Current Distribution Among Transposed Eight- and 16-Parallel REBa₂Cu₃O_y Wires in Single-Phase Armature Coils

Fully superconducting synchronous motors employing superconducting armature and field coils, have a great possibility for electric propulsion systems in aircraft applications, owing to their high output power density (kW/kg). To realize a large current capacity in REBa2Cu3Oy superconducting armature coils, we have proposed a cabling design for the transposed multi-strand parallel conductors. In this study, branch currents among eight- and 16-strand parallel conductors having only one transposition into a coil, were investigated. The analytical calculations showed approximately uniform branch current for the eight- and 16-strand conductors. According to the calculations, the deviations to the uniform branch current of eight-strand parallel conductors were +/- 7%. The approximately uniform current for the eight-strand conductors were also demonstrated experimentally by small-sized sample coils.