Motor J-Box Thermography Route

The AC induction motor is a critical component of our wood processing operation. For years we have performed infrared surveys on the distribution side, from the pad mount transformer downstream to the Motor Control Center. We also performed mechanical IR surveys on our key equipment, primarily air compressors and fans. We recently included the motor junction box as an additional component in our surveys. All of these surveys, however, overlooked the motor lead connections. The majority of the motors are in an outside environment, subject to vibration, temperature changes and humidity. We experienced numerous failures which went undetected, causing significant downtime of entire plants. Our solution was simple: We built guards. The guards shield motors from outside elements so we can safely and accurately take readings with an IR camera. The findings have helped us improve reliability on some of our most critical equipment. This paper will explain the methods we used to ensure the safety of our thermographers and electricians while protecting motors from the elements. In addition, motor leads are now surveyed at operating load and temperature, allowing us to acquire useful IR data.