Generally, there are two types of wiring for common DC cooling fans, namely 4Pin (four wires) fans and 3Pin (three wires) fans. And 2pin is very rare in the market.
The DC cooling fan is originally a 2-wire, one positive and one negative. Later, in order for the CPU to monitor the fan speed, so as to alarm when the fan is damaged, an output signal line was added, and the frequency was used to indicate the fan speed. This is the 3-wire. The colors of the fans of Pin (three wires) are: red is the power line +12v, black is GNG (ground), and yellow is the Sensor signal line. The newly added wiring is used to detect the fan speed.
Later, in order to control the speed of the DC cooling fan, the speed can be reduced when the temperature is low to reduce noise, and an input signal line is added to control the fan speed with the pulse frequency. This is the 4-wire. In order to be compatible with 4-wire and 3-wire, the added wire is added on the outside of the plug. The three-wire and four-wire are compatible with each other and can be plugged in without damaging the hardware.
However, if the socket on the motherboard has only three wires and a fan with four wires is inserted, or if the socket on the motherboard is four wires and the fan is three wires, then the fans will all run at the highest speed. The colors of the 4Pin (four wires) fans are: red is the power wire +12v; black is GNG (ground wire); yellow is the sensor signal wire, which is used to detect the speed of the DC cooling fan;the blue PWM signal line is a new line, which is mainly used for the motherboard to intelligently adjust the fan speed according to the temperature.
DC cooling fan manufacturers will definitely choose the form of increasing the number of leaves to ensure the necessary wind speed and pressure on the fan's pin. But no matter the number of blades of the DC cooling fan, its blade structure is mostly composed of 7, 9, 11 and other odd-numbered leaves. This is due to the fact that odd-numbered blade compositions can bring greater performance advantages than even-numbered blade compositions.
If the total number of blades is designed with an even number, and the ordering method of the corresponding points is generated, it will not only make the stability of the electronic cooling fan itself difficult to change, but also make it easier for the fan to form more resonance when running at high speed. As a result, the blade cannot bear the fatigue caused by the resonance for a long time, and finally the blade cracks and so on. Therefore, the designs of electronic DC fans are mostly different odd-numbered blade designs.