Breakdowns and repairs of various types of Resanta welding machines. Malfunctions of welding inverters Start 220 welding inverter overheating indicator is on

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.

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. Must be protected from dust high humidity, frost, store in a dry place. There are the most typical malfunctions of welding machines that you can fix yourself.

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 working order, 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.

Electrode sticking (arc interruption)

The cause of electrode sticking and arc interruption may be a decrease in voltage due to short circuit in the transformer windings, faulty diodes or loose connecting contacts. A breakdown of the capacitor filter or a 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 from 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 could be restoring the insulation of connecting cables, as well as tightening loose contacts and terminal blocks.

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 protective circuit(automatic), triggered in a critical situation, accompanied by 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 internal spaces 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 exceeding 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, the safety circuit breaker can be installed in electrical panel. To maintain normal functioning of the welding unit, its settings must correspond to the selected modes.

So, some models of such devices ( welding inverter, in particular) in accordance with the instructions, they must work according to a schedule that requires 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 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 constant 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 that ensure trouble-free (without turning off the inverter) operation of the device.

Features of operation

Maintenance and repair of welding machines inverter type 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 such measuring instruments, How digital multimeter, oscilloscope and the like.

Under renovation electronic circuit produced first visual inspection boards 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.

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

Self-repair procedure

If a decision is made to self-repair fees - we recommend using the following tips 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.

If the outcome is favorable, all that remains is to send 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 would like to remind you that the repair of any welding units(and inverters, in particular) is considered a rather complex 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.

When buying an inverter welding machine for work in a garage or in a country house, the first thought is - wow, now I can cook everything! No welding diploma required, the device is designed for users without special education. Handling welding has become easier and more comfortable. The main thing is to understand the principle of operation and first aid in case of difficulties and breakdowns.

Inverter machines - a new generation of manual welding

Since the beginning of 2000, inverter welding machines have become cheaper and more accessible. To spend at home welding work, all you need is this small and easy-to-use device and good electrodes.

Advantages of inverters

Inverter machines are lightweight, compact in size, and their scope of use and welding quality are higher than those of heavy and bulky welding transformers. They carry out their task in full: they weld cars, gates, pipe structures (for example, greenhouses or gazebos). Working with them is mobile - throwing an extendable belt over your shoulder, welding is carried out in any hard-to-reach places.

When vertical, horizontal or overhead welding, the current is reduced by 10–20%, and when welding at an angle, it is increased by the same amount compared to the normal position.

There are also no problems with the connection; the welding machine operates using a regular electrical network. It's great that it won't stop when going down mains voltage. If the deviation is within +/- 15%, the device will continue to operate normally. The current value can be adjusted by selecting the power depending on the type and thickness of the metal. All this makes inverters ideal for both beginners and professionals.

Video: testing a homemade inverter device

How welding inverters work

The inverter apparatus connects the parts DC using electric arc welding with a coated electrode. The big plus is that at the very beginning of the process there are no power surges in the network to which the device is connected. Storage capacitor ensures uninterrupted operation electrical circuit and soft ignition of the arc with its further automatic maintenance. When connected to electrical outlet AC mains voltage with a frequency of 50 Hz is converted first into direct voltage and then into high-frequency modulated voltage. Then, using a high-frequency transformer, the current increases, the voltage decreases, and the output current is rectified. The device provides adjustment of the welding current value and protection against overheating.

The inverter device first rectifies and modulates the input current, and then increases its strength by reducing the voltage until the arc appears

The basic operating mode of inverter welding machines is MMA. This is manual arc welding with piece coating electrodes. For welding steel and cast iron products permanently or alternating current use a diameter of 1.6–5.0 mm.

The devices differ in power and cycle time. The second indicator is the period during which it is allowed to cook at the maximum permissible power in order to prevent the device from overheating. It is designated by the letters PV (on period) and is determined as a percentage relative to a time unit of 10 minutes. For example, if the device indicates a PV of 60%, this means that it can be cooked for 6 minutes and then turned off for 4 minutes. Sometimes the welding cycle is set to 5 minutes. Then a PT value of 60% means a work period of 3 and a rest period of 2 minutes. PV and duty cycle indicators are indicated in the instructions for each device.

Welding machine design

In order not to look for a repair specialist at the first difficulties in the operation of the device, it is advisable to have at least a basic understanding of its design.

DIY inverter assembly diagram

Craftsmen with knowledge of electrical engineering assemble the welding machine themselves. Not only for the sake of economy, but also at the behest creative soul. Posted on the Internet circuit diagrams inverters, drawings and instructions from those who made the inverter themselves. The main thing is to get stability welding arc. Most often, an “oblique bridge” circuit (“Barmaley circuit”) is used using two key transistors: bipolar or field-effect. They are placed on a radiator to remove heat; they open and close synchronously.

In the “Barmaley circuit” the main control elements are two transistors, which open and close synchronously

The electrical solution of the circuit eliminates high-voltage emissions and allows the use of relatively low-level switches. The scheme is used because of its simplicity, reliability and not very expensive consumables.

Video: review of the Barmaley scheme

DIY inverter assembly

The apparatus is assembled from the following blocks:

• power supply for stabilizing input signals. A metal partition is placed between it and other elements and blocks. The multi-winding inductor is controlled by transistors and a capacitor with stored energy. The throttle control system uses diodes;
• power unit, with the participation of which a full cycle of current conversion takes place. Assembled from a primary rectifier, an inverter transistor converter, a step-down high-frequency transformer and an output rectifier;
• Control block. It is based on a master oscillator with a special microcircuit or a pulse-width modulator. They install a resonant choke and 6–10 resonant capacitors;
• protective block. More often collected on power block, installing thermal switches for thermal protection of its elements. To avoid overloads, install a board based on the 561LA7 chip. Snubbers with resistors and capacitors K78–2 protect the converter and rectifiers.

Video: assembling a welding inverter

Reasons for failure of inverters

The design of inverter welding machines is more complex than transformer welding machines and, unfortunately, less reliable. This often leads to failure of various components for the following reasons:

• low protection from dust. When it accumulates inside, a thermal protection signal is triggered and the device turns off. Requires disassembly at least twice a year to clean the internal parts with a jet compressed air or with a soft brush;
• moisture getting inside, causing a short circuit that is dangerous for the unit;
• low quality cooling system in cheap devices. Because of this, the plastic parts of the structure melt and the emergency shutdown does not work. In models with tunnel ventilation, the radiator is located along the body, and the main components are located inside it. Such devices are much more expensive;
• voltage surges, especially drops to 190 V or more;
• overload when cutting thick metal and work for which a particular device is not designed. Then the IGBT power module fails;
• poor-quality fastening in the contacts of the pads, which provokes overheating of these places and sparking;
• sensitivity to shocks and falls due to the presence of plastic parts;
• low quality of spare parts used for repairs;
• violation of the permissible temperature regime. Electronic microprocessors melt and destroy when overheated. It is recommended to adhere to the range from -10 to +40 o C.

Frequent breakdowns of welding inverters

Malfunctions can be either mechanical or related to electronic failure. A welding machine is a complex device, problems can arise anywhere:

Short circuit or breakdown in any important node electrical circuit makes it impossible to operate the welding machine:

• a malfunction of the control board does not provide a stable welding current and does not allow a normal arc to be obtained;
• Damage to the top transistor printed circuit board leads to shutdown of the device;
• Failure of the overheating protection system is determined by the smell of burnt insulation and smoke coming from inside the housing.

Methods for repairing inverter welding machines

When starting to repair a faulty unit, it is worth considering some points.

What can be fixed without opening it?

Poor performance of the device does not always mean internal failure. Wet or poor-quality electrodes are often the culprit. If drying or replacement does not produce a beautiful seam, consider other possible reasons:

• poor ignition, sticking of electrodes to the metal often occurs due to loss of power in the work cables or low welding current. Correct selection cable cross-sections and increasing the current may solve the problem. Do not use power extension cords with a wire cross-section of less than 2.5 mm 2 or more long length. Optimal length up to 15 m, maximum - 40 m, otherwise the device will not work due to loss of current. Welding cable is recommended up to 5 m long;

  To connect the welding machine, you must use an extension cord with a wire with a cross-section of at least 2.5 square meters. mm and length no more than 40 m

• interruption, pulsation of the arc causes instability or low welding current. Check the reliability of the connections or increase the current. If there are significant voltage surges in the network, use a stabilizer;
• strong splashing of metal provokes high welding current or incorrect polarity. The issue is solved by reducing the current strength and maintaining polarity;
• humped, with undercuts, the seam is corrected by increasing the current and correct installation polarity;
• porous seam with big amount defects are caused by unprepared metal or long-arc welding. The number of weld defects can be reduced by cleaning the rusty and dirty surface and bringing the electrode closer to the metal.

  Defects weld occur due to insufficient cleaning of the treated surfaces, incorrect polarity or too far distance of the electrode from the welding site

It is important to choose the correct electrode size for proper operation welding machine.

Table: correspondence between the diameter of the electrodes and the thickness of the metal

Internal organization

To be able to repair a welding machine yourself, you first need to understand its internal structure. The front panel contains sockets for working cables, a current control knob and a power indicator. If the design provides additional functions, operating indicators are located here.

On the front panel of the welding machine there are sockets for connecting cables, a current control knob and an operating mode indicator

The check begins with an external inspection of the device. First of all, check the availability mechanical damage. If there are black spots on the case, most likely there is a short circuit. The tester checks fuses, replaces them if necessary, inspects the insulation of welding cables and connections in sockets. If necessary, tighten the bolts and clean the contacts.

After unscrewing the screws and removing the casing, it opens inner part device containing the following components:

• board with power transistors;
• control board;
• rectifier diode board;
• mains voltage rectification board;
• fan;
• controls - knob and switches.

Tools for work

The following tools will be required for repairs: .

DIY welding machine repair

The filling of the welding machine is clear to those who work with radio electronics. If the necessary skills in this area are not available, intervention will only do harm. Without knowing the rules for handling the board and the technology of such delicate work, you can cause damage much greater than the initial one. It is cheaper and safer to entrust the repair to a professional.

If it is difficult to find a specialized workshop, you have to restore the welding inverter yourself. Important consistently check what stopped the device from working.

If difficulties arise, first read the operating instructions for the welding machine. It must have a section about possible problems when welding, the causes of malfunctions and recommendations for their elimination.

After removing the cover of the device, a violation of the soldering of parts, swelling of the capacitors, and broken contacts are often noticeable. In such cases, damaged spare parts are replaced with similar ones. Torn and burnt areas are removed and re-soldered. If it is not possible to quickly determine the cause of the breakdown, each element of the electrical circuit is checked. Diodes, transistors, zener diodes, resistors and other parts are tested.

A detailed check is carried out sequentially: from the parts that most often fail to the most resistant.

1. Power diodes. To check their continuity, the tester is switched to diode mode, and the probes are touched to the output terminals. If there is ringing in one direction, but not in the other, the power diodes are in order, the lower module of the device is working.

   If the input terminals only ring in one direction, then the power diodes are working properly

2. Power transistors. Power transistors are the most vulnerable parts in the inverter. Keep in mind that when transistors are arranged in blocks, due to one faulty one, the entire arm does not work. They are checked in the following sequence:
   
3. Contact in the button. It is checked in ringing mode by placing the button in the “on” position. If the contacts ring, the button works.

   The button is checked in the “on” mode by ringing its contacts

4. Network bridges. These are reliable elements, but they also sometimes fail. Before checking, it is better to unsolder the wires from them and remove the board. In the ringing mode, the black probe is placed on the positive terminal of the diode, and each terminal of the network bridge is touched in turn with the red one. Then vice versa - red is placed on the negative terminal of the diode, black on each terminal of the network bridge. If the tester shows numbers everywhere, there is no short circuit, the diode bridges are fine.

   The diode bridge is tested by touching each of its terminals in turn.

5. Field effect transistor in the primary power supply. It is checked according to the scheme described in the second paragraph. If there is a charge, the power supply is working.

   The field-effect transistor in the primary power supply is dialed in the same sequence as the power transistors

6. Power nodes. If you don’t have an oscilloscope, use a tester that is set to voltage testing mode. The device is connected to the network via a light bulb. If there is voltage at the output, the light will light up, i.e. the components are working.

   If the light bulb connected in series with the device lights up, the power units are working properly

7. Charging resistor. Break charger possible if the light does not light up when the device is turned on. Check the serial circuit of the PTC and NTC, which ensures the charge of the capacitor. The resistance breaks off when the diode bridges or power transistors are short-circuited.

   To check the charging resistor, check the serial chain of PTC and NTC

8. Key management board. This is a complex element of the inverter, on the functioning of which the operation of the entire device depends. Check the switched on device in voltage mode up to 20 V. Set the regulator to the minimum position, the black probe is installed on the terminal, the red probe on the sixth pin. When the regulator is turned to the maximum position, the tester shows a change in voltage. If on devices 160–200 A the change is in the range of 2.4–3.2 V, the regulator circuit is in order.

   Testing of the key control board is carried out with a tester when the device is turned on in voltage mode up to 20 V

9. Break feedback. Turn on the device, set the voltage on the tester to 20 V. The black probe is placed on the terminal, the red one on the second terminal. A 200 A device will display a voltage of 14–50 mV. If there is a break in the shunt feedback, the tester will show about 500 mV. This means there is no feedback somewhere.
   

   When searching for a break in the reverse connection, the red probe is installed on the second pin of the microcircuit

10. Power unit. In the “on” mode, check for the presence of a voltage of 300 V from the capacitor to the inverter board. Check the integrity of the circuit and transistor. At the output of the power supply, two diodes provide 25 V. If the ringing shows that there is no short circuit, the secondary circuits do not load the power supply, it will start. If there is no startup, the optocoupler or transistor may be broken. If the power supply starts for a short time and then is disconnected from the network, check the transistor. If it gets hot, it means that the diode nearby is broken and needs to be replaced.
    

    Before checking the power supply, unplug the device from the outlet!

    At the first stage of repairing the power supply, check for the presence of a voltage of 300 V on the inverter board

When doing self-repairs, craftsmen use phosphoric acid. If something needs to be soldered to the diode cases (for example, broken stands), they are first tinned. When repairing a broken post, perpendicularity is taken into account. It is important to install it, clearly aligning the holes. If you solder even with minimal distortion, the post will break again when you subsequently tighten the fastener.

If not technical hair dryer, for soldering use a 100–150 W soldering iron. This will prevent damage to the connectors and tracks. Experts recommend for best result Before soldering, heat the block to 160–170 0 C, while the plastic parts of the fan must not be heated. When working with a soldering iron or other heating elements Care is required to avoid touching fusible parts of the device.

Video: welding machine repair and analysis of its main faults

An inverter welding machine is confidently prescribed in home workshops. Before purchasing, it is worth spending time learning the basics of welding and electrical engineering. This will help you navigate the characteristics of the device and, if necessary, repair it yourself. Complex cases It's better to leave it to specialists.

Inverter welding machines are becoming increasingly popular among welders due to their compact size, low weight and reasonable prices. Like any other equipment, these devices can fail due to improper use or due to design flaws. In some cases, you can repair inverter welding machines yourself by studying the design of the inverter, but there are breakdowns that can only be repaired in a service center.

Depending on the model, welding inverters operate both from a household electrical network (220 V) and from three-phase (380 V). The only thing that needs to be taken into account when connecting the device to a household network is its power consumption. If it exceeds the capabilities of the electrical wiring, then the unit will not operate if the network is drained.

So, the inverter welding machine includes the following main modules.

How does an inverter work?

Below is a diagram that clearly shows the principle of operation of a welding inverter.

So, the operating principle of this welding machine module is as follows. The primary rectifier of the inverter receives voltage from the household electrical network or from generators, gasoline or diesel. The incoming current is alternating, but as it passes through the diode block, becomes permanent. The rectified current is supplied to the inverter, where it is converted back into alternating current, but with changed frequency characteristics, that is, it becomes high-frequency. Next, the high-frequency voltage is lowered by a transformer to 60-70 V with a simultaneous increase in current. At the next stage, the current again enters the rectifier, where it is converted into direct current, after which it is supplied to the output terminals of the unit. All current conversions controlled microprocessor unit management.

Causes of inverter failures

Modern inverters, especially those made on the basis of an IGBT module, are quite demanding in terms of operating rules. This is explained by the fact that when the unit is operating, its internal modules generate a lot of heat. Although radiators and a fan are used to remove heat from power components and electronic boards, these measures are sometimes not enough, especially in inexpensive units. Therefore, you need to strictly follow the rules that are indicated in the instructions for the device, which imply periodically turning off the unit to cool down.

This rule is usually called “On Duration” (DS), which is measured as a percentage. Without observing the PV, the main components of the device overheat and fail. If this happens to a new unit, then this breakdown is not subject to warranty repair.

Also, if the inverter welding machine is working in dusty rooms, dust settles on its radiators and interferes with normal heat transfer, which inevitably leads to overheating and breakdown of electrical components. If the presence of dust in the air cannot be eliminated, it is necessary to open the inverter housing more often and clean all components of the device from accumulated contaminants.

But most often inverters fail when they work at low temperatures. Breakdowns occur due to the appearance of condensation on the heated control board, resulting in a short circuit between the parts of this electronic module.

Repair features

A distinctive feature of inverters is the presence electronic board control, therefore only a qualified specialist can diagnose and fix a malfunction in this unit. In addition, diode bridges, transistor units, transformers and other parts may fail electrical diagram apparatus. To carry out diagnostics yourself, you need to have certain knowledge and skills in working with measuring instruments such as an oscilloscope and a multimeter.

From the above, it becomes clear that, without the necessary skills and knowledge, it is not recommended to start repairing the device, especially electronics. Otherwise, it can be completely damaged, and repairing the welding inverter will cost half the cost of a new unit.

Main malfunctions of the unit and their diagnostics

As already mentioned, inverters fail due to the impact on the “vital” units of the device external factors. Also, malfunctions of the welding inverter can occur due to improper operation of the equipment or errors in its settings. The most common malfunctions or interruptions in the operation of inverters are:

The device does not turn on

Very often this breakdown is caused malfunction network cable apparatus. Therefore, you first need to remove the casing from the unit and ring each cable wire with a tester. But if everything is in order with the cable, then more serious diagnostics of the inverter will be required. Perhaps the problem lies in the standby power supply of the device. The method of repairing the “duty room” using the example of a Resanta brand inverter is shown in this video.

Welding arc instability or metal spattering

This malfunction may be caused incorrect setting current strength for a certain electrode diameter.

Advice! If there are no recommended current values ​​on the packaging for the electrodes, then it can be calculated using the following formula: for each millimeter of equipment there should be a welding current in the range of 20-40 A.

It should also be taken into account welding speed. The smaller it is, the lower the current value must be set on the control panel of the unit. In addition, to ensure that the current strength corresponds to the diameter of the additive, you can use the table below.

Welding current is not adjustable

If the welding current is not regulated, the cause may be regulator failure or a violation of the contacts of the wires connected to it. It is necessary to remove the unit casing and check the reliability of the conductor connections, and, if necessary, test the regulator with a multimeter. If everything is in order with it, then this breakdown can be caused by a short circuit in the inductor or a malfunction of the secondary transformer, which will need to be checked with a multimeter. If a malfunction is detected in these modules, they must be replaced or rewound by a specialist.

High power consumption

Excessive power consumption, even if the device is without load, most often causes turn-to-turn short circuit in one of the transformers. In this case, you will not be able to repair them yourself. You need to take the transformer to a mechanic to rewind it.

The electrode sticks to the metal

This happens if the network voltage drops. To get rid of the electrode sticking to the parts being welded, you will need to correctly select and configure the welding mode (according to the instructions for the device). Also, the voltage in the network may sags if the device is connected to an extension cord with a small wire cross-section (less than 2.5 mm 2).

Often, a drop in voltage causing electrode sticking occurs when using a power extension cord that is too long. In this case, the problem is solved by connecting the inverter to the generator.

Overheat light on

If the indicator is on, this indicates overheating of the main modules of the unit. Also, the device may turn off spontaneously, which indicates when thermal protection is triggered. To prevent these interruptions in the operation of the unit from occurring in the future, you again need to adhere to correct mode ON duration (DS). For example, if duty cycle = 70%, then the device should operate in the following mode: after 7 minutes of operation, the unit will be given 3 minutes to cool down.

In fact, various breakdowns and there can be quite a lot of reasons that cause them, and it is difficult to list them all. Therefore, it is better to immediately understand what algorithm is used to diagnose a welding inverter in search of faults. You can find out how the device is diagnosed by watching the following tutorial.

Answer:

Overheating can happen with almost any equipment, especially where work is carried out high currents or temperatures. Therefore, overheating of a welding inverter is a common thing, quite natural, and there is no need to rush to be afraid of it. Moreover, almost all welding machines today are equipped with overheating protection, which is designed to prevent equipment breakdown due to such situations.

Overheating of the welding inverter occurs when the machine is working long time without a break. In this case, the time period for each specific model will be individual. However, for household welding inverters it ranges from thirty minutes to one and a half hours (depending on the quality of components and assembly of the device), for semi-professional models this period increases and ranges from an hour to two hours, and professional welding inverters can often work for a very long time.

It should be taken into account that the operating time interval also strongly depends on the temperature in environment. On a hot sunny day, overheating can occur much faster than during cooler hours in the off-season. By the way, each device has a built-in ventilation system, otherwise it would not be able to work for even a few minutes. But making it very large, efficient, but at the same time cumbersome is impractical. Therefore, than smaller device, the shorter is often the period of work without rest.

How to determine that the welding inverter is overheated? It will turn off and refuse to turn on for a while. This will mean that the protection has worked. However, we do not recommend letting things go to such a semi-emergency shutdown. Determine the approximate working time period for your tool and give the device a rest in advance so that it does not wear out too quickly.

By the way, it is believed that among household welding inverters, and have a long operating time. That is why these devices are purchased with such pleasure by summer residents, who usually use them during hot summers. vacation days. From semi-professional and professional equipment Germans have proven themselves well in this regard

An inverter welder differs from a 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 a device failure, you need to diagnose it: check transistors, resistors, diodes, stabilizers, contacts, etc. Each device is supplied 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 of electronics and the ability to work with electrical circuits are required. Therefore, if self-checking and eliminating simple faults described below did not lead to success, it is better to entrust the repair inverter device to the technicians at the service center.

What are the types of inverter malfunctions?

There are several groups of breakdowns of welding inverters:

• malfunctions arising due to non-compliance with the welding workflow standards specified in the instructions;
• malfunctions arising as a result of incorrect operation or failure of device elements;
• damage resulting from moisture, dust and foreign objects entering the device.

Return to contents

Common faults that you can fix yourself

Let's look at some of the most common malfunctions of welding inverters:

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

1. The welding arc burns unsteadily or the electrode spatters material heavily. The reason for this may lie in wrong choice 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 electrode packaging, then you can start supplying current from 20-40 A for each millimeter of electrode diameter. When the welding speed is reduced, the current must also be reduced.
2. The electrode sticks to the material. This often happens due to low voltage in the network, the value of which is less than the minimum acceptable when working with an inverter. The cause of electrode sticking can also be poor contact in the panel sockets, which can be eliminated by fixing the boards more tightly. Using an extension cord 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 an electrical circuit can also reduce voltage.
3. There is no welding process, while the device is connected to the network. In this case, you need to check the presence of mass on the part being welded. Also check the inverter cable for damage.
4. The device turns off spontaneously. The device is switched off when the transformer is connected to the network, after which its protection is triggered. The reason for this may be a short circuit in the voltage circuit. The protection can be activated not only when the wires are shorted to each other or to the housing, but also when there is a short circuit between the turns of the coils or a breakdown of the capacitors. To repair a hollow part, you first need to disconnect the transformer and find the fault, and then insulate or replace the damaged element.

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

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

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

Welding current is poorly regulated. The reason for this may be a breakdown in the current regulation mechanism: a fault 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 clogging, etc. Remove the casing from the inverter and examine the current regulation mechanism to identify the breakdown.

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

High current consumption at no load. The reason may be short circuit of the turns on the coil. It can be eliminated either by restoring the insulation or by completely rewinding the coil.

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

If a burning smell and smoke appear from the device body, this may indicate a serious breakdown. IN in this case You may need qualified repairs at a service center.

To identify the malfunction, first disassemble the housing. Carry out 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 malfunctions lie precisely in poor-quality soldering; they can be easily eliminated by re-soldering the parts.

All faulty parts should be removed and replaced with new ones corresponding to the given model of the device.

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

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