Maintenance knowledge of induction melting furnace

Judgment of thyristor

A measure the gate (GK) resistance, which is generally between 8 and 50

B measure the resistance of anode and cathode (AK). The open circuit measurement should be K, and the on circuit measurement should be K---

Note: in the circuit or open circuit, use the multimeter to test the positive and negative. In the medium frequency power supply circuit, this test method can only simply judge the quality of the thyristor. Due to the different size and use of the thyristor, this test method may not be applicable to other equipment or components

The main control circuit board of the equipment has the function of displaying and recording the faults of the equipment. When the fault indicator light on the operation panel is on, the fault type can be judged by observing the indicator light on the main control circuit board. The specific meaning is as follows:

Note: in case of fault shutdown, the control power switch cannot be closed, and the intermediate frequency start stop cannot be closed, then the control board can record the fault

1 OP light on

reason:

A main circuit air switch is not closed

B main circuit fuse damaged

C 4 #, 6 #, 2 #, rectifier thyristor cathode (k) line open circuit

2 WPL light on

reason:

Check the water pump and water pipeline

3 ov light on

reason:

A. workpiece and coil are ignited or coil and oxide scale are ignited

Maintenance: adjust the gap between coil and workpiece, clean oxide scale

B. The screws of induction coil, capacitor and main circuit are loose and ignited

Maintenance: fastening screw

C. One (two) inverter thyristors are damaged

When one or two thyristors are damaged, the viewing angle from the meter (leading angle of inverter) is greater than or equal to 2, and the ratio of DC current and DC voltage is much larger than normal

Maintenance: replace the thyristor

Excessive front angle adjustment of D inverter

Maintenance: readjust the front angle of inverter, which should be (1.5)

E inverter resistance capacitance absorption part fault, refer to item 8 inverter resistance capacitance absorption check

4 OC light on

reason:

A. there is a short circuit in the inductor, capacitor and its connecting copper bar

Two (4) thyristors of B inverter are damaged

C inverter silicon quality is not high

5 ov / OC lights up at the same time

reason:

Overpressure is the main phenomenon in maintenance

6 LV light on

reason:

A 17V power transformer damaged

Leakage or failure of filter capacitor on B main control board

6.3 inspection of inverter resistance capacitance absorption

A. after turning off the running power supply (turn off the general air switch inside the power supply), touch the non inductive resistance absorbed by the inverter resistance and capacitance with your hand (it may be hot), and the temperature is basically the same

A. If the temperature of the inductor is much higher than that of other inductors, it means that the capacitor in series with the inductor is leaking

A. 2. If the temperature of the inductive resistor is very low or not hot, it means: a. the capacitance in series with the resistor is reduced or open. B. the wiring among the resistor, capacitor and thyristor is open or the thyristor is damaged

A. 3. If the resistance wire is burnt out, it means that the capacitor in series with the resistance is broken down

A. 4. In normal operation, if resistance heat turns red, please refer to a.1 maintenance

Yiphee Electric Furnace Co.,Ltd specializes in producing induction furnace.Tel(WhatsApp):+86-13450756789, yiphee@yiphee.cn