DC fan and its working principle

DC fan, as the name implies, is a cooling fan that converts electrical energy into electromagnetic energy through DC voltage and electromagnetic induction, and then electromagnetic energy into mechanical energy, and finally into kinetic energy, so that the fan blades rotate.

Conventional DC fans are mainly composed of four parts: rotor, stator, motor, and outer frame. The DC motor consists of a permanent magnet rotor, a multi-stage winding stator, a position sensor, and an electronic commutation drive control circuit. The rotor is composed of: motor shell + permanent magnetic strip + shaft core + fan blades. Stator part: enameled wire + plastic coated silicon steel sheet + bearing + Hall sensor detection + drive circuit board + shaft.

The core components of a DC fan are the stator and the rotor. According to the ampere right-hand rule, we know that a conductor passes current and a magnetic field will be generated around it. If this conductor is placed in another fixed magnetic field, it will generate attraction or repulsion, which will cause the object to move. Inside the fan blade of the DC fan, a rubber magnet filled with magnetism is attached. Around the silicon steel sheet, two sets of coils are wound around the shaft, and a Hall sensor component is used as a synchronous detection device to control a set of circuits. The circuit makes the two sets of coils wound around the shaft work in turn to make the silicon steel sheet produce different magnetic poles. This magnetic pole and the rubber magnet generate repulsive force. When the repulsive force is greater than the static friction of the fan, the fan blade rotates naturally. Since the Hall sensor component provides a synchronization signal, the fan can continue to operate. As for the direction of rotation, it can be determined according to Fleming's right-hand rule. This is how the DC fan works.