A non-reversible electrical machine with gas cooling, comprising a body with built-in gas coolers, said body accommodating a stator winding with end connections in end face areas of the body, a rotor whose shaft carries fans provided with exhaust and pressure chambers, and a stator core with radial vent ducts divided, together with a space between it and the body, in a tangential direction into segments associated with the fan exhaust chambers directly via the area of the end connections of the stator winding, and also into other segments which are arranged in alternate relation to said first segments, are equal in number to the latter and are associated with the fan pressure chambers via the gas coolers, characterized in that the radial vent ducts (4) in each area of the stator core (3) juxtaposed to the stator winding end connections (5) being separated from the remaining radial vent ducts (4) by two cylindrical partitions (14, 18), one of said partitions (18) connected to the inner portion of the stator core (3) and being positioned within a gap (16) between the rotor (1) and the stator core (3) and adapted to form, together with the inner surface of the stator core (3) and the end connections (5) of the stator winding, an inner annular cavity (19) which communicates with a fan exhaust chamber (8), the other cylindrical partition (14) being positioned within a space between the stator core (3) and the body (6) and adapted to form, together with the external surface of the stator core (3), an outer annular cavity (15) which communicates with the segments (12), which in turn, communicate with the fan pressure chambers (9), the both annular cavities (15, 19) communicating with each other via the radial vent ducts (4) located in the end area of the stator core (3) which is juxtaposed to the end connections (5) of the stator winding.