In brief
Infrared thermography is a non-contact measuring method that uses a thermal imaging camera to visualise temperature distributions and detect overheating components early.
Contents
What is Infrared thermography?
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: maintenance and procurement
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.
Synonyms and abbreviations: 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.