Patent ID: 7969051

Claim:
A ventilation system for a rotary electrical machine for a motor vehicle, comprising a rotor mounted so as to rotate in a stator carried by a casing; the ventilation system provided for cooling the rotary electric machine by forced flow of a cooling fluid; the ventilation system comprising: first and second rotor fans fixed to opposite first and second axial ends of the rotor, respectively, and driven by the rotor; and an independent fan spaced apart from the first and second rotor fans and driven independently from the rotor fans for cooling the rotary electric machine at relatively low speeds of rotation of the rotor; the second rotor fan and the independent fan disposed on the same side of the rotor; the second rotor fan having a reduced size compared to the first rotor fan so that an air flow output produced by the first rotor fan being substantially equal to the total air flow output produced by the independent fan and the second rotor fan; the ratio between the outside diameter of the second rotor fan and the outside diameter of the rotor is less than 90%.