Abstract: A cooling system for a rotating electrical machine, such as a power generator, includes a cooling fan that serves to exhaust hot gas from an interior of the machine, a seal ring surface defining a passage for the exhausted hot gas, and a clearance seal positioned in the passage between a rotating body of the machine, such as a generator rotor, and a non-rotating body of the machine, such as a generator stator, to prevent the exhausted gas from entering an inlet to the rotating body. The seal ring surface is shaped to impart sufficient momentum to the exhausted hot gas to prevent the exhausted hot gas from leaking into the rotating body inlet. The contoured shape of the seal ring surface immediately downstream of the rotor is positioned such that the high velocity fan discharge stream is directed to flow along this surface. The high through-flow momentum of this gas stream does not allow any backward flow, thereby eliminating hot gas leakage.

Abstract: A cooling gas ventilation circuit is provided for an end winding of a rotary machine having a rotor of the type having a plurality of radial slots and a plurality of coils respectively seated in the radial slots, the coils extending beyond a pole face of the rotor to form the end winding. The ventilation circuit is composed of first and second cooling gas passages, respectively defined in at least one turn of each coil of the end winding. Each first cooling gas passage extends from an inlet port in communication with a cavity on one longitudinal side of the turn to an exit port defined on the other longitudinal side of the turn. Each second cooling gas passage extends from an inlet port in communication with the cavity on the one longitudinal side of the turn to an outlet in the form of a radial chimney defined through a plurality of the turns of the coil within the respective radial slot.

Abstract: A new stator core cooling concept is provided that can be implemented with a conventional core structure having cooling ducts interspersed at intervals along the axial length of the stator core. To enhance cooling of the stator coils, the cooling ducts are radially closed off so that cooling air is forced to flow circumferentially, preferably through small holes, channels, or slots, to impinge directly on the armature bar surface. Accordingly, rather than flowing cooling gas through the cooling ducts and immediately discharging it into the annular gap between the rotor and stator, cooled gas flows radially down through the cooling duct and then must flow circumferentially whereupon it impinges directly on the armature bar surface itself.

Abstract: Cooling of the rotor endwindings in a dynamoelectric machine is improved by providing radially-extending ducts in the spacers located between the concentric end turns of the rotor winding. The ducts have an inlet located near the radially inward end of the spacer and an outlet located near the radially outward end of the spacer. The inlet can be formed on either an axially-oriented surface of the spacer or a circumferentially-oriented surface of the spacer. The ducts direct cooling air into the cavities between the end turns in such a manner that the circulation velocity in the cavities is increased. This results in increased heat removal capability.