Winding Techniques and Training Histories of Superconducting Force-Balanced Helical Coils

Abstract

Force-balanced coil （FBC） can balance electromagnetic forces by the effect of a helically wound configuration and minimize the required mass of structures for energy storage. The author developed superconducting model coils based on the FBC design using NbTi strands. This article summarizes the design conditions of the FBC, the hand-made winding techniques and training histories of the model coils. From the excitation test results of the model coils using liquid helium cooling, the model coils maintained the training phenomena even after the coils were heated to room temperature. However, the FBC requires repetitive excitation tests to improve its quenching properties. The author also discusses the development status of a small-sized prototype of a helical winding machine for REBCO-coated conductors and the test winding results.