Tangential Forces in Squirrel-Cage Induction Motors

A discussion is presented of the influence of the stator and rotor slotting on the torque characteristics of a squirrel-cage induction motor. The presence of airgap fields having long wavelength is demonstrated. It is shown that these fields exert a large effect on the torque characteristic. Formulas are given for the evaluation of the maximum asynchronous torques developed by the stator step harmonics. The differential leakage of the rotor is shown to have a dominant role in these phenomena.