Experimental Study of Thrusts of a Cylindrical Linear Synchronous Motor With One or More YBCO Bulk Magnets as the Excitation System

The thrusts of a cylindrical linear synchronous motor with one or more YBCO bulk magnets as the excitation system were measured for the first time and are presented in this paper. The YBCO bulk magnets are cylindrical with a diameter of 30 mm and a height of 18 mm. The armature of the motor is three phase and made of copper wire coils. The inner diameter of the armature is 40 mm. At the temperature of 77 K and a radial gap of 5 mm between the armature and the excitation system, with a charging magnetization current of 40 A for one YBCO bulk magnet and the RMS value current of 10 A for the armature coils, a peak thrust of 27.2 N was measured. Effects of armature current, charging magnetization current, running time, and magnetizers were also studied. When the excitation system had two or three full magnetized YBCO bulk magnets and magnetizers between them, the thrust was nearly two or three times as strong as the thrust of one YBCO bulk magnet under the same conditions.