The cooling fan with speed regulation is more and more applied to intelligent devices. Some industrial equipment is also becoming more and more automatic. The speed regulating cooling fan is also being used more and more widely. The speed regulating fan has several modes, such as voltage, resistance, current and pwm speed regulation. Here we will judge whether the cooling fan supports the pwm speed regulation function from several aspects
1. According to the number of lines, the conventional cooling fan without function only has positive and negative double lines. The cooling fan with pwm speed regulation function has three or four lines. The three line is the pwm function line in addition to the positive and negative pole lines. The four line is because the cooling fan with pwm speed regulation function may also have RD operation monitoring function, which forms a four line
2. According to the wire color, the positive and negative poles of the cooling fan are usually red and black, the pwm speed regulation is blue, and the added functions of the four wires are generally yellow if they are monitored by RD
3. Observe the startup status. The PWM speed regulating fan can maintain a very low speed when the device is in standby. Generally, the rotating speed is about 1000 revolutions, which greatly reduces the running noise. The fan speed is obviously accelerated when the equipment is working.
The other is to observe the power on condition. The PWM temperature controlled fan will increase to the highest speed at the moment of power on, and then reduce to the low speed level of standby after several seconds. This feature is also the most obvious feature of PWM intelligent temperature controlled fan, which can be used to judge whether the fan and motherboard really have PWM function or whether their function is faulty.
