Joint Resistance Characteristics of Mechanical Lap Joint of a GdBCO Tape With a Change in Temperature and Magnetic Field

Mechanical joints of a high-temperature superconducting (HTS) conductor has been investigated for a “remountable” (demountable) HTS magnet. In a previous study, prediction method of joint resistance for a large-scale conductor was proposed using experimental data and current distribution analysis. However, the data were obtained by tests conducted at 77 K under self field. The joint resistance consists of contact resistance and resistance of constituted materials of HTS tapes, which depend on temperature and magnetic field. In this paper, therefore, we experimentally and numerically evaluated joint resistance characteristics with changing temperature and magnetic field using mechanical lap joint of a GdBCO tape. The experimentally evaluated joint resistance varied with the temperature and magnetic field as predicted. The joint resistance characteristic also depended on contact materials. The numerically evaluated contact resistance included in the joint resistance depending on temperature shows a tendency similar to the calculated value of the constriction resistance based on the Holm's contact theory.