Superconducting motor

Abstract

A superconducting motor includes: a rotor that is rotatably supported; a stator that is provided around the rotor, and that is provided with a plurality of coils that are respectively formed of superconducting wires and that are wound at an inner periphery of a stator core; and a refrigerator having a cooling portion for cooling the plurality of coils. The cooling portion of the refrigerator is in contact with the plurality of coils.

1 . A superconducting motor comprising:
 a rotor that is rotatably supported;   a stator that is provided around the rotor, and that is provided with a plurality of coils that are respectively formed of superconducting wires and that are wound at an inner periphery of a stator core; and   a refrigerator having a cooling portion for cooling the plurality of coils,   wherein the cooling portion of the refrigerator is in contact with the plurality of coils.   
     
     
         2 . The superconducting motor according to  claim 1 , wherein:
 every predetermined number of coils out of the plurality of coils are connected in series to form a plurality of phase coils; and   the plurality of phase coils are in contact with the cooling portion of the refrigerator at a neutral point at which one end portions of the respective phase coils are electrically connected to each other.   
     
     
         3 . The superconducting motor according to  claim 2 , wherein at the neutral point, the one end portions of the respective phase coils are electrically connected to each other via the cooling portion that is made of an electrically conductive member, rather than being directly connected to each other. 
     
     
         4 . The superconducting motor according to  claim 2 , wherein:
 the neutral point is provided at the side of coil end portions of the plurality of coils, which are axial end portions of the plurality of coils in an axial direction of the superconducting motor; and   the refrigerator is arranged such that the one end portions of the respective phase coils are connected to the cooling portion of the refrigerator at the side of the coil end portions of the plurality of coils.   
     
     
         5 . The superconducting motor according to  claim 2 , wherein the lengths of the superconducting wires forming the respective coils are substantially equal to each other. 
     
     
         6 . The superconducting motor according to  claim 1 , wherein:
 the plurality of coils are provided with an annular heat transfer member that is in contact with coil end portions of the plurality of coils, each of the coil end portions being located at a superconducting motor axial direction end of a corresponding one of the coils; and   the cooling portion of the refrigerator is arranged so as to be in contact with the plurality of coils, and cools the plurality of coils from the coil end portions via the heat transfer member.   
     
     
         7 . The superconducting motor according to  claim 1 , wherein the superconducting motor is a three-phase alternating current motor. 
     
     
         8 . The superconducting motor according to  claim 1 , wherein:
 the refrigerator has a cylinder and a piston; and   the refrigerator is structured such that coolant in an expansion chamber defined in the cooling portion is repeatedly compressed and expanded by the piston reciprocating in the cylinder, while heat of the coolant is absorbed and radiated via a heat absorption member, causing a temperature decrease and thereby achieving a desired cooling temperature at the cooling portion.   
     
     
         9 . The superconducting motor according to  claim 1 , wherein:
 the refrigerator has a coolant compressor coupled with the cooling portion; and   the coolant compressor is electrically insulated from a front end of the cooling portion, which is in contact with the plurality of coils, by an insulator that is provided at an intermediate portion of the cooling portion or at a boundary between the cooling portion and the coolant compressor.