Thermal Imaging and Industrial Maintenance Best Practices

Justin Sheard, Fluke Corporation
Tags: infrared thermography, predictive maintenance, condition monitoring

Monitoring equipment performance with thermal imaging cameras can reduce the likelihood of unplanned downtime due to equipment failure, reduce reactive maintenance fees and equipment repair costs, and extend the lifespan of machine assets.

Thermal imaging is great for spotting a lack of uniformity in equipment by indicating hot and cold spots in surface temperature, through infrared image capture. Heat is often an early symptom of equipment damage or malfunction, making it important to monitor in preventive maintenance programs.

Thermal Inspection Methods

Because there is no universal solution for all infrared inspections with a thermal camera, you need to match your method to the equipment being inspected and level of detail required. There are three typical methods that cover most situations: baseline, thermal trending, and comparative.

Asset Maintenance and Troubleshooting

Motors and Drives

Electric motors are the backbone of industry. Thermal cameras are very useful for both troubleshooting problems as well as for condition monitoring, for long-term preventive maintenance. Using a handheld thermal camera, you can capture infrared temperature measurements of a motor’s temperature profile as a two-dimensional image.



If you suspect overheating is the result of one of the following, consider the action described:

Electrical Panels

Thermal images are an easy way to identify apparent temperature differences in industrial three-phase electrical circuits, compared to their normal operating conditions. By inspecting the thermal gradients of all three phases side by side, technicians can quickly spot performance anomalies on individual legs due to unbalance or overloading.



Check panels and other connections with the covers off. Ideally, you should check electrical devices when they are fully warmed up and at steady state conditions with at least 40% of the typical load. That way, measurements can be properly evaluated and compared to normal operating conditions.

When a thermal image shows an entire conductor is warmer than other components throughout part of a circuit, the conductor could be undersized or overloaded. Check the conductor rating and the actual load to determine which is the case.

Steam Systems

Thermal images of steam systems reveal the comparative temperatures of system components and thereby indicate how effectively and efficiently steam system components are operating.



Look for an upstream problem—a closed valve, pipe blockage, etc. If both the inlet and the outlet temperatures are the same, the trap probably has failed open and is blowing steam into the condensate line. This keeps the system operating but with significant energy loss. Low inlet and outlet temperatures indicate that the trap has failed closed and condensate is filling the trap and the inlet line.

Roller, Chain, and Belt Conveyors

Thermal imaging is especially useful for monitoring low-speed mechanical equipment like conveyors. Overheating signals the impending failure of many different electrical and mechanical conveyor components, from motors, gearboxes, and drives to bearings, shafts, and belts.



For monitor some conveyor components (e.g., drives), thermal imaging complements other condition monitoring technologies such as oil analysis, vibration monitoring, and ultrasound. However, tow chains under the floor and elevated chain conveyors, including power-and-free conveyors, are often most easily and effectively monitored from a distance using thermal imaging. Check the chain as well as the roller turns and curves. Overheating chain or rollers may signal lubrication or wear problems.

Thermal imaging is an ideal monitoring technique for powered roller conveyors, roller-bed belt conveyors and bulk-handling belt conveyors with idlers, whether these conveyors are elevated or not. On such conveyors, the bearings are usually too small, too numerous or too inaccessible—perhaps all three—to be effectively screened by other strategies.