| 摘要 |
PURPOSE:To unnecessitate the lead wire to be provided on a normal temperature part by a method wherein all the component parts of the protective circuit to be used for a superconducting device are provided within a cryogenic temperature. CONSTITUTION:When a superconducting switch 2 is quenched, voltage is generated at both ends of the switch. The voltage generated at both ends of the switch 2 in the beginning of the quenching is feeble. Also, the voltage same as above is applied to the primary winding 10a of the transformer 10 connected to the switch 2 in parallel. On the other hand, the number of turns of the secondary winding 10b of the transformer 10 is larger than that of the winding 10, and as a result, amplified voltage is applied to the winding 10b. When a quenching is generated on the switch 2, a thyristor 6 is brought in a conductive state, and the switch 2 is protected by allowing a circulating current to pass. Also, a constant voltage diode 11 is controlled so as to prevent the application of excessive voltage on the thyristor 6. |
