1. There is carbon powder between the motor rotor and commutator or the carbon brush itself is not good. Based on the principle of "easy first, then difficult to repair", the adjustable resistance is measured first, and the resistance changes regularly with the adjustment. It is proved that the potentiometer of the mine fan is good, and no problem is found in the measurement of thyristor. Because the diode is a large current gold sealed tube, one end of the screw is fastened on the circuit board, the other end is wire welded Connect the diode to the circuit board and remove it from the circuit board. It is found that the positive and negative poles are loose. Measure and shake at the same time to confirm that the diode is good or bad.
2. There is only one problem among the four rectifying diodes of mine fan.
3. There are many problems in SCR, such as breakdown, short circuit, open circuit, failure to trigger or poor internal contact.
4. Adjustable resistance, because the adjustable resistance of mine fan is installed on the control panel, the use frequency is very high, the time is long, and the situation of bad contact is very common.
It can be seen that when the mine fan is in use, the unstable speed is likely caused by the internal parts. You can focus on the parts inspection, and remind us that the daily maintenance and inspection of the product can not be ignored, so that the problem of unstable speed can be avoided in use.
