Current Sharing in Parallel Conductors Using Bi-2223 Tapes in Perpendicular Magnetic Fields

Abstract

Measurements of current distributions among tapes consisted of parallel conductors under perpendicular magnetic fields have been carried out to investigate the effect of such fields on current sharing among tapes in Bi-2223 parallel conductors at 77 K. Samples were formed into double pancake coil with the racetrack shape wound with the parallel conductors composed of three Bi-2223 tapes. Magnetic fields were applied perpendicular to the coil axis, ensuring a perpendicular orientation to the tape face in the straight sections of the coil. Experiments were conducted in liquid nitrogen; current distributions were measured by Rogowski coils. The results show that perpendicular magnetic fields enhance current uniformity between tapes. Although multiple transpositions are usually required in parallel conductors to ensure uniformity, this finding suggests that the number of transpositions required in parallel conductors can be significantly reduced, depending on the conductor design. These insights contribute to the optimization of superconducting devices by minimizing mechanical stresses and manufacturing complexity associated with frequent transpositions.