Ventilation system for dynamoelectric machines

A ventilation system is provided for dynamoelectric machines such as hydro generators having salient pole rotors and in which the rotor and stator have separate ventilation systems sealed from the air gap. The stator ventilation system includes radial vent ducts with longitudinal ducts in the stator core extending between adjacent radial vent ducts. The longitudinal ducts are sealed from the air gap and are disposed in the region of the stator windings, preferably extending through the teeth. Ventilating air flows radially inward through the vent ducts, longitudinally through the longitudinal ducts from one vent duct to the next, and radially outward to the external circuit where it is circulated through coolers, by means of a blower or otherwise.