Flux Linkages in Squirrel-Cage Motor

Abstract

Modeling of squirrel-cage induction motor has traditionally relied on generalization of wound-rotor induction motor claiming their nearly identical operational characteristics. However, the distribution of rotor windings differs profoundly among the two types, as the squirrel-cage rotor features non-sinusoidal distribution of bars along the air-gap. In this paper, a model of squirrel-cage induction motor is derived based on the actual geometry of stator windings and rotor loops. Various types of inductances which are instrumental to the description of the model are computed by means of winding function. Consequently, a winding asymmetry can be easily incorporated in the model as shown for the case of broken rotor bar.