Current Distributions in Armature Coils Comprising Two Sizes of Racetrack Double-Pancakes with REBCO Striated Tapes

We propose transposed parallel conductors that can equalize the current distribution in the coils of a superconducting motor with an armature winding imitating a distributed winding using REBa2Cu3Oy(REBCO) tapes. However, AC loss increases the coil temperature, resulting in a quench. A striated REBCO tape with a filament divided into multiple filaments can effectively reduce AC loss. We measured the current flow distribution in the coils using transposed parallel conductors composed of striated REBCO tapes. Additionally, we experimentally demonstrate current equalization based on the transposition of the previous armature winding using only a small coil. We arranged two REBCO tapes side-by-side to simulate a striated tape divided into two filaments. The double-pancake coils in the armature coils were wound with the striated tapes and transposed at the connection point between each pole and the innermost circumference of the coils. We measured and verified the inductance of each tape. Additionally, we measured the current distributions for both U- and three-phase current flows.