| 摘要 |
PURPOSE:To secure fully safe protection for a switch without the switch enlarged with respect to quenching of a permanent-current switch, by installing protective resistors for the switch extremely neighboring a superconductive magnet. CONSTITUTION:Protective resistors 2 for a permanent-current switch 6 are connected in series with diodes 7 which are provided for preventing current from flowing in the protective resistors 2 because of voltage generated at the time of excitation and demagnetization. This circuit is electrically connected in parallel with each of a superconductive magnet 1 and a permanent-current switch 6 and installed neighboring the superconductive magnet 1. The protective resistors 2 for the permanent-current switch are installed so that they are surrounded through the permanent-current switch 6, coming in close contact with the peripheral surface of a superconductive winding 1a which is wound in a solenoid shaped around a cylindrical bobbin 8 having flanges on its both ends. These protective resistors 2 are made of copper, stainless steel, or the like and they are connected so that currents in the protective resistor layers 2a and 2b flow in the reverse directions to each other, so as not to make the protective resistors have inductance. |
