A Novel Insulation Aging Test System Under Continuous High Voltage Square Wave Pulses for Inverter-fed Traction Motor

Inverter-fed traction motors used in express locomotive experience the continuous square wave pulses voltage with significant harmonics and transients. The insulation aging mechanism under continuous square wave pulses is very different with the aging mechanism under sine waves. In order to study the influence of continuous square wave pulses voltage output by inverter, it is necessary to establish an appropriate method for investigating the ageing properties and failure mechanism of magnet wire insulation for the inverter-fed traction motor. However, the voltage values of existing pulse power sources are below 5kV, it can't meet the demands. In this paper, a new type of high frequency and high-voltage pulse power source is designed to investigate the influences of continuous square wave pulse voltage on insulation of traction motors used in express locomotive. It makes up of a square wave pulse generator and a high frequency transformer. Test results show that the square wave pulse power source can meet the test requirements of traction motor insulation evidently.