The unsteady rotating speed of high pressure fan is a common problem. Speed instability is mostly because of the motor speed instability. Then from the fundamental analysis of motor instability, it is likely to be the following four cases.
Centrifugal fan motor unstable reason:
There is only one of the four rectifying diodes.
Four. There are defects of carbon powder or carbon brush between rotor and motor rotor. Adhere to specific standards for measuring variable resistance. With the periodic change of the adjustment, the resistance value proves to be good.
Variable resistors, because the variable resistors installed in the operation panel, the application of high frequency, long time, poor contact is common.
Three-terminal two-way thyristor problems, usually a penetrating short-circuit fault, resulting in unable to switch off or poor internal contact.
