Welding inverter malfunctions - causes and solutions. Recommendations for the repair of inverter welding machines Inventor Plas shows overheating what to do

It is well known that the repair of welding machines in the vast majority of cases can be organized and carried out independently. The only exception is the restoration of the electronic inverter, the complexity of the circuit of which does not allow for a full repair at home.

Just one attempt to disable the inverter protection can confuse even an electrical engineer. So in this case, it is best to seek help from a specialized workshop.

The main manifestations of malfunctions of electric arc welding machines are:

• the device does not turn on when connected to the mains and starting;
• sticking of the electrode with a simultaneous hum in the area of ​​​​the converter;
• spontaneous shutdown of the welding machine in case of overheating.

Repair always begins with an inspection of the welding machine, checking the supply voltage. It is not difficult to repair transformer welding machines, moreover, they are picky in maintenance. For inverter devices, it is more difficult to determine a breakdown, and repairs at home are often impossible.

However, with proper handling, inverters last a long time and do not break. Must be protected from dust high humidity, frost, store in a dry place. There are the most typical malfunctions of welding machines, which you can fix with your own hands.

Device won't start

In this case, first of all, you need to make sure that there is voltage in the network and the integrity of the fuses installed in the transformer windings. If they are in good condition, use the tester to ring the current windings and each of the rectifier diodes, thereby checking their performance.

If one of the current windings breaks, it will need to be rewound, and in the event of a malfunction of both, it is easier to replace the entire transformer. A damaged or "suspicious" diode is replaced with a new one. After repair, the welding machine is turned on again and checked for serviceability.

Sometimes the filter capacitor fails. In this case, the repair will consist in checking it and replacing it with a new part.

In the event that all elements of the circuit are in good condition, it is necessary to deal with the mains voltage, which can be greatly underestimated and simply not enough for the normal functioning of the welding machine.

Sticky electrode (arc interruption)

The cause of sticking of the electrode and interruption of the arc may be a decrease in voltage due to short circuit in the transformer windings, diode failure or loose connection contacts. Breakdown of the capacitor filter or short circuit is also possible. individual parts on the body of the welding machine.

Organizational reasons, due to which the device does not cook as it should, include excessive length welding wires(more than 30 meters).

If sticking is accompanied by a strong hum of the transformer, this also indicates an overload in the load circuits of the device or a short circuit in the welding wires.

One of the repair options to eliminate these effects can be the restoration of the insulation of the connecting cables, as well as the tightening of loose contacts and terminal blocks.

Spontaneous shutdown

In some cases, repairs can be carried out independently if the device starts to turn off spontaneously. Most models of welding machines are equipped with protective circuit(automatic), triggered in a critical situation, accompanied by a deviation from normal operation. One of the options for such protection involves blocking the operation of the device when the ventilation module is turned off.

After a spontaneous shutdown of the welding machine, first of all, you should check the state of protection and try to return this element to working condition.

If the protective node is triggered again, it is necessary to proceed to troubleshooting using one of the methods described above related to short circuits or malfunction of individual parts.

In this situation, the first thing to do is to make sure that the cooling unit of the unit is working properly and that the overheating interior spaces excluded.

It also happens that the cooling unit does not cope with its functions due to the fact that the welding machine has been under a load exceeding allowable rate. The only right decision in this case is to let it “rest” for about 30-40 minutes, and then try to turn it on again.

In the absence of internal protection, the circuit breaker can be installed in electrical panel. To maintain the normal functioning of the welding unit, its settings must correspond to the selected modes.

So, some models of such devices (a welding inverter, in particular), in accordance with the instructions, must work according to a schedule that involves a break of 3-4 minutes after 7-8 minutes of continuous welding.

Malfunctions of inverter devices

Before repairing an inverter welding machine with your own hands, it is advisable to familiarize yourself with the principle of operation, as well as with its electronic circuit. Their knowledge will allow you to quickly identify the causes of breakdowns and try to eliminate them in a timely manner.

Wiring diagram

The operation of this device is based on the principle of double conversion of the input voltage and obtaining a constant welding current at the output by rectifying a high-frequency signal.

The use of an intermediate high-frequency signal makes it possible to obtain a compact pulse device with the ability to effectively adjust the output current.

Breakdowns of all welding inverters can be conditionally divided into the following types:

• malfunctions associated with errors in the choice of welding mode;
• failures in operation due to failure of the electronic (converting) module or other parts of the device.

The method for identifying inverter malfunctions associated with malfunctions in the operation of the circuit involves the sequential execution of operations performed according to the principle “from simple damage to more complex failure”. The nature and cause of breakdowns, as well as repair methods, can be found in more detail in the summary table.

It also provides data on the main parameters of welding, providing a trouble-free (without turning off the inverter) operation of the device.

Operation features

Maintenance and repair of welding machines inverter type differs in a number of features related to the complexity of the circuit of these electronic units. To repair them, you will need certain knowledge, as well as the ability to handle such measuring instruments, as digital multimeter, oscilloscope and the like.

Under renovation electronic circuit first produced visual inspection boards in order to identify burnt or "suspicious" elements as part of individual functional modules.

If during the inspection no violations can be found, the troubleshooting continues by detecting violations in the operation of the electronic circuit (checking voltage levels and the presence of a signal at its control points).

This will require an oscilloscope and a multimeter, which should be started only if you have full confidence in your abilities. If you have any doubts about your qualifications, the only right decision would be to take (take) the device to a specialized workshop.

Complex repair specialists impulse devices they will quickly find and eliminate the malfunction that has arisen, and at the same time they will carry out maintenance of this unit.

Self-repair procedure

In the event of a decision to self repair fees - we recommend using the following tips experienced professionals.

If burnt wires and parts are found during a visual inspection, they should be replaced with new ones, and at the same time, all connectors should be plugged, which will eliminate the possibility of losing contact in them.

If such a repair did not lead to the desired result, you will have to start a block-by-block examination of the electronic signal conversion circuits.

To do this, it is necessary to find sources that provide diagrams of voltages and currents, designed for a more complete understanding of the operation of this unit.

Based on these diagrams, using an oscilloscope, you can sequentially check all electronic circuits and identify a node in which the normal signal conversion picture is disturbed.

One of the most complex components of an inverter welding machine is the electronic key control board, the serviceability of which can be checked using the same oscilloscope.

If in doubt about the performance of this board, you can try to replace it with a working one (from another working inverter) and try to start the welding machine again.

In the event of a favorable outcome, it remains only to give your board for repair or replace it with a purchased new one. The same should be done if there are suspicions about the serviceability of all other modules or blocks of the welding machine.

In conclusion, we recall that the repair of any welding units(and inverters, in particular) is considered a rather complicated procedure that requires certain skills and the ability to handle complex measuring equipment.

If you have the slightest doubt about your professionalism, you should use the help of specialists and give them the opportunity to return the faulty device to work.

The welding inverter is modern equipment, the use of which in the welding process makes it possible to achieve very High Quality work and gives the welder the opportunity to work in comfortable conditions. But at the same time, the welding inverter also has a more complex design compared to previous models of welding equipment, which increases the chance of a malfunction during its operation.

As a rule, all malfunctions welding inverter can be divided into two groups:

• malfunctions associated with incorrect operation of the electronic "stuffing" of the device

• malfunctions associated with the wrong choice of operating mode.

The second type of malfunction occurs most often, therefore, before contacting a specialized workshop or starting to disassemble the device on your own in order to identify a breakdown, you need to check whether all the settings for the operating mode are set correctly, and in addition, you should read the operating instructions for this device again, to determine if you are making any mistakes in the process. Most manufacturers, when compiling instructions, indicate the causes of malfunctions of the welding inverter that may occur during operation, and also describe how these malfunctions can be eliminated on their own.

Causes of breakdowns of welding inverters and options for their elimination.

There are a number of typical faults that occur when we are talking about welding inverters:

• combustion instability welding arc and strong spattering of metal;
• sticking welding electrode;
• lack of welding process when the machine is turned on;
• lack of reaction of the device when it is turned on.

Let us consider in more detail why this or that situation may arise, and what can be done in the event of any malfunction of the welding inverters.

• Welding arc instability and strong metal spatter.

This malfunction may occur if you incorrectly selected the current during welding. Usually, welding current is selected in accordance with the type and size of the electrode used in welding. But there is one more thing to remember here. important rule: the selected current must also correspond to the speed at which welding is carried out. If the welding speed decreases during operation, then the welding current must also be reduced.

• Sticking welding electrode.

There can actually be several reasons for this type of malfunction. It is possible that during welding, the voltage unexpectedly decreased in the network, which led to a strong sticking of the welding electrode. It can also “stick” even if the inverter is connected to the network with a cable with a too small cross section. Another reason for this "behavior" of the electrode may be poor contact of the electrode with the surface to be welded due to the fact that the surface has undergone oxidation due to exposure to atmospheric oxygen. In this case, welding must be stopped, and the surface of the part must be cleaned from the film.

• Lack of welding process when the machine is turned on.

In the vast majority of cases, this behavior of the welding inverter can be explained by the absence of mass on the surface of the part to be welded. In addition, it would be useful to check the condition of the welding cable - it may be damaged. This situation is quite common in the event that the part being welded has a large weight, as a result of which the fall of the part on the wire can violate its integrity.

• No reaction of the device when turned on.

If nothing happens when the welding inverter is turned on, then the cause of such a malfunction should be sought, in many cases, not in the inverter itself, but in electrical network to which it is connected. The mains voltage may be too low and therefore the machine cannot work. Another reason that the device does not turn on may be an incorrectly selected circuit breaker installed in the shield. A weak switch is able to trip when the inverter is turned on. In addition, turning off the device can lead to the fact that the electricity will disappear throughout the house.

In addition to these faults, there are also interruptions in the operation of the welding inverter, which are not associated with a breakdown of the device, but are the result of a fairly high-quality and timely operation of the protection systems that the inverter is equipped with. So, for example, for a long continuous work the inverter may trip spontaneously. This happens if the device overheats and the temperature protection trips. In this case, you should stop the welding process for about 20-30 minutes, let the machine cool down, after which work can be continued.

An inverter welding machine, like any other equipment, sooner or later may fail. And if this happens, then the problem can be solved in two ways: give the device to service center, whose specialization is the repair of inverter welding machines, or try to fix the problem yourself.

Before repairing the welding inverter, make sure that it is disconnected from the mains.

Having mastered the necessary information, you can fix some malfunctions with your own hands, without resorting to the help of masters. This will of course save you cash. However, it can also take a lot of time. Consider how to repair welding machines with your own hands and what malfunctions are most common.

Features of welding inverters and their repair

Inverter welding machines make it possible to perform high-quality welding with maximum comfort, while having minimal skills in working with it.

The welding inverter is characterized by a more complex, but less robust design than welding transformers and rectifiers. The inverter, unlike its electrical predecessors, is a rather complex electronic product. If the inverter device stops working, then the first thing to test is whether the diodes, stabilizers, transistors and other elements of the electrical circuit are working inverter welding. To do this, you must be able to use a voltmeter, multimeter and oscilloscope.

Inverter welding has its own characteristics when carrying out repairs. For example, it often happens that it is not possible to immediately identify a non-working part and you have to check each element of the apparatus circuit. Therefore, in order to qualitatively repair the inverter, it is very important to own at least basic knowledge in electronics and skills in working with electrical circuits. If you do not own this knowledge, then it is better to give the inverter for repair to specialists. Otherwise, you will simply waste time and energy, or even aggravate the situation.

Each inverter must be accompanied by an instruction that lists possible faults and recommendations for their elimination. Back to index

Diagnostics of malfunctions of welding inverters

In the power supply of the welding inverter, capacitors most often fail.

Before you start repairing inverter welding, you should know what the main types of malfunctions are.

First, a visual inspection of the device is carried out.

If there are places with damaged contacts, the parts must be disconnected, cleaned and connected back.

To the most vulnerable places of welding inverter device applies to the terminal block. The welding cable is connected to it.

A high current rate and poor contact lead to heating at the junctions of the wires, which can be critical for the device.

There are several groups of all malfunctions of inverter welding machines:

• faults that occur when wrong choice operating mode of welding;
• breakdown or malfunction of the electronic parts of inverter welding.

In both cases, welding is either difficult or impossible at all. There are several factors that contribute to the occurrence of malfunctions.

Diagnosis should be carried out sequentially, starting with simple operations and ending with complex ones.

When testing the welding inverter control unit Special attention it is necessary to pay attention to the induction coils of the voltage regulator.

The reasons for the malfunction of the electrical circuit can be:

• moisture ingress into the device (operation of the device during precipitation);
• dust accumulated inside the body of the apparatus leads to a disruption in the normal cooling of the electrical circuit elements (usually this occurs during constant operation at construction sites);
• overheating of the inverter as a result wrong mode work.

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The main types of breakdowns of welding inverters and their elimination

Basically, breakdowns of welding inverters are the result of exposure to any external factors or errors in setting up and operating the devices.

Scheme of the main elements of the welding inverter.

The most common faults:

1. Erratic welding arc or excessive spatter of electrode material. The reason is the mismatch between the current type and diameter of the electrode and the welding speed. The required current strength can be found in the recommendations of the electrode manufacturer, which are indicated on the packaging. If this information is not specified, then you can use the formula for calculating the current: 20-40 A per 1 mm of electrode diameter. When the welding speed decreases, the current value must also be reduced.
2. Sticking of the welding electrode to the metal. This may be due to several reasons. In most cases, this happens due to the fact that the device is connected to a network with insufficient supply voltage. This may also be due to poor contact between the device modules in the panel sockets. You can fix this problem by tightening the fasteners and fixing the boards well. Voltage may drop at the inverter input when using a mains extension cord with a wire size of less than 2.5 mm2. An excessively long extension cord can also cause a voltage drop (with a wire length of 40 m or more, the operation of the device is practically impossible, since large current losses occur in the circuit). The electrode can stick due to oxidation or burning of the contacts in the circuit, which can also lead to a voltage drop. This problem can also be encountered with improper preparation of materials to be welded (the contact between the electrode and the workpiece deteriorates if there is an oxide film on it).
3. Lack of welding when the inverter is on and the indicators are working. The reasons for this in most cases are overheating of the machine and spontaneous disconnection or damage to the welding cables.
4. Spontaneous shutdown of the inverter. When the transformer is connected to the network, its protection is activated and the device turns off. The cause may be a short in the circuit between the wires and the case. Protection can be activated when there is a short circuit between sheets of magnetic wire or turns of coils and a breakdown of capacitors. Remedy: disconnect the transformer from the mains, find defective element and repair it - replace the capacitor, restore the insulation, etc.
5. High current consumption with little or no network load. Possible reason- closing the turns on the coils. The problem is fixed by rewinding or adjusting the insulation layer.
6. The reason for the shutdown welding work mains voltage an incorrectly selected circuit breaker may become. It should be rated for current up to 25 A.
7. Stopping the inverter during long welding. This is most likely due to overheating. When the allowable temperature is exceeded, protection is triggered. Wait 20-30 minutes and continue working.
8. The transformer can hum strongly, which is accompanied by overheating of the device. One of the reasons is the loosening of the bolts that tighten the sheet elements of the magnetic wire. The reason for this may be a malfunction in the core fastener, and an overload of the transformer, and a short circuit between the welding cables. Check and retighten all bolts, repair the core fastening, re-insulate the welding cables.

Malfunctions of welding inverters are most often caused by either illiterate or careless operation, since these are quite reliable devices and there is simply nothing to break. However, there is also the fault of the manufacturer, who installed a low-quality part, or carried out poor installation.
Let's try to summarize typical faults welding inverters and ways to eliminate them.

1. Unstable arc burning or strong metal spatter during the welding process.
This may be the result of an incorrectly chosen . Recommendations for the selection of the manufacturer indicates on the pack of electrodes. If this information is not available, use the simplest formula: 20 to 40 amps of current must be applied to 1 mm of stick electrode thickness.

2. Sticking of the electrode even with the existing "anti-stick" function.
Most often this is caused by too low voltage in the supply network, and if a welding machine with reduced voltage is possible, the latter drops below the minimum when the load is connected.
Another reason for sticking is poor contact in panel jacks. To eliminate it, it is enough to tighten the fasteners or fix the inserts.
The voltage drop may be due to the use of a power extension cable with a wire cross section of less than 2.5 mm, which again leads to a decrease in the effective supply voltage of the welding machine. In addition, the reason may lie in an extension wire that is too long. It should be noted that with a cable length of more than 40 meters effective work impossible - too big losses.
The cause of sticking can also be the burning of contacts in the connections of the supply circuit, which again leads to a significant “drawdown” of the voltage.

3. No welding, although all indicators work.
The first cause of the malfunction is overheating of the welding inverter. In the presence of control lamp or indicator, their glow may not be noticeable if the welding inverter does not have an overheating sound signal.

Transistor damaged due to overheating in a welding inverter

Working transistor in a welding inverter

The second reason is a break in the welding cables, or spontaneous disconnection.
The third is the failure of control parts. To eliminate the cause, you will have to open the case and first visually inspect the filling for damaged parts. Sometimes the reason lies in poor-quality soldering - it is enough to re-solder the parts.

4. Power off when welding.
It is most often caused by a malfunction of the switch itself or by a mismatch of its rated current. The switch must be capable of withstanding up to 25 A.

5. Lighting up of the indicator of an overheat.
Excessive load, especially when either thick layer dust inside the case. If the cooling fan fails, the welding inverter will usually not turn on, although this may depend on the specific model.
Of course, in a small article it is impossible to detail all the causes and possible malfunctions of welding machines. However, careful attention to the welding inverter used can prolong its “life” for a long time, and bring joy to the owner from work.

Welder on a run-in after repair. Thermal control:

Radical repair of malfunctions of the GYS 3200 welding inverter:

The welding inverter differs from the conventional welding machine in an easier and better welding process. However, malfunctions of the welding inverter, due to its more complex device may be more serious and complex.

To determine the cause of the breakdown of the device, you need to diagnose it: check transistors, resistors, diodes, stabilizers, contacts, etc. Each device comes with detailed instructions with a description of the most common faults that you can fix yourself. However, very often repairs may require special equipment: ohmmeter, voltmeter, multimeter, oscilloscope. And you need to know how to use them. And in special cases, knowledge in electronics, the ability to work with electrical circuits is necessary. Therefore, if self-checking and elimination simple faults described below did not lead to success, it is better to entrust the repair of the inverter apparatus to the masters in the service center.

What are inverter faults?

There are several groups of breakdowns of welding inverters:

• malfunctions arising from non-compliance with the norms of the welding workflow specified in the instructions;
• malfunctions arising as a result of improper operation or failure of the elements of the device;
• damage caused by moisture, dust and foreign objects entering the device.

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Common malfunctions that you can fix yourself

Consider some of the most common malfunctions of welding inverters:

To identify and eliminate the cause of the malfunction, the body of the apparatus is opened and a visual inspection of its contents is carried out.

1. The welding arc is unstable or the electrode spatters the material. The reason for this may lie in the wrong choice of current. The current strength must correspond to the type and diameter of the electrode and the speed of the welding process. If the current strength is not indicated on the packaging of the electrodes, then you can start supplying current from 20-40 A per millimeter of electrode diameter. When reducing the welding speed, the amperage must also be reduced.
2. The electrode sticks to the material. Often this is due to low voltage in the network, the value of which is less than the minimum allowed when working with the inverter. The reason for sticking of the electrode can also be poor contact in the sockets of the panel, which can be eliminated by fixing the boards more tightly. Using an extension cable with a wire size smaller than 2.5 mm2 or with a wire that is too long (more than 40 m) may reduce the voltage. Burnt or oxidized contacts in electrical circuit can also lower the voltage.
3. There is no welding process, while the machine is connected to the network. In this case, you need to check the presence of mass on the part to be welded. Also check the inverter cable for damage.
4. The device turns off by itself. The device is switched off at the moment the transformer is connected to the network, after which its protection is activated. The reason for this may be a short circuit in the voltage circuit. Protection can be activated not only when the wires are shorted to each other or with the case, but also when the short circuit between the turns of the coils or the breakdown of capacitors. To repair a floor, you first need to turn off the transformer and find the fault, and then insulate or replace the damaged element.

If there is no welding when the machine is switched on, check the connection of the electrode holder cable.

During a long period of operation, the device turned off. Most likely, this is not a breakdown, but an overheating of the inverter. It is necessary to wait 20-30 minutes, and then resume work. You should follow the rules for operating the device: do not overheat it, that is, take breaks in operation, connect appropriate current values ​​\u200b\u200bto it, do not use electrodes of too large diameters.

The transformer emits a strong hum and overheats. Perhaps the reason for this was the overload of the transformer, the loosening of the bolts that tighten the sheets of the magnetic circuit, or the breakdown of the core fastening. Due to the short circuit between the sheets of the magnetic circuit or cables, the device can also hum strongly. Tighten all fastening elements and restore cable insulation.

Welding current is poorly regulated. The reason for this may be breakdowns in the current regulation mechanism: a malfunction in the current regulation screw, a short circuit between the regulator mounts, a short circuit in the inductor, poor mobility of the secondary coils as a result of blockage, etc. Remove the casing from the inverter and examine the current regulation mechanism in order to identify a breakdown.

The welding arc breaks abruptly, and it is impossible to ignite it, only sparks appear. Perhaps the problem lies in the breakdown of the winding high voltage, a short between the wires, or a poor connection to the inverter terminals.

High current consumption at no load. The reason may be the closure of the turns on the coil. You can eliminate it either by restoring the insulation, or by completely rewinding the coil.

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If excessive spatter of the electrode metal occurs during welding, the cause may be an incorrectly selected value of the welding current.

If a smell of burning and smoke appeared from the body of the device, this may indicate a serious breakdown. AT this case You may need a qualified repair at a service center.

To identify a malfunction, the case is first disassembled. Perform a visual inspection of parts for damage, cracks, burnt contacts and swelling of capacitors. They also check the soldering points of parts and contacts on the inverter boards. Often the causes of a malfunction lie precisely in poor-quality soldering, they can be easily eliminated by re-soldering the parts.

All defective parts should be unsoldered and replaced with new ones corresponding to this model of the device.

You can select parts in accordance with the markings indicated on the body of the device or in a special guide.

You need to solder the parts with a soldering iron that has a suction, which will make the work convenient and fast.