Principle and Application of a Bearingless Slice Motor

Abstract

Recent developments in the field of electrical drives and magnetic bearings have led to so called "bearingless motors". The innovation is that the magnetic forces for the suspension of the electrically powered rotor are generated in the motor itself and not in separate magnetic bearings. Normally, two motor / bearing units are needed for the full stabilisation of five spatial degrees of freedom. In this paper a bearingless motor with a slice-shaped rotor is presented, where three spatial degrees of freedom are passively stable. Only one active radial bearing is needed. Possible applications for the "bearingless slice motor" lie typically in the field of small centrifugal pumps, high speed centrifuges, blowers for dangerous gases or flywheels. The possibilities and advantages of the bearingless slice motor are demonstrated by the example of a disposable blood pump for heart surgery.