| 摘要 |
PURPOSE:To reduce friction heat and hence avoid temperature rise even when there is produced sliding between a superconducting coil and a supporter by bringing only the neighbourhood of the center of the outer peripheral surface of the superconducting coil into contact with the supporter when the coil is not excited, increasing a contact surface between the superconducting coil outer peripheral surface and the supporter as an excitation current is increased, and bringing substantially the entire surface of the coil into contact with the supporter upon completion of the excitation. CONSTITUTION:Although electromagnetic force is sustained in the vicinity of the center of an outer peripheral surface 8 of a superconducting coil upon the starting of excitation of the superconducting coil 1, any sliding between the coil and a supporter produces less friction heat because the electromagnetic force is small in itself. The electromagnetic force is increased in the course of the excitation but a contact area is also increased, so that a significant increase of the stress on the outer peripheral surface 8 of the superconducting coil can be avoided. At the time when the excitation of the superconducting coil 1 is completed, the uniform electromagnetic force is exerted over the entire surface of the semiconducting coil outer peripheral surface 8, so that the upper limit of the force can sharply be reduced. Hereby, any sliding between the superconducting coil 1 and the supporter 2 produces less friction heat to suppress the temperature rise of a superconducting wire. Thus, a stable performance superconducting coil 1 for which quenching is unlikely to occur is yielded. |
