Design Considerations for High-Temperature Motors for Special Applications

The power density of electrical machines has increased significantly over the last century due to tremendous advancements in material science, particularly in the electrical insulation systems (EIS) domain. However, both industry and academia have limited experience with the design and production of electrical machines operating at winding temperatures above 240°C, owing to the application threshold temperature of EISs and other challenges associated with design, manufacturing, and testing. This article examines the key considerations for addressing these challenges and surpassing the prevailing threshold temperature. The design approach for these specialized machines, capable of continuous operation at 350°C, is presented. Additionally, the impact of temperature on various motor performance metrics is examined using finite element analysis (FEA) and further validated through an experimental study. Surpassing the temperature rise limit of conventional polymer-based EIS will enable higher power density, thereby reducing the consumption of critical and precious materials and helping the motor industry better align with green manufacturing initiatives. Furthermore, as components and systems related to the cooling circuit become redundant, system reliability and availability will improve, which is essential for the nuclear, aerospace, medical, and transportation industries.