Critical currents of Nb3Sn superconductors for generators under cyclic mechanical load

Critical currents of Nb₃Sn cabled superconductors were measured under cyclic mechanical compressive force of 30 MPa up to 10000 times. The conductors were developed for a superconducting generator under the Super-GM project. The conductors were designed to apply the field winding of the 70 MW-class superconducting generator. The 10000 repetitions of force application simulate 30 years of centrifugal and electromagnetic force produced by the daily start-and-stop (DSS) operation of the superconducting generator. In the test facility constructed at the Akagi Testing Center of the Central Research Institute of Electric Power Industry (CRIEPI), mechanical compressive force is generated by the cyclic fatigue test machine, which can generate 100 kN of force and is located on top of a cryostat at room temperature. Measured critical currents of two types of Nb₃Sn conductor did not change throughout the test