DC cooling fan "Inflatable Air Blower" is to provide the use of a DC power supply: DC motor has a stator and a rotor of two parts, there is a stator pole (windings or permanent magnet), rotor windings, the power, the rotor is also a magnetic field (magnetic), there is an angle between the stator and rotor poles, the magnetic field in the stator and rotor (N and S poles between) the mutual attraction, "Inflatable Air Blower" is the motor rotation. Change brush seat, you can change the angle between the stator and rotor poles (assuming the angle between the stator pole starting side, "Inflatable Air Blower" rotor pole for the other side, by the direction of the magnetic poles of the rotor stator pole is pointing direction of rotation) direction, thereby changing the direction of rotation of the motor.