When studying the speed of an explosion-proof centrifugal fan, it can usually be regarded as a DC speed regulating motor, and its speed is mainly changed by using an adjustable resistor. As long as the controllable rectification is applied to both ends of the motor, the speed of the centrifugal fan can be controlled. But if the speed is unstable, what is the reason?
On the one hand, it may be because there are four centrifugal fans. There are some problems with the rectifier diode, which will affect the function of the entire device. On the other hand, the carbon powder or carbon brush itself of the motor rotor and the commutator may not be equal. At this time, you can first check the adjustable resistance of the fan. It is good if the resistance changes with adjustment.
On the other hand, the problem may lie in the explosion-proof centrifugal fan thyristor, such as open circuit, poor contact, short circuit, inability to touch, etc., which are all causes of unstable speed. In addition, if the adjustable resistor is in poor contact, the speed stability will also be affected.