Field Analysis of Polyphase Hysteresis Motor

A comprehensive theoretical field model has been developed for hysteresis motors. Using the stator current sheet technique, the motor field equations are rigoriously derived for the air gap and hysteresis ring regions. The analysis takes into account the contribution of the reaction field of rotor magnetization to the primary air gap field due to stator current sheets alone. Unlike induction motor theory, this reaction effect represents reality in the analysis of hysteresis motor. Analytical expressions for the air gap power and rotor hysteresis power loss for the sub- synchronous mode of operation are obtained in terms of machine stator and hysteresis rotor parameters. This analysis furthermore provides a deeper insight into the sub-synchronous energy conversion process in hysteresis motors. The validity of the theory is demonstrated by comparing the experimental and theoretical results. Al though a polyphase motor is used in the analysis, the theory is applicable for single phase motors.