Patent ID: 7816825

Claim:
A cooling gas ventilation chimney for an end region of a dynamoelectric machine having a rotor, a plurality of radial slots provided in said rotor, and a plurality of coils respectively seated in said plurality of radial slots, a plurality of radially stacked turns comprising a coil, said ventilation chimney comprising: one or more chimney slots defined in at least a portion of said radially stacked turns, said one or more chimney slots extending in a substantially radial direction to said rotor, the one or more chimney slots forming an exhaust manifold where an input to the exhaust manifold is a plurality of axially oriented cooling grooves, the one or more chimney slots guiding cooling gas substantially in a direction of centrifugal force, and the input to the exhaust manifold guiding cooling gas substantially in a direction orthogonal to centrifugal force, wherein at least one or more of said chimney slots are at least one of, graduated in size and gradually changing in size, and configured so that smaller chimney slots are located at inner radial positions and larger chimney slots are located at outer radial positions of the radially stacked turns, and wherein at least one or more of said chimney slots having an axial or circumferential length different from another one of said chimney slots, and the exhaust manifold is located in at least one of the slot end region and end winding region of the rotor.