HIGH-TEMPERATURE SUPERCONDUCTING MOTOR USING Y-BA-CU-O BULK MAGNETS

A DC motor equipped with melt-processed Y-Ba-Cu-O (YBCO) superconducto rs as field magnets was constructed. The YBCO bulks were magnetized at temperatures of 65-77 K in a liquid nitrogen vessel by applying a pul sed magnetic field. The maximum output power was 940 W when the YBCO b ulks were cooled to 65 K. Continuous running tests were carried out fo r up to 6 h. We found that the trapped magnetic fluxes are hardly affe cted by the magnetic field of 7500 A/m generated by the armature curre nt and that cooling of the YBCO bulks to low temperatures is very effe ctive for holding the trapped field at a high level and, hence, substa ntially elevating the performance of a high-temperature superconductin g (HTSC) motor.