The difference between AC and DC fans

How the AC fan works:

Because the power frequency of the AC fan is fixed at 50Hz or 60Hz, the frequency generated by the silicon steel sheet changes with a fixed magnetic pole. Therefore, after the coil is energized, the direction is constantly switching, so the repulsive force can be generated without Hall induction to drive the fan to run. The speed of the AC fan is determined by the frequency of the power supply. The higher the frequency, the faster the switching speed of the magnetic field, and the higher the speed, but the frequency should not be too fast, otherwise it will cause difficulty in activation.

The working principle of DC fan:

The operating principle of the DC fan is to pass the mains power through PFC and rectification and filtering to obtain a DC310V DC voltage. There is a magnetic rubber magnet on the fan rotor. The IC on the circuit board senses the N/S pole of the rotor magnetic field through the comparison of the Hall element/current wave/back electromotive force. Accurate position, by controlling the state of the MOS switch, the energized coil will generate a magnetic field, which is derived from the silicon steel sheet, interacts with the magnetic field of the rotor, and the generated repulsive force drives the fan to rotate, and the commutation signal synchronously senses the rotor's rotating magnetic field and then switches the power supply Coil current flows so that the fan can run continuously.