Basic Characteristic of the Multi-Consequent-Pole Bearingless Motor

For low speed applications, such as rotating and swing stages, a multi-consequent-pole bearingless motor is proposed. This paper describes basic characteristics of a multi-consequent-pole bearingless motor. Unlike conventional bearingless motors, suspension force generating on consequent-pole type is independent of rotor rotational position. Thus, multi-pole rotors such as 40, 44, and 46 poles are easy without a penalty of high precision in rotating angular position detection. Basic design of pole number selection is discussed with suspension force and average torque capability. Magnetic force error can be reduced with multi-pole rotor configuration. A test machine has been constructed and driven by a compact drive and a CPU unit.