Effect of Bending Stress on Magnetic Properties of Thin Magnetically Soft Wire for Motor Design

Abstract In recent years, the electrification of automobiles and the studies to electrify also aircraft have accelerated as a measure against global warming, necessitating improvements in motor efficiency and power density to reduce CO 2 emissions. The possibility to increase the motor’s rotation speed is, a key factor in enhancing power density. However, high-speed rotation means that higher operative frequency are used thus increasing eddy currents and iron loss. To mitigate these effects, thin ribbons, powders, and thin magnetically soft wires are effective stator materials. Yet, the magnetic properties of these materials deteriorate when bent to form motor components, making it essential to consider the impact of bending stress on magnetic properties during the motor design stage. This study investigates the effect of bending stress on the magnetic properties of thin wire magnetic materials (electrical steel) using the coaxial H coil method. The magnetic properties and iron loss curves for various bending radii R were determined using this method. The findings of this study will influence the design of motors using thin wire magnetic materials.