Niobium-tin persistent-current switch for the superconducting magnet of Maglev

We designed and manufactured a persistent-current switch consisting of Nb3S n superconductive wire with an on-state current capacity of 600 A and an of f-state resistance of 52 Ohm for the superconducting magnet of Maglev, To d esign a persistent current switch, it is important to suppress the instabil ity such as degradation and training. Nb3Sn has a higher critical temperatu re than that of NbTi which is commonly used for conventional persistent-cur rent switches. Nb3Sn wire is considered, therefore, to have higher stabilit y to disturbance than NbTi wire. We reduced the volume and weight of the Nb 3Sn persistent-current switch to around 0.6 times and 0.7 times, respective ly, that of the conventional NbTi persistent-current switch. Current-carryi ng capacity was tested both under the static and vibrating states. Test res ults of switching performance were compared with a computer simulation of t emperature distribution in heating and cooling.