ELECTRIC-FIELD AND LOSSES IN BSCCO-2223/AG TAPES CARRYING AC TRANSPORT CURRENT

Electric field and losses in single layer coils wound of 0.75 m long multifilamentary BSCCO-2223/Ag tapes carrying ac transport current have been studied at both 4.2 K and 77 K in the frequency range from 0.01 Hz up to 100 Hz with the main effort to 50 Hz. Current amplitudes I-p were ranging from i=I-p/I-c=0.5 to 13, critical current I-c determined by the standard 1 mu V/cm static electric field criterion. I-c of Coil 1 was 15 A at 4.2 K and 3 A at 77 K. Losses due to the wide resistive transition of the coils were found to dominate over self-field losses even well below i=1. Therefore the total losses in the whole applicable i range could not be described well by equations based on the critical state model.