On the effects of high-temperature-induced aging on electrical machine windings

In this paper, the effects of a high temperature storage on phase inductance, ohmic and iron losses and coil quality of the stator windings are investigated. For better significance, 19 stators with different impregnation materials and methods are tested on Arrhenius basis for a useful life of 8000 hours. The results clearly show that, although the insulation resistance and phase-to-ground dissipation factor worsen as expected from literature, no impact of the insulation embrittlement on ohmic and AC winding resistance, inductance or dissipation factor can be observed. As a consequence, it is not necessary to include high-temperature-based aging into standard models for electrical machines. The only measurable high-temperature-induced aging effects seem to concern the winding insulation.