Electric machine with enhanced tolerance to phase failure

摘要

An electrical machine 10 has three phase windings 12. Each phase winding 12 is connected to a respective current source 18. Each current source 18 provides alternating current to the corresponding winding 12. The current source 18 is connected independently to the respective winding 12. The electrical angles of the phase windings 12 are so arranged that none of the phase windings 12 has a zerotorque angle which coincides with a zero torque angle of another phase winding 12. The zero torque angles are preferably evenly distributed in electrical angle. The machine may continue to operate even if only two adjacent phases remain.