US Patent 6844638 Fan for rotating electric machine

A rotating electric machine comprising at least a fan (43) provided with blades providing between them divergent ventilation channels (48) adapted to generate cooling fluid flow through the machine; the angle of incidence (B) of the blades, at the leading edge ranges between 150 degrees and 175 degrees, while the angle of incidence (A) of the blades at the trailing edge ranges between 90 degrees and 165 degrees relative to the tangent to a circle (C) generated during the rotation of the blades, the ratio between the average pitch of the blades (46) and the average length thereof being less than 0.975. The invention is applicable to fans for a motor vehicle alternator.