Troubleshooting methods for the electrical system of the welding machine

1. Troubleshooting of the power supply part:
Voltage check: Use a multimeter to measure the input power voltage of the welding machine to see if it is within the normal voltage range required by the equipment. For example, for a common three-phase 380V input welding machine, the voltage fluctuation should not exceed ±10%. If the voltage is too low or too high, the equipment may not start normally or work abnormally. For example, when the voltage is too low, the motor of the welding machine may not operate normally, and the welding transformer output current is insufficient, affecting the welding quality; when the voltage is too high, the electrical components may be damaged.
Power line check: Check whether the power cord is damaged, open, short-circuited, etc. Check whether the insulation layer of the power cord is intact and whether the internal wires are exposed or broken. If a problem is found in the power cord, it should be replaced in time. In addition, check whether the power plug and socket are in good contact, and whether there is any looseness, burning, etc.
Power switch check: Check whether the power switch of the welding machine can be closed and disconnected normally, and whether the contacts of the switch are oxidized, ablated, etc. If the switch is damaged, the equipment will not be powered on.
2. Check the control circuit:
Controller check: If the welding machine is equipped with a controller, check whether the controller display screen is displayed, whether the buttons can be operated normally, and whether there are obvious signs of damage to the circuit board inside the controller, such as burnt components, loose solder joints, etc. You can make a preliminary judgment by observation, touch, etc., and use professional testing equipment to test the controller if necessary.
Relay and contactor inspection: Check whether the coils of the relays and contactors are energized normally and whether the contacts can be closed and disconnected normally. When the coils of the relays or contactors are damaged, they will not work properly; poor contact of the contacts will cause abnormal circuit on and off, affecting the control function of the welding machine. For example, if the contactor contacts are burned, it may cause unstable current during welding.
Wiring check: Carefully check whether the wiring of the control circuit is correct and firm. Check whether the screws at the terminal are tightened and whether the wires are connected to the correct position. Incorrect or loose wiring may cause the control signal to be unable to be transmitted normally, making the welding machine unable to work according to the set program.
3. Welding transformer inspection:
Appearance inspection: Check whether the outer shell of the welding transformer is deformed, cracked, or leaking. If the transformer casing is damaged, it may affect its insulation performance and even cause safety accidents. At the same time, check whether the heat dissipation device of the transformer is normal, such as whether the cooling fan is running well, whether the heat sink is blocked, etc.
Winding inspection: Use a multimeter or megohmmeter to measure the resistance value and insulation resistance of the primary and secondary windings of the welding transformer. Under normal circumstances, the resistance value of the winding should be within a certain range. If the resistance value is abnormal, it may be that the winding has a short circuit or open circuit fault. The insulation resistance should meet the requirements, otherwise it means that the insulation performance of the transformer has declined, which may cause leakage and other problems.
4. Electrode part inspection:
Electrode connection inspection: Check whether the connection between the electrode and the secondary output end of the welding transformer is firm, and whether the wire is damaged or open circuit. Poor electrode connection will lead to poor current transmission and affect the welding effect.
Electrode wear inspection: Check the degree of wear of the electrode and whether the electrode surface is flat and smooth. Severely worn electrodes will affect the concentration and distribution of current, resulting in a decrease in welding quality and need to be replaced in time.
5. Protection device inspection:
Overload protection inspection: Check whether the overload protection device of the welding machine is working properly. When the welding current is too large or the equipment is overloaded, the overload protection device should be able to cut off the power supply in time to protect the equipment and personnel. If the overload protection device fails, it may cause equipment damage.
Leakage protection check: Use the leakage protector to test the leakage of the welding machine. If there is a leakage problem in the welding machine, the leakage protector should be able to act in time. At the same time, check whether the wiring of the leakage protection device is correct and whether it can work normally.