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 rotating electrical machine with a reverse flow ventilation system is constructed with one or more discharge ducts at the center of the stator core to reduce the air gap pressure and promote more uniform cooling. In a second embodiment, discharge ducts are provided axially displaced from the center line of the core. In another embodiment, end region cooling of the conductor bars is enhanced by a series-parallel flow path constructed with the use of baffles and an apertured plate. In a final embodiment, both stator core center discharge ducts and series-parallel flow end region cooling are incorporated in the same machine.

Abstract: In a ventilated cooling system for a generator, the cooling ducts in the stator are arranged to control the flow of cooling gases through the stator. The ducts in the stator extend radially and direct cooling gases from the outer periphery of the stator to its inner cylindrical surface. Cooling gases flow radially inward through these stator ducts, extract heat out of the stator and exit from the stator ducts into an annular air gap between the stator and rotor. A fan on the rotor draws the heated air out from the air gap and causes more cooling gas to be drawn into the stator. The cooling ducts in the stator are spaced and sized to optimally distribute the flow of cooling gases through the stator by equalizing the pressure drops between the stator outer plenum and the entrance to the rotor exhaust fans. For example, the stator ducts may be spaced close together at the center of the stator and farther apart near the ends of the stator to provide balanced cooling flows and uniform temperatures.