Development of a 1 T/1 kA-class AC superconducting coil

In order to develop AC superconducting apparatus for power use, 10 kA/sub r.m.s./-class AC superconducting coils should be developed. From such a viewpoint, the authors have been investigating AC superconducting coils having a large AC transport current capacity. In this paper, the specification and experimental results of an 1 T/sub r.m.s.//1 kA/sub r.m.s./-class AC superconducting coil are shown. Two experimental AC coils using the sub-cable and single strand of this AC superconducting coil are also fabricated and tested to investigate the stability of AC coils. The quench current of each AC coil is measured and is compared to the DC critical current characteristics of the strand. From the result of the comparison, it is confirmed that the AC quench current of each superconducting coil is close to the DC quench current, and is close to the current which is determined by the critical current characteristics defined by 0.1 /spl mu/V/cm criterion. It is also confirmed that the quench point of the developed AC coil reaches to 1.396 T/sub peak//1288 A/sub peak/.