Magnetisation loss of BSCCO/Ag tape in uni-directional and rotating magnetic field

BSCCO/Ag tape superconductors are used in applications like power cables, t ransformers and motors/generators. In these applications, the superconducto r is exposed to an alternating magnetic field that can have different orien tations with respect to the tape. In applications like three-phase power ca bles and motors/generators, the tape is exposed to a rotating magnetic fiel d. This paper describes a measurement setup to determine the magnetisation loss of short pieces (10 cm) of tape superconductor in uni-directional magn etic field with arbitrary direction and rotating magnetic field. Measuremen ts are performed in liquid nitrogen using the pick-up coil technique. The s ensitivity of the setup is sufficient to measure the magnetisation loss acc urate down to magnetic field amplitudes of 0.5 mT, also in magnetic field a pplied parallel to the wide face of the conductor. A relation is verified t hat described the measured magnetisation loss in a rotating magnetic field with the results obtained for a uni-directional field. The magnetisation lo ss in a rotating magnetic field can be described, in most cases, with the c omponent of the magnetic field perpendicular to the wide face of the tape c onductor. Only when the parallel magnetic field component becomes more than two times larger than the perpendicular component that its contribution to the loss becomes significant. (C) 1999 Elsevier Science B.V. All rights re served.