Transient Characteristics of a Motor using High-Tc Bulk Superconductors in the Rotor

摘要

Because REBaCuO bulk superconductors have large flux pinning forces even in liquid nitrogen, various applications have been investigated. This paper is concerned with a motor using bulk superconductors in the rotor. In order to analyze the characteristics of a bulk superconducting motor in the transient state and those of a bulk superconductor in traveling fields, an experimental apparatus for a hysteresis motor with bulk superconductors in the rotor was constructed. In a pull-out test, the maximum torque of the superconducting hysteresis motor is generated as a speed which is slightly slower than the synchronous speed. The torque decreases with the slip frequency. In a locked rotor test, torque increases with the slip because Joule losses generated in the bulk superconductors decrease the critical current density of the superconductors and consequently their sheidling capability. This paper describes the experimental device, the results of pull-ut and locked rotor test and transient characteristics of the motor.