REFRIGERANT COOLING TYPE ELECTRIC MACHINE COIL

摘要

PURPOSE:To reduce the eddy current loss in a hollow conductor which is wound to form a coil by a method wherein stranded wires are arranged around a hollow pipe through which cooling refrigerant is circulated. CONSTITUTION:A coil conductor 13 is composed of a hollow pipe 11 and stranded wires 12 arranged around the pipe 11. The sectional area of the hollow part 14 of the pipe 11 is determined by the quantity of refrigerant circulated through it but the sectional area of the pipe 11 is determined to be just large enough to maintain mechanical strength as a core of wire stranding. Thus the eddy current loss in this sectional area can be smaller than that in the sectional area of the conductor is not composed of stranded wires and, as the stranded conductors which generate smaller eddy current loss are arranged around the pipe, the eddy current loss of the hollow conductor 13 can be reduced as a whole.