Dual purpose no voltage winding design for the bearingless ac homopolar and consequent pole motors

Winding layouts for the bearingless ac homopolar and consequent pole motors that allow the same coils to be used for both radial force and torque production are investigated. This concept enables a “pure” bearingless motor where the same iron and copper are used for both magnetic bearing operation and torque production. For three phase windings, it is shown that these schemes limit 6-pole machines to integral slot windings, but that 8-pole machines support various fractional slot windings. Conclusions are similarly drawn for two phase windings. A winding design procedure is proposed and 3D finite element analysis (FEA) results are presented for an example design.