No abstract

The electrical jointing of superconducting wires / tapes is a key issue for the construction of the scientific superconducting magnet that required high field stability, such as NMR, FTICR-MS and some inertial navigators. In this paper, the preliminary experiment of electromagnetic formed NbTi superconducting joint was done. The fabrication technique was researched by changing the parameters. The joint resistances were tested in liquid helium using coil current decay method. The contact resistance properties of the superconducting joint were investigated. The plastic deformation and the electrical contact characteristics of the NbTi superconducting joint were discussed. The results show that the electromagnetic formed NbTi superconducting joint has the excellent low-resistance property and good repeatability.

Epoxy resin insulation affects the stress distribution inside a superconducting coil. In this study, the effect of insulation was calculated by adopting an improved wire dynamic simulation method. A real Nb 3 Sn coil was used as an example. The strain distribution was obtained by calculating the motion of the wires and the forces applied on each wire. The strain distribution was compared with that obtained from finite element simulation. Result showed that the strain on the wire increased after considering the insulation. The relationships between the maximum strain in the coil and the thickness/elastic modulus of the insulation were also calculated. Furthermore, impregnation defects may result in strain concentration; the effects of these defects were also discussed at different locations of the coil.