Starting torque analysis of cage induction motor using permeance model considering magnetic saturation by leakage flux

This paper describes a method to analyze harmonic components of the air-gap flux density distribution and the torque of 3-phase cage induction motors, considering the influence of circumferential slot arrangement, stator winding pattern, and distribution of air-gap permeance due to leakage flux. The proposed method is based on an analytical model of the permeance and magnetomotive force distributions. The proposed method considers magnetic saturation caused by the main and leakage magnetic flux. As a result, the harmonic components of the torque in the starting condition can be determined quantitatively. From the comparison between the calculated and experimental results, the proposed method is shown to be appropriate and useful for quantitatively estimating harmonic torque for cage induction motors.