Abstract
An AC current source of the 1, 000A class for AC transport loss measurements was designed and fabricated with the use of an oxide superconducting current transformer. Two cryocoolers were installed for cooling the transformer and a sample holder separately. A parallel conductor of 6 tapes was wound for a secondary winding, and a transposition was performed to make the current distribution uniform in the parallel conductor. Temperatures of the transformer and the sample holder were controlled in the range of 35-50K and 25-77K, respectively. The transformer and the sample holder were thermally separated and independently controlled. The peak current in the secondary winding exceeded 1, 000A in the frequency range of 1-75Hz when the primary peak current was 14A.
