Measurement of Voltage distribution and Partial Discharge Position in Inverter-fed Rectangular Wire Motor

In inverter- fed motors, enough insulation film thickness is required to prevent partial discharge in the air gap between coils caused by high voltage. In this paper, for better insulation design of a motor, the behavior of surge voltage in the motor and position of partial discharge caused by surge voltage is discussed. The partial discharge occurrence position is evaluated by detection of the electromagnetic wave using multiple antennas when the voltage is applied to single phase coils of the motor. The comparison of voltage distribution and partial discharge point indicates the surge voltage waveform between coils due to resonance differs intricately for each coil. Moreover, partial discharge occurs in the part where the voltage value between coils is large.