Development and electrical test of a 30 kVA class fully superconducting generator

We are developing a 4 pole 50 Hz 30 kVA class fully superconducting generator to investigate the characteristics of superconducting armature windings subject to a rotating magnetic field. Compared with other fully superconducting generators that have been developed and tested, our machine is designed to obtain a higher armature current. It is generally observed in coils wound from AC superconducting cable that the AC quench current of the coil is much lower than its DC quench current. Countermeasures against these AC current degradation phenomena were developed and applied to the AC cable and armature winding of our generator. Results of the electrical tests of the generator are presented and the validity of the countermeasures is discussed.>