Insulation melting process of induction melting furnace

Step 1. Observe whether the indication values of the four small meters in the intermediate frequency cabinet are normal: rectification control voltage meter 30V, rectification pulse current meter 130~150mA, inverter control voltage meter 12V, inverter pulse current meter 100~120mA; if the value is in the normal range Inside, it proves that there is no problem with the power supply.

Step 2: Check the rectifier, inverter thyristor anode, cathode resistance and control electrode and cathode resistance value with digital multimeter resistance file: the positive and negative resistance values of anode and cathode are both ∞, and the resistance values of control electrode and cathode are 10～508. In addition, check if the fuse is blown.

Step 3: Place the changeover switch SA in the inspection file, check the waveform of the rectification and inverter trigger pulse with an oscilloscope, and check whether the amplitude and time interval are normal: the rectification trigger pulse is double pulse, the time interval is 3.33 ms; the inverter trigger pulse For continuous pulse trains, the amplitude is typically 4 to 6V; the order of inspection is from the thyristor control pole to the pulse transformer and then to the rectifier and inverter boards.

Step 4: Check if the rectifier board is normal: the inverter board can be unplugged, the switch is placed in the inspection file, and then press the start button to turn the power potentiometer to see if the DC voltage can be adjusted to about 500V. If the voltage can be adjusted 500V, it proves that the rectifier board is normal.

Step 5: Check the capacitor charging circuit in the starting circuit: still unplug the inverter board and turn on the inspection file. Press the start button and measure the voltage across the capacitor cf with a multimeter. If it can reach 500V, it proves that the capacitor charging circuit is activated. normal.

Step 6. Check whether the pre-magnetization resistor R6 is blown and the low-pass filter is disconnected.

Customers who use induction melting furnaces can follow the above steps if they encounter insulation problems, and it may be easy to eliminate such failures.