BigPatents India

A gas cooled dynamoelectric machine is provided that is comprised of a rotor (10), a rotor winding comprising axially extending coils (22) and concentric endwindings (28, 128, 228) and a plurality of spaceblocks (40, 140, 240) located between adjacent endwindings thereby to define a plurality of cavities (42, 142, 242), each bounded by adjacent spaceblocks and adjacent endwindings. To enhance the heat transfer rate from the copper end turns (27, 127, 227) of the field endwinding region, cavity facing surface(s) (144, 146, 156, 244, 246, 256) of the endwinding (128, 228) and/or the spaceblock (140, 240) have a non-planar surface profile to increase surface area, improve turbulent mixing on the surface, and/or provide boundary layer breakup (FIG. - 1)