DC fan works:

According to the right-hand rule, the conductor through the current, the surrounding will produce a magnetic field, if the conductor placed in another fixed magnetic field, it will produce suction or repulsion, causing the object to move in the fan fan inside the fan, A magnetic rubber magnet surrounding the axis of the two sets of coils, and the use of Hall sensor components as a synchronous detection device to control a group of circuits, the circuit to the axis of the two groups of coils in turn work. The magnetic pole and the rubber magnet produce a repulsive force.When the sucking force is greater than the static friction force of the lice fan, the fan blade rotates naturally.As the Hall sensor module provides the synchronizing signal, the fan blade can continue to run, as its running direction, AC fan and DC fan of the difference between the former power supply for the exchange, the power supply voltage will be positive and negative, unlike the DC fan power supply voltage is fixed, must be the same as the DC fan Rely on the circuit control, so that the two groups of turns to work in order to produce different magnetic field. AC fan due to the fixed frequency of power, so the silicon steel chip to produce the magnetic pole change speed, determined by the power frequency, the higher the frequency the faster the magnetic field switching speed, theoretically the speed will be Fast, like the number of DC fans more speed faster the same principle, but the frequency can not be too fast, too fast will cause activation difficulties.

Working principle and use:

A) DC cooling fan is the use of direct current to provide power: DC motor stator and rotor composed of two parts, the stator has a magnetic pole (winding or permanent magnet), the rotor has a winding, power, the rotor also formed a magnetic field Magnetic pole), there is an angle between the stator and the pole of the rotor, and the motor rotates under the mutual attraction of the fixed rotor magnetic field (between the N pole and the S pole). Changing the position of the brush can change the stator and rotor clamp (Assuming that the direction of the magnetic pole of the rotor is the direction of the direction of rotation of the motor), and the direction of rotation of the motor is changed.
B) AC cooling fan is to use alternating power to provide power: single-phase AC motor only one winding, the rotor is squirrel-cage. When the single-phase sinusoidal current through the stator winding, the motor will produce an alternating magnetic field, this The strength and direction of the magnetic field changes sinusoidal time with time, but it is fixed in the spatial orientation, so the magnetic field is also called the alternating pulsating magnetic field. The alternating pulsating magnetic field can be decomposed into two at the same speed, For the opposite rotation of the magnetic field in the rotor to produce two equal size, the opposite direction of the torque, making the synthetic torque is zero, so the motor can not rotate when we use the external force to the motor in a direction of rotation (such as clockwise Rotation), the movement of the cutting magnetic field between the rotor and the rotating magnetic field in the clockwise rotation direction becomes smaller; the movement of the cutting magnetic field between the rotor and the rotating magnetic field in the counterclockwise rotation direction becomes larger, so that the balance is broken and the total The electromagnetic torque will no longer be zero and the rotor will rotate in the direction of the push.