Bearingless motors generate suspension force and drive torque combined in one compact unit. Using a disk-shaped rotor, several degrees of freedom can additionally be stabilized passively by reluctance forces. This requires a magnetic bias flux in the air gap, which is usually excited by permanent magnets in the rotor.

 

However, this monograph focuses on possibilities to avoid permanent magnets in the rotor. Two novel promising concepts without such rotor magnets (the bearingless reluctance slice motor and the bearingless flux-switching slice motor) are described in detail. Their industrial applicability is shown by several prototype systems, allowing the implementation of extraordinary cheap, temperature-robust and easy-tomanufacture rotors.