Analytical and experimental loss examination of a high speed bearingless drive

Bearingless drives have been intensely researched for over a decade since they represent a compact motor-bearing system fulfilling very special requirements. They provide all advantages of a typical magnetically levitated system, including the absence of mechanical wear and bearing friction. Therefore, an application for high-speed processes seems tempting. Nevertheless, there are no high-speed bearingless drives in industry so far and even in scientific research, their rated speed hardly exceeds 20krpm. One of the main obstacles on the way to rotational speeds of up to 100krpm are the occurring losses in stator, winding and air gap. This work deals with their analytical description, appropriate design steps of the drive system and a concluding experimental verification.