Investigation of twisted stacked-tape cable conductor

A cable fabrication method of a twisted stacked tape conductor for HTS YBCO tapes has been developed and tested. A 2 m long, 32–tape conductor of 4 mm width YBCO was fabricated with a 200 mm twist pitch. The measured critical current of the straight cable agreed with the expected values estimated from the self-magnetic field. The 2 m long cable wound on a surface of 0.5 m diameter circle did not show any degradations. It has been confirmed through tests with single tape and cable tests that it is possible to develop a YBCO mutliple-tape stacked cable with a 200 mm twist pitch and to make a coil with an innermost turn of at least 0.5 m diameter. A joint method for multi-tape YBCO cable using BSCCO tapes has been developed and operated at 2.2 kA. AC losses of a twisted stacked YBCO tape cable have also been analyzed. The twisted stacked-tape cabling method for YBCO tapes will be very useful for high-current, high-field magnets for various applications.