Cooling fans can be divided into DC cooling fans and AC cooling fans according to the power supply type.Working principle of DC fan

According to the Ampere's right-hand rule, when a conductor passes through an electric current, a magnetic field will be generated around it. If this conductor is placed in another fixed magnetic field, it will generate suction or repulsion, causing the object to move. A rubber magnet filled with magnetism is attached to the inside of the fan blade of the DC fan. Surrounding the silicon steel sheet, the axis part is wound with two groups of coils, and the hall induction component is used as the synchronous detection device to control a group of circuits, which makes the two groups of coils wound around the axis work in turn. Silicon steel sheet produces different magnetic poles, which generate attraction and repulsion force with rubber magnet. When the suction and repulsion force is greater than the static friction force of the lice fan, the fan blade rotates naturally. Since the hall sensing component provides a synchronous signal, the fan blade can continue to operate. As for its operation direction, it can be determined according to Fleming's right-hand rule.

Working principle of AC fan

The difference between AC fan and DC fan. The power supply of the former is AC, and the power supply voltage will be positive and negative alternating. Unlike the fixed power supply voltage of DC fan, it must rely on circuit control to make the two groups of coils work in turn to produce different magnetic fields. Because the power frequency of the AC fan is fixed, the change speed of the magnetic pole generated by the silicon steel sheet is determined by the power frequency. The higher the frequency, the faster the magnetic field switching speed, and the faster the speed in theory, just like the principle that the more poles of the DC fan, the faster the speed. However, the frequency should not be too fast, too fast will cause difficulty in activation.

Fan speed refers to the number of times the fan blades rotate per minute, in RPM, which is generally measured externally by instruments.