When the intermediate frequency furnace is running, the DC current reaches the rated value, but the DC voltage and the intermediate frequency voltage are low. The waveform of the intermediate frequency is observed with an oscilloscope, the waveform is normal and the front angle of the inverter is normal.

Fault analysis and processing: The fault phenomenon does not belong to the intermediate frequency power supply fault, but is caused by the low impedance of the load, and the load impedance must be readjusted.

1) In the circuit of boost load, the intermediate frequency furnace removes the tandem compensation capacitor due to the damage of the series compensation capacitor, and does not replace it, or the most demanding high-power and uncontrolled increase of the compensation capacitor, so that the compensation amount of the load is over compensated. Cause this malfunction. The solution is to readjust the compensation amount of the compensation capacitor so that the intermediate frequency furnace can operate at the rated power.

2) The intermediate frequency furnace sensor has a short circuit between the turns - if the sensor has a short circuit between the turns, the impedance of the load will also decrease, causing this malfunction. There are two possibilities for short circuit between turns:

The copper tube of the intermediate frequency furnace sensor is directly shorted

 The fixed bakelite column of the sensor is severely carbonized. Due to the conductive property of the carbon, the carbonized bakelite between the inductors causes the direct connection between the turns of the inductor to cause short circuit between the turns of the inductor.

The solution is to eliminate the short circuit between turns.