The DC cooling fan refers to the cooling fan powered by DC power supply. Its operation changes with the heat. When it operates at a slower speed, the DC fan will produce less noise and consume less energy. In most of the design requirements, the air temperature is usually lower than the maximum design temperature after the DC cooling fan runs for several hours at a higher speed.
1、 The types of DC cooling fans are:
1. 1 Mixed flow type: it has the above two air flow modes.
1. 2 Axial flow type: the direction of air flow outlet is the same as that of shaft center.
1. 3 Centrifugal: use centrifugal force to throw the air flow outward along the blade.
2、 DC cooling fan consists of fan frame, fan blade, bearing, PCB control circuit and drive motor.
3、 Plastic material and color selection of DC cooling fan frame and blade:
2. 1 Fan frame+fan leaf: PBT raw material black (plastic thermal deformation temperature 230 ℃)
2. 2 Fan frame+fan leaf: transparent PC raw material (plastic thermal deformation temperature 120 ℃)
2. 3 Fan frame+fan leaf: PBT raw material white (plastic thermal deformation temperature 230 ℃)
4、 Speed: refers to the speed of fan rotation, which is usually measured by the number of revolutions in 1 minute, i.e. rpm. The rotational speed is related to the number of electromechanical winding turns, wire diameter, outer diameter and bottom diameter of fan blade impeller, blade shape and bearing used, etc. The air volume increases with the increase of rotational speed.
5、 Working principle of DC cooling fan: according to the right hand rule of ampere, the conductor will generate magnetic field around it when passing through the current. If the conductor is placed in another fixed magnetic field, it will generate attraction or repulsion, causing the object to move. A rubber magnet filled with magnetism is attached to the fan blade of the DC cooling fan. Around the silicon steel sheet, two groups of coils are wound around the shaft center, and the Hall sensor assembly is used as the synchronous detection device to control a group of circuits, which make the two groups of coils wound around the shaft center 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.
