Predictive reliability and lifetime of insulation in electric motors

The electrification of heavy-duty vehicles and marine transport places increasing demands on the performance, reliability and lifetime of electric motors. Modern oil-cooled electric motors with so-called hairpin windings are exposed to high electrical and thermal stresses, particularly when operated with fast-switching inverters. This increases the risk of partial discharges, which can gradually degrade the motors' electrical insulation and ultimately lead to operational disruptions or failures.

The PRIMA project develops new physics-based methods to understand and predict how electrical insulation in advanced traction motors ages and degrades under realistic operating conditions. Particular attention is given to the interface between the conductors' enamel insulation and the impregnation resin, where electrical, thermal and mechanical stresses interact and can initiate degradation.

By combining experimental studies, advanced material characterization and physics-based modelling, the project investigates the relationship between partial discharges and changes in the properties of insulation materials. A key focus is the voltage level at which partial discharges begin to occur, known as Partial Discharge Inception Voltage (PDIV), and how it is influenced by material properties, manufacturing variations and operating conditions. The results will be used to develop digital twins capable of predicting the lifetime of insulation systems.

RISE contributes expertise in high-voltage testing, partial discharge diagnostics and material degradation under realistic operating conditions. Together with the project's industrial and academic partners, knowledge will be developed on how insulation materials and manufacturing processes can be optimized to improve the reliability of electric motors.

The project results are expected to provide industry with improved tools for material selection, design, quality assurance and predictive maintenance. By enabling more reliable lifetime assessments, the project can contribute to fewer unplanned shutdowns, lower lifecycle costs and more resource-efficient electric propulsion systems for future transport applications.