Design and Evaluation of a 60 000 rpm Permanent Magnet Bearingless High Speed Motor

Bearingless motors are an alternative to motors with active magnetic bearings and have been investigated in low and medium speed range. The aim of this project is to introduce bearingless motor technology into high speed applications, e.g. compressors or special pumps. The design process and test results of a 60 000 rpm, 500 W prototype high speed bearingless PM motor are presented. Motor design is done using analytical equations accompanied by finite element (FE) calculations. Measurements on the existing two-pole prototype verify the different design steps. The successful operation at 60 000 rpm indicates that the bearingless motor technology is well suited for high speed applications.