastics or coatings. The text of the regulation and the current ECHA lists are authoritative; this entry does not constitute legal advice. In practice: For spare parts from non-EU countries that you import yourself, record who bears the REACH obligations as importer. For articles, request an up-to-date SVHC declaration, because the Candidate List changes regularly and older declarations are then no longer complete. Also known as: REACH, Regulation (EC) No 1907/2006, EU chemicals regulation, SVHC obligations Frequently asked questions: - **What is the difference between REACH and RoHS?** RoHS restricts certain hazardous substances exclusively in electrical and electronic equipment and is linked to CE marking. REACH is a comprehensive chemicals regulation that applies to substances, mixtures and articles of all kinds and governs registration, information obligations, authorisation and restrictions. An electronic component therefore generally has to comply with both sets of rules. - **What is the SVHC Candidate List?** The Candidate List contains substances of very high concern, such as carcinogenic substances or substances toxic to reproduction. It is published by ECHA and supplemented regularly. The inclusion of a substance triggers information obligations in the supply chain and can be a step towards a later authorisation requirement. Companies should therefore always relate their supplier declarations to the current version of the list. - **What obligations do distributors have under REACH?** Distributors that pass on articles within the EU must pass on information about SVHC substances contained in them to their professional customers and answer consumer requests if a Candidate List substance is present above the threshold. Anyone who imports goods from non-EU countries themselves also has obligations as an importer. The exact role should be checked in each individual case; this entry does not constitute legal advice. #### RoHS URL: https://www.ktb-europe.com/en/glossary/rohs/ RoHS refers to EU Directive 2011/65/EU, which restricts the use of certain hazardous substances in electrical and electronic equipment. The abbreviation RoHS stands for Restriction of Hazardous Substances. Directive 2011/65/EU stipulates that electrical and electronic equipment may contain certain substances only up to specified maximum concentrations. These include lead, mercury, cadmium, hexavalent chromium and the flame retardants PBB and PBDE. Delegated Directive (EU) 2015/863 added four phthalates that are used as plasticisers. The maximum concentrations refer to homogeneous materials, i.e. to individual materials of a component and not to the device as a whole; a lower value applies to cadmium than to the other substances. For certain applications for which there is not yet a technical substitute, time-limited exemptions are set out in the annexes to the directive. Compliance is part of the conformity assessment and is documented via the CE marking and the EU declaration of conformity. Special rules apply to spare parts: spare parts for the repair or reuse of certain older equipment may fall under exemptions. RoHS must be distinguished from the chemicals regulation REACH, Regulation (EC) No 1907/2006, which governs substances in general, irrespective of product type. In practice: For spare parts for electrical and electronic equipment, it should be clarified whether the manufacturer has issued a RoHS compliance statement or whether an exemption applies. In an individual case, the interpretation of the competent authorities is binding; this entry does not constitute legal advice. Also known as: RoHS Directive, RoHS 2, RoHS 3, Restriction of Hazardous Substances, Directive 2011/65/EU Frequently asked questions: - **What is the difference between RoHS and REACH?** RoHS applies only to electrical and electronic equipment and restricts a defined list of substances in it. REACH, Regulation (EC) No 1907/2006, governs the registration, evaluation, authorisation and restriction of chemical substances in general, including in articles of all kinds. A product can therefore be RoHS-compliant and still trigger information obligations under REACH, for example for substances of very high concern. - **Which substances does RoHS restrict?** Restricted substances are lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE). Delegated Directive (EU) 2015/863 added the phthalates DEHP, BBP, DBP and DIBP. The list thus comprises ten substances, each with maximum concentrations in homogeneous materials. - **What is meant by RoHS 2 and RoHS 3?** RoHS 2 is a common name for Directive 2011/65/EU, which replaced the first RoHS directive. RoHS 3 is often used to refer to the extension by Delegated Directive (EU) 2015/863 to include four phthalates. Legally, this is not a separate third directive but an amendment to 2011/65/EU. - **Do spare parts have to be RoHS-compliant?** In principle, the restrictions also apply to spare parts. However, the directive provides for exemptions, for example for spare parts for the repair of equipment placed on the market before the respective restriction took effect. Whether an exemption applies depends on the individual case; the interpretation of the competent market surveillance authorities is binding. #### SIL (safety integrity level) URL: https://www.ktb-europe.com/en/glossary/safety-integrity-level/ Under IEC 61508, SIL (safety integrity level) is a four-level measure of the reliability with which a safety function reduces a risk. The safety integrity level originates from the IEC 61508 series of standards (DIN EN 61508) on the functional safety of electrical, electronic and programmable electronic systems. There are levels SIL 1 to SIL 4, with SIL 4 imposing the highest requirements. What is assessed is not an individual device but a safety function, such as switching off a pump in the event of overpressure, consisting of sensor, logic and actuator. To determine the required SIL, the risk is first analysed. The level achieved then depends on the probability of failure, expressed as PFD for low demand and as PFH for high or continuous demand, as well as on the hardware fault tolerance, the safe failure fraction and systematic requirements for development and software. Derived standards are IEC 61511 for the process industry and IEC 62061 for machinery. For maintenance and spare parts procurement, what counts is this: components in safety functions may only be replaced by parts with the same or higher SIL capability and comparable parameters, and proof test intervals must be observed. The text of the standard and the manufacturer’s safety manual are authoritative. In practice: For SIL-relevant spare parts, request the certificate or manufacturer’s declaration of SIL capability and the safety manual. After replacement, the safety function must be tested and documented before the plant is put back into operation. Also known as: safety integrity level, IEC 61508, SIL rating, SIL capability Frequently asked questions: - **What is the difference between SIL and performance level?** Both describe the reliability of safety functions but originate from different standards. SIL is based on IEC 61508 and is used in the process industry and, via IEC 62061, also for machinery. The performance level comes from EN ISO 13849-1 and is widespread in mechanical engineering, including for pneumatic and hydraulic control systems. The standards provide guidance on how the two relate. - **What does IEC 61508 cover?** IEC 61508 is the basic standard for functional safety. It describes how electrical, electronic and programmable electronic safety systems are developed, assessed, operated and modified throughout their entire life cycle. This includes risk analysis, determination of the SIL, hardware and software requirements, and verification and validation. Sector standards such as IEC 61511 build on it. - **Can a SIL-certified device be replaced by a different one?** In principle, yes, if the replacement device is suitable for the required SIL and its parameters, such as failure rates and proof test intervals, fit into the calculation of the safety function. A different model may require the safety function to be reassessed. After replacement, a functional test and documentation are required. Responsibility lies with the operator or the competent person. #### UKCA marking URL: https://www.ktb-europe.com/en/glossary/ukca-marking/ The UKCA marking is the British conformity mark for products placed on the market in Great Britain, comparable to the CE marking. UKCA stands for UK Conformity Assessed. The mark was introduced after the United Kingdom left the EU and applies to products placed on the market in Great Britain, i.e. England, Wales and Scotland. Owing to special arrangements, EU rules and CE marking continue to apply in Northern Ireland, supplemented where necessary by a UKNI marking. In terms of content, British product legislation is closely based on the former EU directives, for example for machinery, low voltage or EMC. Instead of an EU declaration of conformity, a UK Declaration of Conformity is drawn up; instead of harmonised standards, designated British standards apply; and instead of notified bodies, there are Approved Bodies. The UK government has extended the recognition of CE marking for many product areas; which rules currently apply to a product group should always be checked against the official UK guidance. For procurement and maintenance, UKCA is relevant when spare parts are delivered to sites in Great Britain or machinery is relocated there. British legislation is authoritative; this entry does not constitute legal advice. In practice: For deliveries to British sites, clarify in advance whether CE is still accepted for the product group concerned or whether UKCA is required. Where appropriate, ask the supplier for both declarations of conformity so that the documentation for plants in the EU and in Great Britain is complete. Also known as: UK Conformity Assessed, UKCA mark, UKNI marking, UK Declaration of Conformity Frequently asked questions: - **What is the difference between UKCA and CE?** CE marking shows conformity with EU law for the European single market. UKCA marking shows conformity with British law for the market in Great Britain. The requirements are often similar in content, but the procedures differ in details such as the declaration of conformity, recognised standards and conformity assessment bodies. Whether CE is still sufficient in Great Britain depends on the product group. - **Does UKCA also apply in Northern Ireland?** No, in Northern Ireland the EU product rules and therefore CE marking continue to apply for many product areas. If a UK conformity assessment body is used for a product, the UKNI marking may also be required. UKCA marking alone is generally not sufficient for the Northern Ireland market. The current official guidance is authoritative in each case. - **Do spare parts for plants in Great Britain need UKCA marking?** That depends on whether the spare part itself falls under a British product regulation, for example as electrical equipment or a safety component, and whether CE is still recognised for that product group. Simple components without their own marking obligation are often not affected. In case of doubt, the manufacturer or the competent British authority should be consulted. #### WEEE (waste electrical and electronic equipment) URL: https://www.ktb-europe.com/en/glossary/weee/ WEEE refers to waste electrical and electronic equipment and to EU Directive 2012/19/EU, which governs its take-back, recovery and producer responsibility. WEEE stands for Waste Electrical and Electronic Equipment. Directive 2012/19/EU requires producers that place electrical and electronic equipment on the market in a Member State to register, to mark their products and to finance take-back and disposal. In Germany, it is transposed by the Electrical and Electronic Equipment Act (ElektroG); registration is carried out with a central body appointed for this purpose. The identifying mark is the crossed-out wheeled bin symbol on the equipment. A distinction is made between equipment that can be used in private households and purely B2B equipment, for which different take-back rules apply. Certain products are excluded from the scope, such as large-scale stationary industrial tools and large-scale fixed installations. A party that first offers or imports equipment in a country may also count as a producer within the meaning of the law. For maintenance and procurement, WEEE is relevant in two directions: when disposing of removed controllers, drives, sensors or operator panels, and when importing electronic spare parts from non-EU countries. Whether a part counts as equipment or as a component is not always clear-cut. The legal text and the competent authority are authoritative; this entry does not constitute legal advice. In practice: For removed electronics, clarify whether the supplier offers take-back or an authorised waste management company is engaged, and document what happens to the equipment. If you import electronic equipment yourself, check in advance whether this gives rise to registration obligations. Also known as: electronic waste, WEEE Directive, Directive 2012/19/EU, ElektroG (Germany) Frequently asked questions: - **What does the WEEE symbol mean?** The symbol of a crossed-out wheeled bin indicates that an electrical or electronic device must not be disposed of with household waste or mixed commercial waste but must be collected separately. It is applied by the producer. A bar beneath the symbol can indicate that the equipment was placed on the market after a certain cut-off date. - **Does WEEE also apply to industrial equipment?** Yes, in principle, electrical and electronic equipment used commercially, such as controllers, measuring instruments or drives, is also covered by the WEEE rules. However, different take-back rules apply to purely B2B equipment than to household appliances. Exclusions include large-scale stationary industrial tools and large-scale fixed installations. Whether a specific product is covered must be checked in each individual case. - **What is the difference between WEEE and RoHS?** RoHS governs which hazardous substances new electrical and electronic equipment may contain and thus applies at the manufacturing stage. WEEE, by contrast, governs how waste equipment is collected, recovered and financed at the end of its life. The two sets of rules complement each other and often concern the same products, but have different obligations and scopes. ## Blog articles ### Packaging Machine from Italy: How to Get Spare Parts Faster URL: https://www.ktb-europe.com/en/blog/italian-packaging-machine-spare-parts/ · 2026-10-22 Packaging machine from Italy down? How to find spare parts faster: identify machine number, bill of materials, change parts and bought-in parts reliably. Frequently asked questions: - **Where can I find the machine number of an Italian packaging machine?** The machine number is on the machine’s nameplate, often labelled “matricola” or “numero di serie”. Next to it you will usually find the model and year of manufacture (“anno di costruzione”). The number is often also shown on the cover page of the operating manual and the bill of materials. - **What are change parts on packaging machines?** Change parts (format parts) are components tailored to a specific product or pack, such as grippers, guides, suction cup plates or sealing tools. They are swapped during a format changeover and are usually custom-made by the machine manufacturer. To source them, you therefore generally need the manufacturer’s drawing number. - **Do I have to order all spare parts from the machine manufacturer?** No. Many components such as motors, gearboxes, pneumatic cylinders, valves, sensors or bearings come from suppliers and carry their nameplate. With the component’s manufacturer and order number, these parts can often be sourced directly. Change parts and machine-specific parts, by contrast, usually come only from the machine manufacturer or from reproduction. - **What do I do if the Italian manufacturer no longer exists?** For bought-in parts, the components’ nameplate data helps you source the original or a successor type. Change parts and special parts can often be reproduced from a sample or drawing. It is important to secure bills of materials and drawings early, while they are still available. - **Which region of Italy is known for packaging machines?** The best known is Emilia-Romagna around Bologna, often called the “Packaging Valley” in the industry. Over decades, many specialised packaging machine manufacturers have settled there. There are also manufacturers in other regions of Italy. ### NEMA or IEC? How to Replace a US Motor in Your Plant URL: https://www.ktb-europe.com/en/blog/nema-vs-iec-motor-replacement/ · 2026-10-22 NEMA or IEC? Frame sizes, inch shafts, 60 Hz, service factor, enclosure and efficiency compared – how to replace a US motor in your plant safely. Frequently asked questions: - **What is the difference between NEMA and IEC motors?** NEMA motors follow the US standard NEMA MG 1, with frame numbers, inch dimensions and power ratings in HP, usually for 60 Hz. IEC motors follow the IEC 60034 series and IEC 60072-1, with shaft heights in millimetres and power ratings in kW. Frame sizes, shafts, flanges and power steps therefore don’t match directly. - **Can I run a 60 Hz motor on a 50 Hz supply?** Often technically possible, but only if approved by the nameplate or the manufacturer. The speed drops by one sixth, and at the same torque the power drops accordingly. Voltage and frequency must be in the right ratio, otherwise the motor becomes overexcited and runs hot. - **What does service factor 1.15 mean on a NEMA motor?** A service factor of 1.15 means that, at rated voltage and rated frequency, the motor may be loaded continuously at 1.15 times its rated power, with a higher temperature rise. IEC motors have no service factor. If the old motor ran in this range, the IEC replacement should be sized up accordingly. - **Which IP rating corresponds to a TEFC motor?** There is no official equivalence. TEFC refers to a totally enclosed, fan-cooled motor, which in practice often corresponds to a degree of protection around IP54 or IP55 to IEC 60034-5. What matters for the replacement is which degree of protection the environment at the installation site requires. - **Does NEMA Premium correspond to efficiency class IE3?** For many power ratings, the NEMA Premium efficiency level is roughly equivalent to IE3 to IEC 60034-30-1. However, the values are determined for 60 Hz and using different methods. For a replacement motor in the EU, the requirements of Regulation (EU) 2019/1781 apply. ### How to Create a Maintenance Plan: 8 Steps to a Plan That Actually Gets Used URL: https://www.ktb-europe.com/en/blog/create-maintenance-plan-steps-template/ · 2026-10-22 Create a maintenance plan in 8 steps: record equipment, assess criticality, define tasks and intervals. Includes a ready-to-use template in table form. Frequently asked questions: - **What goes into a maintenance plan?** For each machine, a maintenance plan contains the specific tasks, the type of task, the interval, an inspection criterion or limit value, the materials required and the person responsible. Add a column for documenting completion. Statutory inspection obligations should also be included. - **How do I set maintenance intervals?** The starting point is the manufacturer’s information in the operating manual. Depending on the task, time-based, usage-based or condition-based intervals are suitable. Based on findings and failures, you adjust the intervals over time to your actual operating conditions. - **What is preventive maintenance?** Preventive maintenance means planning tasks such as servicing and inspection in advance, before damage occurs. The opposite is reactive maintenance, where repairs are only made after a failure. The maintenance plan is the central tool of preventive maintenance. - **What software do you need for a maintenance plan?** To get started, a spreadsheet or a checklist at the machine is often enough. As the number of machines grows, maintenance software (CMMS) pays off: it sends automatic reminders, generates work orders and stores the history. More important than the tool is that the plan is used and maintained consistently. - **What is the difference between servicing and inspection?** According to DIN 31051, servicing covers tasks that slow down the depletion of the wear reserve, such as lubricating, cleaning or readjusting. Inspection serves to determine the actual condition, for example through visual checks or measurements. Both types of task typically belong in a maintenance plan. ### Calibration of Measuring Equipment: How Often, by Whom, with What Proof? URL: https://www.ktb-europe.com/en/blog/calibration-measuring-equipment-intervals/ · 2026-10-22 Calibration of measuring equipment: how it differs from legal verification and adjustment, sensible intervals, DAkkS certificates and ISO 9001 rules. Frequently asked questions: - **What is the difference between calibration and legal verification?** Calibration determines and documents the deviation of a measuring instrument against a more accurate standard. Legal verification (Eichung), by contrast, is a test required by the German Measurement and Verification Act (MessEG) that only verification authorities or state-approved testing bodies carry out. It mainly concerns instruments used in trade, such as scales used for billing. - **What does adjustment mean?** Adjustment means setting or trimming a measuring instrument so that its deviation is as small as possible. Unlike calibration, it involves intervening in the device. The sensible order is calibrate, adjust, calibrate again, so that the condition before and after the intervention is documented. - **How often do you need to calibrate measuring equipment?** There is no fixed legal interval for all measuring equipment. You set the interval yourself, depending on the manufacturer’s recommendation, usage, the importance of the measurement and the calibration history. One year is a common starting value, which is extended or shortened depending on the results. - **What is a DAkkS calibration certificate?** A DAkkS calibration certificate comes from a laboratory accredited by the German Accreditation Body to ISO/IEC 17025. It contains the measurement results with measurement uncertainty and proves traceability to national standards. It is particularly useful for reference standards and critical measurements. - **Does ISO 9001 require DAkkS calibration?** No. In clause 7.1.5, ISO 9001 requires that, where traceability is required, measuring equipment is calibrated or verified against traceable standards, identified and safeguarded. Accreditation of the calibration laboratory is not explicitly required there. Customers or industry regulations may, however, demand it. ### FMEA in Maintenance: Find Failures Before Your Plant Stops URL: https://www.ktb-europe.com/en/blog/fmea-in-maintenance/ · 2026-10-22 FMEA in maintenance: the process in 7 steps, rating with RPN or action priority, a worked example on a pump and the most common mistakes made by teams. Frequently asked questions: - **What does FMEA mean?** FMEA stands for failure mode and effects analysis. A team systematically examines which failures can occur in a product, process or piece of equipment, what effects they have and how the risk can be reduced. The method is preventive, i.e. it works before any damage occurs. - **How do you calculate the RPN?** The risk priority number is obtained by multiplying severity, occurrence and detection, each usually rated from 1 to 10. The result lies between 1 and 1,000. Because identical numbers can describe different risks, serious effects should always be considered separately. - **What is the difference between RPN and action priority?** The RPN multiplies the three ratings into one number. Action priority from the AIAG/VDA FMEA Handbook uses a table to assign each combination to the levels high, medium or low. Severity carries the most weight, so serious effects don’t get lost in a low number. - **Which standard applies to FMEA?** Across industries, IEC 60812 describes how to carry out an FMEA. In the automotive industry, the joint AIAG and VDA FMEA Handbook is also authoritative. Many companies outside the automotive sector also follow its seven-step approach. - **Who should take part in an FMEA?** An FMEA thrives on knowledge from different areas. In maintenance, the team typically includes maintenance technicians, operators, production and, where needed, electrical, health and safety and procurement. A facilitator makes sure the method is followed and that actions are assigned owners. ### MTBF and MTTR Explained Simply: How to Measure Your Plant’s Reliability URL: https://www.ktb-europe.com/en/blog/mtbf-mttr-explained/ · 2026-10-22 MTBF and MTTR explained simply: formulas, a fictitious worked example, the link to availability and OEE, and typical mistakes that distort your metrics. Frequently asked questions: - **How do you calculate MTBF?** Divide a machine’s actual operating time by the number of unplanned failures in the same period. If a machine runs for 585 hours, for example, and fails five times, the MTBF is 117 hours. Planned stoppages such as maintenance or cleaning count neither as operating time nor as failures. - **What is the difference between MTBF and MTTR?** MTBF describes how long a machine runs on average between two failures, so it measures reliability. MTTR describes how long it takes on average until a failed machine is working again. The goal is a high MTBF and a low MTTR. - **What is a good MTBF value?** There is no universal benchmark, because MTBF depends heavily on machine type, load and recording rules. The most meaningful comparison is the same machine over time or similar machines against each other. What matters is that failures are always recorded according to the same rules. - **How are MTBF, MTTR and OEE related?** MTBF and MTTR can be used to calculate technical availability: MTBF divided by the sum of MTBF and MTTR. OEE availability is broader and also includes stoppages such as changeovers or material shortages. Reducing MTTR therefore also improves OEE. - **What does MTBF mean in a device’s data sheet?** The MTBF in a data sheet is a statistical value determined or calculated under defined conditions. It describes the average behaviour of many devices, not the service life of a single one. An individual device can fail much earlier or later. ### Siemens S7-300 Discontinued: What It Means for Your Plant URL: https://www.ktb-europe.com/en/blog/siemens-s7-300-discontinued/ · 2026-10-22 S7-300 discontinued: which modules are affected, what status PM410 means and how to decide between stocking spare parts and migrating to the S7-1500. Frequently asked questions: - **Has the Siemens S7-300 been discontinued?** Yes. On 1 October 2025, Siemens moved the SIMATIC S7-300 and the ET 200M to lifecycle status PM410, i.e. product discontinuation. Since then, the products are no longer supplied as new products for new installations, only as spare parts. - **What does status PM410 mean?** In the Siemens lifecycle, PM410 stands for product discontinuation. The product is no longer intended for new installations and is only supplied as a spare part. How long individual items remain available can be checked per article number in Siemens Industry Online Support. - **What is the successor to the S7-300?** Siemens names the S7-1500 as the successor, and the S7-1200 for smaller applications. For distributed I/O, the ET 200MP and ET 200SP replace the ET 200M. The successors are programmed in the TIA Portal, so the existing program has to be migrated and adapted. - **Do I have to convert my S7-300 plant immediately?** Not necessarily. Existing plants keep running, and modules are supplied as spare parts. A sensible first step is an inventory with a risk assessment for each plant. Then decide whether selective spare parts stocking is enough or whether a step-by-step or complete migration should be planned. - **What information do I need to request S7-300 spare parts?** The decisive detail is the module’s complete article number with every digit, plus the product or firmware version and the quantity required. A photo of the device labelling helps avoid transcription errors. Also state whether a different product version is acceptable for your plant. ### Control Cabinet: 10 Spare Parts You Should Always Keep in Stock URL: https://www.ktb-europe.com/en/blog/control-cabinet-spare-parts-checklist/ · 2026-10-22 Control cabinet checklist: 10 spare parts, from interface relays to safety relays, that prevent downtime – plus the data you need to stock them right. Frequently asked questions: - **Which spare parts should you keep in stock for the control cabinet?** Proven items are fuse links, miniature circuit breakers, contactors, motor protection circuit breakers, interface relays with sockets, safety relays, 24 V power supplies, I/O modules, the controller’s memory card and backup battery, fans with filter mats, and contact and LED elements. Check the exact list against your bills of materials and the criticality of your equipment. - **What do I need to consider when replacing a safety relay?** The replacement must match the installed type or be approved by the person responsible for safety, because the safety function has been assessed. Settings on the device must be carried over. After the swap, a documented functional test of all connected safety circuits is required. - **Which components belong in a control cabinet?** Typical control cabinet components are the incoming supply and main switch, fuses and miniature circuit breakers, contactors, motor protection circuit breakers, relays, power supplies, the controller with input and output modules, frequency inverters, terminals and fans or cooling units. The design depends on the machine and the requirements of the EN 61439 series. - **How do I decide how many spare parts to stock?** What matters is the impact of a failure, the number of identical parts in your equipment, the failure frequency and the replenishment lead time. Parts that can stop several machines and are hard to obtain deserve a higher minimum stock. Review the list regularly after modifications and discontinuations. - **Why does the coil voltage of a contactor have to be exactly right?** A contactor’s coil is designed for a specific voltage and type of current, such as 24 V DC or 230 V AC. A contactor with the wrong coil will not pull in or will be damaged. That is why the coil voltage, alongside the rated current, is one of the most important details when stocking spares. ### Planetary Gearbox or Helical Gearbox? When Each One Pays Off URL: https://www.ktb-europe.com/en/blog/planetary-gearbox-vs-helical-gearbox/ · 2026-10-22 Planetary gearbox or helical gearbox? How they work, benefits and limits compared – and what you must check when replacing a gearbox in your plant. Frequently asked questions: - **How does a planetary gearbox work?** A central sun gear drives several planet gears that roll inside an internally toothed ring gear. With the ring gear fixed, the planets take the planet carrier with them, which forms the slow output. Because the load is shared across several planets, the gearbox is very compact. - **What are the advantages of a planetary gearbox over a helical gearbox?** For the same frame size, planetary gearboxes transmit more torque, are coaxial and lighter. In precision versions they have very low backlash, which makes them suitable for servo axes. Helical gearboxes, on the other hand, are simpler, more robust and often more economical. - **Where are helical gearboxes typically used?** You will find helical gearboxes mainly in conventional drives with an induction motor, such as conveyor belts, pumps, agitators and fans. They are robust, easy to maintain and available in many sizes and designs, including parallel shaft gearboxes with a hollow shaft. - **Can I replace a helical gearbox with a planetary gearbox?** Technically this is often possible, but it is not a simple like-for-like swap. Ratio, output torque, output shaft, mounting, shaft height and permissible radial load must all match. Modifications to the machine are usually needed, so the change should be technically reviewed and documented. - **Which nameplate data do I need for a replacement gearbox?** Key details are manufacturer, complete type designation, serial number, exact ratio, output speed and torque, service factor, mounting position and mounting type. For geared motors, add the motor data. Photos of the nameplate, output shaft and mounting also help. ### Plain Bearing or Rolling Bearing? Differences, Benefits, Uses URL: https://www.ktb-europe.com/en/blog/plain-bearing-vs-rolling-bearing/ · 2026-10-22 Plain bearing or rolling bearing? Principle, types, benefits and limits compared – plus what to specify when you need a replacement bearing. Frequently asked questions: - **What is the main difference between a plain bearing and a rolling bearing?** In a plain bearing, the shaft slides on a lubricant film or a sliding layer inside a bush. In a rolling bearing, balls or rollers roll between two rings. This gives them different strengths: rolling bearings have low start-up friction, while plain bearings dampen shocks and need less installation space. - **What are the advantages of a plain bearing?** Plain bearings dampen shock and vibration, run very quietly and are radially compact. Large plain bearings can be split and replaced without removing the shaft. Maintenance-free bushes also often cope better than rolling bearings with dirt, moisture and slow oscillating movements. - **What types of rolling bearing are there?** The main types are deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, tapered roller bearings, spherical roller bearings, needle roller bearings and thrust bearings. They differ mainly in which loads they carry, how much installation space they need and whether they can compensate for misalignment. - **Can I simply replace a plain bearing with a ball bearing?** Only after a technical review. Changing the bearing type affects installation space, shaft seat, lubrication, axial location and behaviour under shock loads. It is therefore a design change that should be approved and documented. If in doubt, stick with the original bearing type when replacing. - **What information does a supplier need for a plain bearing bush?** The key details are inside and outside diameter, width and, for flanged bushes, the flange dimensions. Add the material, lubrication grooves or holes and the shaft material. The spare part number from the machine documentation is especially helpful, because fit and material are defined there. ### Buying a pressure gauge: these 7 details must be right URL: https://www.ktb-europe.com/en/blog/buying-pressure-gauge-checklist/ · 2026-10-22 Buy the right pressure gauge first time: measuring range, nominal size, accuracy class, connection, materials, filling and safety. A checklist to EN 837. Frequently asked questions: - **What measuring range should a pressure gauge have?** With steady pressure, the normal operating pressure should be no more than about three quarters of the full-scale value; with fluctuating pressure, no more than about two thirds. That leaves a reserve for pressure peaks. A measuring range that is far too large, on the other hand, makes the reading inaccurate. - **What does the accuracy class of a pressure gauge mean?** The class indicates the permissible deviation as a percentage of the full-scale value. A gauge with 0 to 10 bar and class 1.0 may therefore deviate by up to 0.1 bar, across the entire measuring range. For most operational measurements, class 1.0 or 1.6 is usual. - **When do I need a liquid-filled pressure gauge?** Whenever vibrations or pulsating pressure occur, for example on piston pumps, compressors or hydraulic power units. Filling with glycerine or silicone oil damps the pointer and protects the movement from wear. This keeps the value readable and makes the gauge last longer. - **What is the difference between G and NPT threads on a pressure gauge?** G threads are parallel and seal via a gasket; NPT threads are tapered and seal in the thread itself. G threads are widespread in Europe, NPT mainly on equipment from North America. The two are not readily interchangeable, even if they look similar. - **What details can I find on the old pressure gauge for the replacement?** The dial usually shows the manufacturer, measuring range, unit and accuracy class, often also a symbol for the measuring element. The type and item number are frequently on the case or the back. Add photos and the measured connection thread. ### Industrial vacuum pump: which type suits your process? URL: https://www.ktb-europe.com/en/blog/industrial-vacuum-pump-types/ · 2026-10-22 Choosing an industrial vacuum pump: rotary vane, claw, screw and liquid ring pumps compared, with pressure ranges, typical applications and common faults. Frequently asked questions: - **Which vacuum pump is right for my process?** The decisive factors are the required working pressure, the pumping speed and the medium being pumped. For packaging and clamping tables, rotary vane or claw pumps are often used; for vapours and solvents, screw or liquid ring pumps. High vacuum requires a pumping station with a backing pump. - **How does a rotary vane pump work?** An eccentrically mounted rotor with sliding vanes forms chambers in the housing that draw in, compress and expel gas. In oil-lubricated pumps, oil seals the gaps and dissipates heat. Single-stage versions reach rough vacuum down to around 0.1 mbar; two-stage versions go further into the medium vacuum range. - **Why does my vacuum pump no longer reach its ultimate pressure?** Common causes are leaks in the plant, oil that is contaminated or emulsified by water vapour, a clogged inlet filter or worn vanes. Use a vacuum gauge directly at the inlet flange to check whether the pump reaches its ultimate pressure on its own. If it does, the problem usually lies in the plant. - **What does pumping speed mean for vacuum pumps?** Pumping speed indicates the volume of gas a pump moves per unit of time, usually in cubic metres per hour. It determines how quickly a vessel is evacuated. As it decreases with falling pressure, you should look at the pumping speed curve in the data sheet. - **When do you need an oil-free vacuum pump?** Oil-free pumps make sense if oil could contaminate the process or the product, for example in food, pharmaceutical or cleanroom applications. Dry screw or claw pumps are also often the better choice if vapours would quickly contaminate the oil. ### Leaking hydraulic cylinder? Reseal, repair or replace URL: https://www.ktb-europe.com/en/blog/leaking-hydraulic-cylinder-reseal-repair/ · 2026-10-22 Leaking hydraulic cylinder? How to tell an external from an internal leak, find the cause and choose between a seal kit, a repair or a new cylinder. Frequently asked questions: - **How can I tell whether a hydraulic cylinder is leaking internally?** Typical signs are a load that sinks with the directional valve closed, loss of force, slower movements and a rising oil temperature. A test in the end position provides certainty: one side is pressurised and the other side is checked for escaping oil. Valves such as load-holding valves should be ruled out as the cause beforehand. - **Is it enough to replace only the leaking seal?** No, as a rule the complete seal kit with wiper, rod and piston seals, guide rings and static seals should be replaced. The other seals have usually aged to a similar extent. If you renew only one seal, the next leak often follows after a short time. - **When is it worth repairing a hydraulic cylinder?** A repair makes sense if the piston rod or tube is damaged but the cylinder is fundamentally intact. The rod is then rechromed or replaced, for example, and the tube honed. With special cylinders, this is often faster than procuring a new one. - **Do stop-leak additives in hydraulic oil help?** Such additives can reduce a slight leak in the short term, but they fix neither damaged running surfaces nor contaminated oil. They also change the fluid throughout the entire system. In industrial plants they are at most a stopgap until the next shutdown and should be agreed with the manufacturer. - **What data do I need for a seal kit?** The manufacturer, type and serial number of the cylinder, plus bore and rod diameter, stroke, operating pressure, hydraulic fluid and temperature. Groove dimensions and profile designations of the old seals are helpful, as are photos of the cylinder and nameplate. ### Ball valve vs butterfly valve: how to make the right choice URL: https://www.ktb-europe.com/en/blog/ball-valve-vs-butterfly-valve/ · 2026-10-22 Ball valve vs butterfly valve: design, pros and cons, and clear criteria on nominal size, pressure, medium and actuator. With a table and replacement tips. Frequently asked questions: - **What is the main difference between a ball valve and a butterfly valve?** A ball valve shuts off with a rotating ball that has a bore through it; a butterfly valve uses a disc mounted on a shaft in the middle of the pipe. The ball valve is very tight and, with a full bore, has hardly any pressure loss. The butterfly valve is shorter, lighter and usually more economical in large nominal sizes. - **Can you regulate flow with a ball valve?** A standard ball valve is only intended for opening and closing. In an intermediate position, the fast flow damages the seat rings and the valve starts to leak. For regulating, there are special designs such as segment or V-port ball valves. - **From what nominal size is a butterfly valve worthwhile?** There is no fixed limit. In many water and air applications, the butterfly valve becomes attractive from around DN 100 to DN 150, because ball valves then become large, heavy and torque-intensive. Pressure, temperature and medium can, however, shift the decision. - **How does a butterfly valve work?** A round disc is mounted on a shaft so that it can rotate within the pipe cross-section. When open, it is parallel to the flow; when closed, it is crosswise and presses against a sealing ring or liner. Offset designs lift the disc off the seat faster when opening and are suitable for higher pressures and temperatures. - **What do I need to specify when replacing an isolation valve?** The important details are the design, nominal size, nominal pressure, connection and flange standard, and the face-to-face length. Then there are the materials of the body, closure element and seal, the medium with pressure and temperature, and the type of operation including the actuator interface. ### Check valve: how it works, types and the most common faults URL: https://www.ktb-europe.com/en/blog/check-valve-function-types/ · 2026-10-22 Check valve explained: how it works, types such as the swing check valve, correct installation and how to spot slamming, chattering and leaks. Frequently asked questions: - **How does a check valve work?** A closing element such as a ball, cone, disc or flap rests on a sealing seat. When the medium flows in the direction of flow, it lifts the closing element and the valve opens. At standstill or with reverse flow, a spring, the element’s own weight or the back pressure pushes it back onto the seat, without any auxiliary power. - **What is the difference between a check valve and a swing check valve?** The swing check valve is a type of check valve with a swinging disc. It has a low pressure loss and is used mainly for large nominal sizes, but closes more slowly. Spring-loaded check valves close faster and can often be installed in any position. - **Can a check valve be installed vertically?** That depends on the type. Spring-loaded valves are usually permitted in any position, whereas swing check valves and springless ball valves in vertical lines are generally only permitted with upward flow. The manufacturer’s installation instructions are always what counts. - **Why does a check valve slam when the pump stops?** After the pump stops, the liquid column flows back, and a slow-closing valve is only slammed shut by the reverse flow. This creates a pressure surge. Fast-closing types such as nozzle or spring-loaded valves, or a gentle pump shutdown, reduce the problem. - **How can I tell if a check valve is leaking?** Typical signs are a pump that turns backwards after switching off, a vessel that drains, or a pressure drop in an isolated line. The causes are usually foreign bodies on the seat, deposits or worn seals. ### Solenoid valve not working? 8 causes and how to find them URL: https://www.ktb-europe.com/en/blog/solenoid-valve-not-working-causes/ · 2026-10-22 Solenoid valve not working? 8 typical causes, from voltage and pressure to dirt, with practical checks and the data you need to order a replacement. Frequently asked questions: - **Why does a solenoid valve not open even though voltage is applied?** Common reasons are too little voltage directly at the coil, a faulty or wrong coil and, with servo-assisted valves, too low a pressure differential. Dirt in the pilot orifice or excessive operating pressure can also prevent it from opening. Measure voltage and pressure before you replace the valve. - **What is the difference between direct-acting and servo-assisted?** In a direct-acting solenoid valve, the armature opens the valve seat itself, so it works from 0 bar. In a servo-assisted valve, the armature only opens a small pilot orifice, and the medium pressure then opens the main seat. This requires a minimum pressure differential, which is stated in the data sheet. - **How do I test the coil of a solenoid valve?** With the coil disconnected, measure its resistance and compare it with the data sheet or an identical coil. Infinite resistance means an open circuit. With the coil energised, you can also use a steel screwdriver to check whether a magnetic field is present. - **How hot can a solenoid valve coil get?** Coils for continuous duty get noticeably warm, often so warm that you would not want to touch them for long. A coil is a concern if it is significantly hotter than identical coils, shows cracks in the encapsulation or is discoloured. The permissible coil and ambient temperatures are given in the data sheet. - **What details do you need for a replacement solenoid valve?** The important details are function and switching position, type of operation, connection and nominal size, pressure range with minimum pressure differential, medium, temperature and materials. For the coil, voltage, type of voltage, power and connector type count. Photos of both nameplates make clear identification easier. ### Faulty frequency inverter: repair or replace? URL: https://www.ktb-europe.com/en/blog/frequency-inverter-repair-or-replace/ · 2026-10-22 Frequency inverter faulty? How to check whether the unit is really broken, and how to decide between repair and a new unit using clear, practical criteria. Frequently asked questions: - **Is it worth repairing a frequency inverter?** Often yes, especially for medium and high power ratings, complex integration into the control system and faults in wear parts such as fans or capacitors. For low power ratings, discontinued product ranges or extensive fire damage, replacement usually makes more sense. How long the plant can stand still is also decisive. - **What fails most often on a frequency inverter?** Typical weak points are fans and DC link capacitors, which age over time. Then there are power semiconductors, which fail as a result of short circuits, overload or overheating. Some fault messages, however, have no cause in the unit at all, but in the motor, cable, mechanics or parameter settings. - **How does a frequency inverter work?** A rectifier converts the mains voltage into DC voltage, and capacitors in the DC link smooth it. An inverter stage with power semiconductors uses pulse width modulation to produce a voltage with variable frequency. This allows the speed of a three-phase motor to be controlled steplessly. - **Can I simply replace a frequency inverter with a different model?** Only after careful checking. As well as power and voltage, the output current, overload capacity, control, fieldbus, safety functions, EMC measures and dimensions must match. If the old unit is integrated into the safety system, the machine safety assessment must be reviewed. - **What do I need to consider with a spare inverter kept in storage?** After long storage without voltage, the DC link capacitors can lose dielectric strength. Many manufacturers then require the capacitors to be reformed before commissioning. Note the date of storage and follow the operating instructions. ### Motor protection circuit breaker setting: how to find the right value URL: https://www.ktb-europe.com/en/blog/motor-protection-circuit-breaker-setting/ · 2026-10-22 Motor protection circuit breaker setting in 7 steps: read the current off the nameplate, check the connection, handle star-delta and avoid common errors. Frequently asked questions: - **What value should I set a motor protection circuit breaker to?** Normally to the rated current of the motor shown on the nameplate, for the voltage and connection with which the motor actually runs. For a motor marked 400/690 V Δ/Y on a 400 V supply, the current for the delta connection applies. Special cases such as overload relays in the phase lines with star-delta starting have their own rules. - **Can you set a motor protection circuit breaker higher than the rated current?** No, you should not. A higher value will trip less often, but the motor is then no longer protected against overload. Frequent tripping points to a cause such as mechanical overload, phase loss or excessive ambient temperature. - **How do you set overload protection with star-delta starting?** If the motor protection circuit breaker sits in the supply line upstream of the star-delta combination, it is set to the full rated current. If an overload relay sits in the phase lines downstream of the main contactor, it is set to 0.58 times the rated current. The plant’s circuit diagram is what counts. - **Does a motor on a frequency inverter need a motor protection circuit breaker?** A motor protection circuit breaker upstream of the inverter protects the supply line and the inverter, but not the motor reliably. Motor protection is usually provided by the inverter itself, via current limiting, a thermal motor model or a PTC thermistor in the winding. The inverter manufacturer’s specifications must be followed. - **What does CLASS 10 mean on a motor protection circuit breaker?** The trip class according to EN 60947-4-1 defines how quickly the overload protection trips from cold at 7.2 times the setting current. For CLASS 10, this time is between 4 and 10 seconds. For heavy starting, devices with CLASS 20 or CLASS 30 are available. ### Contactor vs relay: the difference simply explained URL: https://www.ktb-europe.com/en/blog/contactor-vs-relay-difference/ · 2026-10-22 Contactor vs relay compared: how each one works, what they are built for, how to tell them apart and what you must specify when ordering a replacement. Frequently asked questions: - **Can I use a relay instead of a contactor?** Not for motors and other power loads. A relay has no arc-quenching features, and its current rating usually applies to a resistive load. When a motor is switched off, the contacts can weld or burn away. - **What does AC-3 mean on a contactor?** AC-3 is a utilisation category according to EN 60947-4-1. It applies to squirrel-cage motors that are started and switched off while running. The AC-3 current is the most important value when you select a contactor for a motor. - **What is a contactor relay?** A contactor relay (auxiliary contactor) looks like a small contactor but has only auxiliary contacts and no main contacts. It is used in control systems for interlocks, latching circuits and contact multiplication. Technically it sits between a relay and a power contactor. - **What happens if the coil voltage is wrong?** Too high a voltage, or an AC coil on DC, leads to overheating and can destroy the coil. Too low a voltage, or a DC coil on AC, makes the armature pull in poorly, so the component hums or the contacts bounce. Always check the voltage and type of voltage on the nameplate. - **How do I recognise a contactor in the control cabinet?** Contactors have main terminals marked 1/L1, 3/L2, 5/L3 and 2/T1, 4/T2, 6/T3, plus coil terminals A1 and A2. The nameplate shows details such as AC-3 or a motor power in kW. Relays are usually smaller and often plug into a socket. ### Ball bearing failing? 7 signs of bearing failure URL: https://www.ktb-europe.com/en/blog/bearing-failure-signs-ball-bearing/ · 2026-10-22 Spot bearing failure early: 7 warning signs on a ball bearing, simple checks, typical damage patterns and the details you need to order a replacement. Frequently asked questions: - **What does a failing ball bearing sound like?** Typical sounds are grinding, rumbling, periodic knocking or a high-pitched whistle. What matters is the change compared with the usual running noise. Comparing it with an identical bearing position on another machine helps with the assessment. - **Can you keep running with bearing damage?** With slight anomalies and a stable trend, the replacement can often be postponed until the next planned shutdown, provided you monitor closely. With knocking, severe heating or noticeable play, you should shut the machine down in a controlled manner. A seized bearing often damages the shaft and housing as well. - **What does C3 mean on a ball bearing?** C3 stands for a radial internal clearance that is greater than normal clearance. It is used in electric motors, for example, because the shaft and inner ring heat up more in operation than the outer ring. A replacement bearing should have the same internal clearance as the original. - **How do you recognise bearing damage caused by electric current?** Electrical erosion often shows up as a fine, regular fluting pattern across the raceway, sometimes also as a dull, grey running track. It frequently occurs on motors driven by a frequency inverter. Remedies are good earthing, electrically insulated bearings or measures against bearing currents. - **What are the most common causes of bearing failure?** The cause usually lies outside the bearing: wrong or missing lubrication, ingress of dirt, fitting errors and misalignment. Pure material fatigue at the end of the service life is less common. That is why it pays to take a close look at the removed bearing before disposing of it. ### End-user statement: why your supplier asks so much when you buy spare parts URL: https://www.ktb-europe.com/en/blog/end-user-statement-origin-eori-export/ · 2026-10-18 End-user statement, dual use, certificate of origin and EORI explained: why suppliers ask questions when exporting and what buyers can prepare. Frequently asked questions: - **What is an end-user statement?** An end-user statement is a document in which the recipient confirms who will ultimately use the goods, for what purpose and in which country. Suppliers request it to meet their obligations under export control law. For exports subject to licensing, it is often part of the licence application. It must be signed by an authorised signatory. - **What are dual-use goods?** Dual-use goods are goods, software and technologies that can be used for both civilian and military purposes. In the EU, their export is governed by Regulation (EU) 2021/821. Industrial spare parts such as certain controllers, measuring instruments, pumps or converters can also be affected depending on their technical specification, and therefore require a licence. - **What is the difference between preferential and non-preferential origin?** Non-preferential origin is relevant for trade policy, import restrictions and marking, and is often proven with a certificate of origin. Preferential origin is relevant when a trade agreement exists and can lead to reduced customs duties. It requires the goods to meet the rules of origin of the agreement in question. - **What is an EORI number?** EORI stands for Economic Operators Registration and Identification. The EORI number is an identification number that companies use to identify themselves to the customs authorities in the EU, for example for imports and exports. In Germany, it is applied for from the German customs administration. Companies outside the EU usually only need one if they file customs declarations in the EU themselves. - **Why does my supplier ask about the intended use?** Exporters must check whether goods are subject to licensing or could be intended for a critical use. To do so, they need information on the end user and the purpose of use. A clear, factual description, such as the plant in which the spare part will be used, speeds up this check and prevents unnecessary delays to your order. ### Rolling stock spare parts: what to do when parts are no longer made URL: https://www.ktb-europe.com/en/blog/rolling-stock-spare-parts/ · 2026-10-18 Rolling stock spare parts: how manufacturers and depots deal with long service life, obsolescence, fire protection and documentation requirements. Frequently asked questions: - **Why is spare parts supply for rail vehicles so difficult?** Rail vehicles are designed to be used for several decades, but many of their components, such as electronics, controllers or fans, are only produced for a few years. On top of that come approval requirements, fire protection standards and documentation obligations. A technically suitable part is therefore not automatically permitted for use in the vehicle. - **What does EN 45545 cover?** The EN 45545 series of standards sets out the fire protection requirements for rail vehicles in Europe. Among other things, it specifies which requirements materials such as cables, plastics, seals and insulating materials must meet depending on where they are used and the vehicle category. Spare parts containing such materials must meet the relevant requirements. - **Can rail vehicle spare parts be replaced with industrial parts?** For non-safety-relevant bought-in components, this is possible in principle if the part is technically equivalent and meets rail-specific requirements such as fire protection. For safety-relevant components in the brakes, running gear or train protection, strict approval rules apply. Every change should be assessed and approved by the responsible manufacturer or maintainer. - **How do you plan spare parts for a vehicle overhaul?** Overhauls are easy to plan because the material requirement is largely known. Draw up the material list early, check the life cycle status of the components, bundle orders and request the required evidence at the same time. For assemblies that are no longer available, exchange cycles with repaired parts help. ### Printing press spare parts: 5 ways to keep older presses running URL: https://www.ktb-europe.com/en/blog/printing-press-spare-parts/ · 2026-10-18 Printing press spare parts: why older offset, web and flexo presses are hard to keep supplied, and which strategies help print shops keep them running. Frequently asked questions: - **Why are spare parts for older printing presses hard to get?** The printing industry has changed dramatically. Manufacturers have merged, discontinued series and thinned out spare parts programmes. Electronic assemblies and special mechanical parts made specifically for one series are particularly affected. Yet the presses themselves often keep running for decades, creating a gap between service life and spare parts supply. - **Can you source printing press spare parts without the manufacturer?** For bought-in components such as motors, pumps, pneumatics, bearings and sensors, often yes. These parts usually carry the nameplate of their actual manufacturer and are available independently of the press manufacturer. For machine-specific parts such as grippers or control boards, the routes remain the manufacturer, remaining stock, repair or reproduction. - **What can you do when an electronic assembly is discontinued?** Pursue three routes in parallel: buy spare assemblies from remaining stock, have defective assemblies repaired by specialised electronics workshops and plan a modernisation of the controls in the medium term. The key is to know your critical assemblies before they fail, so you do not have to decide under time pressure later. - **Is a donor machine for spare parts worth it?** If a series is barely supported any more and your own press keeps running economically, a decommissioned identical press can be a valuable source of parts. However, the effort for dismantling, storing and inspecting the parts is considerable. Check beforehand which critical parts the donor machine actually provides and what condition they are in. ### Turnaround in the Gulf: how to plan spare parts for a major shutdown URL: https://www.ktb-europe.com/en/blog/turnaround-gulf-spare-parts-planning/ · 2026-10-18 Turnaround in the Gulf region: how cement plants and process plants plan spare parts for major shutdowns, considering heat, dust, deadlines and documents. Frequently asked questions: - **What is a turnaround in industry?** A turnaround, also called a shutdown or major outage, is a planned shutdown of an industrial plant for extensive maintenance work. Inspections, repairs, replacement of wear parts and modernisations are bundled into a fixed time window. Turnarounds are common in the process industry, refineries, power stations and cement plants and are often prepared over months. - **When should you order spare parts for a turnaround?** As early as possible. Parts with long lead times, known as long-lead items, such as large gearboxes, special pumps or special valves, often need to be ordered many months in advance. For the rest of the list: the parts should arrive with enough buffer before the start to safely allow for inspection, clearance and transport to the plant. - **What should you pay particular attention to with spare parts for the Gulf region?** Heat, dust and salt-laden air put more strain on plants and stored parts. Spare parts and storage conditions should be designed for this. On top of this come import and conformity requirements, such as registration via SABER in Saudi Arabia, as well as rules on certificates of origin and commercial invoices. These points should be clarified well before the turnaround. - **How do you deal with unexpected damage during a turnaround?** For parts whose condition only becomes visible during inspection, you need either reserve stock or a fast sourcing channel. Prepare complete part data and work with a partner who can send enquiries to suppliers in several regions in parallel. This shortens the search when every hour counts. ### Ordering ship spare parts: 5 details that prevent wrong orders URL: https://www.ktb-europe.com/en/blog/ship-spare-parts-identification/ · 2026-10-18 Sourcing ship spare parts: why manufacturer, type, serial number, drawing and item number all matter, and how you can avoid costly wrong orders. Frequently asked questions: - **What details do I need to order a ship spare part?** The key details are the manufacturer of the unit, and for licence-built machinery the licensee too, the exact type designation, the serial number, the drawing and item number from the spare parts catalogue and the part number. Photos of the nameplate and the defective part, as well as details of any required evidence, are also helpful. - **Why is the part number often not enough for ship spare parts?** Marine units are often decades old, manufacturers have changed part numbers over the years, and many engines are licence-built with differing parts. Only the combination of type, serial number, drawing and item number ensures that the correct part is identified. This reduces the risk of costly wrong orders. - **Can non-original parts be used on ships?** In principle yes, if the part is technically equivalent and meets the requirements of the classification society and international regulations. For safety-relevant components, evidence or approvals may be required. The decision should always be agreed with the shipowner’s technical superintendent and documented. - **What is an item number in a spare parts catalogue?** Manufacturer manuals for marine units usually contain exploded views in which each individual part is marked with an item number. Together with the drawing number, this gives a unique reference that manufacturers and suppliers can use to determine the valid part number, even if it has changed over the years. ### Plant in Brazil: why spare parts need more lead time there URL: https://www.ktb-europe.com/en/blog/plant-in-brazil-spare-parts-planning/ · 2026-10-18 Spare parts for a plant in Brazil: why imports need lead time, what NCM, INMETRO and Ex-Tarifário mean, and how to plan stock and sourcing channels. Frequently asked questions: - **Why does sourcing spare parts for Brazil often take longer?** Brazil has a complex import system with several taxes, its own customs classification and, in some cases, certification requirements from INMETRO. On top of this come document requirements and often long distances to plants inland. Each of these steps takes time. Errors in classification or documents quickly lead to further delays. - **What is NCM in Brazil?** NCM stands for Nomenclatura Comum do Mercosul, the common customs nomenclature of the Mercosur states. It is based on the international Harmonised System and determines which duties and taxes apply to a product and which requirements apply. Correct NCM classification is crucial for every import into Brazil, including spare parts. - **What is Ex-Tarifário?** Ex-Tarifário is a Brazilian scheme under which import duty can be reduced for certain capital goods as well as IT and telecommunications goods if there is no equivalent domestic production. It mainly concerns machinery and equipment, less so individual spare parts. For larger projects it is worth reviewing with a specialist consultant. - **Should you stock more spare parts in Brazil than in Europe?** For critical imported parts, usually yes. Because rush procurement from abroad is laborious and time-consuming, the trade-off between tied-up capital and downtime risk more often favours higher stock. This does not apply to parts that are available locally in equivalent quality. That is why it pays to check every imported part for domestic alternatives. ### Steel mill spare parts: why heat and huge components need their own planning URL: https://www.ktb-europe.com/en/blog/steel-mill-spare-parts/ · 2026-10-18 Steel mill spare parts: why heat, large components and ageing equipment call for their own strategy, and how maintenance teams can plan ahead. Frequently asked questions: - **Which spare parts are particularly critical in a rolling mill?** Large components such as rolls, gearboxes, cardan shafts and large drive motors are particularly critical, because they have long lead times and can stop a line. Add to that multi-row roll neck bearings, hydraulic servo valves for roll gap control and automation components affected by discontinuations. These parts need reserve stock or secured supply channels. - **How do you plan large components in a steelworks?** Assess the criticality of every large component, keep a spare for the most important ones and establish repair cycles of installed part, spare and part under overhaul. Regularly check the spares against the current plant configuration and use condition monitoring to trigger purchases in good time. - **Why is obsolescence a major issue in steelworks?** The mechanics of a rolling mill last for decades, whereas the automation lasts only a few years before manufacturers discontinue components. That is why many plants run old controllers and drives alongside new mechanics. Without an inventory, safeguarding through last time buys or remaining stock and planned modernisation, long periods of downtime loom. - **How do you avoid counterfeit bearings in a steelworks?** Buy bearings through reliable, traceable channels and avoid offers with conspicuously low prices from unknown sources. Have the goods inspected for marking, packaging, dimensions and condition before installation. With large bearings in particular, the damage caused by an inferior part far exceeds any saving on the purchase. ### European machines in the US: 60 Hz, UL, inches – what it means for spare parts URL: https://www.ktb-europe.com/en/blog/european-machines-us-plants-spare-parts/ · 2026-10-18 European machines in US plants: what 60 Hz, 480 V, UL, NEMA and imperial sizes mean for spare parts, and how to organise reliable supply for your plant. Frequently asked questions: - **Why do European spare parts not always fit US machines?** European machines are usually adapted for the US market: to 60 Hz instead of 50 Hz, to other voltages such as 480 V and to standards such as UL and NFPA. As a result, many components have a different version and part number than in Europe. If you order by the European standard number, you may receive a variant that does not fit. - **Can I replace a European motor with an American one?** In principle yes, but not without checking. European motors follow IEC standards, American motors NEMA standards. Frame sizes, flanges and shaft diameters are not compatible. Output, speed, voltage, frequency and degree of protection must also match. Adapters or modifications are often needed. Equivalence should be checked technically and documented. - **Which standards matter for spare parts in US plants?** Frequently relevant are UL 508A for industrial control panels and NFPA 79 for the electrical equipment of machines. In Canada, CSA approvals play a similar role. A spare part without a suitable listing can become a problem during inspections. The requirements that apply in each case are best clarified with your qualified electrician or your safety officer. - **How do I organise spare parts for European equipment in the US?** Document the versions actually installed using the nameplates, separate metric and imperial parts in the master data, check American alternatives technically and stock critical parts that only come from Europe. A partner with a presence in Europe and the US can compare sourcing channels and procure the right version. ### Strategic procurement: 7 spare parts misconceptions that cost money URL: https://www.ktb-europe.com/en/blog/strategic-procurement-spare-parts-misconceptions/ · 2026-10-18 Strategic procurement and spare parts: 7 misconceptions that cost purchasing teams money and availability, and what a real MRO strategy looks like. Frequently asked questions: - **What is strategic procurement?** Strategic procurement defines how a company sources its categories over the long term. This includes market analyses, supplier selection, contract design, risk assessment and targets for cost and security of supply. Operational purchasing turns these requirements into concrete purchase orders. Strategic procurement thinks in years, operational purchasing in days and weeks. - **What is the difference between strategic and operational procurement?** Strategic procurement develops category strategies, selects suppliers, negotiates framework agreements and assesses risks. Operational purchasing places orders on this basis, tracks delivery dates and resolves discrepancies. Each depends on the other. With spare parts the strategic level is often missing, so operational purchasing works without clear guidelines. - **What is the Kraljic matrix?** The Kraljic matrix is a portfolio tool used in strategic procurement. It sorts categories by profit impact and supply risk into four quadrants: non-critical items, leverage items, bottleneck items and strategic items. Each quadrant calls for a different sourcing strategy. Many spare parts fall into the bottleneck quadrant, meaning low value with high risk. - **How do you develop a strategy for spare parts?** Segment your spare parts together with maintenance by value and supply risk. Define suitable sourcing channels for each segment, such as catalogues, framework agreements or secured multiple channels. Define the role of your suppliers, improve your master data and measure availability, process costs and downtime instead of just prices. ### Indirect procurement: where companies quietly lose money on small items URL: https://www.ktb-europe.com/en/blog/indirect-procurement-mro/ · 2026-10-18 Indirect procurement explained simply: what it covers, why process costs are often higher than the value of goods and how to manage MRO and C-parts better. Frequently asked questions: - **What is meant by indirect procurement?** Indirect procurement covers all goods and services a company needs for its operations that do not go into the product it sells. These include MRO parts, C-parts, consumables, occupational safety equipment, tools and services such as maintenance or cleaning. Direct procurement, by contrast, buys raw materials and components for production. - **What is the difference between direct and indirect procurement?** Direct procurement buys material that becomes part of the end product and is usually easy to plan. Indirect procurement buys materials and services for operations. It involves many items, many suppliers, small order values and often unpredictable demand. That is why the levers there lie more in process costs than in unit prices. - **What is tail spend?** Tail spend refers to the many small expenses with many suppliers that together make up only a small part of the purchasing volume. However, they generate a large share of ordering transactions and invoices. Tail spend usually builds up unnoticed, because individual orders seem harmless. Consolidation and clear supplier guidelines help to manage it. - **How can costs in indirect procurement be reduced?** The most effective levers are transparency over suppliers and orders, consolidating demand with fewer suppliers, framework agreements for recurring items and clean master data. Complex individual cases, such as rare spare parts or parts for plants abroad, can be outsourced to a sourcing partner that handles searching, comparing and inspection. ### New plant in Mexico: how to plan spare parts before production starts URL: https://www.ktb-europe.com/en/blog/plant-in-mexico-spare-parts-start-up/ · 2026-10-18 New plant in Mexico? How to plan spare parts for start-up: initial spares, 60 Hz, local standards, sourcing from Europe and the USA, language and data. Frequently asked questions: - **Which spare parts does a new plant in Mexico need for start-up?** The initial spares package should include wear parts for the first maintenance cycles, critical parts with long replenishment lead times to Mexico and parts that are not available locally. The basis is the machine builders’ spare parts recommendation, but it should be adapted together with maintenance to the site, the mains frequency and local sourcing options. - **What technical points apply to European machines in Mexico?** Mexico uses a mains frequency of 60 Hz, Europe 50 Hz. Motors, pumps and fans are therefore often installed in a different version. Mexican standards, the NOM, also apply and may require proof or labelling for certain products. In many plants European and American components also meet, such as metric and imperial parts. - **Can you buy spare parts from European manufacturers locally in Mexico?** For widespread brands there are often local distributors. However, many specialist European manufacturers have no representation of their own in Mexico, and local distributors do not carry their parts. That leaves sourcing from the USA or directly from Europe. A partner with a presence in Europe, the USA and Mexico can compare and combine these channels. - **What is the IMMEX programme?** IMMEX is a Mexican programme that allows companies the temporary duty-advantaged import of material, machinery and parts for export production. Whether spare parts are covered depends on how it is set up in the specific company. Clarify this with your customs department or customs broker before the first spare parts orders come in. ### Single sourcing: just one supplier – when it saves money and when it gets risky URL: https://www.ktb-europe.com/en/blog/single-sourcing-advantages-risks/ · 2026-10-18 Single sourcing, dual sourcing or multiple sourcing? Advantages, risks and a clear decision guide for procurement and maintenance teams buying MRO parts. Frequently asked questions: - **What is single sourcing?** Single sourcing means that a company deliberately covers a particular requirement through just one supplier, even though alternatives exist. The aim is lower administrative effort, better terms through consolidated volume and closer collaboration. The downside is dependency, which should be secured through stock, contracts and regular evaluation. - **What is the difference between single sourcing and sole sourcing?** With single sourcing, you voluntarily choose one supplier, even though others exist. With sole sourcing, there is only one provider, for example because a manufacturer sells a part exclusively or holds a patent. Single sourcing is therefore a strategy, while sole sourcing is a market reality you have to respond to. - **What are the risks of single sourcing?** The biggest risk is the supplier failing, for example through insolvency, capacity bottlenecks or disruptions in its own supply chain. Add creeping price increases without competition and the loss of market knowledge in your own procurement team. You can secure against this with safety stocks of critical parts, your own master data and annual evaluations. - **Is single sourcing worthwhile for MRO parts?** Often yes, if the chosen partner buys across manufacturers. You then consolidate the interface, meaning enquiries, purchase orders and invoices, but keep many sources of supply in the background. That lowers process costs without making supply dependent on a single manufacturer. You should also secure critical parts yourself. ### Bought used equipment? How to secure your spare parts supply URL: https://www.ktb-europe.com/en/blog/used-equipment-spare-parts-supply/ · 2026-10-18 Bought used equipment or relocating a plant? How to secure the spare parts supply: documentation, nameplates, discontinuations and initial spares. Frequently asked questions: - **What should I look out for regarding spare parts when buying used equipment?** Request bills of materials, circuit diagrams, maintenance history and spare parts catalogues. Include the seller's existing spare parts stock in the negotiations. For the main components, check whether the manufacturers still exist and still supply the parts, especially for controls, drives and operator panels. These points should be clarified before the contract is signed. - **Why is dismantling so important for the spare parts supply?** During dismantling, you see the equipment in its installed state for the last time. If you photograph all accessible nameplates and installation details now, you get a realistic bill of materials. It shows what is actually installed, including parts that have been replaced over the years. After reassembly, this takes far more effort. - **Which spare parts belong in the initial package for the new plant?** The initial package includes wear parts for the first maintenance cycles, critical parts with no fast source of supply in the new country and discontinued components, as long as they are still available. Pay attention to technical differences such as mains voltage, frequency and local approvals, so that the parts can actually be used in the new plant. - **Can I buy spare parts from European manufacturers locally abroad?** That depends on the country and the manufacturer. For common brands, there are often local sales organisations. However, many specialist manufacturers do not have a presence in every country. Local distributors then have to order internationally themselves. A procurement partner with a presence in Europe and in the destination country can compare both routes and choose the right one. ### C-parts management: 7 mistakes that make screws and other small parts expensive URL: https://www.ktb-europe.com/en/blog/c-parts-management-mistakes/ · 2026-10-18 C-parts management in industry: 7 typical mistakes that drive up process costs, and how to procure C-parts reliably and with far less internal effort. Frequently asked questions: - **What are C-parts?** C-parts are low-value items that are needed frequently and in large numbers. The term comes from ABC analysis. In industry, they mainly include standardised parts and fasteners, small electrical parts, seals, consumables and basic personal protective equipment. They account for little procurement spend, but many ordering processes. - **What is C-parts management?** C-parts management refers to all the measures companies use to organise the procurement of C-parts efficiently. The focus is not on the unit price but on reducing process costs. Typical tools are supplier consolidation, clean item master data, range rationalisation, Kanban systems, catalogues, framework agreements and outsourcing to external partners. - **Why are process costs so high for C-parts?** Every order goes through the same sequence: requisition, approval, purchase order, goods receipt, invoice check and payment. This effort is independent of the value of the goods. With low-value C-parts and many individual orders, process costs therefore often exceed the price of the goods themselves. Consolidation and standardisation tackle exactly this. - **Are all small parts non-critical?** No. An O-ring in a hydraulic press, a special retaining ring in a control system or a bolt in a coupling can bring equipment to a standstill. Technically relevant small parts like these need clear specifications covering standard, material and tolerance, as well as approval by engineering. Keep them deliberately separate from pure consumables. ### Spare parts management: have the right part ready – without a full warehouse URL: https://www.ktb-europe.com/en/blog/spare-parts-management-maintenance/ · 2026-10-18 Practical spare parts management: assess criticality, use ABC/XYZ analysis, set stock levels and keep parts available without tying up too much capital. Frequently asked questions: - **What is meant by spare parts management?** Spare parts management covers all the tasks that ensure spare and wear parts are available when maintenance needs them. These include identification, assessing criticality, defining stock levels and ordering rules, procurement, storage, care and removing parts that are no longer needed. The aim is a balance between availability and tied-up capital. - **How do you identify critical spare parts?** The deciding question is what happens in the event of a failure. If the missing part stops a plant with no fallback option, it is highly critical. Replenishment lead time, market availability and the number of sources of supply also come into it. A critical part with a long lead time and only one manufacturer almost always belongs in your own store. - **What does an ABC/XYZ analysis achieve for spare parts?** ABC analysis ranks parts by share of value, XYZ analysis by how regularly they are consumed. Combined, it shows which parts need precise planning and which need lean processes. For spare parts, it should always be supplemented by a criticality assessment, because rare and cheap parts can still stop a plant. - **How many spare parts should you keep in stock?** There is no one-size-fits-all number. The quantity depends on criticality, consumption, replenishment lead time and the number of parts installed. For regularly consumed parts, minimum and maximum stock levels help. For rare repair parts, what matters most is how long a plant can be down and how quickly the part can be sourced in an emergency. ### Supplier management: 10 questions that reveal a good spare parts supplier URL: https://www.ktb-europe.com/en/blog/supplier-management-evaluate-mro-suppliers/ · 2026-10-18 Supplier management for MRO: 10 questions that help procurement and maintenance evaluate, compare and further develop their spare parts suppliers. Frequently asked questions: - **What is meant by supplier management?** Supplier management covers all the activities a company uses to select, evaluate, develop and steer its suppliers. These include supplier selection, regular evaluations, joint improvements, the management of risks and dependencies, and the question of how many suppliers per category make sense. The aim is a reliable and cost-effective supply. - **What criteria should be used to evaluate MRO suppliers?** Besides price, quality and delivery reliability, what counts most in MRO is the range of manufacturers, the handling of unclear enquiries, the offer of technical alternatives, inspection of the goods, the international set-up and language skills. Ultimately, what matters is whether the supplier takes work off your hands or creates more. - **How often should suppliers be evaluated?** For the most important MRO suppliers, an annual evaluation followed by a meeting has proven effective. If noticeable problems occur, such as repeated incorrect deliveries, you should respond promptly. What matters is that the evaluation has consequences, whether that is a joint improvement, a shift in volume or, in individual cases, a change of supplier. - **Who should be involved in supplier evaluation?** Besides procurement, maintenance, goods receipt and accounts should contribute their views. Maintenance assesses technical expertise and help with difficult enquiries, goods receipt the accuracy of deliveries, and accounts the effort involved in checking invoices. This creates a realistic and fair overall picture. ### Spare part no longer available? Obsolescence management prevents downtime URL: https://www.ktb-europe.com/en/blog/obsolescence-management-discontinued-spare-parts/ · 2026-10-17 Obsolescence management for maintenance: spot discontinuations early, plan a last time buy properly and find alternatives for discontinued components. Frequently asked questions: - **What is obsolescence management?** Obsolescence management is the systematic control of components that the manufacturer is discontinuing or that will soon no longer be available. It involves recording critical parts, regularly checking their life cycle status, assessing the risk of failure and choosing a strategy such as a last time buy, an alternative, repair or modernisation. - **What does ‘discontinued’ mean for spare parts?** Discontinued means that the manufacturer no longer produces a part or will stop doing so in the foreseeable future. There is often an advance notice with a final ordering deadline. After that, the part is only available from remaining stock, through repair or as a technically compatible alternative. Manufacturer support may end as well. - **What is a last time buy?** A last time buy is the final order of a part before production ends. You buy the estimated remaining demand up to the planned end of your plant's life. The quantity depends on the number of parts installed, the failure rate so far, the remaining service life and the shelf life. The decision should be made together with maintenance. - **What should you do if a spare part is no longer available?** Identify the part as precisely as possible: manufacturer, full part number, version status, photos of the nameplate. Then check three routes in parallel: remaining stock on the international market, repair of the defective assembly and technically compatible alternatives. Have third-party goods inspected for condition and authenticity before installation. - **Which parts are particularly affected by obsolescence?** Electronics and automation technology are affected most often, such as control modules, operator panels, frequency inverters, servo drives and special sensors. Their product cycles are much shorter than those of the mechanical plants they sit in. But special mechanical parts from smaller manufacturers can also suddenly disappear after takeovers or range rationalisations. ### Spare parts enquiry: 12 details that get you the right quote faster URL: https://www.ktb-europe.com/en/blog/spare-parts-enquiry-checklist/ · 2026-10-17 Checklist for your spare parts enquiry: the 12 details every MRO supplier needs for a fast, accurate quote. Includes a template you can copy. Frequently asked questions: - **What is the most important detail in a spare parts enquiry?** The full part number together with a sharp photo of the nameplate. The number identifies the part unambiguously, while the photo protects against transcription errors and shows suffixes that are often decisive. In automation technology in particular, variants often differ only in the last few characters of the order number. - **What can I do if the nameplate is no longer legible?** In that case, key technical data, photos of the installation, dimensions and a description of the application help. The serial number of the machine can also help, because machine manufacturers can often use it to trace the installed components. Send everything you have and say openly which details are missing. - **Should I allow alternatives in my enquiry?** If technically possible, yes. An equivalent part from another manufacturer or a successor type may be available faster or at a lower price. State who checks and approves alternatives technically. This allows the supplier to offer targeted options, while you keep control of the decision. - **Why is the delivery location important for the enquiry?** The delivery location determines import regulations, the documents required and sometimes also the permitted version of a part, for example because of mains voltage or approvals. It also affects lead time and costs. If you only name the country after receiving the quote, you risk the quote having to be prepared again. - **How do I enquire about many items at once?** Use a table with one row per item and columns for manufacturer, part number, quantity, technical data and target date. Number the items and name the photos with the same number. That way, even long lists for maintenance shutdowns stay clear, and follow-up questions can be assigned unambiguously. ### Machine down, part missing: emergency spare parts procurement done right URL: https://www.ktb-europe.com/en/blog/emergency-spare-parts-procurement-scenario/ · 2026-10-17 Emergency spare parts procurement: a typical scenario shows step by step which details and decisions count. With a checklist for your maintenance team. Frequently asked questions: - **What information do I need for fast spare parts procurement?** The most important items are the manufacturer and the full order number, a sharp photo of the nameplate, the serial numbers of the part and the machine, and a photo of the installation. Key technical data, the quantity required, the delivery location and a realistic target date also help. The more complete the enquiry, the fewer follow-up questions there will be. - **Should I contact several suppliers at the same time in an emergency?** Yes. Manufacturers, distributors and repairers each need their own time to check and quote. If you ask one after the other, you add those times up. Parallel enquiries shorten the path to a decision considerably. It is important to give everyone the same complete information so that the quotes are comparable. - **Can I use a spare part from a different manufacturer?** Often, yes, if the part is compatible in form, function and connections. For drives and control components, this also includes encoder type, communication and software. The approval should be technically justified and documented. Ideally, clarify alternatives for critical parts in advance, not in the middle of an emergency. - **How do I prevent an emergency like this from happening again?** Assess the criticality of your spare parts together with maintenance, store photos, data sheets and full part numbers for critical parts in your master data, and check whether the parts in stock really match the parts installed. Have faulty parts repaired and keep them as a reserve. ### What is MRO? The parts you only notice when they are missing URL: https://www.ktb-europe.com/en/blog/what-is-mro/ · 2026-10-17 What is MRO? The meaning of maintenance, repair and operations, typical MRO parts, how it differs from direct materials and tips for lean procurement. Frequently asked questions: - **What does MRO mean?** MRO stands for maintenance, repair and operations. It refers to all the parts and materials that keep plants and machines running without becoming part of the product sold. These include spare and wear parts, standard parts, tools, lubricants and personal protective equipment. - **What is the difference between MRO and direct materials?** Direct materials go into the end product, such as sheet steel into a housing. MRO material keeps production running but is not built in. Direct materials are usually easy to plan and linked to production volumes. MRO demand, by contrast, often arises unplanned, in small quantities and spread across many different items and manufacturers. - **What are examples of MRO parts?** Typical MRO parts are ball bearings, seals, V-belts, couplings, pneumatic valves, hydraulic hoses, sensors, contactors and frequency inverters. Add to that standard parts such as screws and fuses, tools, measuring equipment, lubricants and protective equipment. Larger components such as gearboxes, motors or pumps also count when they serve as replacements. - **Why is MRO procurement so time-consuming?** Because many different items are ordered in small quantities from many manufacturers. Each order goes through the same process as a large purchase. Add incomplete part data, discontinued items and time pressure during breakdowns. Process costs are therefore often close to the value of the goods, or even higher. - **Is it worth outsourcing MRO procurement?** That depends on your structure. If your plant has many manufacturers, many small orders or sites in several countries, a specialised MRO partner can bundle enquiries, approach suppliers worldwide and check alternatives. That takes the load off procurement and maintenance. With a few easily planned items, going directly to the manufacturer is often enough. ### 50 years of KTB - More than an anniversary. An attitude. URL: https://www.ktb-europe.com/en/blog/50-years-of-ktb-more-than-an-anniversary-an-attitude/ · 2026-02-17 Since 1976, KTB Europe has stood for international MRO procurement, stable supply chains and supply chain solutions based on partnership. 50 years of experience worldwide. Frequently asked questions: - **When was KTB founded?** KTB was founded in Hamburg in 1976. KTB Import-Export Handelsgesellschaft mbH & Co. KG goes back to the entrepreneurial vision of Bringfried Kitzinger and the co-founders. Today, the company is managed in the second generation by Lars Kitzinger. Since 1976, KTB has developed from a Hanseatic family business into an internationally active MRO specialist. - **What does an MRO specialist like KTB do?** An MRO specialist procures spare parts, components and operating supplies for the maintenance, repair and operation of industrial plants. KTB sees itself as a strategic partner: requirements are analysed, procurement channels structured and supply chains optimised. The aim is to reduce complexity for customers and ensure a reliable supply of MRO parts. - **What values define KTB?** KTB describes its value compass in terms of trust, transparency, responsibility and long-term thinking. This attitude has shaped the company since its foundation in 1976 and remains in place under second-generation management. It is intended to create stability in complex supply chains and strengthen partnerships rather than relying on short-term business. - **How does KTB plan to develop MRO procurement in the future?** KTB relies on AI-supported process automation, ERP integration and data-driven supply chain optimisation to make processes more transparent and controllable. Sustainable procurement strategies are intended to combine ecological responsibility with economic efficiency. The international presence is being expanded in order to be closer to customers and make MRO processes more resilient. ### Mastering Mexican MRO Procurement: The key to nearshoring success URL: https://www.ktb-europe.com/en/blog/mastering-mexican-mro-procurement-the-key-to-nearshoring-success/ · 2025-09-08 Perfect Mexican MRO Procurement. Nearshoring advantages, consolidated industrial parts procurement, customs expertise. Frequently asked questions: - **What does nearshoring in Mexico mean for MRO procurement?** Through nearshoring, companies relocate production to Mexico to be closer to the North American market. This shortens supply routes but raises the requirements for spare parts supply: genuine parts, error-free documentation and on-time deliveries become mandatory. Plants therefore need reliable, well-organised MRO supply chains. - **What documents does Mexican customs require for spare parts?** Commercial invoices, packing lists, correct HS codes, certificates of origin and, where applicable, supplier declarations are standard. The documents should be in the formats the customs broker expects. Precise and complete documents lead to predictable clearance and avoid long waiting times at the border or airport. Incorrect information, on the other hand, can trigger re-inspections and additional costs. - **What is kitting in spare parts supply?** With kitting, all parts needed for a specific maintenance job are assembled and labelled in advance, for example by line, equipment or work order. When the kit is opened, work can begin immediately instead of searching for parts. This saves time during planned maintenance windows and reduces installation errors. - **What is brand-independent MRO procurement?** Brand-independent means that the procurement partner is not tied to specific brands. It sources genuine parts from authorised channels of various manufacturers and consolidates them into one delivery. If an original part is discontinued, it can propose functionally equivalent alternatives based on the form-fit-function principle. This reduces dependencies and supports parts standardisation. ### Putting an end to chaos: Modern MRO sourcing strategies for industrial parts URL: https://www.ktb-europe.com/en/blog/put-an-end-to-the-chaos-modern-mro-sourcing-strategies-for-industrial-parts/ · 2025-09-08 Modern MRO sourcing strategies for industrial parts. Consolidated suppliers, optimized processes, measurable cost reduction. Frequently asked questions: - **What does fragmented MRO procurement really cost?** Every order placed with an additional supplier generates process costs: requests for quotation, approvals, invoice checks and follow-up. With thousands of small parts, this effort adds up considerably, often exceeding the actual price of the part. On top of this come duplicate stocks caused by inconsistent master data. Consolidation makes these hidden costs visible and reduces them. - **How does ABC analysis work in spare parts management?** ABC analysis classifies items by importance and consumption value. A parts are critical, for example because their absence stops a line, and should be closely monitored. B and C materials such as consumables can largely be reordered automatically. This allows the team to focus on the truly critical components. - **What is vendor managed inventory in MRO?** With vendor managed inventory (VMI), the supplier takes over monitoring and replenishing certain stock, usually consumables. It ensures that minimum stock levels are maintained without every order having to be triggered internally. This takes the load off procurement and maintenance and reduces the risk of stockouts. - **How do you start consolidating MRO procurement?** A practical starting point is a review of the top items by spend and consumption: how many duplicates and how many suppliers are there for identical parts? Then clean up master data, choose a partner for the long tail and retain strategic alternatives. Pre-kitted deliveries can first be tested during a maintenance window. ### The real reason why Top MRO Suppliers do not show prices online URL: https://www.ktb-europe.com/en/blog/the-real-reason-why-top-mro-suppliers-dont-show-prices-online/ · 2025-06-05 Why Top MRO Suppliers do not show prices online. Industrial MRO Suppliers rely on advice instead of Automation Parts price lists. Frequently asked questions: - **Why don't many MRO suppliers show prices online?** Industrial spare parts and automation components are often not standard goods. Configuration, calibration, certification, quantity, urgency and shipping route strongly influence the price. A flat list price would therefore often be misleading. Added to this are competitive reasons and individual terms for different customers and projects. An individual quotation reflects the actual requirement more accurately. - **What does price on request mean in B2B?** Price on request means that the price is calculated individually on the basis of the specific requirements. In B2B, costs often depend on quantity, technical version, documentation requirements, lead time and delivery terms. A quotation on request makes it possible to take exactly these factors into account and to propose suitable alternatives. - **What determines the price of an industrial part?** In addition to the part itself, quantity, availability, lead time, technical configuration, required certificates and documents, packaging, transport route as well as customs and delivery terms influence the price. Emergency orders with express delivery also usually cost more than planned orders. That is why precise enquiries are the basis for a fair quotation. - **How do you get a quick quote for industrial parts?** Complete details help: manufacturer, part number, quantity, required delivery date, delivery address and, if needed, technical documents or a photo of the nameplate. Information on operating conditions or required certificates also speeds up the review. The clearer the enquiry, the faster and more accurately the price can be calculated. ### Space boom: How space projects are creating new MRO USA markets URL: https://www.ktb-europe.com/en/blog/space-boom-how-space-projects-create-new-mro-usa-markets/ · 2025-06-05 Space boom creates new MRO USA markets. American Industrial Suppliers supply industrial parts for space projects and satellites. Frequently asked questions: - **Why is the space industry creating new MRO markets in the USA?** Private space companies, government programmes and commercial satellite projects are generating new demand for specialised industrial components. In addition to rockets and satellites, launch sites, control centres, test facilities and production plants also require ongoing maintenance, repair and spare parts. For MRO providers in the USA, this creates a growing segment with high quality requirements. - **What requirements do space projects place on industrial components?** Components must function where repairs are hardly possible: in extreme cold, under radiation and over long periods without maintenance. Quality controls and documentation requirements are correspondingly strict. These high standards set benchmarks from which industries such as automotive engineering, medical technology and power generation later also benefit. - **Which MRO services does space ground infrastructure need?** Launch sites, antenna systems, control centres and test facilities require conventional industrial parts such as pumps, valves, sensors, drives and controls, but in particularly high quality and reliability. Test facilities are subject to heavy wear and need continuous maintenance. As delays are very expensive, availability and quality count for more there than the lowest price. - **How do other industries benefit from space technology?** Many technologies developed for satellites and rockets flow back into terrestrial applications, such as robust sensors, radiation-resistant controls or new materials such as composites. As a result, factories receive more durable and smarter components. For MRO providers, this means new product categories and higher requirements for expertise in procurement. ### Brazil's industrial awakening: Why MRO Brazil 2025 is exploding URL: https://www.ktb-europe.com/en/blog/brazils-industrial-awakening-why-mro-brazil-will-explode-in-2025/ · 2025-06-05 MRO Brazil explodes in 2025 due to industry upheaval. Industrial Parts and International Procurement Companies rediscover Brazil. Frequently asked questions: - **Why is the MRO market in Brazil growing?** Brazil is developing from a raw materials supplier into a modern industrial location. New factories, investment in ports, roads and digital networks as well as energy transition projects are increasing demand for industrial parts and maintenance services. Added to this is nearshoring: international companies see Brazil as an alternative to Asian sourcing markets. - **What role does the Port of Santos play for industry?** Santos is one of the most important ports in Brazil and South America. Its expansion improves the exchange of goods with Europe and other markets. Together with regional distribution centres, Brazil can thus serve as a hub for supplying South America with industrial and automation parts. For MRO supply chains, this means better logistical options. - **How is the energy transition driving demand for industrial parts in Brazil?** Brazil is investing heavily in solar parks, wind farms and hydrogen technology. These plants require specialised components and regular maintenance, for example for control systems, drives and smart grids. On top of this come robust automation parts for demanding climatic conditions. This is creating a growing market for MRO services and spare parts. For internationally active procurement partners, this opens up new supply opportunities. - **What should you consider in MRO procurement for Brazil?** Brazil has its own quality standards, customs rules and documentation requirements. Exchange rate fluctuations affect costs and pricing. Success comes to those who combine local expertise with international standards and prepare deliveries, including paperwork, properly. Partners with experience in Latin America help to avoid delays at ports and in customs. ### Return of production: Why factories are returning to Europe URL: https://www.ktb-europe.com/en/blog/return-of-production-why-factories-are-returning-to-europe/ · 2025-06-05 Factories return to Europe. European MRO Services and Industrial MRO Suppliers benefit from the reshoring and automation parts boom. Frequently asked questions: - **What does reshoring mean?** Reshoring refers to relocating production from abroad back to the home country or home region. Nearshoring means relocating to nearby countries. Both strategies aim to shorten supply chains, reduce dependencies and improve response times. In Europe, they are being driven by automation, a focus on resilience and sustainability targets. - **Why are factories returning to Europe?** Automation makes low labour costs less decisive, while fragile global supply chains have exposed risks. In addition, there are sustainability targets that make long transport routes less attractive, as well as European strengths in quality, engineering know-how and skilled workers. Technologies such as additive manufacturing and flexible automation also make smaller batch sizes economical. - **What does the return of production mean for MRO services in Europe?** More production in Europe means more demand for spare parts, automation components and on-site maintenance services. Shorter distances enable faster response times and reduce the risk of supply disruptions. At the same time, requirements are rising for digital processes, predictive maintenance and suppliers that can bundle parts from different countries of manufacture. - **What role does automation play in reshoring?** When robots and automated plants do most of the work, differences in labour costs between regions become less significant. Industrial automation parts such as sensors, controls and drives thus become the basis for the competitiveness of European sites. Their reliable availability is crucial for stable operation. ### Extreme weather consequences: How climate change is transforming MRO services URL: https://www.ktb-europe.com/en/blog/extreme-weather-consequences-as-climate-change-alters-mro-services/ · 2025-06-05 Extreme weather fundamentally changes MRO services. Industrial MRO Suppliers adapt Automation Parts to the consequences of climate change. Frequently asked questions: - **How does climate change affect the maintenance of industrial plants?** Heatwaves, storms, floods and fluctuating humidity put more strain on equipment than in the past. Components wear out faster, cooling systems operate at their limit and lubricants lose their properties. Maintenance cycles based on average values from previous years therefore often no longer fit. Maintenance has to plan more for weather risks. - **Which components are particularly at risk in hot weather?** Electronic components, drives, bearings, seals and cooling systems are particularly sensitive. In sustained heat, electronics can drift out of their specifications, lubricants lose effectiveness and seals age faster. For affected equipment, heat-resistant materials, enhanced cooling and temperature-stable automation parts are becoming more important. - **How do companies make their spare parts supply climate-resilient?** Proven measures are multiple transport routes, decentralised warehouses, alternative suppliers and greater regionalisation of critical procurement. In addition, weather and climate data feed into demand planning. This makes it possible to provide spare parts even when ports, roads or waterways are blocked by extreme weather. - **Why is corrosion protection becoming more important for industrial components?** More frequent storms, salt-laden air, stronger UV radiation and fluctuating humidity attack materials more severely. This affects housings, sealing systems and electronic components. More robust specifications, better protection ratings and suitable coatings help to prevent failures. What used to seem over-engineered may be necessary today. This should be taken into account in spare parts specifications. ### Industrial Automation Parts: The future of manufacturing URL: https://www.ktb-europe.com/en/blog/industrial-automation-parts-the-future-of-manufacturing/ · 2025-06-05 Industrial Automation Parts revolutionize manufacturing. Automation Parts Suppliers deliver intelligent components for Industry 4.0 production. Frequently asked questions: - **What are industrial automation parts?** Industrial automation parts are components that control and monitor production processes, such as sensors, actuators, controllers, drives and communication modules. They turn rigid production lines into flexible, networked systems. Modern versions have their own intelligence, monitor their condition and exchange data with other components. - **What does decentralised intelligence mean in manufacturing?** Instead of a central computer controlling all processes, intelligence is distributed across many components. Sensors, actuators and controllers make local decisions and communicate directly with each other. This makes systems more robust and flexible: if one component fails, others can take over tasks, and new requirements can be implemented through reconfiguration. - **What is edge computing in industry?** With edge computing, data is processed directly at or near the machine instead of in a central data centre. This reduces latency, increases reliability and enables real-time applications such as quality control or condition monitoring. Automation components thus become small computers with a specialised function. For procurement, this means keeping an eye on software and firmware versions as well. - **What changes when procuring smart automation parts?** Conventional specifications are often no longer sufficient because software updates and firmware versions affect functionality. Lifecycle management is becoming more important, as is compatibility with existing protocols. Buyers should also assess suppliers on their innovative strength and future viability. At the same time, standardised interfaces make it easier to switch to alternatives. ### Self-learning factories: When machines order their own Industrial MRO Suppliers URL: https://www.ktb-europe.com/en/blog/self-learning-factories-when-machines-order-their-own-industrial-mro-suppliers/ · 2025-06-03 Self-learning factories order automatically from Industrial MRO Suppliers. AI revolutionizes MRO sourcing and automation parts procurement. Frequently asked questions: - **What is a self-learning factory?** In a self-learning factory, sensors continuously collect data on vibrations, temperatures, power consumption or noise. Artificial intelligence detects patterns in this data, predicts wear and learns from every operating cycle. This allows maintenance and spare parts requirements to be planned early, in some cases up to the automatic ordering of the required parts. - **Can machines order spare parts automatically?** In advanced plants, this is already possible. If a system detects an impending defect, it can automatically compare quotations and trigger an order. The prerequisites are clean master data, interfaces to suppliers and clear approval rules. However, complex cases, special parts and strategic decisions still require human judgement. - **How is AI changing the procurement of industrial parts?** MRO procurement is shifting from reactive to proactive. Instead of waiting for failures, requirements are forecast and parts are procured in good time. Data on service life and delivery reliability makes quality measurable. To hold their own in automated decisions, suppliers must offer interfaces, transparent availability data and reliable product quality. - **Does human expertise remain important in automated purchasing?** Yes. Automation is suitable for standard procurement, but special cases, discontinued parts, technical clarifications and strategic supplier decisions require experienced people. The role of purchasing is shifting from operational processing to strategic management. What is needed are partners who offer both automated processes and individual advice. ### Saudi Arabia's rise to global procurement hub URL: https://www.ktb-europe.com/en/blog/saudi-arabias-rise-as-a-global-procurement-hub/ · 2025-06-03 Saudi Arabia's rise to a global procurement hub. MRO services and industrial parts sourcing between Europe, Asia and Africa. Frequently asked questions: - **Why is Saudi Arabia becoming a procurement hub?** Saudi Arabia is located between Europe, Asia and Africa and is investing heavily in ports, airports and industrial parks. Simplified rules for company formation and imports as well as free trade zones make the country attractive for international procurement. As part of Vision 2030, it is to become a hub for industrial parts and MRO services. - **What are free trade zones and what advantages do they offer for MRO?** Free trade zones are areas in which goods can be stored, processed and transported onwards under simplified customs conditions. For MRO providers, they are suitable as interim storage to keep spare parts available regionally and to deliver them quickly to different markets when required. The exact rules depend on the respective zone and the destination country. - **What are the challenges of procurement via Saudi Arabia?** Cultural differences, extreme climatic conditions and political uncertainties in the region can make business more difficult. In addition, dependence on oil makes the economy vulnerable to fluctuations, even though diversification is under way. Successful companies take these factors into account in their strategy and rely on local expertise. - **How are sensitive automation parts stored in hot regions?** Electronic and mechatronic components are sensitive to heat and humidity. In hot regions, they are therefore kept in climate-controlled warehouses, protected from dust and temperature peaks. Packaging and transport should also be adapted to the conditions so that sensors, controls and drives are fully functional when installed. ### International MRO Compliance: Customs, standards, certificates URL: https://www.ktb-europe.com/en/blog/international-mro-compliance-customs-standards-certificates/ · 2025-06-03 International MRO Compliance Guide: Customs, Standards, Certificates for Industrial Parts. International Procurement Companies Compliance successfully. Frequently asked questions: - **What does MRO compliance mean in international trade?** MRO compliance covers all regulations that apply to the cross-border trade in spare parts and industrial components: customs classification, rules of origin, standards, certificates and documentation. Even one missing certificate or an incorrect customs code can hold up a shipment for days or weeks. Compliance is therefore a strategic factor in global procurement. - **Why is the correct customs tariff number so important for industrial parts?** The customs tariff number determines the customs duty rate and import regulations. For parts with multiple functions, such as smart sensors, classification is not always clear-cut: electronic device or mechanical component? Incorrect classification can result in back payments, delays or penalties. If in doubt, experts or a binding tariff information ruling can help. - **What is the difference between ATEX and IECEx?** Both govern the explosion protection of equipment and components. ATEX is the legally binding framework in the European Union. IECEx is an international certification system based on IEC standards that is recognised in many countries. There are also country-specific approvals. Which one is required depends on the country of use. - **How can companies turn MRO compliance into an advantage?** Companies that approach compliance proactively enter new markets faster and have fewer problems with audits and regulatory inspections. This includes complete documentation, up-to-date certificates and a process that tracks changes in regulations. Experienced procurement partners supply the appropriate documentation and help overcome regulatory hurdles. ### MRO distributor vs. direct sourcing: which is better? URL: https://www.ktb-europe.com/en/blog/mro-distributor-vs-direct-sourcing-which-is-better/ · 2025-06-03 MRO Distributor vs. direct sourcing comparison. Which strategy is better for Industrial Parts and MRO Suppliers? Advantages and disadvantages. Frequently asked questions: - **What is the difference between an MRO distributor and direct sourcing?** With direct sourcing, a company buys directly from the manufacturer. An MRO distributor, by contrast, bundles products from many manufacturers and serves as a single point of contact for different categories. Direct sourcing offers direct access to technical know-how and can be cheaper for large volumes; the distributor reduces administrative effort and the number of suppliers. - **When is direct sourcing from the manufacturer worthwhile?** Direct sourcing is worthwhile above all for strategic components, regular large volumes of identical parts and highly specialised automation parts. Here, manufacturer relationships bring cost advantages, direct technical support and access to product roadmaps. However, they require intensive maintenance, as each manufacturer has its own processes and minimum order quantities. - **When is an MRO distributor the better choice?** For wear parts, consumables and smaller components from many categories, a distributor is usually superior. Orders can be consolidated, saving time, transport costs and accounting effort. Experienced distributors are particularly valuable for obsolete or hard-to-find parts that manufacturers often no longer support. - **What is a hybrid sourcing approach in MRO?** In a hybrid approach, main components are sourced directly from the manufacturer, while day-to-day business with spare and wear parts runs through a capable distributor or procurement partner. This makes it possible to use the advantages of both routes. A clear division of roles is important so that no duplicate structures or conflicts of responsibility arise. ### The 5 most expensive mistakes when changing automation parts suppliers URL: https://www.ktb-europe.com/en/blog/the-5-most-expensive-mistakes-when-changing-automation-parts-suppliers/ · 2025-06-03 Avoid the 5 most expensive mistakes when changing automation parts suppliers. Tips for successful industrial MRO supplier partnerships. Frequently asked questions: - **What are the most common mistakes when changing automation parts suppliers?** Typical mistakes are unverified assumptions about compatibility, underestimated qualification times, an ignored service level, overlooked hidden costs and a lack of risk diversification. Each of these mistakes can wipe out an expected price advantage, for example through downtime, emergency purchases at high prices or dependence on a single new supplier. A structured switching plan with tests and backup suppliers prevents most of these mistakes. - **How do you check the compatibility of spare parts from a new supplier?** In addition to the part number, voltages, communication protocols, firmware versions and mechanical tolerances should be compared. The safest approach is to test sample parts in a real application before ordering larger quantities. This way, incompatibilities are detected before they bring entire production lines to a standstill or require modifications to downstream systems. - **What hidden costs arise when changing suppliers?** In addition to the unit price, there are minimum order quantities, express freight, additional certification and qualification costs, internal inspection effort and possible price increases after attractive introductory terms. A lack of emergency service can also be expensive. A total cost analysis shows whether the switch is really worthwhile. Once the switch has been made, returning to the previous supplier is often complicated and expensive. That is why all cost items should be compared in advance. - **How can you change suppliers without risk?** A step-by-step approach has proven effective: start with small test orders, gradually expand the scope of supply and keep existing suppliers as a backup. Parallel supply relationships create security and room for negotiation. What matters is not the lowest price but the balance between cost, risk, service quality and delivery capability. ### China's new Silk Road: game changer for MRO China Sourcing URL: https://www.ktb-europe.com/en/blog/chinas-new-silk-road-game-changer-for-mro-china-sourcing/ · 2025-06-03 China's new Silk Road revolutionizes MRO China Sourcing. Shorter delivery times for industrial parts and MRO companies thanks to better logistics. Frequently asked questions: - **What is the New Silk Road?** The New Silk Road, also known as the Belt and Road Initiative, is an infrastructure programme driven by China for trade routes between Asia, Europe and Africa. Particularly relevant for logistics are the freight train connections across Eurasia. They offer an alternative to sea freight and have changed the options for sourcing industrial parts from China. - **How long does rail freight from China to Europe take?** Freight trains on the New Silk Road routes typically take around two to three weeks from China to Europe. This makes them generally much faster than sea freight and cheaper than air freight. The actual transit time depends on the route, border clearance and the current situation in the transit countries. - **What are the advantages of rail over sea freight for spare parts from China?** In addition to the shorter transit time, rail freight is less susceptible to disruptions such as congestion in the Suez Canal or port strikes. Delivery times become more predictable and stock levels can be smaller. Logistics centres along the route also make it possible to store goods temporarily and forward them to different European countries as required. - **What are the risks of MRO sourcing from China?** Challenges include language barriers, different quality standards and cultural differences in collaboration. In addition, there is the political situation in the transit countries along the rail route. Well-thought-out risk management with clear specifications, quality inspections and alternative transport routes, as well as experienced procurement partners, help to limit these risks. This makes China sourcing predictable. ### Predictive maintenance: How AI is revolutionizing your MRO supply chain URL: https://www.ktb-europe.com/en/blog/predictive-maintenance-how-ki-is-revolutionizing-your-mro-supply-chain/ · 2025-06-03 AI revolutionizes MRO supply chain through predictive maintenance. Top MRO suppliers optimize procurement with artificial intelligence. Frequently asked questions: - **What is predictive maintenance?** Predictive maintenance uses sensor data such as vibration, temperature and pressure to continuously assess the condition of machines. AI algorithms detect patterns that indicate wear and predict when a component should be replaced. This makes maintenance plannable before an unplanned breakdown occurs. - **How does predictive maintenance change the MRO supply chain?** When it is foreseeable which parts will be needed in the coming weeks or months, reactive emergency procurement becomes strategic purchasing. Orders can be bundled, shipping routes chosen without time pressure and better terms negotiated. Stock can be held in a more targeted way without critical components running short. - **What data does AI need for predictive maintenance?** Typical inputs are readings for vibration, temperature, pressure, current draw and wear, supplemented by operating hours and maintenance history. The better the data quality, the more reliable the forecasts. External factors such as seasonal fluctuations, production cycles or supply bottlenecks can also feed into planning. Clean master data on equipment and spare parts is an important prerequisite for this. - **What are the challenges of implementing predictive maintenance?** Common hurdles are the integration of different systems, poor data quality and cybersecurity issues. In addition, maintenance, procurement and suppliers have to adapt their processes to predictive requirements. Companies that overcome these hurdles reduce unplanned downtime, lower inventory costs and can plan production more accurately. ### Why American automation parts dominate the European market URL: https://www.ktb-europe.com/en/blog/why-american-automation-parts-dominate-the-european-market/ · 2025-06-03 Why American automation parts are conquering the European market. Innovation, scaling and technology from US Industrial Suppliers. Frequently asked questions: - **Why are American automation parts so widespread in Europe?** US manufacturers are considered particularly innovative, for example in control technology, safety systems and drive technology. The large domestic market enables high volumes, and high investment in research drives new solutions. In addition, many European plants were originally equipped with American components, so spare parts often have to come from the USA. - **Which automation components often come from the USA?** Programmable logic controllers (PLCs), safety systems, drive technology, sensor technology and components for complex control tasks often come from US manufacturers. Many of these products set standards that other markets follow. When expanding existing plants, it is often more economical to stay with the same technology. This makes American manufacturers established partners for many European production lines. - **What should you consider when importing automation parts from the USA?** Factors to consider include longer lead times, customs regulations, possible export controls and different technical standards, for example regarding voltages or approvals. Time differences and communication with US suppliers can also slow down processes. Specialised international procurement partners bundle these tasks and reduce the effort for European buyers. This keeps access to US technology predictable. - **Is it worth sticking with existing US components?** Often, yes. If a plant was originally equipped with American components, switching systems is often more expensive than procuring compatible spare parts from the same technology family. This avoids reprogramming, modifications and new qualifications. What matters is organising procurement in such a way that lead times and customs formalities remain manageable. ### Trusted MRO companies in the USA and how KTB Europe is building the global bridge URL: https://www.ktb-europe.com/en/blog/trusted-mro-companies-in-usa-and-how-ktb-europe-is-building-the-global-bridge/ · 2025-06-03 Looking for trusted MRO Companies in USA? KTB Europe connects you with top American Suppliers and simplifies international sourcing for industrial needs. Frequently asked questions: - **What are the well-known MRO companies in the USA?** Among the best-known MRO suppliers in the USA are Grainger, MSC Industrial, Fastenal, Motion Industries and Applied Industrial Technologies. They cover a broad spectrum, from fasteners and tools through mechanical components to power transmission, fluid power and automation technology. Many also offer warehousing and inventory management services. - **Can a European company order directly from US MRO suppliers?** In principle this is possible, but outside the USA it often involves hurdles: time differences, export regulations, customs, shipping coordination and sometimes limited international delivery options. A procurement partner with experience in US sourcing can bundle these steps and take over communication with American suppliers. This saves time and reduces the risk of delays. - **Why do European factories need spare parts from the USA?** Many machines and systems in European plants were originally developed and built in the USA. Spare parts, upgrades and compatible accessories therefore often have to come from American manufacturers. In some cases, OEM components are only available through US channels, or local distributors have long lead times. - **What should you consider when importing MRO parts from the USA to Europe?** Important points are correct customs classification, export control regulations, complete commercial and shipping documents and checking technical differences, for example in voltages and approvals. Consolidating shipments from several suppliers lowers logistics costs. A partner who understands specifications and OEM requirements avoids incorrect orders. Regular status updates also help to plan maintenance work reliably. ### MRO sourcing that actually works - without the guesswork URL: https://www.ktb-europe.com/en/blog/reliable-mro-sourcing-for-the-industry-ktb-europe/ · 2025-06-03 Problems with MRO sourcing? KTB Europe takes the stress out of finding the right parts-on time, every time, across global supply chains. Frequently asked questions: - **Why is MRO sourcing often so difficult?** Long lead times, unclear specifications, unresponsive suppliers, wrongly delivered parts and customs delays without status updates make procurement difficult. Such problems pile up especially with international suppliers and older equipment. Every missing critical part puts production at risk. A single point of contact who checks specifications and accompanies the process through to delivery provides a remedy. - **What should you do if a spare part is no longer available?** First, all available information should be gathered: part number, manufacturer, drawing, nameplate or a photo. This makes it possible to check whether remaining stock exists worldwide or whether a technically equivalent replacement is an option. It is important that alternatives are checked carefully against the equipment's requirements before use. - **What information do I need for a spare parts enquiry?** Ideally the part number, manufacturer, type designation and quantity. If the number is missing, a drawing, a technical description or a photo of the part and the nameplate will help. Details about the equipment, the application and the required delivery date speed up the review. The more precise the enquiry, the faster a suitable quotation is possible. - **Why is accuracy more important than pure speed in MRO sourcing?** A part that is delivered quickly but is wrong causes returns, additional costs and further downtime. Specifications, part numbers and any alternative spare parts should therefore be checked carefully before ordering. Only the combination of accuracy and short lead time ensures reliable spare parts supply. No guesswork, no costly returns. ### MRO Procurement doesn't have to be complicated URL: https://www.ktb-europe.com/en/blog/mro-procurement-without-headaches-ktb-europe/ · 2025-06-03 Tired of chasing parts? KTB Europe makes MRO Procurement simple, reliable and fast - so your operations never miss a beat. Frequently asked questions: - **What is MRO procurement?** MRO procurement refers to the procurement of spare parts, components and operating supplies for the maintenance, repair and operation of equipment. This includes ordering, technical clarification, comparing quotations, transport coordination, customs formalities and follow-up. Well-organised MRO procurement keeps production lines running and avoids downtime due to missing parts. - **Why does MRO procurement become complicated over time?** As the installed base grows and ages, new suppliers are gradually added, often in different countries and time zones. Stock is recorded inconsistently, backup solutions are lacking and international paperwork takes time. In the end, uncertainty leads to duplicate orders. Bundling with a single point of contact restores clarity. - **What parts does MRO procurement typically include?** Frequently requested items are electrical and automation components such as PLCs, relays and sensors, pneumatics such as valves, fittings and air preparation units, hydraulics such as pumps, cylinders and hoses, as well as bearings, drive systems and safety and control components. Older parts that are no longer in stock are also included. For these, the task is to find remaining stock or tested alternatives. - **What are the benefits of a single point of contact in MRO procurement?** A single point of contact takes care of the search, confirms specifications, obtains quotations and coordinates shipping, customs and delivery. Shipments from several suppliers can be consolidated, which lowers freight costs. Internal teams have fewer suppliers to chase and receive clear delivery dates instead of many individual shipments. Reorders also become easier. ### How KTB Europe keeps Europe's MRO operations running smoothly URL: https://www.ktb-europe.com/en/blog/europe-mro-support-industrial-procurement-ktb-europe/ · 2025-06-03 Do you need MRO support throughout Europe? KTB Europe connects you with the right parts, fast service and expert sourcing in all major industries. Frequently asked questions: - **What causes delays in MRO procurement in Europe?** Common reasons are limited local availability of spare parts, long transport times from overseas, communication problems with foreign suppliers, unclear technical specifications and overly complicated procurement processes. Even one missing small part can stop production. Better organisation of procurement significantly reduces these risks. - **What are the benefits of a single point of contact for MRO procurement?** A single point of contact reduces the number of suppliers, saves time on follow-ups and lowers the risk of downtime. Orders can be bundled, which reduces transport and customs effort. KTB Europe coordinates procurement, shipping, quality control and paperwork so that purchasing teams do not have to coordinate everything themselves. - **What part categories does MRO procurement typically cover?** These include automation components such as controllers and sensors, pneumatics, hydraulics, electrical and mechanical parts, and wear parts such as bearings or seals. Depending on the industry, specialised components are added. It is important that the procurement partner can correctly interpret part numbers, wiring diagrams and manufacturer codes. Only then is the right part delivered the first time. - **How do European plants get spare parts from the USA?** For equipment from overseas, spare parts often have to be sourced from US manufacturers. Hurdles include time differences, language barriers, export regulations and missing specifications. A procurement partner with an international network and export experience can close this gap and combine access to North American stock with support in Europe. ### The changing automotive industry: flexibility in spare parts supply URL: https://www.ktb-europe.com/en/blog/automotive-industry-in-transition-flexibility-in-the-supply-of-spare-parts/ · 2025-02-20 How the transformation of the automotive industry is changing spare parts logistics: From classic components to e-mobility. Frequently asked questions: - **How is e-mobility changing spare parts supply?** Electric vehicles have significantly fewer moving parts than combustion engine vehicles, but introduce new components such as battery modules, power electronics and thermal management systems. At the same time, millions of combustion engine vehicles remain in use. Spare parts supply must serve both worlds in parallel, build new supply chains and still maintain proven structures. Flexibility thus becomes the decisive success factor. - **Which new spare parts matter for electric vehicles?** Key components are battery modules, power electronics, electric motors, charging technology and thermal management systems. As a result, battery manufacturers and electronics specialists are gaining importance as suppliers. Many traditional wear parts of the combustion engine are no longer needed, but the requirements for electronics know-how, handling and documentation are rising. Spare parts logistics must adapt to this without neglecting supply for existing combustion engine vehicles. - **How does data analysis help with spare parts planning in the automotive industry?** Connected vehicles and production plants supply data on wear and usage. Artificial intelligence can use this to forecast demand, and stock levels can be planned in a more targeted way. In some cases, software updates even take the place of replacing parts. Physical spare parts nevertheless remain indispensable, but are scheduled more in line with demand. This reduces both stock shortages and overstock. - **Why is flexibility so important in automotive spare parts logistics?** Regions are developing at different speeds: some are focusing heavily on e-mobility, others continue to rely on combustion engines. Workshops, warehouses and supply chains have to cover both realities. On top of this come new suppliers and requirements for recycling and the circular economy. Only flexible concepts can serve this parallel world efficiently and without supply gaps. ### Industrial pumps: From specification to delivery URL: https://www.ktb-europe.com/en/blog/industrial-pumps-from-specification-to-delivery/ · 2025-02-20 From technical specification to final delivery: How industrial pumps are optimally procured and delivered on time. Frequently asked questions: - **What information do you need to specify an industrial pump?** The most important factors are the pumped medium, its viscosity, its solids content and its chemical composition, plus temperature, head or pressure and the required flow rate. The installation situation and existing connections also play a role. The more complete this data is, the more precisely the right pump can be selected. - **How does the pumped medium affect pump selection?** The medium determines the design, materials and seals. A pump for clear water differs fundamentally from one for abrasive slurries, viscous oils or aggressive chemicals. Solids cause wear, while corrosive media attack materials. That is why the medium should be described as precisely as possible in every enquiry. - **Which materials are used for industrial pumps?** Stainless steel is often used for corrosive media, special alloys for extreme temperatures and wear-resistant coatings for abrasive substances. Seal materials must also match the medium. Every application requires its own material combination, which largely determines the pump's service life, operational reliability and maintenance effort. That is why the original material specifications should always be provided with spare parts for pumps. - **Which documents come with the delivery of an industrial pump?** Technical drawings, data sheets, material certificates, test certificates and operating and maintenance instructions are customary. These documents are important for installation, commissioning, audits and later spare parts orders. For international deliveries, commercial and customs documents are added. Missing documents can delay commissioning and acceptance. It is worth specifying the required documents in the enquiry so that they are delivered in full with the pump. ### Managing Asian suppliers correctly: a practical guide URL: https://www.ktb-europe.com/en/blog/managing-asian-suppliers-correctly-a-practical-guide/ · 2025-02-20 From partner selection to long-term cooperation: discover the success factors for effective management of Asian suppliers. Frequently asked questions: - **How do you work successfully with Asian suppliers?** The foundation is trust, which grows over time. A contract is often seen as the beginning of a partnership, not its conclusion. Clear communication, precise quality definitions, regular personal presence and patience with decisions are crucial. Those who understand and respect cultural differences gain long-term, reliable partners. - **What are the communication differences with Asian business partners?** In many Asian business cultures, communication is more indirect. A yes does not always mean agreement, and silence does not automatically mean rejection. Subtle signals and non-verbal communication play a greater role. It helps to summarise agreements in writing, clarify open questions tactfully and address misunderstandings early. - **How do you ensure quality with suppliers in Asia?** Quality requirements should be defined as precisely as possible, for example with drawings, tolerances, material specifications and inspection criteria. What seems self-evident in Europe often has to be stipulated explicitly, not for lack of ability but because of different perspectives. Sample approvals and pre-shipment inspections provide additional security. - **How do you resolve conflicts with Asian suppliers?** Harmony is important in many Asian business cultures, and direct confrontation often proves counterproductive. Diplomatic discussions that put solutions first and allow everyone involved to save face work better. Patience, personal relationships and a partnership-based approach usually achieve the goal faster than pressure. ### Import compliance: What you need to know about certificates URL: https://www.ktb-europe.com/en/blog/import-compliance-what-you-need-to-know-about-certificates/ · 2025-02-20 From the certificate of origin to the declaration of conformity: get to know the most important certificates for compliant imports. Frequently asked questions: - **What is import compliance?** Import compliance covers all obligations that must be met when importing goods: correct customs tariff classification, proof of origin, declarations of conformity, licences and complete accompanying documents. The aim is legally compliant and smooth importation. Even a missing stamp or an incorrectly completed form can result in goods being stuck in customs for weeks. - **What is a certificate of origin needed for?** A certificate of origin proves the country in which goods were manufactured. This is important for customs duty rates, trade restrictions and possible benefits from free trade agreements. In modern supply chains with components from several countries, the origin is not always obvious. A correctly issued certificate of origin provides clarity for the authorities here. - **What is the difference between CE, UL and CCC?** These are conformity marks for different markets. CE marking indicates conformity with EU regulations, UL is a product safety mark widely used in North America, and CCC is the mandatory certification for certain products in China. Which mark is required depends on the target market and the type of product. - **How do you avoid customs delays?** Prevention is key: check documents in full before dispatch, determine customs tariff numbers correctly, keep certificates up to date and clarify the requirements of the destination country early on. As regulations change constantly, compliance should be understood as a continuous process. Experienced partners with local knowledge help to rule out typical sources of error. ### Saudi Arabia: Local expertise for global procurement URL: https://www.ktb-europe.com/en/blog/saudi-arabia-local-expertise-for-global-sourcing/ · 2025-02-20 Discover the special features of spare parts procurement in Saudi Arabia and how local expertise ensures business success in the region. Frequently asked questions: - **What is Saudi Arabia's Vision 2030?** Vision 2030 is Saudi Arabia's strategic programme to make the economy less dependent on oil. It drives industrialisation, technology hubs and infrastructure. With new production plants and industrial parks, demand for professional MRO procurement also rises, i.e. for spare parts and operating supplies for maintenance. - **What cultural aspects should you consider in industrial procurement in Saudi Arabia?** In Saudi Arabia, business relationships are strongly based on personal trust that grows over time. Decision-making processes follow their own rules, and contacts are maintained in person. Those who understand and respect these principles build lasting partnerships. Technical know-how alone is usually not enough for successful procurement in the region. - **Which quality standards apply to spare parts in Saudi Arabia?** In Saudi Arabia, international standards meet local requirements. Spare parts and components often have to meet both, and certifications should be prepared accordingly. The field is complex and continues to change with industrialisation. It is advisable to clarify the specific documentation requirements with market experts before ordering. - **Why is Saudi Arabia logistically attractive for procurement?** Saudi Arabia is strategically located between Europe, Asia and Africa and has modern ports and developing infrastructure. This creates good conditions for regional logistics. At the same time, local particularities such as climate and regulations require adapted concepts. Local expertise helps to bring global procurement and regional requirements together. ### Containers, customs and co: The crash course for international spare parts logistics URL: https://www.ktb-europe.com/en/blog/container-customs-and-co-the-fast-course-for-international-spare-parts-logistics/ · 2025-02-20 From container loading to customs clearance: learn the key basics for successful international spare parts logistics. Frequently asked questions: - **What is the difference between FCL and LCL?** FCL stands for full container load: a shipper books an entire container for itself alone. LCL stands for less than container load: the goods share a container with shipments from other shippers. FCL pays off for larger quantities and offers more control; LCL is usually cheaper for smaller shipments but can take longer due to handling. - **What documents do you need to ship spare parts internationally?** The basics are the commercial invoice and packing list, often also a certificate of origin or proof of preferential origin. Depending on the goods and destination country, export licences, certificates or declarations of conformity may be added. Every country has its own requirements. An incorrectly completed document can end up costing more than the spare part itself. The documents should therefore be fully checked before shipping. - **What is an HS code?** The HS code comes from the Harmonized System of the World Customs Organization and is used for the internationally uniform classification of goods. The national customs tariff numbers, which determine customs duty rates and import regulations, are based on it. Correct classification is important to avoid delays, back payments or problems with export control. - **What costs are involved in international spare parts logistics?** In addition to transport costs, there are expenses for packaging, insurance, customs duties, import VAT, documentation and, where applicable, storage or port charges. Who bears which costs is governed by the agreed Incoterms. A realistic calculation takes all these items into account and not just the freight price alone. Knowing all the items early avoids surprises when it comes to invoicing. ### Overseas transportation: What to consider for heavy machine parts URL: https://www.ktb-europe.com/en/blog/overseas-transportation-what-to-consider-for-heavy-machine-parts/ · 2025-02-19 From packaging to customs clearance: find out what really matters when transporting heavy machine parts overseas. Frequently asked questions: - **How do you pack heavy machine parts for sea freight?** The packaging must protect against impacts and at the same time prevent corrosion. Salty sea air and condensation are the biggest risks. Common measures are corrosion protection coatings, films, desiccants or dehumidification systems and sturdy, custom-made crates or frames. Professional packaging is the first line of defence for safe overseas transport. - **How is heavy cargo secured on a ship?** The basis is load distribution calculations as well as defined lashing points and special transport restraints. Heavy parts must not move even in rough seas, as otherwise there is a risk of damage to the cargo and the ship. Cargo securing is therefore planned in advance and matched to the weight, centre of gravity and dimensions of the machine part. - **Which documents are needed for overseas shipping of machine parts?** Depending on the goods and the destination country, these include the commercial invoice, packing list, certificate of origin, material certificates, export licences where applicable and, for dangerous goods, the corresponding declarations. Missing or incorrect documents can cause delays of several weeks. The documents should therefore be checked in full before dispatch. Ideally, a checklist is kept for each destination country and agreed with everyone involved. - **Why do temperature fluctuations affect sea freight?** On longer routes, the cargo passes through several climate zones. Large temperature differences cause materials to expand and contract and encourage condensation in the packaging and container. This can cause corrosion or damage to sensitive components. Breathable packaging, dehumidification and, where appropriate, monitoring of humidity and shocks reduce this risk. ### Conveyor belts: Precision in modern industrial production URL: https://www.ktb-europe.com/en/blog/conveyor-belt-precision-in-modern-industrial-production/ · 2025-02-19 From automotive manufacturing to the packaging industry: How modern conveyor systems optimize production processes and increase efficiency. Frequently asked questions: - **What makes modern industrial conveyor belts stand out?** Modern conveyor systems are far more than moving transport surfaces. They communicate with robots, set the cycle of processes, coordinate material flows and adapt flexibly to new requirements. Sensors monitor every movement and intelligent controls optimise the sequences. In this way, they combine high speed with great precision in production. - **How does predictive maintenance help with conveyor systems?** Sensors continuously record data on drives, bearings and belts. Analyses detect unusual vibrations, temperatures or load peaks before a failure occurs. As a result, maintenance and parts replacement can be planned. As conveyor technology is often the backbone of production, this prevents costly downtime of entire production lines. - **Which spare parts are most frequently needed for conveyor belts?** Typical wear parts are belts, rollers, bearings, drives, gearboxes as well as sensors and control components. They are exposed to constant movement and load. A good spare parts strategy keeps critical components available and knows the exact specifications so that replacement parts fit into modular systems without modification. - **Why are modular conveyor systems important for flexible production?** Today, production plants must be able to switch quickly between large-scale series and very small batches. Modular conveyor systems can be reconfigured relatively quickly, and intelligent controls adapt sequences to new products. This makes manufacturing more flexible and reduces changeover times. At the same time, energy efficiency and service life increase thanks to new materials and controls. ### Food grades: standardizing specifications internationally URL: https://www.ktb-europe.com/en/blog/standardize-food-grade-specifications-internationally/ · 2025-02-19 From FDA to EG1935: How the global food industry is harmonizing its technical standards and making MRO procurement safer. Frequently asked questions: - **What does food grade mean for spare parts and seals?** Food-grade components must not release harmful substances in impermissible quantities when in contact with food and must be resistant to the product and cleaning agents. In Europe, Regulation (EC) No 1935/2004 is the relevant standard; in the USA, it is FDA compliance. Corresponding documentation is mandatory for seals, hoses or pump parts in the food industry. - **What is the difference between EC 1935/2004 and FDA compliance?** EC Regulation 1935/2004 generally governs materials and articles in contact with food in the EU. FDA compliance refers to the regulations of the US food authority. Both pursue the goal of food safety but differ in their requirements and documentation. Japan, China and other countries also have their own rules that must be observed when exporting. - **Why does the choice of material depend on the food?** Food contact means chemical interaction. A seal material that works reliably with dairy products can fail with acidic beverages or high-fat products. Temperature and cleaning processes also play a role. That is why operating conditions should always be stated precisely in procurement so that the suitable, approved material is chosen. - **How do harmonised standards simplify spare parts procurement?** Uniform specifications mean fewer tests, faster approvals and simpler stockholding. Companies that produce globally can use identical parts at several sites. Many manufacturers already align themselves with the strictest requirements in each case, and certification bodies partly recognise each other's tests. For MRO procurement, this is a clear efficiency advantage. ### Hot iron: Spare parts procurement for high-temperature applications URL: https://www.ktb-europe.com/en/blog/high-temperature-spare-parts-solutions-for-extreme-conditions/ · 2025-02-19 From industrial furnaces to steel mills: Discover the challenges and solutions in the procurement of spare parts for high-temperature applications. Frequently asked questions: - **Which materials are suitable for high-temperature spare parts?** High-temperature applications mainly use nickel-based alloys, ceramic components and special heat-resistant steels. Each material has its own strengths and limits, for example in terms of thermal expansion, material fatigue or oxidation. The right choice of material determines service life and safety and should always be matched to the specific temperature and load. - **Why do standard components fail at high temperatures?** Ordinary rolling bearings, seals or sensors are designed for moderate temperatures. In extreme heat, materials lose their strength, seals disintegrate and electronics drift out of specification. What works perfectly at room temperature can fail completely at several hundred degrees. That is why furnaces, steelworks and thermal plants require special parts. - **Can spare parts in industrial furnaces be replaced during operation?** This is often necessary, because an industrial furnace cannot simply be cooled down without being damaged by thermal shock. Spare parts must therefore be selected and prepared in such a way that replacement is possible under difficult conditions. This places high demands on material, accuracy of fit, planning and the safety of personnel. - **How can you plan the procurement of high-temperature spare parts?** As special parts often have longer procurement times, forward planning is crucial. Critical components should be identified early, specifications documented properly and sources of supply clarified in advance. Strategic partnerships with experienced procurement specialists and complete quality documentation help to obtain the right certified part quickly in an emergency. ### Understanding Latin America: Successful MRO procurement in the emerging market URL: https://www.ktb-europe.com/en/blog/understanding-latin-america-successful-mro-procurement-in-the-emerging-market/ · 2025-02-19 Discover the special features of MRO procurement in Latin America - from local market specifics to successful procurement strategies. Frequently asked questions: - **What should you consider in MRO procurement in Latin America?** In Latin America, personal relationships and trust count above all, alongside technical expertise. Each country has its own regulatory requirements, quality standards and logistical particularities. Successful MRO procurement combines international standards with local knowledge and relies on long-term partnerships rather than short-term one-off deals. Coordinating customs formalities and documentation with local partners early on avoids delays. - **Which industrial countries in Latin America are particularly relevant for MRO?** Mexico is strong in the automotive industry and closely interlinked with North America. Brazil is an industrial heavyweight with its own quality standards. Argentina combines traditional industry with modern technology, and Chile is considered a pioneer in digitalisation and sustainability. Each market places its own demands on procurement, documentation and logistics. - **Why are local partners important for procurement in Latin America?** Local partners know the markets, mentalities and regulatory requirements. They understand logistical challenges, cultural nuances and regional quality standards. Combined with global know-how, spare parts can be sourced from all over the world and used smoothly on site. Business relationships grow through personal trust. - **How digital is industrial procurement in Latin America?** Latin America frequently leapfrogs traditional stages of development. Communication often takes place via WhatsApp or video call rather than email or fax. New technologies are adopted quickly if they offer clear added value. Modern MRO procurement can use this digital affinity to make enquiries, coordination and deliveries faster and more transparent. ### Paper industry under pressure: Fast solutions for critical parts URL: https://www.ktb-europe.com/en/blog/paper-industry-under-pressure-fast-solutions-for-critical-parts/ · 2025-02-19 When every minute counts: Learn how the paper industry uses innovative MRO strategies to minimize downtime and safeguard production. Frequently asked questions: - **Why is downtime so expensive in the paper industry?** Modern paper machines are very long, several storeys high and run around the clock at high web speeds. If a roll, a bearing or a shaft fails, the entire production comes to a standstill. An unplanned shutdown can therefore cause high costs per hour. Fast spare parts supply and preventive maintenance are crucial for profitability. - **Which spare parts commonly fail on paper machines?** Typical critical parts are rolls, bearings, shafts, seal kits and suction rolls. They operate at temperatures of up to around 140 degrees Celsius, in a humid environment and partly with aggressive chemicals. Standard components are often not designed for this. Spare parts must match these conditions exactly, which is why specialist knowledge is important in procurement. - **How can paper machine failures be prevented?** Numerous sensors monitor roll temperatures, bearing vibrations and felt tensions. With predictive maintenance and digital twins, wear and impending failures can be detected early. In addition, a well-planned spare parts strategy for critical parts and a procurement network that can respond quickly in an emergency help to keep downtime short. - **How is sustainability changing spare parts requirements in the paper industry?** Rising recycling rates and falling energy consumption place new demands on machines and components. There is demand for durable materials, energy-efficient drives and parts that can cope with changed raw materials. At the same time, intelligent systems and targeted stockholding are increasingly replacing large spare parts warehouses. Spare parts supply must continuously adapt to these developments. ### From São Paulo to Shanghai: a screw on a world tour URL: https://www.ktb-europe.com/en/blog/from-sao-paulo-to-shanghai-a-screw-on-a-world-tour/ · 2025-02-19 Follow the amazing journey of a special screw from São Paulo to Shanghai and experience the complexity of global spare parts procurement. Frequently asked questions: - **What to do if the manufacturer of a spare part no longer exists?** In that case, a systematic analysis of the original part helps: dimensions, threads, material and function are precisely recorded and documented. On this basis, a specialised manufacturer can reproduce the part or an equivalent component can be found. Clean technical documentation as well as testing and certification of the spare part before use are essential. - **How does reverse engineering of spare parts work?** In reverse engineering, an existing component is measured and analysed in order to create new manufacturing data from it. In addition to the geometry, material analysis plays an important role, for example with heat-resistant or acid-resistant alloys. The design can often be optimised in the process, for example adapted to different environmental conditions or to newer material standards. - **Why is a simple copy of a spare part not always the best solution?** Operating conditions differ from site to site, for example due to climate, media or load. In addition, better materials are often available today than at the time of the original design. Instead of making a pure copy, the part can be specifically improved. This turns a reproduction into an optimised solution that lasts longer and is better suited to the application. - **Which documents should be supplied with a reproduced special part?** Test reports, material and quality certificates, technical drawings and, where applicable, installation instructions are advisable. These documents prove that the part meets the requirements and make later repeat orders easier. For international deliveries, commercial and customs documents are added. Complete documentation turns a one-off part into a reproducible solution. ### Ten misconceptions about import-export in spare parts procurement URL: https://www.ktb-europe.com/en/blog/ten-mistakes-about-import-export-in-spare-parts-procurement/ · 2025-02-19 From customs clearance to quality assurance: Find out the truth about widespread assumptions in the international spare parts trade. Frequently asked questions: - **Is importing spare parts directly always cheaper?** Not necessarily. Direct imports involve export licences, customs handling, transport insurance, documentation and internal coordination effort. These administrative costs often exceed the hoped-for savings on the unit price, especially for urgent or small orders. A total cost analysis shows which route is actually more economical. Lead time and risk should also be taken into account. - **How is quality ensured in international spare parts procurement?** Professional import-export processes work with multi-stage quality assurance: from supplier selection and evaluation through clear specifications to incoming inspection. Every step is documented. This means international procurement is not a matter of luck but a controllable process with traceable inspections. In addition, material and inspection certificates ensure that customers can trace the quality at any time. - **Why is the cheapest spare part not always the most economical?** The true costs become apparent in operation. A cheap part that has to be replaced more often or causes downtime quickly becomes more expensive than a high-quality original. In addition to price, service life, lead time, documentation and reliability count. What matters is the total cost over the life cycle. - **Is keeping spare parts in stock a waste?** No, not as a rule. Just-in-time does not work for every part. Critical components with long lead times or a high risk of failure should be stocked strategically. What matters is intelligent planning that sets stock levels according to criticality, consumption and replenishment lead time, rather than stocking as little or as much as possible across the board. ### Global machine tool manufacturing: spare parts supply without borders URL: https://www.ktb-europe.com/en/blog/machine-tool-manufacturing-global-spare-parts-supply-without-limits/ · 2025-02-19 From CNC controls to special spindles: How the international machine tool industry secures its spare parts supply worldwide. Frequently asked questions: - **Why is spare parts supply in machine tool manufacturing so demanding?** Modern machine tools work in the micrometre range, main spindles rotate at very high speeds and bearings have to withstand high temperatures for thousands of hours. Even minimal wear can make the difference between a precision part and scrap. Spare parts must therefore fit exactly, be available quickly and offer the same quality as the original. - **What to do when a CNC machine spindle fails?** First, the manufacturer, type and part number of the spindle as well as the machine data should be recorded. Next, stocks available worldwide need to be checked and the fastest transport route chosen. For critical components, it pays to work with a procurement partner with an international network who identifies original or equivalent parts and coordinates logistics and documentation. - **How does predictive maintenance help with machine tools?** Many modern machines are equipped with sensors that monitor vibrations, temperatures and other values. These show when wear parts such as bearings should be replaced before they fail. Maintenance becomes plannable, spare parts can be ordered in good time and unplanned production downtime becomes significantly less frequent. - **What role does additive manufacturing play in spare parts for machine tools?** Additive manufacturing, i.e. 3D printing, can make it possible to produce certain spare parts directly on site and thus shorten transport routes. For highly stressed precision parts such as spindles or bearings, however, conventional manufacturing remains the standard. Together with artificial intelligence in ordering processes and warehousing, it is gradually changing global spare parts supply. ### From the port to the world: Hamburg's role in global spare parts logistics URL: https://www.ktb-europe.com/en/blog/from-the-port-to-the-world-hamburgs-role-in-global-spare-parts-logistics/ · 2025-02-19 Discover how the Port of Hamburg is revolutionizing global MRO supply as a logistics hub and intelligently networking global flows of goods. Frequently asked questions: - **What role does the Port of Hamburg play in spare parts logistics?** The Port of Hamburg is one of the most important ports in Europe and a multimodal logistics hub. Sea freight, rail connections, air freight via the airport and express services interlock here. For spare parts logistics, this means good connections to Scandinavia, Eastern Europe and the Baltics as well as to global shipping routes. - **What transport options are there for spare parts in international trade?** Air freight is suitable for time-critical shipments, sea freight for large volumes and heavy goods, rail connections, for example to Asia, offer a middle ground between time and cost, and express couriers handle particularly urgent small shipments. Which option fits depends on urgency, weight, volume and budget. - **What is multimodal logistics?** Multimodal logistics combines different modes of transport such as ship, rail, truck and aircraft in one transport chain. The aim is to use the appropriate means of transport for each leg. Ports such as Hamburg with strong hinterland connections are ideal hubs for this, where containers are efficiently transshipped and forwarded. - **How is port logistics in Hamburg becoming more sustainable?** Measures include shore power for ships in port, the electrification of port vehicles and handling equipment, optimised traffic flows and emission reduction. Digital technologies such as connected containers and AI-supported route planning also help to make processes more efficient and shorten waiting times. ### MRO in the chemical industry: When spare parts are critical URL: https://www.ktb-europe.com/en/blog/mro-in-the-chemical-industry-when-spare-parts-are-critical/ · 2025-02-19 From acid-resistant seals to explosion-proof drives: How the chemical industry secures its critical MRO supply. Frequently asked questions: - **Why are spare parts particularly critical in the chemical industry?** In the chemical industry, plants operate with corrosive acids, aggressive alkalis, high temperatures and high pressures. If a seal, an O-ring or a pump shaft fails here, the result is not only a production outage but also a danger to people and the environment. That is why every component must match the medium, the process and the safety requirements exactly. - **Which materials are used for chemical-resistant seals and components?** PTFE is often used instead of rubber, Hastelloy instead of stainless steel, or ceramic instead of metal. What matters is resistance to the product itself, but also to cleaning agents, steam and environmental influences. A wrongly chosen material can be destroyed very quickly or fail unnoticed, which is why material selection is a key safety factor. - **Which certificates are important for spare parts in the chemical industry?** Depending on the application, different documentation is required, for example ATEX for potentially explosive atmospheres, FDA compliance for food contact or TA Luft requirements for emission control. In addition, there is batch documentation, material certificates and declarations of conformity. In the chemical industry, the rule is: the paperwork is often just as important as the part itself. - **How is predictive maintenance changing MRO in the chemical industry?** Predictive maintenance replaces rigid maintenance intervals with condition monitoring. Sensors and data analysis show early on when a component is wearing, so that replacement can be planned. This reduces unplanned shutdowns, which can quickly become very expensive in the chemical industry. At the same time, digital material passports, sustainability and global standards are becoming more important in parts selection. ### Consolidation in concrete terms: How 100 suppliers become one solution URL: https://www.ktb-europe.com/en/blog/consolidation-how-100-suppliers-become-one-solution/ · 2025-02-19 Find out how professional supplier consolidation in the MRO sector can simplify your procurement processes and reduce costs in the long term. Frequently asked questions: - **What is supplier consolidation?** Supplier consolidation is the targeted reduction and reorganisation of the supplier base. Instead of managing many individual suppliers for similar material groups, volumes are bundled and processes standardised. The aim is not maximum reduction but a good balance between efficiency and flexibility in procurement. Proven regional structures can be retained in the process. - **What are the benefits of supplier consolidation?** Fewer suppliers mean fewer interfaces, negotiations, orders and invoices. This reduces administrative effort and sources of error. Bundled volumes create resources for better quality assurance and uniform standards. In addition, bundled flows of goods reduce transport effort and environmental impact. Clear contacts and standardised processes also create transparency for procurement, maintenance and accounting. - **Does quality suffer if you have fewer suppliers?** No, often the opposite is true. With bundled volumes and clear contacts, quality standards are easier to define, check and enforce. It is nevertheless important to keep alternatives in view for critical parts, so that no one-sided dependency arises and supply remains secure even in the event of disruptions. - **How do you start supplier consolidation?** It starts with an overview: which material groups are procured, from how many suppliers, and where are there overlaps? Processes are then standardised and volumes bundled in a targeted way. Digital tools help to plan requirements and measure results. Consolidation is not a one-off project but a continuous process. ### The spare parts detective: How we find impossible parts after all URL: https://www.ktb-europe.com/en/blog/the-spare-parts-detective-how-we-can-still-find-the-impossible-parts/ · 2025-02-19 Find out how even the most difficult spare parts are tracked down worldwide - from obsolete components to exotic custom-made parts in the MRO sector. Frequently asked questions: - **Why are some spare parts no longer available?** Common causes are mergers and acquisitions of manufacturers, discontinued production, outdated technologies, relocated production sites and incomplete documentation. With older equipment in particular, this is not the exception but everyday reality. With a systematic search, many supposedly impossible parts can still be procured or replaced with an equivalent. - **How do you find obsolete spare parts?** A systematic approach is successful: analyse technical documentation, search international databases and markets in parallel, check manufacturers' company histories and identify alternative manufacturing options. An international network opens up sources that are not available locally, such as remaining stock in other regions. Technical expertise also helps to identify functionally equivalent alternatives when the original no longer exists. - **What is a technically equivalent spare part?** A technically equivalent spare part performs the same function as the original, matches its design and connections and withstands the same loads, but may come from a different manufacturer. Sometimes it is even an improved version. The prerequisite is a good understanding of the technical function and careful testing before use. - **How can shortages of critical spare parts be avoided?** Critical components should be identified early and their availability checked regularly. Preventive procurement strategies, alternative suppliers and timely evaluation of modern replacement solutions make sense. Pre-qualified partners for custom manufacturing and parallel search strategies help to significantly shorten downtime in an emergency. In addition, every difficult search yields insights for future procurement strategies. ### Expanding Horizons: Opening New Doors in the Middle East – KTB Establishes Presence in the Region URL: https://www.ktb-europe.com/en/blog/expanding-horizons-opening-new-doors-in-the-middle-east-ktb/ · 2023-12-19 Expand your business prospects in the Middle East with KTB! Discover our new presence and be inspired by first-class products and services. Frequently asked questions: - **What is a representative office abroad?** A representative office is a local presence of a company in another country or region. Its main purposes are customer support, building partnerships and establishing a market presence on the ground. For customers, this means shorter communication channels, contacts in their own time zone and a better understanding of regional requirements. - **Why is the Middle East attractive for MRO procurement?** The Middle East has a growing economy, a rapidly developing business environment and numerous new industrial projects. With every new plant, demand rises for spare parts, wear parts and operating supplies for maintenance. A local presence helps to serve this demand reliably and to maintain business relationships in person. - **What does MRO stand for?** MRO stands for maintenance, repair and operations. It covers all spare parts, components and operating supplies that keep industrial plants running, such as bearings, seals, sensors, valves or drives. Well-organised MRO procurement reduces downtime and ensures that maintenance teams receive the parts they need on time. - **What are the benefits of a local team for customers in the Middle East?** A local team knows the region, its business culture and its expectations of collaboration. Combined with international experience, global procurement options can be paired with personal support on the ground. In the Middle East region, KTB relies on a team of local talent and experienced professionals to build strong relationships with customers and partners. ### Avoiding problems in logistics - strategies for procuring individual parts URL: https://www.ktb-europe.com/en/blog/avoiding-problems-in-logistics-strategies-for-the-procurement-of-individual-parts/ · 2022-03-30 Avoid problems in logistics: which strategies secure the procurement of individual parts and keep your supply chains running reliably. Frequently asked questions: - **How can supply chain bottlenecks be avoided?** Proven approaches are flexible supply chains with multiple sources and alternative transport routes, forward-looking inventory planning and close networking with reliable suppliers. If a distributor or a route fails, alternatives are then ready. The procurement of individual parts thus remains independent of individual weak points in the supply chain. - **What is a multiple supply chain strategy?** In a multiple supply chain strategy, several suppliers or supply routes are set up in parallel for important parts or material groups. If a supplier cannot deliver or a transport route is blocked, it is possible to switch to alternatives. This increases security of supply and reduces the risk of production stoppages. - **How do you recognise a reliable procurement partner for individual parts?** Important characteristics are fast and committed order processing, short lead times, good availability with competent customer service, forward-looking inventory planning and flawless quality of the parts delivered. Transparent communication between the customer, the procurement partner and the transport service providers involved is the basis for a smooth process. Many years of experience in international trade are also a good sign. - **How does optimised inventory management reduce logistics costs?** When stock and demand are matched as closely as possible, tied-up capital, warehousing costs and emergency orders decrease. Central warehouse management systems help to consolidate data from different sites and adapt transport routes flexibly. This keeps individual parts available without having to build up unnecessarily large stocks. At the same time, warehouse utilisation is improved. ### ISO standards for containers - These types of containers exist URL: https://www.ktb-europe.com/en/blog/iso-standards-for-containers-these-container-types-are-available/ · 2022-03-22 ISO container standards explained: which container types exist and how they make the global transport of MRO goods and spare parts safe and reliable. Frequently asked questions: - **What are the dimensions of a 20 ft container?** A 20 ft standard container is about 6.06 metres long, 2.44 metres wide and 2.59 metres high on the outside. The interior measures around 5.90 by 2.35 by 2.39 metres, and the volume is about 33 cubic metres. The exact values may vary slightly depending on manufacturer and design, which is why the container data should be checked before loading. - **What do TEU and FEU mean?** TEU stands for twenty-foot equivalent unit and corresponds to the capacity of a 20 ft container. FEU stands for forty-foot equivalent unit, i.e. a 40 ft container. One FEU equals two TEU. The units are used to state cargo volume, vessel capacities and port throughput uniformly. In practice, shipping lines and freight forwarders often quote freight rates and capacities in these units. - **What types of containers are there for special cargo?** In addition to the standard container, there are, among others, high cube containers with greater height, open top containers for oversized goods, flat racks for bulky or heavy machinery, side door containers with a side opening, ventilated containers, reefer containers, and tank and bulk containers for liquids and bulk cargo. The choice depends on the goods, weight and loading method. - **Why are ISO standards for containers important?** Standardised dimensions and corner castings ensure that containers can be transported on ships, trucks and rail wagons worldwide, stacked safely and handled in ports without reloading the goods. Cranes, forklifts and loading platforms are also designed for them. This makes intermodal transport efficient and lowers costs in international logistics. ### TIR Carnet simply explained - Simplifying transit with TIR URL: https://www.ktb-europe.com/en/blog/carnet-tir-simply-explained-simplify-shipping-with-tir/ · 2022-03-15 A Carnet TIR simplifies cross-border shipping – here's how the procedure works and why it speeds up the supply of MRO goods and spare parts. Frequently asked questions: - **What is a TIR Carnet?** The TIR Carnet is an international customs document for the transport of goods by road under customs seal. It is based on the TIR Convention of 1975. Goods are sealed at the start of transport and do not have to be inspected and cleared again in each transit country. This significantly simplifies and speeds up cross-border truck transport. - **Who issues TIR Carnets?** TIR Carnets are issued by the International Road Transport Union (IRU) in Geneva through its national member associations. The associations also provide the guarantee for customs duties within the TIR system. Transport companies must be authorised to use the system and must use vehicles or containers that are suitable for customs sealing. - **What is the difference between a TIR Carnet and an ATA Carnet?** The TIR Carnet is used for the transit of goods by road under customs seal. The ATA Carnet, on the other hand, is intended for temporary import or export, for example of trade fair exhibits, commercial samples or professional equipment that will return. It replaces national customs documents and avoids security deposits for import duties in the destination country. - **What principles apply in the TIR procedure?** The TIR system rests on several pillars: secure vehicles or containers suitable for customs sealing, an international guarantee chain, mutual recognition of customs controls, controlled access to the procedure, and the validity of the TIR Carnet and its carriage with the goods. Together, they ensure that border crossings take place with few formalities. ### Incoterms explained quickly - What are International Commercial Terms? URL: https://www.ktb-europe.com/en/blog/incoterms-quickly-explained-what-are-international-commercial-terms/ · 2022-02-27 Incoterms explained simply: what the International Commercial Terms regulate and what manufacturers and dealers must consider when buying internationally. Frequently asked questions: - **What are Incoterms?** Incoterms, short for International Commercial Terms, are delivery terms published by the International Chamber of Commerce (ICC). They govern who bears which transport costs, risks and obligations in international trade, such as loading, insurance or customs clearance. The current version is Incoterms 2020. In the purchase contract, they are stated with abbreviation, place and version. - **What does EXW (Ex Works) mean?** With EXW, the seller makes the goods available for collection at its premises or another named place. It does not have to load them or clear them for export. The buyer bears all costs and risks from the point the goods are made available. EXW thus means the minimum obligation for the seller and the greatest effort for the buyer. - **What is the difference between FOB and CIF?** With FOB (Free on Board), risk passes to the buyer as soon as the goods are on board the vessel at the port of shipment. The buyer pays for sea transport. With CIF (Cost, Insurance and Freight), the seller pays freight and minimum insurance to the port of destination, but risk likewise already passes on loading on board. - **What does DDP mean in Incoterms?** DDP stands for Delivered Duty Paid. The seller bears all costs and risks up to the named place of destination, including export and import clearance and import duties. The goods are made available ready for unloading. DDP means the maximum obligation for the seller and is particularly convenient for the buyer. ## Products and manufacturers The online catalogue lists 49,393 product pages from 5,637 manufacturers. Parts that are not listed can also be requested. - [Product catalogue](https://www.ktb-europe.com/en/products/) - [Manufacturer index](https://www.ktb-europe.com/en/manufacturer/) - [Product categories](https://www.ktb-europe.com/en/products/category/) - [Pumps](https://www.ktb-europe.com/en/products/category/pumps/): 2,245 products - [Pneumatics & Vacuum](https://www.ktb-europe.com/en/products/category/pneumatics-vacuum/): 2,044 products - [Hydraulics & Fluid Power](https://www.ktb-europe.com/en/products/category/hydraulics-fluid-power/): 1,572 products - [Valves & Fittings](https://www.ktb-europe.com/en/products/category/valves-fittings/): 3,679 products - [Seals](https://www.ktb-europe.com/en/products/category/seals/): 2,643 products - [Bearings & Linear Motion](https://www.ktb-europe.com/en/products/category/bearings-linear-motion/): 2,171 products - [Couplings & Brakes](https://www.ktb-europe.com/en/products/category/couplings-brakes/): 941 products - [Drives & Motors](https://www.ktb-europe.com/en/products/category/drives-motors/): 5,621 products - [Sensors & Measurement](https://www.ktb-europe.com/en/products/category/sensors-measurement/): 6,246 products - [Lubrication & Consumables](https://www.ktb-europe.com/en/products/category/lubrication-consumables/): 526 products - [Control & Automation](https://www.ktb-europe.com/en/products/category/control-automation/): 2,444 products - [Electrical Engineering & Switchgear](https://www.ktb-europe.com/en/products/category/electrical-engineering-switchgear/): 4,202 products - [Cables & Connectors](https://www.ktb-europe.com/en/products/category/cables-connectors/): 2,454 products - [Filtration](https://www.ktb-europe.com/en/products/category/filtration/): 1,117 products - [Fasteners](https://www.ktb-europe.com/en/products/category/fasteners/): 1,118 products - [Tools & Clamping](https://www.ktb-europe.com/en/products/category/tools-clamping/): 2,108 products - [Welding](https://www.ktb-europe.com/en/products/category/welding/): 384 products - [Safety Technology](https://www.ktb-europe.com/en/products/category/safety-technology/): 731 products - [Conveying & Lifting](https://www.ktb-europe.com/en/products/category/conveying-lifting/): 841 products - [Cooling, HVAC & Ventilation](https://www.ktb-europe.com/en/products/category/cooling-hvac-ventilation/): 838 products - [Lighting & Signalling](https://www.ktb-europe.com/en/products/category/lighting-signalling/): 598 products - [Machine Elements & Spare Parts](https://www.ktb-europe.com/en/products/category/machine-elements-spare-parts/): 4,870 products Manufacturers with the most product pages: - [SIEMENS](https://www.ktb-europe.com/en/manufacturer/siemens/): 2,531 product pages - [Bosch Rexroth](https://www.ktb-europe.com/en/manufacturer/bosch-rexroth/): 1,141 product pages - [Festo](https://www.ktb-europe.com/en/manufacturer/festo/): 1,038 product pages - [Rockwell Automation](https://www.ktb-europe.com/en/manufacturer/rockwell-automation/): 791 product pages - [ABB](https://www.ktb-europe.com/en/manufacturer/abb/): 645 product pages - [SKF](https://www.ktb-europe.com/en/manufacturer/skf/): 601 product pages - [Parker Hannifin](https://www.ktb-europe.com/en/manufacturer/parker-hannifin/): 572 product pages - [Schneider Electric](https://www.ktb-europe.com/en/manufacturer/schneider-electric/): 506 product pages - [SEW-EURODRIVE](https://www.ktb-europe.com/en/manufacturer/sew-eurodrive/): 498 product pages - [TÜNKERS](https://www.ktb-europe.com/en/manufacturer/tuenkers/): 443 product pages - [Balluff](https://www.ktb-europe.com/en/manufacturer/balluff/): 350 product pages - [DEMAG](https://www.ktb-europe.com/en/manufacturer/demag/): 343 product pages - [Atlas Copco](https://www.ktb-europe.com/en/manufacturer/atlas-copco/): 341 product pages - [SICK](https://www.ktb-europe.com/en/manufacturer/sick/): 319 product pages - [HYDAC](https://www.ktb-europe.com/en/manufacturer/hydac/): 314 product pages - [KSB](https://www.ktb-europe.com/en/manufacturer/ksb/): 306 product pages - [Phoenix Contact](https://www.ktb-europe.com/en/manufacturer/phoenix-contact/): 281 product pages - [Emerson](https://www.ktb-europe.com/en/manufacturer/emerson/): 268 product pages - [Norgren](https://www.ktb-europe.com/en/manufacturer/norgren/): 259 product pages - [Heidenhain](https://www.ktb-europe.com/en/manufacturer/heidenhain/): 245 product pages - [Endress+Hauser](https://www.ktb-europe.com/en/manufacturer/endresshauser/): 243 product pages - [Eaton](https://www.ktb-europe.com/en/manufacturer/eaton/): 242 product pages - [Tucker](https://www.ktb-europe.com/en/manufacturer/tucker/): 216 product pages - [Trelleborg](https://www.ktb-europe.com/en/manufacturer/trelleborg/): 215 product pages - [Turck](https://www.ktb-europe.com/en/manufacturer/turck/): 202 product pages - [Sandvik](https://www.ktb-europe.com/en/manufacturer/sandvik/): 196 product pages - [Danfoss](https://www.ktb-europe.com/en/manufacturer/danfoss/): 195 product pages - [INA](https://www.ktb-europe.com/en/manufacturer/ina/): 192 product pages - [FAG](https://www.ktb-europe.com/en/manufacturer/fag/): 191 product pages - [SMC](https://www.ktb-europe.com/en/manufacturer/smc/): 184 product pages - [ALLWEILER](https://www.ktb-europe.com/en/manufacturer/allweiler/): 178 product pages - [DUMMYKRE](https://www.ktb-europe.com/en/manufacturer/dummykre/): 176 product pages - [Graco](https://www.ktb-europe.com/en/manufacturer/graco/): 175 product pages - [Rittal](https://www.ktb-europe.com/en/manufacturer/rittal/): 174 product pages - [MAGIASGM](https://www.ktb-europe.com/en/manufacturer/magiasgm/): 174 product pages - [Gates](https://www.ktb-europe.com/en/manufacturer/gates/): 169 product pages - [Vickers](https://www.ktb-europe.com/en/manufacturer/vickers/): 167 product pages - [NIMAK](https://www.ktb-europe.com/en/manufacturer/nimak/): 161 product pages - [IFM Electronic](https://www.ktb-europe.com/en/manufacturer/ifm-electronic/): 161 product pages - [Dürr](https://www.ktb-europe.com/en/manufacturer/duerr/): 161 product pages - [Werner Bayer GmbH Maschinenfabrik](https://www.ktb-europe.com/en/manufacturer/werner-bayer-gmbh-maschinenfabrik/): 160 product pages - [PEPPERL+FUCHS](https://www.ktb-europe.com/en/manufacturer/pepperlfuchs/): 157 product pages - [Stäubli](https://www.ktb-europe.com/en/manufacturer/staeubli/): 152 product pages - [Flender](https://www.ktb-europe.com/en/manufacturer/flender/): 151 product pages - [Fronius](https://www.ktb-europe.com/en/manufacturer/fronius/): 150 product pages - [Schunk](https://www.ktb-europe.com/en/manufacturer/schunk/): 145 product pages - [Igus](https://www.ktb-europe.com/en/manufacturer/igus/): 143 product pages - [ALBANY](https://www.ktb-europe.com/en/manufacturer/albany/): 143 product pages - [Honeywell](https://www.ktb-europe.com/en/manufacturer/honeywell/): 138 product pages - [Röhm](https://www.ktb-europe.com/en/manufacturer/roehm/): 136 product pages - [Omron](https://www.ktb-europe.com/en/manufacturer/omron/): 135 product pages - [Weidmüller](https://www.ktb-europe.com/en/manufacturer/weidmueller/): 134 product pages - [TOX](https://www.ktb-europe.com/en/manufacturer/tox/): 134 product pages - [Rivit](https://www.ktb-europe.com/en/manufacturer/rivit/): 131 product pages - [EUCHNER](https://www.ktb-europe.com/en/manufacturer/euchner/): 130 product pages - [Lenze](https://www.ktb-europe.com/en/manufacturer/lenze/): 127 product pages - [MURR](https://www.ktb-europe.com/en/manufacturer/murr/): 123 product pages - [Fuchs](https://www.ktb-europe.com/en/manufacturer/fuchs/): 121 product pages - [Moog](https://www.ktb-europe.com/en/manufacturer/moog/): 118 product pages - [Lapp",](https://www.ktb-europe.com/en/manufacturer/lapp/): 118 product pages - [SMC Pneumatics](https://www.ktb-europe.com/en/manufacturer/smc-pneumatics/): 115 product pages - [Konecranes](https://www.ktb-europe.com/en/manufacturer/konecranes/): 115 product pages - [Samson](https://www.ktb-europe.com/en/manufacturer/samson/): 111 product pages - [FANUC](https://www.ktb-europe.com/en/manufacturer/fanuc/): 110 product pages - [ALT](https://www.ktb-europe.com/en/manufacturer/alt/): 108 product pages - [HARTING](https://www.ktb-europe.com/en/manufacturer/harting/): 105 product pages - [KTR Systems](https://www.ktb-europe.com/en/manufacturer/ktr-systems/): 104 product pages - [ALBA](https://www.ktb-europe.com/en/manufacturer/alba/): 104 product pages - [Terex Fuchs](https://www.ktb-europe.com/en/manufacturer/terex-fuchs/): 103 product pages - [Grundfos](https://www.ktb-europe.com/en/manufacturer/grundfos/): 103 product pages - [WIKA](https://www.ktb-europe.com/en/manufacturer/wika/): 102 product pages - [Marposs](https://www.ktb-europe.com/en/manufacturer/marposs/): 102 product pages - [Bürkert](https://www.ktb-europe.com/en/manufacturer/buerkert/): 102 product pages - [Bonfiglioli](https://www.ktb-europe.com/en/manufacturer/bonfiglioli/): 102 product pages - [Freudenberg](https://www.ktb-europe.com/en/manufacturer/freudenberg/): 100 product pages - [Ebm-papst](https://www.ktb-europe.com/en/manufacturer/ebm-papst/): 97 product pages - [BRINKMANN](https://www.ktb-europe.com/en/manufacturer/brinkmann/): 97 product pages - [Römheld](https://www.ktb-europe.com/en/manufacturer/roemheld/): 96 product pages - [KUKA](https://www.ktb-europe.com/en/manufacturer/kuka/): 94 product pages - [Merkel](https://www.ktb-europe.com/en/manufacturer/merkel/): 91 product pages - [MIEBACH](https://www.ktb-europe.com/en/manufacturer/miebach/): 90 product pages - [THK](https://www.ktb-europe.com/en/manufacturer/thk/): 88 product pages - [Henkel](https://www.ktb-europe.com/en/manufacturer/henkel/): 88 product pages - [AEG](https://www.ktb-europe.com/en/manufacturer/aeg/): 88 product pages - [Kromschroder](https://www.ktb-europe.com/en/manufacturer/kromschroder/): 87 product pages - [Schmalz](https://www.ktb-europe.com/en/manufacturer/schmalz/): 86 product pages - [SUPFINA](https://www.ktb-europe.com/en/manufacturer/supfina/): 85 product pages - [BARMAG](https://www.ktb-europe.com/en/manufacturer/barmag/): 81 product pages - [Alfa Laval](https://www.ktb-europe.com/en/manufacturer/alfa-laval/): 81 product pages - [Beckhoff](https://www.ktb-europe.com/en/manufacturer/beckhoff/): 80 product pages - [SUN HYDRAULICS](https://www.ktb-europe.com/en/manufacturer/sun-hydraulics/): 78 product pages - [Schmersal](https://www.ktb-europe.com/en/manufacturer/schmersal/): 78 product pages - [FIBRO](https://www.ktb-europe.com/en/manufacturer/fibro/): 78 product pages - [HBM](https://www.ktb-europe.com/en/manufacturer/hbm/): 77 product pages - [WALTHER-PRÄZISION](https://www.ktb-europe.com/en/manufacturer/walther-praezision/): 76 product pages - [CAB-PROD](https://www.ktb-europe.com/en/manufacturer/cab-prod/): 76 product pages - [VERDER](https://www.ktb-europe.com/en/manufacturer/verder/): 75 product pages - [SMC Corporation](https://www.ktb-europe.com/en/manufacturer/smc-corporation/): 75 product pages - [NORELEM](https://www.ktb-europe.com/en/manufacturer/norelem/): 75 product pages - [KNOTHAUT](https://www.ktb-europe.com/en/manufacturer/knothaut/): 74 product pages ## Language versions - English: [https://www.ktb-europe.com/en/](https://www.ktb-europe.com/en/) · https://www.ktb-europe.com/llms.txt · https://www.ktb-europe.com/llms-full.txt - Deutsch: [https://www.ktb-europe.com/](https://www.ktb-europe.com/) · https://www.ktb-europe.com/llms-de.txt · https://www.ktb-europe.com/llms-full-de.txt - Español: [https://www.ktb-europe.com/es/](https://www.ktb-europe.com/es/) · https://www.ktb-europe.com/llms-es.txt · https://www.ktb-europe.com/llms-full-es.txt - Français: [https://www.ktb-europe.com/fr/](https://www.ktb-europe.com/fr/) · https://www.ktb-europe.com/llms-fr.txt · https://www.ktb-europe.com/llms-full-fr.txt - Italiano: [https://www.ktb-europe.com/it/](https://www.ktb-europe.com/it/) · https://www.ktb-europe.com/llms-it.txt · https://www.ktb-europe.com/llms-full-it.txt - Português: [https://www.ktb-europe.com/pt/](https://www.ktb-europe.com/pt/) · https://www.ktb-europe.com/llms-pt.txt · https://www.ktb-europe.com/llms-full-pt.txt - 中文: [https://www.ktb-europe.com/cn/](https://www.ktb-europe.com/cn/) · https://www.ktb-europe.com/llms-zh.txt · https://www.ktb-europe.com/llms-full-zh.txt ## Optional - [Short index](https://www.ktb-europe.com/llms.txt) - [XML sitemap](https://www.ktb-europe.com/sitemap_index.xml) _Generated: 2026-10-24_