Infrared Electrical Inspections for Industrial Plants

Using thermal imaging technology, you can reduce unplanned downtime occurrences caused by equipment failure. You can also cut down reactive maintenance fees and the repair cost of various equipment. Timely repairs in response to issues located during a thermal inspection can also ensure the long life of your machine assets.

Thermal imaging is very practical for locating anomalies in equipment, with the thermal imaging cameras helping identify hot and cold spots in surface temperatures indicating leakages. The release of heat indicates equipment damage or malfunction, giving thermal inspections a vital role in planning programs for preventive maintenance.

Methods of Thermal Inspection

While using a thermal camera for infrared inspections, you’ll find no universal solutions. Therefore, the method you are to adopt needs to sync with the equipment you want to inspect and how much detail you seek. Baseline, thermal trending, and comparative are the three typical methods suitable for most situations.

Baseline Thermography: This is an effective method suitable for virtually all applications. This method shall require you to scan the equipment during its commissioning or sometime later when operated under standard conditions. The results of this inspection are to be used as a reference point for inspections carried out in the future during the equipment’s lifetime. You may compare the findings on your camera or your PC using software with the initial findings taken as the reference point to locate anomalies in the equipment’s functioning.

Thermal Trending Thermography: After identifying the baseline, you can check temperature distribution in particular components over time using thermal trending inspections. It helps you identify any trend of deterioration in equipment over time, helping you know when to schedule downtime maintenance.

Comparative Thermography: This method involves scanning similar components in equipment under the same conditions and then comparing the results. It works on the assumption that identical components display a similar temperature profile in similar conditions. You can spot an anomaly easily if you are using two to three components. However, there’s one complex issue you’ll have to handle- the actual temperature difference you are to consider as an anomaly varies based on the components you are comparing.

How to Maintain Some Vital Assets and Troubleshoot

  • Motors and Drives: Electric motors are the foundation industry stands on. Thermal cameras play a pivotal role in troubleshooting problems and monitoring the condition of the motors, helping carry out preventive maintenance. Handheld thermal cameras allow you to capture a motor’s infrared temperature measurements in the form of a two-dimensional image.
  • What you should check: In ideal situations, you should check the motors while keeping them running under standard operating conditions. Thermal cameras can capture the surface temperature of multiple points simultaneously, which makes it different from an infrared thermometer, which captures the temperature of a single point. You should check the temperature of all the critical components like the motor, shaft coupling, bearings, and gearbox at the same time. Please bear in mind that there’s a specific internal temperature each of the motors is designed to operate at. The components should never be as heated as the motor housing.
  • You should look for: You should mention the average operating temperature of all the motors on the nameplate. The external temperature is an ample indication of inside temperature, even though thermal cameras can’t see the motor’s insides. The motor gets hot outside as well when it gets hotter inside. Such anomalies in surface temperature tell an experienced thermographer about issues like inadequate airflow, shaft coupling problems, insulation degradation, and impending bearing failure that exist or may crop up in the motor’s rotor or stator.

Here’s the action you should take for the situations mentioned above

  • Inadequate airflow: If you can manage a short shutdown that doesn’t affect the plant’s operations, you should turn off the motor and clean the air intake grills. You should then schedule a thorough cleaning when you plan the next shutdown.
  • Shaft coupling problem: Vibration analysis in most instances confirms misalignment in a coupling. If a shutdown is possible, a laser alignment device’s dial indicators can be used for a then and there correction of the misalignment.
  • Insulation degradation: You shall have to de-rate the motor as per NEMA standards if it doesn’t significantly impact production. After this, you’ll have to generate a work order for arranging a quick replacement of the motor.
  • Impending bearing failure: You’ll need a general maintenance order for replacing or lubricating a bearing when thermal imaging indicates overheating in it. Carry out a vibration analysis as well, so you can decide what can be done best.
  • Steam Systems: You can gauge how effectively the steam system components work by thermal imaging, which indicates the components’ comparative temperatures.
  • You should check: The detection rate of problems in steam systems multiplies when you use both thermal inspections and ultrasound. You’ll have to check the steam transmission lines, all steam traps, as well as underground lines. Additionally, you should also check heat exchangers, boilers, and other equipment using steam.
  • You should use thermal imaging and ultrasonic testing to locate steam traps that have failed to open or close. You should look for: The purpose of having steam traps is to remove condensate and air from the systems. High inlet temperature coupled with a low outlet temperature indicates the correct functioning of the trap. However, if the inlet temperature recorded is considerably less than the system temperature, it indicates steam not entering the trap.

Conclusion

Thermal imaging is a very effective tool in plant maintenance and inspection. By indicating leakages in the form of temperature anomalies, it alerts you about components needing immediate attention so you can prevent unscheduled downtime. Our article sheds light on how you should maintain some of the vital assets in your plant and the action you should take when issues are identified. As the saying goes – “A stitch in time saves nine” timely detection of issues in your plant components helps avoid costly repairs later.

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