150-kW experimental superconducting permanent-magnet motor

A permanent-magnet motor with a superconducting armature associates the high current densities in superconductors and the simplicity of a rotating permanent-magnet inductor. Those characteristics make them very attractive drives for moving systems with low weight requirements. We carry out a research and development program on this structure. After a first 15-kW, 750-rpm successfully tested model, a demonstrator of 150-kW and 400-rpm has been built. The layout of this eight-pole, 150-kW machine is conventional with a horizontal axis and a rotating neodymium-iron-boron inductor cooled at 150 K. The three phase winding is made with a (6+1) superconducting ultra fine niobium-titanium cable. The 24 saddle-shape coils are distributed among four concentric tubes. Their holding has been well studied. The liquid-helium cryostat (1000 mm long and 630 mm in diameter) was built using essentially composites. It has successfully suffered first cryogenic and some electrical tests which are reported.