Techniques for off-line measurement and analysis of PD pulses in inverter-fed induction motors

Results of offline measurements of partial discharge in AC motors supplied by PWM inverter is presented in this paper. The test circuit is based on a differential configuration and is optimized resorting to signal processing techniques. The measured signals are sent to a personal computer via an A/D board for further processing through time/frequency transformations. The obtained results can be employed to infer the status of induction motor insulation subjected to PWM supply voltage.