In the technical parameters of centrifugal fan, the focus is on its speed, because in the actual operation process, due to some factors, the speed will change. In order to maintain a stable and suitable speed, the speed of centrifugal fan is usually regulated by changing the conduction angle of thyristor through adjustable resistance, and then by controlling the voltage at both ends of the motor after rectification by thyristor.
That is to say, if the centrifugal fan speed instability, it is likely to be related to thyristor, once thyristor has problems such as breakdown short circuit, open circuit, can not trigger or poor foundation, the speed will fluctuate accordingly. At the same time, it can be thought of that the reason is adjustable resistance. It is normal that poor contact occurs due to long-term use, but it will also affect the speed of centrifugal fan.
In addition, carbon powder or carbon brush itself between motor rotor and rectifier may also be the culprit. So when we encounter similar problems, we should not rush to solve them, but find the root of the problem, and then take effective measures to solve them.