Patent ID: 7075396

Claim:
A superconducting coil system comprising a superconducting coil solely made of superconducting wires housed in a metal conduit without pure copper wires and a normal conducting coil which is electrically coupled to the superconducting coil and allows a portion of current flow to bypass the superconducting coil by induction, the superconducting coil and the normal conducting coil being arranged separately in a coil case, and the normal conducting coil having a current time constant (L 2 /R 2 ) which is larger than L 1 /R 1 , or the time constant at which the current through the superconducting coil decays rapidly after the conductors in the superconducting coil made a transition to the normal conducting state, in which L 1 and L 2 represent the self-inductances of the superconducting coil and the normal conducting coil, respectively, R 1 represents the resistance for causing rapid decay of the current flow through the superconducting coil, and R 2 represents the resistance of the normal conducting coil.