For plant engineers, finding new ways to avert costly failures in their facilities is practically second nature. Particularly when it comes to industrial maintenance, thermography testing is one approach that's become much more popular over the last five years or so. Used as a condition-monitoring technique, thermal imaging enables users to identify potential areas of equipment failure and limit downtime.As part of a comprehensive preventive or predictive maintenance program, it's a good idea to create a regular inspection route that includes scanning systems associated with critical assets those whose failure would threaten people, property, or product. That way, you'll have baseline images for comparison, which will help you determine whether or not a hot spot is unusual and requires repair as well as verify that repairs are successful.Consider using key safety, maintenance, and operations personnel to quantify warning and alarm levels for critical assets. In addition, the InterNational Electrical Testing Association (NETA) provides guidelines to determine when immediate repair is required by comparing the difference in temperature (?T) between similar components under similar loading. NETA recommends making immediate repairs when the difference in temperature exceeds 15C (27F).Whenever you use a thermal imager and find a problem, document your findings in a report that includes a digital photograph as well as a thermal image. That's the best way to communicate problems you find and to suggest repairs. With the aid of a handheld thermal imager, you can check all electrical panels for loose and corroded connections, and scan critical electrical systems including motor control centers, motor/drive combinations, pumps, fans, compressors, electrical connections, industrial gearboxes, and transformers. Let's take a look at how you can boost your predictive maintenance strategy in each of these areas.Motor control centers. Thermal imaging can be used to evaluate the operating condition of the components within motor control centers (MCCs) by comparing their relative temperatures under load. A typical MCC is a standalone arrangement with one or more combination motor control units for controlling an AC motor in a specific application. Each unit has an external disconnect, branch circuit and motor overcurrent protection, and a magnetic motor starter along with pilot devices located on the panel door.Underwriters Laboratory (UL) allows panelboards and switchboards for branch-circuit protection within an MCC, provided they do not constitute a major portion of the center. That means a complex MCC can contain bus bars, controllers, starters, contactors, relays, fuses, breakers, disconnects, feeders, and transformers.Use your thermal imager to scan all components and connections within MCCs with the enclosures open and the equipment running. Measure the load at the time of each scan so that you can properly evaluate your measurements against normal operating conditions.In general, look for components that are hotter or cooler than similar components under similar loads, which can identify broken or undersized wires, defective insulation, faulty (corroded, too loose, or over tightened) connections and electrical unbalance among phases.Be aware that connection-related hot spots usually (but not always) appear warmest at the spot of high resistance, cooling with distance from that spot. Unbalance, whether normal or out of specification, will appear equally warm throughout the phase or part of the circuit that is overloaded. Harmonic unbalance creates a similar pattern. Note: A cooler-than-normal circuit or leg might signal a failed component.Since all electrical currents produce some heat, temperature alone is not an indicator of problems. Equally, warm conductors in all three phases represent a good pattern. Differentiation between phases should be investigated.Motors. Thermal images of electric motors reveal their operating conditions as reflected by their surface temperature, capturing infrared temperature measurements of a motor's temperature profile as a two-dimensional image. Unlike an infrared thermometer that only captures temperature at a single point, a thermal imager can capture temperatures at thousands of points at once, for all of the critical components: the motor, shaft coupling, motor and shaft bearings, and the gearbox.Ideally, you should check motors when they are running under normal operating conditions. All motors should list the normal operating temperature on the nameplate. And while the infrared camera cannot see the inside of the motor, the exterior surface temperature is an indicator of the internal temperature. As the motor gets hotter inside, it also gets hotter on the outside surface.