Predictive Monitoring of Turn-to-Turn Insulation in Single Tooth Coils

This work focuses on the investigation on both local and global dielectric properties for a random wound single tooth winding, which represents a segment of the in-field electrical machine used on an Hybrid Wheel Loader. Finite Element Analysis (FEA) is used to predict the temperature stress while loading and illustrate the influences of dielectric properties (i.e. conductivity and dielectric constant) on the global dielectric properties (i.e. dielectric resistance and capacitance). Based on the thermal simulation, dielectric response measurements are performed in the most thermally stressed region, which is between two randomly grouped winding strands. Both DC and AC dielectric characteristics are measured and analyzed, which provide a good insight to understand 1) the dielectric response 2) temperature dependent dielectric properties for strand to strand insulation. This provides a great foundation for the future work on stator winding degradation.