Comparison of magnetically induced and transport current ac losses in silver-sheathed (Bi,Pb)(2)Sr2Ca2Cu3O10 tapes

A quantitative comparison has been made for ac losses at power frequencies, which were determined by a magnetically induced technique and a transport current technique, for silver-sheathed (BiSb)(2)Sr2Ca2Cu3O10 tapes. A meaningful comparison of these losses can be made based on the normalized currents (with respect to the respective deduced critical current) rather than the amplitudes of surface magnetic fields. Then, the intrinsic difference in the losses is shown to originate from a geometrical factor and a difference in the deduced critical currents. The discrepancy in the critical currents arises from the facts that the directions of penetrating magnetic field to the tape face are different in these cases and the critical currents are highly dependent on the field direction.