Prototype coils wound from high-Tc superconducting composites

The construction and performance of three prototype pancake coils wound from high-Tc superconducting composite tapes fabricated using the techniques of Powder-In-Tube (PIT) and Electrophoretic Deposition (EPD) are described. Numerous potential taps were incorporated in the coils to enable determination of conductor homogeneity. Results are presented of measurements of transport critical currents of complete coils and sections of coils. The homogeneity of these sectional critical currents is shown to be much improved when the composite tape is multilayer rather than single layer. In addition data are presented on critical current anisotropy with respect to applied field direction, at 4.2K and 77K, for a short sample of the tape used in the construction of one of the coils