3) If compensation capacitor open circuit. When the medium frequency compensation capacitor is open circuit, it has little influence on the normal operation of the SCR medium frequency power supply, but the frequency of the SCR medium frequency power supply is on the high side. At this time, only a few more medium frequency compensation capacitors are connected in parallel to make the frequency reach the normal value.

4) Inductor inter turn short circuit. When the inductor turns are seriously short circuited, the thyristor medium frequency power supply can not start. If the inductor only two turns collide, the thyristor medium frequency power supply may start, but the frequency is higher, the current is larger, and the power slightly increases, which will cause the inverter failure. Another phenomenon is that the inductor is loose. When the power is low, the SCR medium frequency power supply does not appear abnormal. However, when the power is increased, the electromagnetic force is increased due to the increase of current, and the inductor turns absorb each other, or the vibration during charging will cause the instantaneous short circuit between turns, making the sound of the medium frequency power supply abnormal and the meter swing. The main reason for the above fault is that the inductor is water cut off when it is working, and the insulation part of the inductor is burnt out.

5) The charge passes through the crucible and is short circuited with the inductor. This situation is equivalent to the transformer primary and secondary side short circuit, also equivalent to the inductor short circuit, so that the induction furnace can not work.

6) Broken core of water supply flexible cable. When the induction furnace dumps molten steel, the flexible cable and the induction furnace tilt together, which often leads to twists and turns. In particular, the connector of the flexible cable is welded with copper, so it is easier to break at the welding point, resulting in high voltage. If the over-voltage protection is not reliable, the inverter thyristor will be damaged.

7) The connecting bolts between intermediate frequency compensation capacitor and output bus, bus and bus, bus and flexible cable are loose. Because the bus current is too large and the temperature is high in the working process, it is easy to cause the connection bolts to loosen, resulting in the increase of contact resistance and the temperature at the connection, and even the oxidation of the bus connection surface, resulting in ignition phenomenon, resulting in inverter failure.

8) The shell of furnace inductor and intermediate frequency compensation capacitor has poor insulation to ground. When the inductor and the compensation capacitor shell are short circuited to the ground, it will cause the serious failure of burning the thyristor, just as the main circuit is short circuited to the ground. When the thyristor is burned, in addition to focusing on the inspection of the protection system, it is also necessary to check whether the inductor coil is short circuited to the ground or the medium frequency compensation capacitor shell is poorly insulated.

Yiphee Electric Furnace Co.,Ltd specializes in producing induction furnace.Tel(WhatsApp):+86-13450756789, yiphee@yiphee.cn