Abstract: This invention relates to a brushless motor driving system for driving an outdoor fan of an air conditioner. The driving system comprises a Hall probe for detecting a position of a rotor of a brushless motor, an inverter circuit consisting of a plurality of switching elements connected in bridge-connection, the inverter circuit supplying ON-OFF electric current to stator coils of the brushless motor, and a control means for switching the switching elements of the inverter circuit based on the output signal of the Hall probe. Before starting the motor, the control means controlls the switching elements to supply DC PWM-controlled current to the stator coils of the motor in synchronization with the output signal of the Hall probe, so that the rotor is braked, stopped and set to home position.