Abstract: A dynamo-electric machine of the gas-cooled type, for example, an induction of synchronous machine is comprised of a casing which houses a rotor and a stator. A gas-coolant inlet space is provided within the casing at each end thereof and a gas-coolant outlet space is provided between the periphery of the stator and the inner surface of the casing. The internal space occupied by the stator and rotor components is separated from the gas-coolant inlet spaces provided within opposite end portions of the casing and the gas-coolant is force-circulated from the inlet spaces in a radially outward direction through radially extending slots provided in the rotor and stator to the outlet space, the rotor slots functioning as a centrifugal fan in establishing the forced circulation of the gas-coolant through the machine.