Motor control system for driving an air damper

The passenger cabin ventilator DC drive motor (1) control system (2) includes two two-way switches working together (3), to reverse the polarity of the motor. A control circuit (7) as connected in series with the motor. It incorporates a PTC (Positive Temperature Coefficient) element (4) with a diode (5) and a fixed resistor (6) in parallel, all in series with the motor.