Abstract: A control device for an electric motor of a cooling fan for the radiator of a motor vehicle has a control transistor connected to the motor, and an electronic control unit for controlling the speed of the motor. The control unit controls the transistor in such a manner as to limit the current flowing in the motor to a predetermined value when, by effect of the load conditions of the motor and the voltage applied to the motor, the current in the motor tends to exceed the predetermined value.

Abstract: A control circuit for an electric fan, has a MOSFET transistor connected essentially in series with the motor of an electric fan between the two terminals of a first D.C. voltage source and having its source terminal connected to the motor; a transistor driving stage, having an input intended to receive a pulse-width modulation control signal and an output connected to the gate terminal of the MOSFET transistor, and a bootstrap capacitor connected between a second D.C. voltage source and the source terminal of the MOSFET transistor. A controlled electronic switch having a parallel-connected diode for conducting current from the bootstrap capacitor to the motor is arranged between the bootstrap capacitor and the source terminal of the MOSFET transistor. The electronic switch has a control input or gate connected to the output of the transistor driving stage.

Abstract: A voltage regulator for a pair of electric motors has an input for a signal indicative of the desired speed for the motors and a pulse width modulation control circuit device. A control module provides a conditioning signal to the control circuit to output to the motors a square wave voltage having a duty-cycle which varies according to a predetermined function of the signal applied to the input of the regulator. The control circuit device has first and second electronic solid state switches associated with the motor and controlled by the control module.

Abstract: A voltage regulator for a pair of electric motors has an input for a signal indicative of the desired speed for the motors and a pulse width modulation control circuit device. A control module provides a conditioning signal to the control circuit to output to the motors a square wave voltage having a duty-cycle which varies according to a predetermined function of the signal applied to the input of the regulator. The control circuit device has first and second electronic solid state switches associated with the motor and controlled by the control module.

Abstract: A control device for an electric motor of a cooling fan for the radiator of a motor vehicle has a control transistor connected to the motor, and an electronic control unit for controlling the speed of the motor. The control unit controls the transistor in such a manner as to limit the current flowing in the motor to a predetermined value when, by effect of the load conditions of the motor and the voltage applied to the motor, the current in the motor tends to exceed the predetermined value.