An Investigation of the Impedance Spectroscopy Suitability for Traction Motor Windings Insulation Health Assessment

Stator inter-turn faults are among the most critical faults in electrical machines due to their fast evolution into a catastrophic breakdown. This type of fault is especially critical for electric vehicle applications because it may compromise human safety. This fault is directly linked to the reliability of the electric insulating system. In this paper, the authors investigate the impact of accelerated ageing on the dielectric properties of traction motor windings insulation. The aim is to understand if the impedance spectroscopy is reliable for assessing the health of the insulation and lead to appropriate diagnostic outcomes. The results indicate that the impedance spectroscopy should be used with caution and secondary analysis and criteria need to be developed.