Five common fault analysis and treatment methods of medium frequency melting furnace

The reason for the failure of the intermediate frequency furnace equipment is very simple, but it is not easy to check one by one. Only by deeply understanding the basic principles of the intermediate frequency power supply, can we see the essential cause of the failure through the phenomenon. The following introduces five kinds of faults that often occur in intermediate frequency furnace equipment.
Five kinds of failure analysis and treatment methods of intermediate frequency furnace equipment
(1) The main circuit is closed normally, and the intermediate frequency starts to fire instantly. The inspection finds that the two-way fuse and the corresponding thyristor are burned out, and the main control board is burned out.
Solution: Check whether the installation positions of the two thyristors correspond to the gate wiring, and pay attention to the installation positions of the thyristors.
(2) The equipment can run and start, but when the adjustment power rises and falls in a certain section, the equipment has abnormal noise and vibration, and the ammeter and voltmeter keep swinging.
Solution: Don’t panic when this phenomenon occurs, because this kind of fault usually occurs on the potentiometer. This is because the resistance of a certain section of the potentiometer with a given power changes smoothly, which will cause the intermediate frequency furnace to work unstable, and even burn out in severe cases. Thyristor. This phenomenon only needs to replace the potentiometer.
(3) The intermediate frequency heavy load can be started normally, and the inverter voltage can be increased to 300 V, and it will trip for 30 s and automatically restart.
Solution: At this time, we checked and found that the ratio of intermediate frequency voltage to DC voltage is 1.2, which can be adjusted slightly, but it is found that it cannot be increased. At this point, we only need to replace the main control board, and then normal production can be done after re-commissioning.
(4) When the intermediate frequency furnace starts, the DC current is large, the DC voltage is low, and the intermediate frequency voltage cannot rise.
Solution: Check whether the compensation capacitor is short-circuited. Throw off the capacitors one by one and then restart, and immediately judge the short-circuit capacitor.
(5) After starting, the knob of the power adjustment potentiometer is set to the maximum, but the indication value of the ammeter and voltmeter is still very small, and the discharge temperature cannot meet the process requirements.
Solution: At this time, we need to check the thyristors of the rectifier part, and no abnormality is found. Replace the original thyristors with new thyristors one by one, and find that the faulty component is a rectifier thyristor.
The above is for the convenience of everyone to summarize the 6 kinds of phenomena that appear in the intermediate frequency furnace equipment. Only by constantly exploring, analyzing and summarizing fault phenomena and fault characteristics, can we accumulate more experience, improve the speed and quality of maintenance, and seek more convenience for the enterprise.