Since the "Micro Cooling Fan" stator is stationary, so the rotor rotates under the force of. Commutator DC motor is a special apparatus, and by changing the composition of a number of segments, each two adjacent commutator intermediate insulating sheet. The surface of the commutator by a spring pressing the fixed brush, "Micro Cooling Fan" to the rotating armature winding is coupled with an external circuit. When the rotor turned at an angle, the commutator will access another supply voltage winding, and continue to produce a magnetic field in the winding Seen, due to the presence of "Micro Cooling Fan" commutator, the armature coil by the electromagnetic torque remains unchanged, the electromagnetic torque acts in the armature to rotate.