Design considerations of a bearingless motor for high-purity mixing applications

This paper presents how a bearingless motor with exterior rotor can be implemented successfully in high-purity mixing applications. Important design parameters are identified and their influence on the system performance is demonstrated. The mechanical setup, the principle of bearing force and torque generation, the power electronics, the closed-loop control and the cooling concept are introduced in detail. Moreover, design considerations about optimizing the motor performance, the efficiency and the heat distribution are presented. Finally, the performance of the new motor is verified with a laboratory prototype.