The inverter hums, but does not cook - how to fix the problem in 5 minutes

To repair a welding inverter with your own hands, you need very little: some knowledge of electrical engineering, basic amateur radio skills, a regular multimeter and a soldering iron suitable for soldering printed circuit boards. An additional incentive to decide on self-repair will be the result of studying the price lists of service companies, especially if the welding machine costs less than ten thousand rubles. In order to understand the operating principle and design of a welding inverter, popular literature, which is abundantly available on the Internet, is sufficient. The task is also made easier by the fact that the internal layout and composition of the main modules for all devices for household use are almost the same (see figure below).

Figure 1 - Welding machine design

The welding machine welds intermittently

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 occurring during its operation.

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

malfunctions associated with improper operation of the electronic “stuffing” of the device

malfunctions associated with incorrect choice of operating mode.

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

Causes of breakdowns of welding inverters and options for eliminating them.

There are a number of typical faults that occur when it comes to welding inverters:

instability of the welding arc and strong spattering of metal;
welding electrode sticking;
lack of welding process when the machine is turned on;
lack of response from 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 welding inverters.

Instability of the welding arc and strong spattering of metal.

This malfunction can occur if you select the wrong current when welding. As a rule, the welding current is selected in accordance with the type and size of the electrode used for welding. But here it is necessary to remember one more important rule: the selected current must correspond to the speed at which welding is carried out. If the welding speed decreases during operation, then the welding current must be reduced.

Welding electrode sticking.

In fact, there may be several reasons for this type of malfunction. It is quite possible that during welding the voltage in the network suddenly decreased, which led to severe sticking of the welding electrode. It can also “stick” if the inverter is connected to the network with a cable with too small a 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 of 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 lack of mass on the surface of the part being welded. In addition, it would be useful to check the condition of the welding cable - it may be damaged. This situation occurs quite often if the part being welded is heavy, as a result of which the part falling onto the wire can damage its integrity.

The device does not respond when turned on.

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

In addition to the indicated malfunctions, there are also interruptions in the operation of the welding inverter, which are not related to the breakdown of the device, but are a consequence of the fairly high-quality and timely operation of the protection systems with which the inverter is equipped. For example, during prolonged continuous operation, the inverter may turn off 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, allow the device to cool, after which work can be continued.

Repair and diagnostics of welding machine malfunctions

When a welding machine breaks down, work plans are disrupted. It is necessary to find the cause of the breakdown and eliminate it. If the equipment is no longer under warranty, it is not necessary to contact the service center. Some problems can be recognized and repaired on your own. In this article we will look at possible malfunctions in different inverter devices, diagnostic methods and repair techniques. We’ll also touch on which welding machines are best to buy in order to be less likely to experience breakdowns.

In this article:

To increase the chances of success when repairing a welding machine, you need to understand a little about its structure. All types of equipment for MMA, TIG and MIG welding have a common inverter unit, only in the case of manual arc welding the process is carried out with a consumable electrode in a coating, and the argon torch has a non-consumable tungsten electrode and a channel for supplying shielding gas. Semi-automatic machines additionally have a drum and a feed mechanism.

The inverter unit, which produces converted direct current for welding, consists of the following elements:

Primary rectifier
. It is a diode bridge that rectifies the current flowing from the socket into the device. To prevent the bridge from overheating, it has a temperature sensor that cuts off the circuit when it reaches 90 degrees. Air cooling is implemented in the form of a supply fan.
Capacitor filter
. It has a parallel connection to the bridge and smooths out pulses from alternating voltage.
Noise filter
. During operation of the inverter device, electromagnetic waves are created that can interfere with the operation of other equipment connected to the common network. The filter eliminates the negative impact.
High frequency transformer
. Increases the frequency of alternating current, lowering the voltage.
Secondary rectifier
. Installed at the exit. The diode bridge has a high opening/closing speed. Radiators are provided to remove heat. Two terminals for connecting welding cables extend from it.

The main element is the control board with keys. These are transistor switches of the Mosfet type or more modern ones - IGBT. They contain 2 or 4 keys, respectively divided into half-bridge and bridge. Provide economical power consumption, load and fine settings of welding current.

The essence of the inverter's operation is to receive alternating current from the mains with a frequency of 50 Hz, rectify it, and convert it back into alternating current, but with a frequency that has already been increased many times. At the output, the current is rectified again and welding is carried out with direct current.

Diagnosis of breakdowns of inverter welding machines

When the welding machine does not work, smoke comes out of it, a burning smell is felt, diagnostics are necessary. At home this is done like this:

Disconnect the device from the network
Unscrew the side cover screws
Inspect boards, capacitors, transistors, terminals
Tug the wires with your hand

You need to look for black marks (if something is burned) or a weak, loose contact. Most often, inverters stop working due to burnout of one of the elements. Then the device does not turn on completely or hums, but does not cook. The task is to find the problematic module and replace it or restore contact.

If a visual inspection does not yield anything, the diagnosis continues using a multimeter. A non-specialist should not climb into an inverter that is energized. Checking the resistance and declared parameters for voltage and current is the job of specialists. An amateur can only ring an electrical circuit that is disconnected from power.

To do this, set the switch in the multimeter to ringing mode. This is often indicated by a bell or continuity check icon. Depending on the radio component that you plan to check, various testing methods are used, as well as selecting parameters on a multimeter. In a general sense, it is necessary to lean one contact of the part in one probe, and the other - against the other. A unit should light up on the multimeter screen (there is a contact or another designation). If the display shows zeros, you have found a burnt-out element (depending on the type of radio component).

It needs to be unsoldered and replaced with a new one with a similar marking. It is better to perform soldering using a station with a desoldering pump, so as not to fill the adjacent contacts with solder, creating a path for a short circuit after switching on:

Heat the legs of the burnt element and stir it in the printed circuit board, remove it out
Degrease the joint with rosin
Insert the new element into the holes on the PCB
Apply solder and wait until it hardens

To test diode bridges with a tester, as a rule, they will first need to be removed from the general circuit, because sometimes they are paralleled, which makes it impossible to correctly identify a faulty bridge.

These are the general principles of diagnosis and repair. Next, we will consider breakdowns of varying degrees of complexity, possible causes and solutions.

Specific symptoms of malfunction and repair methods

Welding inverter breakdowns can be divided according to the degree of complexity. Some can be easily eliminated with your own hands at home.

The welding inverter sparks, but does not weld HideRead more

The problem is characterized by the absence of a welding arc, but slight contact appears when the electrode is passed over the workpiece. This is a simple failure due to a weak connection. Check the rigidity of the connection of the welding cable and ground to the sockets in the machine. If they are loose, secure them. Check the ground connection to the product. If it is a homemade hook, it is better to grab it by welding. Even if you use a crocodile, move it to improve contact.

The electrode can spark due to incorrectly selected current strength. Sometimes the “twist” accidentally gets knocked down when rearranging the device if it gets touched by clothing. To prevent this from happening, use inverters with a protective shield covering the control panel. This is available, for example, in the EWM PICO 160 CEL PULS MMA welding machine

The inverter may spark but not cook due to low input voltage. Check the readings at the outlet with a tester. If they are below 220 V, then a voltage stabilizer or welding machines designed to work with a reduced incoming current will help. For example, the RESANTA SAI-220 welding inverter welds at an input voltage of 140 V. Of course, it does not produce 220 A with low input current parameters, but it will be possible to weld sheets of iron to gates, weld a tank for a summer house, etc.

The greater the voltage drop, the lower the welding current. Here is a table of voltage per board when welding with an inverter with a limit of 160 A, showing the interdependence of the parameters.

Mains voltage, V	Resistance, Ohm	Welding current, A
220	0	160
210	1	150
197	2	145
180	3	115
165	4	105

A long power cord leads to increased resistance and reduces the incoming current. Reconnecting to a closer outlet with a short wire or using inverters designed for lower voltage will help here.

Long welding cables of the workpiece and the electrode holder also act as increased resistance, reducing the current strength. Try connecting short cables of 3-4 m and repeat arcing.

The electrode sticks to the metal HideRead More

The electrode can stick for the same reasons as sparking: low welding current, long power cord and welding cables, low voltage in the network. But sometimes this happens when welding thin metal. A welding current of 60-80 A burns through the metal, and a low current of 30-50 A causes the electrode to stick.

Then choose a welding inverter with an anti-stick function. For example, ESAB BUDDY ARC has a special mode that, at reduced operating currents, “feels” the moment of electrode sticking and briefly supplies an increased current. The action lasts a second, after which the current strength drops to the one set by the welder. This is enough to prevent the electrode from sticking and from burning the metal.

The current is not regulated HideRead more

When it is impossible to change the current, the problem is in the switch itself. It is mechanically or electrically faulty. Remove the plastic “twist” and try turning the rod with pliers.

If the regulator does not respond, then you need to ring its contacts with a multimeter. In the event of a break, the regulator is replaced entirely by unsoldering the terminals and unscrewing it from the housing. Install a new regulator and check the operation of the device.

Why does the welding machine turn on but not weld? HideRead More

If the “Power” light is on and the fan is humming, but the welding machine is not welding, it is most likely overheated. Each inverter has its own on-duration (PO) or load duration (LO). It is indicated in % and means how many of 10 minutes the equipment can operate continuously at a certain current.

Household models most often have a PV indicator of 30-40%, so after boiling for 5-10 minutes in a row, the device goes into protection so as not to burn out. Wait 20-30 minutes until the device has cooled down and try cooking again. If long-term regular welding work is required, use devices with a duty cycle of 60-100%, such as the BARSVELD Profi ARC-507 D inverter for a three-phase network or the TORUS-250 Extra welder for a two-phase network. Among semi-automatic machines, the Aurora PRO OVERMAN 200 has proven itself well in terms of load duration.

The welding inverter does not turn on/does not work HideRead More

If the lights on the inverter do not light up, the power cord may be broken. Disassemble the case and check the reliability of the network cable contacts. The second probable reason is a large layer of dust on the board; the device went into protection to avoid a short circuit. Disassemble the housing and blow out the device with compressed air from the compressor. If you don't have a compressor, use a soft brush.

When the inverter does not turn on, check the input diode bridge and power capacitors.

Welding Tips

To prevent welding machines from breaking, it is important to follow a number of simple tips:

Select the correct welding modes
Periodically check the tightness of the contacts of the welding cables and the power cable
At low voltage, use devices designed for sag
Do not overload the inverter beyond its rated capacity. Let the equipment cool down
Make sure that the body is not covered on top with work clothes or other materials that retard heat transfer
Do not place the inverter in dusty areas

If you regularly weld in difficult construction conditions, use welding machines with body protection with rubber pads, such as the argon model Svarog REAL TIG 200 or MMA semi-automatic ESAB Rebel EMP

You can choose reliable semi-automatic machines, TIG inverters and RDS devices from trusted brands EWM, Fronius, Lincoln Electric, ESAB. Or pay attention to the “professional” and “semi-professional” categories, where models are initially designed for longer work. Then you will have to deal with breakdowns and repair them less often.

Answers to questions: how to repair a welding machine with your own hands?

How often should the inverter be blown out of dust? HideMore details

This depends on the degree of dust in the room where it is located. If abrasive cutting of metal, grinding, or polishing of stainless steel is carried out nearby, then it is recommended to clean it weekly. Blowing is necessary every month, or better yet every week. In normal garage conditions, preventive blowing is sufficient once every 6 months.

What to do if the inverter cooks poorly? HideMore details

Check the voltage in the outlet, it must comply with GOST. If it is low, try brewing at a different time of day. If the voltage is normal, try to connect the device to a network with a minimum wire length (220 V network wires create additional resistance).

What and how to remove dust from the inverter? HideMore details

Any compressor will do this. Most models do not require any disassembly. There is perforation on the front side for ventilation. Place the hose on it and turn on the air supply. Dust will come out from the back side behind the fan.

What to do if the welding machine rattles a lot when welding? HideMore details

For transformers, this is a normal operating sound. Nothing can be done. If the inverter begins to rattle, check the tightness of the housing. Often the screws become loose due to vibration and the body begins to resonate.

What to do if the ground cable/holder socket becomes loose? HideMore details

If the connector is loose, it will create poor contact, which will lead to damage to the device. The connector needs to be replaced. interferes with cooking. The connector can be replaced by accessing the back side. Buy exactly the same one for your inverter model.

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There is not enough voltage for the welding machine

Probably, many people are familiar with the situation when, when welding metal with a household machine, the electrode “sticks” and a welding arc does not form. This happens due to insufficient voltage in the network, because you can cook with an electrode with a diameter of 3 mm only at a voltage of at least 200 V, and 2 mm - 180 V. But sometimes when measuring the voltage in the outlet you can find much lower values - up to 160-150 B. The problem of low voltage in the network in many localities can be associated with various reasons:

wear of distribution wires, which leads to zero burnout and voltage imbalance across phases;

the presence of a low-power transformer substation that cannot cope with the increased load or increase in the number of consumers;

phase imbalance on the transformer and others.

Are there any weaknesses in welding inverters?

The appearance of inverters was a real breakthrough in the field of welding technology. They differ from classic machines in their compactness, light weight, noiselessness and the ability to produce high-quality seams even with minimal welding experience. Today, inverters are considered the best purchase for both domestic and professional use. However, despite all its advantages, even such equipment periodically breaks down.

Operating principle and main components of welding inverters

Welding inverters, unlike classic machines, are classified not as electrical, but as electronic devices. They implement a different principle of converting an electrical signal (and the signal changes its characteristics several times). First, the alternating electric current is rectified using semiconductors and becomes constant. It is then passed through a filter for additional smoothing. At the next stage, the signal enters a transistor inverter (its other name is a modulator) and is again converted into an alternating current with a frequency of about 100 kHz. After this, it passes through a transformer, which lowers the voltage and increases the current. Next, the signal goes to a high-pass filter and, at the last stage, to a rectifier.

The use of high-frequency converters has made it possible to reduce the weight and size of welding machines. The electronic “filling” makes it possible to regulate and maintain the parameters of the electric arc with high precision and maintain them at the required level. The main elements of inverters are diode bridges, transistors (MOSFET or IGBT) and control boards. They make the design of the devices quite complex, but convenient to use. To maintain high performance characteristics of the devices, electronic control systems are used to monitor the operation of powerful transistors, power supply parameters and output current.

Compact welding inverter Semiconductor devices began to be used in electronic devices back in the 60s of the twentieth century. A little later, a thyristor pulse voltage converter was developed and tested in practice, intended for welding work. In fact, it was the first welding inverter.

Why do inverters break down?

All breakdowns of welding inverters can occur for three reasons:

Due to violation of welding technology. In this case, the estimated time of continuous operation of the device specified in its passport (PV) is exceeded. As a result, the device overheats and the risk of failure of its transformer or electronic components increases.
Due to the wrong choice of work location. In this case, moisture or a large amount of construction dust with metal inclusions can get inside the inverter, to which devices of this type are very sensitive (this is the main one of the few weak points of inverters). The result is highly likely to be failure of the electronic boards.
Due to a broken cooling fan. Its cause, in turn, may be a manufacturing defect or improper operating conditions of the inverter.

Electronic “filling” of the welding inverter

Main types of breakdowns of welding inverters

There are several most common types of breakdowns of inverter welding machines:

Spontaneous shutdown of the device. Its cause is most often a breakdown of capacitors, short circuit of turns of transformer coils or wires. The device is saved from permanent failure by a timely triggered protection that turns it off. It should be noted that spontaneous shutdown is not necessarily a consequence of a breakdown. The protection may trigger if the inverter overheats and simply needs timely rest.
No arc when the device is turned on. In this case, the cables may be damaged or their connection may be unreliable.
Electrode sticking. There may be several reasons for this: low voltage in the network, unsatisfactory preparation (cleaning) of the surfaces to be welded, the use of a long extension cord (more than 40 m) or a small cross-section (less than 2.5 mm2).
Unstable arc combustion and increased metal spattering. Most often, the reason for this is the incorrect choice of welding current.
Increased power consumption when there is no load. This is possible as a result of the short circuit of the turns of the transformer coils. In this case, it needs to be restored, rewinded or replaced.
Breakage of the welding arc and the impossibility of its re-ignition. The reason may be a short circuit in the wires or a breakdown of the high voltage winding of the transformer.
Violation of the accuracy of welding current adjustment. This may occur due to deterioration in the mobility of the secondary coils of the transformer due to the accumulation of dust or debris in it, or a malfunction of the adjusting screw.
Increased noise during operation of the transformer and heating of the latter. There may be several reasons for this situation: failure of the transformer core fastening, loosening of the bolts holding the magnetic core sheets together, or overload of the transformer.

Welding inverter repair

Conclusion

Inverters are rightfully considered reliable and functional welding equipment, but they still have several weak points. One of them can be called their electronic components. They make the devices extremely convenient and efficient, but at the same time vulnerable to water and construction dust. To ensure a long service life, inverter devices must be protected from moisture and dust.

The second weak point of the devices is the cooling fans. If they break down, the inverters will overheat with subsequent possible failure.

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Welding inverter malfunctions - causes and solutions

This option is quite expensive, because the generator needs very high power, which should be enough for welding. Otherwise, there is a high risk of destroying an expensive generator with a constant peak load.

Secondly, you can purchase a voltage stabilizer for the welding inverter. This device will help equalize both low and high voltage to ensure a normal welding process and protect the inverter from failure. Most inverters are capable of operating in a voltage range of +/- 30% of the rated voltage, that is, 160-280 V, which is sufficient in most cases. But even if your voltage is 140-150 V, it is possible to use a stabilizer after installing a step-up transformer. The latter will raise the voltage by a given fixed value, and the stabilizer will level it to the required parameters.

The popular solution among “traditional craftsmen” of installing only a transformer without a stabilizer is categorically not recommended. This is because the voltage drop in the network may be a temporary phenomenon, and after correcting the problem, it may suddenly return to normal. In this case, the transformer will still increase the voltage, as a result of which it can even reach 300 V. This leads not only to damage to household appliances, but also to burnout of thin old wiring, fires, etc. If you install a stabilizer after the transformer, then it will equalize the increased voltage or shut down the system if it cannot cope with too large a surge.

Therefore, it is worth thinking about buying not only a voltage stabilizer for a welding inverter, but also a large stabilizer for installation on the entire household network. Such a solution, although it will be significantly more expensive, will help get rid of problems with power surges forever, preserve your equipment and extend its service life, and can also protect your home from fire.

Welding cast iron with metal Popular brands of Electrodes Electrodes with blue coating

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 circuitry of which does not allow for a full repair at home.

Just trying to disable the inverter protection can baffle even an electrical specialist. So in this case, it is best to seek help from a specialized workshop.

How to weld correctly with a modern inverter welding machine?

Date: 06/24/2015
Rating: 36

Welding is one of the most popular technological types of work in modern construction. This is due to the fact that the weld forms a strong and reliable connection between the metal elements of the structure. The material from which it is made can be very diverse with the incredible complexity of the configuration of the final part. In order to carry out high-quality tasks for welding several parts, it is necessary to select the right equipment and have some execution skills. But if there is no or little experience, then learning how to properly weld with a welding inverter yourself is quite possible.

Design of a welding inverter.

Some features of an inverter welding machine

A welding inverter is equipment that consists of such elements as:

control system;
frequency converter;
a transformer with a high frequency;
storage device;
power and network rectifiers;
network filter.

A special feature of the inverter welding machine is that it does not lead to power surges in the network to which it is connected. This is due to the fact that it includes a storage capacitor, which ensures uninterrupted power supply, as well as soft ignition of the arc and its further retention.

Welding inverter circuit.

Despite this rather complex composition, this device is small-sized, which allows it to be worn on the shoulder. At the same time, the small size does not affect the quality of the seam made with its help. An inverter welding machine can be used for domestic purposes, as well as in production. Given its ease, work can be carried out in rather difficult places to which other machinery and equipment cannot be delivered.

To ensure safe work with an inverter welding machine, you must have a welding mask or goggles. The required number of electrodes that correspond to the steel grade must also be available.

The characteristics by which you can choose an inverter welding machine are:

Possibility of adjusting welding current. For domestic needs, this indicator should be in the range of 160-200 A.
Time of continuous operation of an inverter welding machine. In passport data this value is indicated as a percentage. For example, if 40% is indicated, this means how long the device can operate reliably and without overheating. The remaining 60% comes from leisure. Overheat protection is installed by the manufacturer. It turns off the equipment automatically when this coefficient is reached. These percentages are based on the maximum load on the inverter welding machine.
The power it can consume. Two values are indicated: in working condition, that is, when the welding process is taking place, and at idle.
Housing structure. If the casing design provides additional protection from moisture and dust, then such a device can be used in industries with increased these characteristics. For domestic use, amplification of these indicators is not required.

Preparation at work

Diagram of the front panel of the inverter.

In order to begin welding work, you need to prepare:

welding mask;
special protective clothing or any clothing that can protect against sparks;
gloves made of rough fabric;
a hammer with a sharp tip, which will be used to knock off scale and sharp corners formed during welding;
electrodes that match the type and grade of steel.

When choosing electrodes, it is necessary to take into account not only the composition of the metal, but also its thickness and the direction of the weld. It should be borne in mind that with a large electrode diameter, current consumption increases. And its small diameters are suitable only for small metal thicknesses. Therefore, if you do not have much experience in welding, then you should choose a 2-3 mm electrode.

In order to weld correctly with an inverter welding machine, you need to select the current strength and brand of electrode. These parameters are determined by the thickness of the metal that needs to be connected.

The electrode is installed in a special holder. Do not bring the electrode quickly to the surface. This can lead to sticking, that is, the electrode will stick to the metal, and further welding will be impossible. The ground terminal is hung on the surface on which welding is performed.

Inverter welding diagram.

Next, you need to ignite the arc. To do this, the electrode is brought at a certain angle to the metal surface and touched 2-3 times. This activates the welding electrode and forms an arc. The optimal distance from the tip of the electrode to the surface to be welded, when the arc will always be kept at the required size, is equal to the diameter of the electrode itself. It is advisable to hold the electrode at this height throughout the entire seam. Next, the electrode is guided along the joint. The seam is formed by fusing metal.

You cannot quickly move the electrode along the joint of the surfaces to be welded. This is due to the fact that:

The quality of the weld decreases, that is, the deposition of the metal will be uneven.
The arc between the welding surface and the electrode goes out. Reigniting it may lead to excessive melting or burning.

If scale and excess deposited material have formed during the work, they must be removed. This is done using a hammer or other metal tool.

The weld seam may not necessarily be continuous. If it is necessary to interrupt it, the electrode is raised higher. This causes the arc to break and the process of making the seam stops. Next, the arc is ignited in a new place, and the process continues.

Some nuances of welding

Methods for connecting a welding inverter.

In order for the seam to have minimal defects and to weld correctly with an inverter welding machine, it is necessary to place the bath line lower than the surface of the metal being welded. If the penetration of the arc into the metal part is deep, then it pushes the bath back, thereby forming a seam. Therefore, when performing work, it is necessary to ensure that the seam formed is flush with the metal.

The movement of the electrode along the seam itself may be different. A reliable and perfect seam can be formed by performing circular or zigzag movements. When performing circular movements, it is necessary to carefully control how the seam is formed so that the bath is evenly distributed around the circle. When moving the electrode in a zigzag, you need to carefully ensure that the seam begins to form at one edge of the bath, then at its top, and then at the other end. In this case, everything should happen evenly.

A zigzag seam is quite difficult to perform and can be done efficiently by an experienced welder.

Table of required technical characteristics for a welding inverter.

For domestic needs, it is quite enough to master the technique of a continuous seam with a roller.

Cutting through a metal part occurs when there is not enough electrode to completely fill the weld pool during transverse movement. Controlling the outer boundaries of the bath will prevent the formation of a side cut. In order to regulate the bath, use the arc force, which is located between the surface to be welded and the electrode. An inverter welding machine allows you to control it smoothly and constantly.

In addition, if you change the angle of the electrode to the surface, you can change the size of the bath. That is, with the electrode positioned as vertically as possible, a convex seam is nevertheless formed. This is due to the fact that with this arrangement, all the necessary heat is located directly below it.

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This means that the bathtub is entirely directed downward, and the metal around it is well melted. If you tilt the electrode, then all the temperature is directed back, thereby lifting the metal and forming a seam.

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Frequent malfunctions

The main manifestations of problems with electric arc welding machines are:

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

Repairs always begin with an inspection of the welding machine and checking the supply voltage. Repairing transformer welding machines is not difficult, and they are not picky about maintenance. With inverter devices, it is more difficult to determine a breakdown, and repairs at home are often impossible.

However, if handled properly, inverters last a long time and do not break down. It is necessary to protect from dust, high humidity, frost, and store in a dry place. There are the most typical malfunctions of welding machines that you can fix yourself.

Common breakdowns

Inverter sparks

One of the most common malfunctions in a budget inverter. Often, under such circumstances, the device sparks but does not cook. That is, the arc is ignited for a split second and then goes out again. There can be many reasons for this breakdown. But first things first.

Start by carefully inspecting the welding cables you use in your welding. Often they are the problem. Even if you do not see any noticeable defects, connect other (preferably new) cables to the holder and ground, and try to strike the arc again. Also check that all connectors are secure.

If the inverter continues to spark, then the problem may lie in the electrolytic capacitors in the inverter. Replace them if you have sufficient skills. If this does not help, then look at the wires on the package. They may be burnt and need to be replaced.

If unsuccessful, it is better to take the device to a service center. Because there may be a dozen reasons for this problem. The service center will give you a full diagnosis and be able to find out the true cause.

The inverter does not cook

The inverter welding machine may be turned on, all indicator lights may be normal, but no welding is taking place. The most common cause of such a breakdown is overheating of the device. We will talk about how to eliminate overheating below.

Also check the condition of the welding cables, they may be damaged or simply need to be replaced. Connect new welding cables and try again to check the operation of the machine.

The inverter is overheating

One of the main reasons why a welding machine welds poorly or does not weld at all. If you cook for more than 10 minutes without a break, the appliance may overheat. Many inverters are equipped with overheat protection, but sometimes it does not work. Then the inverter simply stops working, but remains turned on.

The problem can be solved very simply. Stop welding for half an hour. Leave the inverter to rest. In half an hour it will return to normal and you can continue working.

The inverter does not work, does not turn on

Another one of the most common problems. You plug the device into the outlet, but it shows no signs of life. There may be several reasons. It's usually all about your mains voltage. It may not be enough to turn on the welding machine. If you cook at the dacha, then the probability of low voltage at the output is very high. The problem is solved by purchasing a voltage stabilizer and connecting it to the device.

Another reason is a problem with the network cable with which the device is connected to the outlet. Check the integrity of the cable and plug. You can remove the body of the device and see if everything is in order with the rest of the network cable, hidden from view.

If everything is fine with the cable, but the stabilizer did not help, then the cause of the malfunction is probably in the power supply of the inverter itself. In this case, we recommend contacting a service center. There is a high probability that you will not be able to repair the welding inverter at home without outside help.

Current is not adjustable

You turn the current control, but nothing happens. Most likely, the problem lies in the regulator itself. It is necessary to replace either the regulator or check the reliability of its connection to the wires. Remove the body of the device and check everything carefully. Use a multimeter to diagnose the regulator.

If the regulator is working, but the current is not regulated, then the reason may be a shorted inductor or a malfunction of the secondary transformer. Replace these components or take the device to a specialist. He knows what to do with it.

Electrode sticks to metal

Many modern inverters are equipped with an anti-stick function that prevents the electrode from sticking to the metal. But sometimes this function does not work correctly or does not work at all due to other device failures.

The first reason for the electrode sticking to the metal is an incorrectly selected welding mode. We talked in detail about how to set up the welding mode in this article.

The second reason is the same low voltage of your electrical network. There are inverters that can operate at reduced voltage. But in some places the voltage is so low that even such devices cannot cope with the work. The problem is solved by purchasing a voltage stabilizer.

The third reason is the use of welding extensions. Sometimes the welding cable is simply not long enough to complete the welding job. In this case, you can use a special extension cord. But keep in mind that if its length exceeds 40 meters and its cross-section is less than 2.5 mm2, then there is a high probability of a decrease in voltage during welding. And after this, the electrode sticks to the metal.

The fourth reason is poor preparation of the part before welding. For example, you are welding metal with an oxide film on the surface, but you did not clean the part thoroughly enough before performing the work. As a result, the film formed again and worsened the contact of the electrode with the metal, causing sticking

The device does not 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, you should use a 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 rewinded, and if both are faulty, it is easier to replace the entire transformer. The 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 of checking it and replacing it with a new part.

If all elements of the circuit are in working order, it is necessary to deal with the mains voltage, which can be greatly underestimated and is simply not enough for the normal functioning of the welding machine.

Spontaneous shutdown

In some cases, repairs can be carried out independently if the device begins to turn off spontaneously. Most models of welding machines are equipped with a protective circuit (automatic) that is 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 spontaneous shutdown of the welding machine, first of all, you should check the state of the protection and try to return this element to working condition.

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

In this situation, first of all, you should make sure that the cooling unit of the unit is working normally and that overheating of the internal spaces is excluded.

It also happens that the cooling unit does not cope with its functions due to the fact that the welding machine was under a load for a long time that exceeded the permissible norm. The only correct solution 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, a circuit breaker can be installed in the electrical panel. To maintain normal functioning of the welding unit, its settings must correspond to the selected modes.

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

The inverter hums, but does not cook - what could be?

So, the most common problem with welding inverters is overheating and lack of arc (contact). Everything is clear with overheating. In this case, the inverter goes into protection and needs to be given time to cool down.

But what to do with the lack of a welding arc? Why does the inverter hum but refuse to cook?

The most common reason for this is damage to the holder cable or ground. Accordingly, there is no contact, no welding. Moreover, the cable breaks off, as a rule, at the electrode holder, right under the insulation.

Thus, it is impossible to notice the damage, but it is there, and you just need to pull the cable a little towards yourself. All this brings confusion and certain difficulties in troubleshooting. The inverter seems to work, but does not cook.

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 its electronic circuit. Knowing them will allow you to quickly identify the causes of breakdowns and try to eliminate them in a timely manner.

Electrical diagram

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

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

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

malfunctions associated with errors in choosing the welding mode;
operational failures caused by failure of the electronic (converter) module or other parts of the device.

The method for identifying inverter malfunctions associated with disturbances in the operation of the circuit involves sequential execution of operations carried out according to the principle “from simple damage to more complex damage.” 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 welding parameters, ensuring trouble-free (without turning off the inverter) operation of the device.

Features of operation

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

In the process of repairing an electronic circuit, a visual inspection of the circuit boards is first carried out in order to identify burnt or “suspicious” elements within individual functional modules.

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

To do this, you will need an oscilloscope and a multimeter, which you should start working with only if you have complete confidence in your abilities. If you have any doubts about your qualifications, the only right decision is to take (take) the device to a specialized workshop.

Specialists in the repair of complex pulse devices will quickly find and eliminate the malfunction, and at the same time carry out maintenance of this unit.

Self-repair procedure

If you decide to repair the board yourself, we recommend using the following advice from experienced specialists.

If burnt wires and parts are discovered during a visual inspection, you should replace them with new ones, and at the same time reconnect all connectors, which will eliminate the possibility of loss of contact in them.

If such repairs do not lead to the desired result, you will have to begin a block-by-block examination of the electronic signal conversion circuits.

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

Focusing on these diagrams using an oscilloscope, you can sequentially check all electronic chains and identify a node in which the normal signal conversion pattern is disrupted.

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 you have doubts about the functionality of this board, you can try replacing it with a working one (from another, working inverter) and try to start the welding machine again.

Procedure for repairing devices

Failure and failure of the welding inverter can occur either due to a serious breakdown or due to a minor malfunction. Before contacting a service center or a familiar technician, it makes sense to consider the option of doing the repair yourself, especially if the owner has specialized education or amateur radio skills. The inverter should be disassembled, cleaned and carefully inspected from the inside, as the problem may be excess dust or some loose wiring, and no major repairs are really needed.

If you decide to carry out repairs yourself, then the following minimum set of tools is required:

Digital multimeter. The most common one, the “diode test” function is optional, since all semiconductors can be checked in resistance measurement mode.
Soldering iron with accessories. A soldering station is better, but you can get by with a soldering iron with a thin tip of 40–60 W.
Screwdrivers, pliers, wire cutters, tweezers.

It is often written that to check the condition of an inverter device you definitely need an oscilloscope. But this is a different level of knowledge and skills with different recommendations for troubleshooting. Our actions for diagnosing and repairing the inverter will be limited to a visual inspection, continuity testing, basic measurements of the condition of the main elements of the inverter’s electronic circuit and their replacement in the event of a malfunction. If all this does not bring results, then you need to contact specialized specialists.

The procedure for the first stage is as follows:

Remove the housing and clean the inverter from dust with compressed air. Select the pressure so as not to damage printed circuit boards and electronic components.
Check the condition of the fan blades and the ease of their rotation. If problems are found, replace them with new ones. Check that all wires and connectors are securely connected.
Check the connection and condition of the welding current adjustment potentiometer. In case of malfunction, repair or replacement.
Inspect the windings of transformers and chokes for burning. If there are defects, dismantle and send for inspection or immediately rewind.
Check the elements of the power circuit (capacitors, charging resistor, diodes, transistors) for damage to the external housing. If defects are found, replace with the same or analogues.
Carry out an external inspection of the control system printed circuit board. If there are damaged elements, then carefully remove them and replace them with new ones (if you have never soldered printed circuit boards, then it is better not to do this, but immediately contact a specialist).

If, after an external inspection and elimination of detected problems, the inverter does not turn on or operates incorrectly, it is necessary to diagnose individual circuits and power elements (see below).

Inverter diagnostics

Testing of semiconductor electronic components is carried out by measuring the resistance at their terminals by changing the polarity of the multimeter. In one case it should be close to zero, in the other - infinitely large.

Before you begin diagnosing the inverter, you must connect a 100÷150 W incandescent light bulb in series with it, which will stabilize the current and serve as protection against short circuits. In addition, by the glow of the light bulb one can judge the working condition of capacitors and power transistors.

We diagnose the inverter in the following sequence:

Checking the power diodes of the output rectifier. We measure the resistance at the output terminals of the inverter with a multimeter. One way should be zero, the other should be infinity. If this is not the case, then we proceed to repair: we identify the faulty diode and replace it.
Checking the power transistors of the RF converter. First you need to determine the type of arrangement of the transistor pins. We measure for “breakdown” by changing the polarity between the gate and the other two terminals. If it is zero in both directions, then the transistor is faulty and must be replaced.
Checking the diodes of the LF rectifier. Here the diodes are connected in a bridge circuit, so first you need to determine the four contact points. At zero in both directions the diode must be replaced.
If all power semiconductors of the devices are in good condition, you can connect the inverter to the network. In this case, the light bulb connected in series with it will first flash for a few seconds, and then, as the LF rectifier capacitors charge, it will begin to dim noticeably. If at least one of the transistors of the RF converter is broken, the light bulb will burn at full intensity.
The inverter can then be turned on and off several times using the key on the front panel. After this, it is necessary to measure the open circuit voltage in several positions of the current regulator (it will be slightly less than the nominal one).

Before repairing the welding inverter, it must be disconnected from the power supply. The light bulb circuit can only be used at idle. It is best to check the device under load with a ballast rheostat.

Replacing transistors

When repairing a welding inverter, you may have to replace transistors, zener diodes, resistors and other electronic parts. To do this, you need to have some skills in soldering such products. When replacing transistors (IGBT and MOSFET), you must remember that they can fail under the influence of static electricity. It is recommended to work with them on antistatic surfaces and wearing wristbands to protect against static. In fact, few people fully follow these instructions, but it is still necessary to know about them.

In order to replace the power transistor, you need to unscrew the screw that holds it to the radiator, separate its body from the surface, and then carefully unsolder it. Installation of the new transistor is carried out in the reverse order; before pressing it with a screw to the radiator, you need to apply a thin layer of heat-dissipating paste to the contact point.

Rectifier repair

The inverter contains three rectifiers: a half-wave output and two bridge rectifiers: an input and an internal power supply (“standby”). The first one contains two diodes and is checked with a multimeter through the input terminals of the inverter, and bridge diodes - at four points (on the connectors or on the board). When repairing rectifiers, diodes, capacitors and ballast resistors are most often replaced. There are no special precautions when soldering these elements, although when replacing parts of the internal power supply you need to be extremely careful: they are installed on the printed circuit board. The diodes of the input and output rectifiers are mounted on radiators. When installing a new element, be sure to use heat-dissipating paste before fixing it with a clamping screw.

Capacitor diagnostics

The main reasons for the failure of electrolytic capacitors are mechanical damage, significant excesses of the rated voltage, failure of internal contacts and aging. In the first two cases, malfunctions can be detected visually, while the ends of most models of electrolytic capacitors have special notches that rise or open when the electrolyte “explodes” (see photo below).

Figure 7 — Capacitor diagnostics

Hidden faults are quite easily detected by a device with a capacitance measurement function or a conventional multimeter. In the latter case, the pre-discharged capacitor initially shows a small resistance, which increases to infinity as it is charged from the multimeter source. When measuring at the contacts of a faulty capacitor, the device shows either an open circuit or some kind of constant resistance.

Control board repair

If simple diagnostics with a multimeter and subsequent repairs do not give the desired result, then the source of the problem is most likely the control board. Without an oscilloscope, here you can only check the voltage values at the contact points of the board indicated on the diagram, as well as measure the supply voltages and ring the semiconductor devices (which, most likely, will have to be soldered). In addition, to repair the control board, you need good knowledge of radio electronics and the ability to understand the circuits of electronic devices. For those who do not have such qualifications, there is only one option left - to a service center or to a specialist with a good reputation.

We think this article lists all the possible steps to diagnose inverter faults using a multimeter. If we missed any important points, write about it in the comments and tell us about your experience in repairing an inverter device.

PS. Experienced and serial production of printed circuit boards with a guarantee can be viewed at this link.

Content:

A welding inverter is modern equipment, the use of which in the welding process allows one to achieve very high quality work and provides the welder with 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 occurring during its operation.

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

malfunctions associated with improper operation of the electronic “stuffing” of the device

malfunctions associated with incorrect choice of operating mode.

Why does the electrode stick when welding?

Electrodes are the main consumables for welding. They are produced in a wide variety, since each model is designed for its own type of metal and special conditions of use. Correctly selected surfacing material and the mode of its use protects against many negative phenomena that lead to defects during welding. This requires not only adherence to the technical part, but also the skill of a master. After all, the reasons why the electrode sticks during welding can be completely different.

Electrode sticking when welding with an inverter

The consumables themselves undergo various degrees of control during production, so that customers are often supplied with high-quality, proven items. In the future, all that remains is to choose them correctly and apply them to achieve the desired result. Selecting reliable products with quality certificates will help solve many problems, but the electrodes may be damaged due to improper storage or transportation, so this factor should also be taken into account before starting work. Sticking of electrodes when welding with an inverter is extremely undesirable when it comes to critical structures, as this spoils the structure of the seam and harms the welding machine itself.

One of the reasons for filler material sticking to the base metal is insufficient coating of the welding electrode. The end, as a rule, is the most vulnerable point and the coating is often sprinkled here. Without it, the arc is quite unstable and unprotected, so sticking in this case will be quite common. Even increasing the welding current will not help here. Problems with the coating can also arise in another way, since it often accumulates moisture whenever possible. In addition to the fact that you should not weld with wet electrodes due to the potentially high hydrogen content in the weld, which will lead to the formation of cracks, it will also provoke sticking. One of the reasons why an electrode sticks is that it is damp. If the coating has absorbed a large amount of moisture, then it is quite difficult for the electric arc to ignite. Increasing the welding current also does not help here, therefore, it is better to choose other materials for the process.

Lack of welding electrode coating

One of the most common reasons why an electrode sticks when welding with an inverter is an incorrectly selected mode. Many craftsmen are afraid to burn out the base metal, so they try to choose a setting that is a little weaker than it should be. Insufficient current means there is not enough energy to ignite the arc. Even if it lights up for a while, it quickly disappears and the electrode sticks again. It is for this reason that it is worth paying attention to precise welding modes and using techniques with precise adjustment of parameters, especially when the thinnest electrodes are used.

Selecting the correct mode when welding with an inverter

Lack of experience very often becomes the reason why electrodes stick when welding, since even with correctly selected parameters nothing may come of it. This requires experience in igniting a specific electrode diameter, as well as knowledge of the nuances of operation in various positions. Here you need to confidently catch the arc and its position. Otherwise, it will either be interrupted if the electrode is too high, or stick if it is too low. The height of the arc depends on the specific brand and its diameter. Considering that experts recommend keeping the arc as low as possible, beginners often reduce the whole situation to the fact that the electrode is constantly sticking.

The most common reason why the electrode sticks when welding with an inverter is the low quality of the consumables. Brands that are too cheap often do not perform well and can carry with them a whole range of negative aspects.

Recommendations

One of the easiest ways to overcome this problem is the additional “anti-stick electrode” function, which is available on modern welding machines. Naturally, it will not help in the most difficult cases, but it will make their use much simpler and easier.

You also need to pay attention to the correct selection of the electrodes themselves and the modes of their use. This is the main way to avoid sticking. After all, sometimes it is enough just to raise the current to the required level and the arc will stabilize.

Before using consumables, they should be dried and calcined to remove moisture. Even if these are new consumables, these procedures should be carried out, since during transportation and storage they could absorb liquid from the air.

It is necessary to check the end of the electrode, both during the first ignition and during subsequent ignitions. Since at the very beginning the coating may crumble. And then slag may stick to the end, which will interfere with welding.

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Causes of breakdowns of welding inverters and options for eliminating them.

There are a number of typical faults that occur when it comes to welding inverters:

instability of the welding arc and strong spattering of metal;
welding electrode sticking;
lack of welding process when the machine is turned on;
lack of response from 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 welding inverters.

Instability of the welding arc and strong spattering of metal.

Welding electrode sticking.

Lack of welding process when the machine is turned on.

The device does not respond when turned on.

The main reasons for the failure of inverters and their manifestations

The main reasons for the failure of welding inverters are violations of the rules of their operation. You can learn about the operating modes and maintenance features of a particular device from its passport; in general, approximately the same list of activities is given:

daily external inspection of the main unit and cables;
periodic internal cleaning of the device with compressed air;
routine inspection, cleaning, pulling and repair of connections of internal power contacts;
measuring insulation resistance and checking protective grounding circuits.

The main factors that cause inverter malfunction are:

Sudden changes in input voltage. Its fall leads to instability and termination of the inverter's operation, while a significant excess can cause failure of the elements of the input rectifier.
Mineral dust. Covers the surfaces of the internal parts of the device and clogs the ribbed surfaces of radiators for cooling diodes and transistors. This leads to a violation of the thermal regime and can cause failure of individual elements.
Metal dust and fine shavings. It gets inside the inverter through the input fan if work is being done next to it with grinders, grinders, etc. It can cause an internal short circuit.
Water and high humidity. Causes oxidation of wires and contacts and can lead to a short circuit.
External mechanical damage. Sometimes they cause failure of controls and internal structural elements on which electronic components are attached.

The following describes the main malfunctions in the operation of inverters and their causes.

Arc instability, metal spatter

If there are significant fluctuations in the input voltage or incorrect operation of the inverter control system, abrupt changes in the welding current occur, which leads to arc instability. In this case, first of all it is necessary to check the network voltage. If it is normal, but the oscillations continue, internal diagnostics of the inverter should be performed.

Spattering of metal during welding is usually a consequence of incorrect selection of welding current. The reason for this may be either a human factor or a malfunction of the current regulator or control system.

Inverter does not turn on

This phenomenon may have several reasons:

poor contact of the ground cable clamp;
input voltage too low;
the input circuit breaker has turned off (the reason for this may be an internal short circuit);
The thermal protection has tripped.

In the latter case, you need to wait until the device cools down and try to turn it on again. If the protection trips repeatedly, the inverter requires maintenance or repair.

Inverter overheating

The main reason for overheating of the inverter is a violation of thermal conditions due to a large amount of dust in the internal space of the device. Dust acts as thermal insulation, covering the surfaces of components cooled by the air flow, and does not allow fans to operate normally. If there is constant overheating, before talking about diagnostics and repairs, it is necessary to carefully and very carefully clean all internal modules with compressed air. Another reason for overheating of the inverter is non-compliance with the recommended value of the PV parameter (on duration).

Figure 3 - PV parameters

Increased power consumption

Increased power consumption at idle at the standard value of the input voltage of the network is usually associated with a short circuit between the turns of one of the windings of the high-frequency transformer. Externally, such a malfunction looks like burning of the insulation around its live parts and is most often accompanied by a drop in the no-load voltage (sometimes by two to three times). It is not difficult to remove, disassemble and inspect the transformer yourself, but it is better to entrust its repair to someone who is well versed in this.

Electrode sticking to metal

If the electrode sticks during the welding process, most likely this is caused by incorrect selection of technological parameters and poor preparation of the surfaces to be welded. In addition, to prevent this phenomenon, all modern inverters are equipped with an automatic Anti-Stick function. When the value of the welding current corresponds to the diameter of the electrode and the thickness of the metal being welded, and the welding zone is cut and cleaned properly, the cause of sticking (sticking) may be a periodic decrease in voltage both from the electrical network and directly in the welding circuit.

In the first case, it is necessary to stabilize the mains power supply or use an inverter with the ability to operate at reduced voltage. On the welding chain side, the contacts must be periodically cleaned and their reliability checked. In addition, a voltage drop can be caused by the use of cables whose length and cross-section do not meet regulatory requirements.

Inability to adjust current

First of all, we can talk about a malfunction of the indicator that displays the current value. Also, one of the most common reasons is a broken wire, breakdown or internal wear of the potentiometer, which sets the value of the welding current. If all this is in order, then the problem may be a malfunction of the inverter control system. Only an experienced specialist can understand it and perform such repairs.

Spontaneous shutdown

The reasons for sudden shutdowns of the welding inverter can be sudden surges in the supply voltage, a malfunction of the input circuit breaker, and the operation of temperature protection. In the first case, it is necessary to somehow stabilize the input voltage or use a device designed to operate in this range. If the temperature protection is frequently triggered, it is necessary to clean the internal part from dust and check compliance with the manufacturer's recommendations for the duration of continuous operation. You can check the serviceability of the input machine without complex repairs by temporarily connecting a known-good device instead.