Analysis of common failures of induction melting furnace load

1. Broken core of water-passing flexible cable

When the induction melting furnace pours molten steel, the water-passing flexible cable and the induction melting furnace tilt together, which often causes twists and turns. Especially the connection head and flexible cable connection with the smelting furnace are all welded with copper, so it is easier to break at the welding place. In the process of multi-strand flexible cable breaking, most of the cables are often broken first, and the last broken part is quickly burned out during high-power operation. At this time, the intermediate frequency power supply will generate a very high voltage. If the overvoltage protection is unreliable, it will be damaged. Inverter thyristor. Tube. After the universal soft cable is disconnected, the intermediate frequency power supply cannot start to work.

2. The casing of the furnace sensor and the intermediate frequency compensation capacitor is poorly grounded or insulated

When the short circuit of the inductor and the compensating electrical appliance shell to ground is the same as the short circuit of the main circuit to ground, it will often cause a serious failure of the burnt thyristor. Therefore, when a burnt thyristor failure occurs, in addition to the focus on checking the protection system, Should check the induction coil to the ground or intermediate frequency compensation electrical appliances.

3. Short circuit between inductors of induction melting furnace

When there is a severe short circuit between the turns of the inductor, the intermediate frequency power supply cannot start to work, and there are only one or two waves when the attenuated oscillation is seen with an oscilloscope. If two turns of the induction coil collide, the intermediate frequency power supply may start at this time, but the frequency is higher, the current is larger, and the power is slightly increased, which will cause the inverter to fail.

4. The connecting bolts between the intermediate frequency compensation capacitor and the output bus bar, the bus bar and the bus bar, the bus bar and the flexible cable, etc. are loose

Due to the high current of the busbar, the temperature of the busbar is also high during operation, so it is easy to cause loosening of the connection screw. After the loosening, the contact resistance increases, and the temperature of the connection is increased.