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 at 50 Hz. Current amplitudes (I/sub p/) ranged from i=I/sub p//I/sub c/=0.5 to 1.3, critical current (I/sub c/) determined by the standard 1 /spl mu/V/cm static electric field criterion. I/sub 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.<
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