Feasibility Study on a 400 kW–3600 rpm REBCO Fully Superconducting Motor

We conceptually designed a 400 kW-3600 rpm synchronous motor with RE (RE: Rare earth, Y, Gd and so on, REBCO) superconducting tapes and studied the feasibility of fully superconducting ones. First the ac loss properties and the dependences of the critical current, , on temperature, , magnetic field, , and applied magnetic field angle, , of the REBCO tapes at 30 K to 77 K were measured. Next, 400 kW-3600 rpm fully superconducting motors were designed by taking into account of and then their properties, e.g. ac losses, efficiency, torque ripple and so on, were numerically calculated. According to the conventional theories, the induced ac losses in the armature windings exceeded several kW and the efficiency decreased rather than conventional normal motors. On the contrary, by taking account of the tremendous low-ac-loss properties of REBCO superconductors which were recently discovered as magnetic phase transition, the ac losses were reduced to around one hundredth. In consequence a feasible prospect of advantageous REBCO fully superconducting motors was obtained.