AC transport current losses of multifilamentary Bi(2223) tapes with varying filament geometries

We have measured the ac transport current loss of eight different Bi(2223) tapes with varying filament geometries in the frequency range from 13 to 500 Hz at 77 K. The investigated tapes have an Ag sheath (i.e. 37 or 703 filaments) or a modified sheath using AgMg. Furthermore tapes with novel geometries such as multifilamentary win-in-tube (WIT) tapes and jelly-roll tapes have been studied. In addition we have investigated twisted tapes with a twist-pitch of 1.4 cm in the 37 filamentary Ag and the 85 filamentary AgMg tapes. To compare these tapes with different I-c values we calculated the loss factors of the tapes. We find that all the loss factors lay within the limits given for on elliptical or a strip like conductor. Furthermore ne find differences in the loss factors due to the filament geometries, (C) 1998 Elsevier Science B.V.