Magnetic field angular dependence of AC losses in Bi-2223 superconducting wires

We investigated the magnetic field angular dependence of the AC loss in stacked Bi-2223 silver-sheathed superconducting multifilamentary tapes. The form of sample stacked tapes corresponds to parallel conductors, which were adopted to a 22 kV–1000 kVA liquid-nitrogen-cooled superconducting transformer and a 4 kJ conduction-cooled pulse coil. We measured the AC losses in stacked Bi-2223 tapes by using a saddle-shaped pickup coil and rotating the sample stack around its central axis. On the basis of the observed results, we discussed the influence of stacking and the field angular dependence of the AC losses in stacked superconducting tape. In addition we confirmed that the AC losses in stacked superconducting tapes can be estimated for any field angle as the simple sum of the respective AC losses due to the parallel magnetic field component and the perpendicular one.