Investigation on Insulation Failure Mechanisms of Stators used for E-Mobility

The upheaval in industry and in the private sector towards electrification and mobilization is associated with the increasing use of electric motors, for example in cars, bicycles, robots, wheelchairs and also in the aircraft industry. Therefore, developments on the production technology for E-motors are necessary in order to meet the increasing demand and to ensure all actual requirements. This development includes the quality and service life. This contribution describes insulation failure mechanisms that can occur in a stator and examines the effect on various diagnostic options. For this purpose, faults in the slot insulation of a stator are modeled and then investigated with regard to partial discharges and insulation resistance. The modeled faults, holes, cracks, conductive particles and the layer thickness, are varied in size and amount. In this study it was shown, that insulation resistance provides more valuable information about the magnitude and number of faults than PDIV.