An electric machine comprises: a cylindrical rotor having a first end, a second opposite end, and axial (X1-X1) first air channels, a stator surrounding the rotor having axial (X1-X1) second air channels (21, 22, 23) and cooling fins on the outer surface of the stator, a first air chamber at the first end of the rotor and a second air chamber at the second end of the rotor, whereby a flow path is formed between the first air channels and the second air channels through the first air chamber and the second air chamber, a third air chamber at the second end of the rotor axially (X1-X1) outside the second air chamber, said third air chamber having an outlet opening directed axially (X1-X1) along the outer surface of the stator, a first fan for circulating internal air in a closed air circulation from the first air chamber through the first air channels to the second air chamber and further through the second air channels back to the first air chamber, a second fan for blowing external cooling air from the outside of the electric machine through the third air chamber and from the outlet opening of the third air chamber along the outer surface of the stator, characterized in that: the number of second air channels (21, 22, 23) in the stator is three and formed of two lower second air channels (21, 22) and of one upper second air channel, whereby the lower second air channels (21, 22) are positioned symmetrically in lower corners of the cross section of the electric machine in connection with support structures (251, 252) of the electric machine, and the upper second air channel is positioned on a vertical centre axis (Y-Y) on the uppermost point of the cross section of the electric machine. a cylindrical rotor having a first end, a second opposite end, and axial (X1-X1) first air channels, a stator surrounding the rotor having axial (X1-X1) second air channels (21, 22, 23) and cooling fins on the outer surface of the stator, a first air chamber at the first end of the rotor and a second air chamber at the second end of the rotor, whereby a flow path is formed between the first air channels and the second air channels through the first air chamber and the second air chamber, a third air chamber at the second end of the rotor axially (X1-X1) outside the second air chamber, said third air chamber having an outlet opening directed axially (X1-X1) along the outer surface of the stator, a first fan for circulating internal air in a closed air circulation from the first air chamber through the first air channels to the second air chamber and further through the second air channels back to the first air chamber, a second fan for blowing external cooling air from the outside of the electric machine through the third air chamber and from the outlet opening of the third air chamber along the outer surface of the stator, the number of second air channels (21, 22, 23) in the stator is three and formed of two lower second air channels (21, 22) and of one upper second air channel, whereby the lower second air channels (21, 22) are positioned symmetrically in lower corners of the cross section of the electric machine in connection with support structures (251, 252) of the electric machine, and the upper second air channel is positioned on a vertical centre axis (Y-Y) on the uppermost point of the cross section of the electric machine.