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　　 Medium-frequency furnace What are the causes of abnormal startup? As a manufacturer of medium-frequency induction furnaces, let me walk you through the reasons behind abnormal furnace startups.

　　Phase failure in the rectifier: The fault manifests as abnormal operating sounds, a significant increase in output voltage below the rated value, and increasingly loud extraneous noises coming from the power cabinet. At this point, you can reduce the output voltage to around 200V and use an oscilloscope to observe the rectifier’s output waveform. Normally, the input voltage waveform of a medium-frequency induction furnace should show six distinct waveforms per cycle; however, in the event of a phase failure, two of these waveforms will disappear. You should use an oscilloscope to check the gate pulses of all six rectifier thyristors. If any gate pulses are missing, after shutting down the system, use a multimeter to measure the resistance across each gate resistor at approximately 200Ω. Click on each gate resistor individually, then replace any thyristor that shows an open circuit or a gate resistor with particularly high resistance.

　　The three-arm operation of the frequency converter: After the medium-frequency furnace is started, the fault manifests as excessive output current—this is also true when the furnace is empty. When the power cabinet is operating, it produces a very loud noise. If you adjust the power knob of the medium-frequency furnace’s melting furnace to a lower position, you’ll notice that the medium-frequency output voltage ratio is typically quite high. Use an oscilloscope to observe the voltage waveforms across the anodes and cathodes of the four inverter thyristors. If three bridge arms are functioning properly, you’ll find that... Medium-frequency furnace In the inverter, two adjacent thyristors have normal waveforms, while only two adjacent thyristors show no waveform at all—and the other one exhibits a sinusoidal waveform.

　　Induction Coil Failure: The induction coil of the medium-frequency furnace serves as the load for the medium-frequency power supply. It is made from square copper tubing with a wall thickness ranging from 3 to 5 millimeters. Its common failures are as follows: Medium-frequency furnace The induction coil is leaking, which could lead to arcing between the coil windings and necessitate prompt repair and welding. Molten steel has adhered to the induction coil in the medium-frequency furnace, causing the steel slag to heat up and turn red, ultimately leading to damage of the copper tubing. Therefore, it’s essential to clean this up promptly.