Calculation of cogging torque in squirrel-cage induction motors

This paper presents the analytical method and finite element method(FEM) for calculation of cogging torque in squirrel-cage induction motors. The analytical method is based on inductance coefficient and permeance wave technique, taking into account effects of slotting, saturation and winding connections. Based on finite element method, classical Maxwell stress method, modified Maxwell stress method and virtual work method are used to calculate cogging torque. Calculation results obtained by the analytical method and those obtained by finite element method are compared. The results reveal that the three methods in FEM give approximately the same results and FEM is better than the analytical method in calculating cogging torque.