A machine, such as a motor or generator, includes a rotatable rotor assembly comprising a plurality of salient poles and a stationary stator assembly comprising a superconducting field coil. The superconducting field coil and the salient poles are configured relative to each other such when the rotor assembly is rotated relative to the stator assembly around a predetermined axis, a rotating magnetic field is produced with an airgap flux direction substantially along the predetermined axis.