Dynamoelectric machine with rotor ventilation system including axial duct inlet fairing

Claim 1

A dynamoelectric machine comprising: a stator and a rotor centrally disposed on a shaft for rotation within said stator; said rotor comprising an outer body portion having axially opposing end faces, said body portion having a plurality of axially extending coil slots in each of which is located an insulating slot cell adjacent the surface of said body portion, an axial ventilating channel at the bottom of each said slot, a plurality of coil turns, and a wedge closing the upper end of each said slot; said coil turns extending axially out of said body portion beyond at least one of said end faces, said cell and said channel extending axially out of said body portion beyond said end face to an extent less than said coil turns; a fairing of solid material disposed outward from said at least one of said end faces between said shaft and the extended portions of said coil turns, said fairing extending beyond the axial extent of said cell and said channel and less than the extent of said coil turns; and said fairing fitting closely around the extended portion of said cell and, at the inlet to said channel, having a curved portion providing a smooth flow transition region through which coolant gas flows into said channel without encountering the protruding sharp edges of said channel and said cell that would disturb the flow and cause a higher pressure drop.