Stability of a shorted Nb/sub 3/Sn coil cooled by a refrigerator for a magnetic shield type fault current limiter

A stabilizing method for a shorted Nb/sub 3/Sn coil, which will be cooled by a refrigerator at around 10 K and be applied to a magnetic shielding body for a magnetic shield type fault current limiter, is proposed. The stabilizing method is realized by short-circuiting the terminals of the limiting coil through a semiconductor device and keeping the voltage across the Nb/sub 3/Sn coil constant. The stability is studied in a single layer Nb/sub 3/Sn coil operated in a constant AC voltage mode in liquid helium or helium gas. The method has shown to be quite effective for stabilization.