ELECTRIC CURRENT LEAD OF SUPERCONDUCTING MAGNET DEVICE

PURPOSE:To obtain an electric current led which can continue to feed an electric current to a superconducting coil, which can prevent an oxide-based superconducting conductor from being damaged and in which creeping heat is small even when a low temperature side lead composed of the oxide-based superconductor is quenched. CONSTITUTION:A bypass circuit which detects an abnormal voltage due to the quenching of an oxide-based superconducting conductor and which is then set to a continuity state is installed so as to be parallel to a low temperature side lead for electric current lead constituted of a series body by a high temperature side lead and by the low temperature side lead; an excitation current is fed to a superconducting coil by using the bypass circuit as a bypass. As the bypass circuit, one out of a power diode, a switching semiconductor element and a voltage-dependent nonlinear resistance element is used.