Bearingless Slice Motors: General Overview and the Special Case of Novel Magnet-Free Rotors

In the last decades extensive research has been conducted in the field of magnetically levitated drives and bearingless motors. Due to its simple mechanical construction, bearingless slice motors are especially attractive for industrial applications. In this paper, the developments of bearingless slice motors are reviewed in terms of mechanical structure, winding types, test results and applications. Additionally, the novel bearingless slice motor types featuring magnet-free rotors are presented.