Impact of Core Material Grades on the Performance of Variable Speed Induction Motors Fed by Inverters

In this paper, we investigate the variation in performance of variable speed induction motors fed by inverters with grades of core materials used for stators and rotors from both results of measurement and finite element analysis. Identical shaped stator/rotor cores are manufactured by using several kinds of electrical steel sheets from low to high grades. Then, the characteristics of these motors are measured. Finite element analysis is applied to these motors to understand the measured results by separating losses and torques according to origins. The measured motor characteristics are found to be in good agreement with the results of the analysis. The analysis reveals the variation in each loss component with electrical steel sheets. Finally, the strong and weak points of the application of high-grade electrical steel sheets to the variable speed induction motors are discussed.