"220V Cooling Fan" governor has inductive and electronic speed control, inductive governor is an adjustable inductor in series with the fan motor circuit for changing the voltage drop on the fan, to adjust the speed of the sub-file purpose, electronic speed potentiometer is adjusted by an SCR conduction angle to change the voltage "220V Cooling Fan" motor speed reaches stepless adjustment purposes. No matter what form the governor, as long as the governor circuit in series with the fan on the line. Household roof "220V Cooling Fan" has a capacitance 400V1-2μf, this capacitor is to start capacitor start motor running from the role. Then the distribution cabinet sink, do not add, because the motor does not need to start capacitor.