| 摘要 |
PURPOSE:To quicken the decay time of a coil current which flows in a quenched part of a superconducting coil for preventing a burning of the quenched part by connecting by a lead wire a specified point on the superconducting coil at which the superconducting coil is electrically divided and a specified point on a protection resistor at which the protection resistor is electrically divided. CONSTITUTION:If a quench occurs on a part 4 of a superconducting coil 3 on one side from the center, a dc breaker 2 is opened and current flow to the superconducting coil 3 is stopped. A current flows in a parallel circuit composed of the superconducting coil 3 and a protection resistor 5 by energy stored in the superconducting coil 3. At this time, the current is divided into two from a lead wire 6; a current I1 which flows in the quenched coil and a current I2 which flows in the sound coil. A circuit in which the current I1 flows has a shorter time constant than the one in which a current I3 flows while a circuit in which the current I2 flows has a longer one than a circuit of the current I3. In the case that the electrically divided circuits are connected magnetically, the current I2 sometimes increases even more than the initial value by magnetic induction of the current I1. There is no problem if a current decay time is long since the current I2 flows in the quench-free coil. |
