Development of a superconducting linear synchronous motor

High Tc superconducting (HTS) wires were applied to primary coils of a small size permanent magnet linear synchronous motor. Three-phase racetrack shaped test coils were fabricated and tested. The HTS coils were cooled down to 33 K by using a GM-cryocooler in order to overcome the decrease of the critical current density due to high intensity of magnetic field in the coil. A vacuum chamber and thermal shield for reduction of the radiation and the convection heat penetrations were fabricated. The parameters of the linear motor were calculated by using finite element method, and verified by experiment. It is possible to achieve large thrust force compared with that of a conventional machine because large current can flow in HTS primary coil.