Computation of hysteresis motor performance including negative sequence excitation

Torque/slip characteristics for a hysteresis motor with a cobalt-steel rotor are computed using a multilayer electrical circuit concentrated-parameter analogue to represent the electromagnetic field equations. Hysteresis in the material is represented using a digital simulation technique together with an empirical method for the inclusion of the rotational hysteresis component. Reverse acting torques due to the backward rotating fields produced by negative phase sequence excitation are examined. It is shown that the forward torque is altered by the backward rotating field owing to the nonlinearity of the rotor material