A high speed superconducting rotor

As a result of the predicted savings in weight and volume offered by superconducting field windings, the USAF initiated a technology advancement program on superconducting machines. The initial phase of this program was devoted to the preliminary design and analysis of certain critical components judged to be essential in constructing a high speed, high power superconducting generator suitable for airborne application. As a final feasibility test, the most critical components, i.e., the dynamic cryogenic seals, power leads, and superconducting field winding, were to be assembled into a complete working rotor and tested under full operating conditions. This paper will review the overall design, fabrication and final test results of a prototype 12,000 rpm 4-pole superconducting rotor. The main emphasis will be placed on the design, fabrication and test of the superconducting coils, and on the description of the cryogenic cooling scheme for the 4-pole coil structure.