Impact of stator windings and end-bells on resonant frequencies and mode shapes of switched reluctance motors

One of the main drawbacks of switched reluctance motors (SRMs) is vibration and acoustic noise, which limits their application. An accurate predication of the modal vibration frequencies of the SRM stator is essential in order to design a low-vibration motor and operate it quietly. Electronic techniques for noise reduction also depend on knowledge of the resonant frequencies, which depend on the mechanical structure surrounding the laminations. This paper examines the effects of the stator windings and end-bells on stator modal vibration frequencies. The error in the calculation of the resonant frequencies can be up to 20% if the influence of end-bells is neglected. The numerical computations of the stator mode shapes and resonant frequencies are validated with experimental results.