Development of a 1 kA, 25-ohm magnetically controlled persistent current switch for SMES

A 1-kA, 25-/spl Omega/ magnetically controlled persistent current switch (PCS) was developed and tested. In a single test of the PCS, it was found that the primary consideration to realize switching from normal state to superconducting state, PCS recovery, for large current should be a control of PCS current. In a connecting test of the PCS and 1-MJ SMES, the PCS showed rapid switching characteristics of less than 0.4 s. In the persistent current mode operation, PCS operation at 1 kA for a six-hour period was demonstrated. By the various tests, primary factors affecting design of magnetically controlled PCS are analyzed.