Performance Test of a 100 kW HTS Generator Operating at 67 K–77 K

A systematic test program is in progress to fully characterize a 100 kW HTS synchronous generator which was successfully constructed in 2004. The machine was one of the first HTS synchronous generator/motors to operate at liquid nitrogen temperatures while achieving a power rating relevant to practical application. It has a conventional 3-phase stator and a cold rotor with a magnetic core and a superconducting winding consisting of 10 HTS Bi2223 pancake coils separated by magnetic flux diverters. The test program includes a series of tests at various speeds, field currents and temperatures (65 K-77 K) with the machine in open circuit to determine the critical currents of the HTS rotor, the waveform and harmonic characteristics of generated voltage at different levels of iron saturation. Stationary measurements of the rotor critical current are carried out using dc current in the stator windings to quantify the influence of stator field on the performance of the superconducting winding. The voltages and temperatures of the rotor are measured using a radio frequency telemetry system.