Demonstration of two synchronous motors using high temperature superconducting field coils

The design, construction and testing of two synchronous motors, having output powers of 1.5 kW and 3.7 kW respectively, is described. Both motors have a salient pole field structure excited by high-temperature superconductor (HTS) coils. The first motor (1.5 kW) is a vertical axis, two-pole machine operating at 3600 rpm with a stationary field structure and a rotating armature whereas the second motor (3.7 kW) has a more conventional rotating field structure with four salient poles operating at 1800 rpm. The racetrack-shaped coils are made with flexible multifilamentary BSCCO conductor and operate at liquid nitrogen temperature and remained superconducting under all operating conditions. Each HTS coil contains approximately 170 m of conductor. The coils used in these motors have experienced over 40 thermal cycles with no degradation in performance. These demonstration motors represent a significant advancement in the application of HTS to electrical rotating machinery.<>