Environmental protection 1T molten steel furnace repair

When the environmental protection 1T molten steel furnace starts, the DC current is large and the DC voltage and the intermediate frequency voltage are low. The 1T molten steel furnace sounds dull and overcurrent protection.

Intermediate frequency furnace maintenance method The thyristor of the inverter bridge with one bridge arm may be short-circuited or open circuit, causing the inverter bridge three-arm bridge to operate. Observe the thyristors on the four bridge arms of the inverter bridge with an oscilloscope. If the tube voltage drop waveform has a tube pressure on the thyristor on the bridge arm, the waveform of the drop is one line, the thyristor has been punched through; if it is a sine wave, the thyristor is not guided. Pass, replace the thyristor, and find the thyristor unguided

The reason for the pass.

When the 1T molten steel furnace is started, the DC current is high and the DC voltage is low. The intermediate frequency voltage cannot be established normally.

Analysis Processing Compensation Capacitor Short-Circuit Disconnect Capacitor Use a multimeter to find the short-circuit capacitor to replace the short-circuit capacitor.

When the 1T molten steel furnace heavy-duty cold furnace is started, the electrical parameters and sounds are normal, but the power does not rise to overcurrent protection.

Intermediate frequency furnace maintenance method :

(1) The inverse frequency of the intermediate frequency furnace is too small. Use an oscilloscope to view the commutation angle of the inverter thyristor and adjust the commutation angle to an appropriate value;

(2) The furnace insulation resistance is low or short-circuited, and the resistance of the furnace body is detected by a megohmmeter to eliminate the short-circuit point of the furnace body;

(3) The medium-frequency furnace charge steel has a low resistance relative to the induction coil, and the megohmmeter is used to detect the resistance of the furnace relative to the induction coil; if the resistance is low, the furnace is rebuilt.

1T molten steel furnace zero voltage it does not have a dedicated signal source starting circuit is not good start.

Intermediate frequency furnace maintenance method :

(1) The current negative feedback amount is not adjusted properly, and the reverse diode connected in series with the current transformer is broken;

(2) Whether the signal line is too long or too thin;

(3) Whether the phase of the signal synthesis is wrong;

(4) Whether the IF transformer and the isolation transformer are damaged, especially pay attention to the re-adjustment of the inter-turn short circuit of the transformer, and replace the damaged parts with the current negative feedback amount.

1.5 The cause of the fault is zero voltage. It is not good to start the sweep frequency starting circuit.

Intermediate frequency furnace maintenance method :

(1) The sweep start frequency selection is inappropriate to reselect the start frequency;

(2) The frequency sweeping circuit is faulty. Observe the waveform and frequency of the sweeping circuit with an oscilloscope to eliminate the fault of the sweeping circuit.

1.6 Fault Causes All electrical parameters and sounds are normal when starting. When the power is raised, there is no voltage to the rated overvoltage and overcurrent protection.

Analyze the processing load open circuit to check the load copper bus connector and water cooled cable.