Effect of High-Strength Electrical Steels on the Electromagnetic-Mechanical Performance of High-Speed Traction Motors

With an increase in demand for the maximum speeds of electric motors exceeding 20,000 rpm, there is an ongoing initiative to improve the motor's efficiency and reduce its overall weight. For high-speed applications, the rotor is subjected to high centrifugal forces during rotation, resulting in high stresses. Advancements in materials engineering have introduced new grades of electrical steel that offer acceptable trade-offs in electromagnetic properties while maintaining high mechanical strength. This paper evaluates the impact of these high-strength electrical steels on both mechanical and electromagnetic performance in traction motor applications using finite element analysis. Enhanced mechanical properties enable higher operational speeds without compromising structural integrity, thereby allowing for a reduction in stack length and ultimately lowering the overall cost of the traction motor. This study demonstrates that a cost savings of up to 25% is attainable by the utilization of high yield strength electrical steel, enabling a maximum rotor speed of 21,000 rpm while maintaining the same rotor structure.