To effectively cool a converter that converts AC obtained on a rotor side to a DC, by performing non-contact power feeding to a superconducting coil installed in a rotor.

The field superconducting coil 15 is fixed to the rotor 12, an armature coil 14 is fixed to a stator 11; a non-contact power feed means 16 that leads and feeds power to the rotor 12 side from the stator 11 side is arranged; an AC received by the non-contact power feed means 16 at the rotor 12 side is converted into a DC by the converter 19 and fed to the superconducting coil 15, the superconducting coil 15 is arranged at a cooled space 23 in the rotor 12; a cooling medium lead-in passage 22, to which a cooling medium is fed from the outside and a cooling medium lead-out passage 24, to which the cooling medium whose temperature is raised by heat exchange with the superconducting coil 15 is discharged are arranged in the cooling space 23; and the converter 19 is cooled by the temperature-raised cooling medium of the cooling medium lead-out passage 24.

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