"24V DC Cooling Fan" is used to provide DC power supply: DC motor has a stator and a rotor composed of two parts, there are poles on the stator, the rotor winding, the power, but also form a magnetic pole of the magnetic field, the stator and rotor of the rotor inter has a angle to the magnetic field in the stator and rotor mutual attraction under the motor rotation. Change "24V DC Cooling Fan" brush position, you can change the direction of the angle between the stator and rotor poles, thereby changing the direction of rotation of the motor. Fans used for a long time, there will be a lot of protective cast metal rust spots, difficult to remove, but if you dip some detergent and water applied with a cloth cover, and then dipped in some talcum powder wipe rust spots, and soon will be able to "24V DC Cooling Fan" wipe the rust spots.