Abstract: The magnet frame of a dynamoelectric machine comprises a removable, generally cylindrical inner member concentrically disposed inside a cylindrical outer member. The inner member is supported in a cantilever fashion at only one of its ends, and most of its outside surface is normally separated by a relatively small circumferential gap from the cooperating inside surface of the outer member. The outer member of the frame rotatably supports the hub of a motorized wheel, which hub is coupled via a torque tube and gearing to a rotor inside the inner member. Conventional means is provided in the inner member for producing a field of magnetic flux in both the magnet frame and the rotor, and the path of this flux will include parallel branches in the inner and outer frame members.