Abstract: A method for controlling an electromagnetic retarder comprising a current generator into which an excitation current is injected. The method consists in determining a maximum allowable intensity (Im) of the excitation current to be injected into the stator primary coils of the retarder which includes a shaft bearing secondary windings and field coils which are supplied by the secondary windings, said primary coils and secondary windings forming the generator. The retarder includes a jacket inside which the field coils generate Foucault currents and a circuit for the liquid cooling of said jacket. More specifically, the method consists in determining the maximum allowable intensity in real time, such as to reach a critical temperature of the cylindrical jacket and determining said critical temperature taking account of a temperature value of the coolant. The method is suitable for retarders that are intended for vehicles such as heavy vehicles.

Abstract: A method for controlling an electromagnetic retarder. More specifically, the method relates to determining, in a control unit, a maximum allowable intensity (Im) of an excitation current to be injected into an electromagnetic retarder (1). The retarder includes a shaft bearing secondary windings (5) and field coils (13) which are supplied by the secondary windings (5), the primary coils (8) and secondary windings (5) forming a generator. The retarder also includes a jacket (9) inside which the field coils (13) generate Foucault currents and a circuit for the liquid cooling of said jacket. The method consists in determining the maximum intensity in real time from data and values that are representative of the speed of rotation of the rotary shaft, the heat load that the cooling circuit can dissipate and the flow rate (D) of the coolant. The method is suitable for electromagnetic retarders which are intended for vehicles such as heavy vehicles.

Abstract: The invention relates to a self-disengaging embodiment for a fan in an electromagnetic retarder. The retarder comprises a rotating shaft, a rotor rotationally fixed to the rotating shaft, induction coils, arranged in a crown on the rotor, a generator with a rotor mounted on one end of the rotating shaft and supplying the induction coils and a fan to circulate a cooling gas around the induction coils. The fan is fitted to freely rotate about the rotating shaft and is provided with means forming an armature which may be exposed to an electromagnetic field created by the induction coils and causing the fan to rotate.