Design considerations for the drive system of an ultra-high speed spinning ball motor

This paper presents considerations for the drive system of a magnetically levitated ultra-high speed spinning ball motor. The system shall provide rotation speeds in the range of several million rotations per minute in future. In a first approach, the functionality is analyzed and verified on a system, which is enlarged by a factor of four compared to the motor size which shall provide the targeted rotational speed of the rotor. Possibilities of improvement for the final drive design are investigated in detail by using 3D FEM analysis. Finally, a new coreless drive unit, which shall provide higher rotor speeds of smaller rotors, is developed.