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Medium-frequency furnace Debugging method

1. Turn on the power supply and slowly increase the power potentiometer until the intermediate-frequency voltage reaches 750 volts. Then, adjust the overvoltage protection potentiometer W8 clockwise until the overvoltage protection is activated and the overvoltage indicator light comes on.

2. The power potentiometer returns to zero, and the quenching device’s automatic reset protection system is activated. Turn the piezoelectric potentiometer W8 counterclockwise by two to three full turns to release the potentiometer’s limit stop.

3. Restart the power supply and increase the medium-frequency furnace voltage to 800 V to 820 V. Slowly adjust the overvoltage potentiometer W8 clockwise until the medium-frequency power supply’s overvoltage protection is triggered and the overvoltage indicator light comes on. Then, re-check whether the overvoltage protection setting is correct.

4. Restore the pressure-limiting setpoint, adjust the potentiometer on the inverter angle ceramic disc to ensure that the ratio of intermediate-frequency voltage to DC voltage reaches 1.4.

Note: Overlimit pressure adjustment should be performed under no-load conditions. These two adjustments must not be carried out under heavy-load conditions—otherwise, the consequences could be severe.

Two
Medium-frequency furnace Power supply overvoltage protection adjustment
                         

1. Turn on the power, start the inverter, and slowly increase the power potentiometer to gradually raise the intermediate-frequency voltage clockwise to 750V.

2. Adjust the voltage-limiting potentiometer W9 so that the intermediate-frequency voltage does not increase as the power supply potentiometer is rotated.

3. During the debugging process, the intermediate-frequency induction furnace voltage may drop below 750 volts... There are three possible reasons:

① First, slightly turn the current-limiting potentiometer Ws counterclockwise.

② Check whether the intermediate-frequency voltage has risen.

③ If it cannot rise, the transfer should be halted.

Three
Medium-frequency furnace Throttling debugging

1. First, start the power supply once under no-load conditions to confirm that the power supply’s basic startup performance and all instruments are functioning properly.

2. Fill the medium-frequency furnace completely with charge material—preferably larger chunks. The medium-frequency furnace is used to vary the amount of charge material (typically filled to capacity; in a heavy-duty furnace).

3. Start the furnace slowly and check whether it starts up properly. If the intermediate-frequency voltage is difficult to establish or the furnace fails to start, adjust the IC signal of the ceramic disc potentiometer to increase the reverse phase shift angle. 4. Start the furnace again slowly, and adjust the current-limiting potentiometer voltage so that the current does not rise as the power potentiometer is rotated.

Four
Medium-frequency furnace Overcurrent adjustment

1. Slowly turn on the power supply to bring the current up to its rated value, then adjust the current regulator W8 so that the overcurrent protection activates.

2. Loosen the flow-limiting potentiometer Ws and rotate the overcurrent potentiometer W7 counterclockwise by two to three turns.

3. To ensure the starting power reaches 1.2 times the rated current, adjust the current switch W7 to activate the overcurrent protection.

4. The overcurrent indicator light is on. During debugging, repeat the process once or twice to confirm that the overcurrent value is indeed about 1.2 times the rated current.

Five
Medium-frequency furnace Several situations may arise during debugging:
1. When the rated value is not reached, overcurrent protection will be activated first. At this point, simply adjust potentiometer W7 counterclockwise to increase the operating threshold for overcurrent protection.

2. If the power potentiometer is set to its maximum position yet the current fails to reach the rated value, and there’s a large gap between the charge materials, this indicates a problem with the induction melting furnace. Simply adding small pieces of material into the gaps between the charging materials will help ensure proper charging.

3. If the reverse angle is small and the current cannot increase, simply adjust the 1C signal ceramic disc potentiometer upward to increase the reverse angle.