Resin-impregnated bulk RE–Ba–Cu–O current leads for the superconducting magnet on maglev train

Bulk RE–Ba–Cu–O (RE: rare earth elements) superconductors exhibit high critical current density ( J c) and low thermal conductivity, that are the characteristics desired for the current lead applications. In this study, we studied whether the resin-impregnated Y–Ba–Cu–O rods can be used as the current lead for the superconducting magnet on a magnetically levitated train. The fatigue test showed that the mechanical properties of resin-impregnated Y–Ba–Cu–O rods are sufficiently good for maglev applications. We could also pass the electric currents of 500 A without heat generation. This was further confirmed by field distribution measurements, which showed that the superconducting state of the current lead was well maintained when the currents of 500 A were passed.