（1） Induction furnace power supply: use a multimeter to test whether there is power behind the main circuit switch (circuit breaker or contactor) and control line fuse, which will eliminate the possibility of these components open circuit.

（2） Rectifier: the rectifier adopts three-phase full control bridge rectifier circuit. The simple method to measure the thyristor is to measure the resistance of its cathode anode and gate cathode with a multimeter. The thyristor does not need to be removed during measurement. Under normal conditions, the resistance between anode and cathode should be close to infinity, and the resistance between gate and cathode should be between 10 and 50. If it is too large or too small, it indicates that the gate of this thyristor is invalid, and it will not be triggered.

The secondary side of the pulse transformer is connected to the thyristor, and the primary side is connected to the main control board. The primary side resistance is about 50 when measured with a multimeter. The freewheeling diode is not easy to fail. When checking, use the diode of the multimeter to block the two ends. In the forward direction, the voltage drop of the junction indicated by the multimeter is about 500 MV, and the reverse direction is blocked.

（3） Inverter: the inverter of induction furnace includes four or eight fast thyristors and four pulse transformers, which can be checked according to the above methods.

（4） Transformer: each winding of each transformer should be connected. Generally, the primary side resistance value is about tens of ohm, and the secondary pole resistance value is several ohm. It should be noted that the primary side of the medium frequency voltage transformer is in parallel with the load, so its resistance value is zero.

（5） Capacitor: the capacitor in parallel with the load may be broken down. The capacitors are generally installed on the capacitor rack in groups. The group of the broken down capacitor should be determined first during the inspection. Disconnect the connection point between the bus bar and the main bus bar of each group of capacitors, and measure the resistance between the two bus bars of each group of capacitors. Normally, it should be infinite. After confirming the bad bank, disconnect the soft copper sheet from each capacitor to the bus bar, and check one by one to find the broken capacitor. Each capacitor is composed of four cores. The shell is one pole, and the other pole is led to the end cover through four insulators. Generally, only one core will be broken down. If the lead on the insulator is removed, the capacitor can continue to be used, and its capacity is 3 / 4 of the original. Another fault of the capacitor is oil leakage, which generally does not affect the use temporarily.

The angle steel for capacitor installation is insulated from the capacitor frame. If the insulation breaks down, the main circuit will be grounded. The insulation condition of this part can be judged by measuring the resistance between the lead wire of capacitor shell and the capacitor frame.

（6） Water cooled cable: water cooled cable is used to connect intermediate frequency power supply and induction coil. It is made of 0.6 Ф 0.8 purple copper wire with each diameter. The outer rubber tube of the water-cooled cable is a 5kg pressure rubber tube with cooling water inside. It is a part of the load circuit. When it works, it is pulled and twisted and tilts with the furnace body, so it is easy to break at the flexible connection after a long time. During the fracture process of water-cooled cable, most of the water-cooled cable is broken first, and then a small part of the water-cooled cable is burned out quickly in high-power operation. At this time, the medium frequency power supply will produce a high overvoltage. If the overvoltage protection is not reliable, the thyristor will be burned out. After the water cooling cable is disconnected, the induction melting furnace cannot start. If it is not checked out and started repeatedly, it is likely to burn out the medium frequency voltage transformer. When the cable core is broken, first disconnect the water-cooled cable from the output copper bar of the capacitor, and measure the resistance value of the cable with the resistance block of the multimeter. The resistance value is zero in normal condition and infinite in disconnection condition. When measuring with a multimeter, the furnace body should be turned over to the dumping position to make the water-cooled cable fall off, so that the broken part can be completely separated, so as to correctly judge whether the core is broken.

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