Design and Test of a Novel Thermal Insulated Torque Coupling for a 15-kW Fully HTS Synchronous Generator

A 15-kW/150-rpm fully high-temperature superconducting (HTS) synchronous generator, which installs HTS windings on both the rotor and the stator, is under development. The thermal insulated torque coupling (TITC) is one essential part in the generator, which can transmit torque from the outside warm shaft to the inside cryogenic rotor shaft and reduce the heat conduction as well. In this work, a modular TITC structure has been proposed, which mainly consists of several G10 rods and two metallic flanges. An analytical model for evaluating the stress level and the heat leakage power was built. Design principles for TITCs at different load levels were discussed. Based on the aforementioned knowledge, a sample TITC for our 15-kW/150-rpm generator was designed, produced, and tested under the static load. It was found that the TITC cracked at the load of 2500 Nm, which corresponds to a safety factor of 2.6. Key structural parameters for TITCs working under higher torque levels (0.5-10 MNm) were also calculated.