The influence of rotor skew on unbalanced magnetic pull in cage induction motors with eccentric rotors

A simple coupled circuit model has been developed in order to assess the effect of rotor skew on the UMP (unbalanced magnetic pull) in a cage induction motor with dynamic rotor eccentricity. It was found that, with further refinement, the model may be suitable for predicting UMP over the steady-state operating range of the motor but is inaccurate at higher slips due to it not accounting for other MMF waves. Higher eccentricities also lead to inaccuracy because of the restricted range field components due to permeance modulation which are taken into account.