Iron or other ferromagnetic material is utilized in the magnetic circuit of dynamoelectric machines having superconductive field or excitation windings. In DC machines, a stationary salient pole field structure with a superconductive main field winding is utilized. An armature winding is wound about a smooth rotor. In AC machines, a ferromagnetic structure that encloses and rotates with a superconductive excitation winding is utilized. The ferromagnetic structure may include either salient poles interconnected by ferromagnetic shunts or a slotted or toothed rotor.