| Popis: |
Since Bi2Sr2Ca2Cu3O10/Ag, [Bi2223/Ag], tapes have geometrically large aspect ratios, and have highly anisotropic properties along its crystallographic directions, it is not clear to what extent the ac loss theories, which are based on the critical-state model of an isotropic superconductor, are applicable to these conductors. We report on tests of these models against magnetically measured ac losses of a Bi2223/Ag tape, in magnetic environments similar to those in power devices. It is shown that the self-field critical currents are not appropriate for calculations of the losses in either parallel or perpendicular fields to the tape face. In addition, the use of the field- dependent critical currents, such as in Kim’s model, is important to understand the behavior of the losses in perpendicular applied fields. |
