SUPERCONDUCTING DYNAMO-ELECTRIC MACHINES

An A.C. generator has a superconducting D.C. field winding on the rotor and a multi-phase A.C. winding on the stator. To prevent A.C. loss in the superconducting winding an electromagnetic flux screen is interposed between the windings and is secured to the rotor. In a preferred construction the flux screen is part of an outer rotor cylinder of strong mechanical construction which operates at ambient temperature. The outer rotor cylinder is coupled for rotation with an inner cylinder which carries the superconducting winding, is of relatively light construction to minimize heat inflow and is separated from the outer cylinder by a vacuum space.