AC losses in multifilamentary HTS-composite tapes based on BiPbSrCaCuO

Some results of AC loss measurements are presented for 19, 61, 127-filament ary Bi-2223/Ag tapes prepared by the 'powder-in-tube' method. All measureme nts have been made at T = 77 K under sinusoidal transport current with freq uency in the range of 30-500 Hz and the current amplitude up to 30 A. The m easurements have been carried out both in self field conditions and at the external magnetic field applied to the tape at the different angles. The de pendencies of the AC losses on current amplitude and frequency have been ob tained. It is found that for all tapes the current amplitude dependencies o f the AC losses show good agreement with the Norris prediction for an ellip tical or strip geometry. The AC loss dependencies on frequency were Linear. The measurements of AC losses in external magnetic field show that the cha nge of AC losses is only through the change of the critical current. So the transport AC losses in the tapes are the 'saturation losses' that is they are different from classic hysteresis losses. (C) 1998 published by Elsevie r Science B.V. All rights reserved.