ABSTRACT

This chapter considers machine designs with 12 poles and tries to determine a more reasonable design for the low vibration. It examines the effects of different shapes of the stator laminations and frame, which is a new contribution to low-vibration motor design. The primary cause of vibration and acoustic noise is stator ovalization, excited by normal attractive magnetic forces. The advantages of switched reluctance machines (SRM) over induction and Permanent Magnet machines include higher reliability, and speeds and ease of manufacturing. A high stiffness stator can help reduce vibration deformation, and low vibration and noise can be achieved furthermore by mismatching the waveforms and frequencies of the excitation force with the stator mode shapes and resonant frequencies of the SRM. The machines are also face-mounted in automotive applications rather than foot-mounted in industrial applications, opening doors for vibration reduction. Frameless designs are also possible, giving rise to different vibration and acoustic noise characteristics than designs with frames, particularly with ribs.