A dynamoelectric machine comprises: a stator that comprises a plurality of stator poles arranged around a stator surface of revolution with a stator axis for the stator surface of revolution; at least one rotor that comprises a plurality of permanent rotor magnets arranged around a rotor surface of revolution with a rotor axis for the rotor surface of revolution that is coincident with the stator axis and with the rotor surface of revolution adjacent the stator surface of revolution; a drive shaft with a drive shaft axis of rotation that is substantially coincident with the stator axis coupled to the rotor for rotating the rotor relative to the stator about the drive shaft axis of rotation; and a at least one actuator for axially displacing the rotor surface of revolution along the drive shaft relative to the stator surface of revolution to change magnetic flux interaction between the stator poles and the rotor magnets; wherein at least one of the surfaces of revolution tilts with respect to the drive shaft axis of rotation.