The function of the induction melting furnace water-cooled cable is to connect the intermediate frequency power supply and the induction coil. It is usually made of twisted copper wires each with a diameter of Φ0.6-Ф0.8 (also made of enameled wire). For a 500 kg electric furnace, the cable cross-sectional area is 480 square millimeters, and for a 250 kg electric furnace, the cable cross-sectional area is 300 to 400 square millimeters. The outer hose of the water-cooled cable adopts a pressure rubber hose with a pressure resistance of 5 kg, which is filled with cooling water. It is part of the load circuit. It is subjected to tension and torsion during work, and it tilts with the furnace body and twists and turns. Therefore, it is easy to be bent after a long working time. The flexible connection is broken.
The breaking process of the water-cooled cable generally involves cutting off most of the parts first, and then quickly breaking the unbroken part during high-power operation. At this time, the intermediate frequency power supply will generate a very high overvoltage. If the overvoltage protection is unreliable, Will burn out the thyristor.
After the water-cooled cable is disconnected, the intermediate frequency power supply cannot start to work. If you restart repeatedly without finding out the cause, the intermediate frequency voltage transformer is likely to be burned out.
When checking the fault, use an oscilloscope to clamp the oscilloscope probe at both ends of the load and observe whether there is attenuation waveform when the start button is pressed. When confirming that the cable is broken, first disconnect the water-cooled cable from the output copper bar of the electric heating capacitor, and measure the resistance value of the cable with a multimeter (200Ω block). The resistance value is zero when it is normal, and it is infinite when it is disconnected. When measuring with a multimeter, the furnace body should be turned to the dumping position to make the water-cooled cable fall off, so that the broken part can be completely separated, so that it can be correctly judged whether the core is broken.
