Reliability Oriented Design of Low Voltage Electrical Machines Based On Accelerated Thermal Aging Tests

In transport applications, electrical machines (EMs) are required to be highly reliable, in order to fulfill the intended mission profile over the expected lifetime. This task has been conventionally addressed through the adoption of safety-factors that might lead to an over-engineered EM. Only recently, few works have started championing a paradigm shift towards physics of failure methodologies, which allow to achieve an appropriate trade-off between optimal performance and demanded reliability figures. Thus, this paper proposes a reliability oriented methodology for low voltage (LV) EMs and outlines its critical implementation steps. Accelerated thermal aging (ATA) tests are preliminarily performed on custom made samples to assess the aging trend of the inter-turn insulation. The thermal endurance graph at different percentile values is then determined and a lifetime model suitable for variable duty motors is developed. Finally, this model is used to predict the inter-turn insulation cycles-to-failure of an EM installed on full-electric vehicle.