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.