9623119 McInerny This research planning grant will address the questions of: (1) what signal or quantities should be measured, and (2) what signal processing methods should be used to detect insulation breakdown in AC induction motors that use pulse width modulation (PWM) control. While it is a powerful speed control method with many commercial applications, PWM control causes electrical harmonics when used on old motors or new high efficiency motors not designed for adjustable speeds. These harmonics lead to motor losses, torque pulsations, overheating, acoustical noise and mechanical vibration, and ultimately the destruction of the electrical insulation and the motor. Dynamic analysis and preliminary experiments indicate that signature analysis may be a useful way to track and monitor the condition of these systems. Kalman filtering or spectral techniques, such as wavelets, are promising methods. Because PWM control is common in drive systems and modern air handling systems, diagnostic methods to reliably track insulation degradation in mechanical equipment will impact both productivity and health in factories and offices. ***
