The speed of the tunnel fan is unstable, it is likely that there is a problem with thyristor, which is generally caused by short circuit, open circuit caused by eating and wearing, can not start or is caused by bad temperature contact inside, which is possible.

(2) Adjustable resistance. Tunnel fan is mastering the panel because of the adjustable resistance device. The frequency of use is very high, the time is long, and the emergence of contact is not good.

What is the cause of the unstable speed of the tunnel jet fan? There are four rectifier diodes in the tunnel jet fan. If there is a problem with one of these four diodes, the speed will also be unstable, so you can check this.

⑷ Between the generator rotor and the whole group of toner or carbon brush itself is not good, in line with the first easy after difficult repair criteria, take the lead in measuring adjustable resistance, resistance value with the rule of change, confirmed that the flood level is good, and then measuring thyristor is not found, because the polar tube is a large DC gold seal tube, one end of the screw is fastening on the path plate, The other end of the line riveted to the path plate, removed from the path plate, found that the positive cathode has a loose scene, on the one hand to measure on the other hand shake, prove that the bipolar tube is good or bad.

In fact, it can be seen from the above points that there are many reasons for the unstable speed of the tunnel jet fan, but most of these can be avoided. As long as the tunnel jet fan is correctly used according to the instructions or is regularly maintained, most of the faults can be avoided if the damaged place is repaired in time.