Development of 50-kW-Class High-Temperature Superconducting Induction/Synchronous Motor With Continuous Drive Characteristics from Room Temperature

We investigate the rotational characteristics of a 50-kW-class high-temperature superconducting induction/synchro- nous motor in superconducting and non-superconducting states. The prototype motor was first placed in liquid nitrogen, and the efficiency contour was obtained. The liquid nitrogen was then gradually removed from the motor under the partial load (10 kW) condition. This showed that continuous operation is possible even at temperatures exceeding 130 K. Furthermore, we succeeded in driving at 11% of the rated output, even at room temperature. As a result, a practical high-temperature superconducting motor that can continue to operate with reduced output even when the cooling system fails could be realized.