The difference between AC and DC fans the principle of operation of AC FANS: AC Fans because the power frequency fixed 50 Hz or 60 Hz, so the frequency of fixed silicon steel pole changes, so the coil power, the direction is constantly switching, so it doesn't take a Houle sensor to generate the repulsion force that drives the fan. The speed of AC fan is determined by the frequency of power supply. The higher the frequency, the faster the magnetic field switching speed, the higher the speed, but the frequency can not be too fast, too fast will cause activation difficulties. DC Fan Operation Principle: DC Fan operation principle is the city power after the PFC and rectification filter to get DC310V DC voltage, fan rotor magnetic rubber magnets, circuit board IC through Houle component current wave back emf contrast, sensing the precise position of the N / S Pole of the Rotor's magnetic field, by controlling the MOS switch state, the coil will generate a magnetic field, which is derived from the silicon steel sheet and interacts with the Rotor's magnetic field, generating a repulsive force that drives the fan to rotate The commutation signal synchronously inducts the rotor to rotate the magnetic field, and then switches the current direction of the electric coil, so that the fan can keep running.

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