Analysis and Determination of Ring Flux Distribution in Hysteresis Motors

This paper presents the results of an experimental determination of the flux distributions inside different layers of the hysteresis ring. The flux measurements were made by means of search coils embedded in the stationary ring of an inside-out three phase hysteresis motor. It is found that the flux distribution is quite nonuniform and there exist phase shift between the flux waveforms at various ring layers. There are evidences of rotational hysteresis effects on the ring flux. Analytical expressions for field components and motor developed power are provided. It takes into account the contribution of rotational hysteresis effects and provides results showing good agreement between the measured and predicted values of motor terminal characteristics.