When turned on, the welding machine overheat indicator lights up. Welding inverter malfunctions - causes and solutions. Inverter devices - a new generation of manual welding
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Overheating can happen to almost any equipment, especially where there is work with high currents or temperatures. Therefore, overheating of the welding inverter is a common, quite natural thing and you should not rush to get scared 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 if the machine is running 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 the components and assembly of the device), for semi-professional models, this interval increases and ranges from one to two hours, and professional welding inverters can often work for a very long time.
It should be taken into account that the value of the working time interval also strongly depends on the temperature in environment. On a hot sunny day, overheating can occur much faster than during the cool hours of the off-season. By the way, each device has a built-in ventilation system, otherwise it could not work for even a few minutes. But to make it very large, efficient, but at the same time cumbersome, is impractical. Therefore, than smaller apparatus, so, often, his period of work without rest is less.
How to determine that the welding inverter has 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 bringing the case 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 differs in a long time working interval. That is why these devices are purchased with such pleasure by summer residents who work with them, usually in hot summers. vacation days. From semi-professional and professional equipment well in this regard, the German
It is well known that repairs welding machines in the vast majority of cases, it can be organized and carried out independently. The only exception is the restoration of the electronic inverter, the complexity of the circuit of which does not allow for a full repair at home.
Just one attempt to disable the inverter protection can confuse even an electrical engineer. So in this case, it is best to seek help from a specialized workshop.
The main manifestations of malfunctions of electric arc welding machines are:
- the device does not turn on when connected to the mains and starting;
- sticking of the electrode with a simultaneous hum in the area of the converter;
- spontaneous shutdown of the welding machine in case of overheating.
Repair always begins with an inspection of the welding machine, checking the supply voltage. It is not difficult to repair transformer welding machines, moreover, they are picky in maintenance. For inverter devices, it is more difficult to determine a breakdown, and repairs at home are often impossible.
However, with proper handling, inverters last a long time and do not break. Must be protected from dust high humidity, frost, store in a dry place. There are the most typical malfunctions of welding machines, which you can fix with your own hands.
Device won't start
In this case, first of all, you need to make sure that there is voltage in the network and the integrity of the fuses installed in the transformer windings. If they are in good condition, use the tester to ring the current windings and each of the rectifier diodes, thereby checking their performance.
If one of the current windings breaks, it will need to be rewound, and in the event of a malfunction of both, it is easier to replace the entire transformer. A damaged or "suspicious" diode is replaced with a new one. After repair, the welding machine is turned on again and checked for serviceability.
Sometimes the filter capacitor fails. In this case, the repair will consist in checking it and replacing it with a new part.
In the event that all elements of the circuit are in good condition, it is necessary to deal with the mains voltage, which can be greatly underestimated and simply not enough for the normal functioning of the welding machine.
Sticky electrode (arc interruption)
The cause of sticking of the electrode and interruption of the arc may be a decrease in voltage due to a short circuit in the transformer windings, faulty diodes or loose connecting contacts. Breakdown of the capacitor filter or short circuit is also possible. individual parts on the body of the welding machine.
Organizational reasons, due to which the device does not cook as it should, include excessive length welding wires(more than 30 meters).
If sticking is accompanied by a strong hum of the transformer, this also indicates an overload in the load circuits of the device or a short circuit in the welding wires.
One of the repair options to eliminate these effects can be the restoration of the insulation of the connecting cables, as well as the tightening of loose contacts and terminal blocks.
Spontaneous shutdown
In some cases, repairs can be carried out independently if the device starts to turn off spontaneously. Most models of welding machines are equipped with protective circuit(automatic), triggered in a critical situation, accompanied by a deviation from normal operation. One of the options for such protection involves blocking the operation of the device when the ventilation module is turned off.
After a spontaneous shutdown of the welding machine, first of all, you should check the state of protection and try to return this element to working condition.
If the protective node is triggered again, it is necessary to proceed to troubleshooting using one of the methods described above related to short circuits or malfunction of individual parts.
In this situation, the first thing to do is to make sure that the cooling unit of the unit is working properly and that the overheating interior spaces excluded.
It also happens that the cooling unit does not cope with its functions due to the fact that the welding machine has been under a load exceeding allowable rate. The only right decision in this case is to let it “rest” for about 30-40 minutes, and then try to turn it on again.
In the absence of internal protection, the circuit breaker can be installed in electrical panel. To maintain the normal functioning of the welding unit, its settings must correspond to the selected modes.
So, some models of such devices (a welding inverter, in particular), in accordance with the instructions, must work according to a schedule that involves a break of 3-4 minutes after 7-8 minutes of continuous welding.
Malfunctions of inverter devices
Before repairing an inverter welding machine with your own hands, it is advisable to familiarize yourself with the principle of operation, as well as with its electronic circuit. Their knowledge will allow you to quickly identify the causes of breakdowns and try to eliminate them in a timely manner.
Wiring diagram
The operation of this device is based on the principle of double conversion of the input voltage and obtaining a constant output at the output. welding current by rectifying the high frequency signal.
The use of an intermediate high-frequency signal makes it possible to obtain a compact pulse device with the ability to effectively adjust the output current.
Breakdowns of all welding inverters can be conditionally divided into the following types:
- malfunctions associated with errors in the choice of welding mode;
- failures in operation due to failure of the electronic (converting) module or other parts of the device.
The method for identifying inverter malfunctions associated with malfunctions in the operation of the circuit involves the sequential execution of operations performed according to the principle “from simple damage to more complex failure”. The nature and cause of breakdowns, as well as repair methods, can be found in more detail in the summary table.
It also provides data on the main parameters of welding, providing a trouble-free (without turning off the inverter) operation of the device.
Operation features
Maintenance and repair of welding machines inverter type differs in a number of features related to the complexity of the circuit of these electronic units. To repair them, you will need certain knowledge, as well as the ability to handle such measuring instruments, how digital multimeter, oscilloscope and the like.
In the process of repairing an electronic circuit, first visual inspection boards in order to identify burnt or "suspicious" elements as part of individual functional modules.
If no violations can be detected during the inspection, the troubleshooting continues by detecting violations in the operation of the electronic circuit (checking voltage levels and the presence of a signal at its control points).
This will require an oscilloscope and a multimeter, which should be started only if you have full confidence in your abilities. If you have any doubts about your qualifications, the only right decision would be to take (take) the device to a specialized workshop.
Complex repair specialists impulse devices they will quickly find and eliminate the malfunction that has arisen, and at the same time they will carry out maintenance of this unit.
Self-repair procedure
If you decide to repair the board yourself, we recommend using the following tips experienced professionals.
If burnt wires and parts are found during a visual inspection, they should be replaced with new ones, and at the same time, all connectors should be plugged, which will eliminate the possibility of losing contact in them.
If such a repair did not lead to the desired result, you will have to start a block-by-block examination of the electronic signal conversion circuits.
To do this, it is necessary to find sources that provide diagrams of voltages and currents, designed for a more complete understanding of the operation of this unit.
Based on these diagrams, using an oscilloscope, you can sequentially check all electronic circuits and identify a node in which the normal signal conversion picture is disturbed.
One of the most complex components of an inverter welding machine is the electronic key control board, the serviceability of which can be checked using the same oscilloscope.
If you doubt the performance of this board, you can try to replace it with a working one (from another working inverter) and try to start the welding machine again.
In the event of a favorable outcome, it remains only to give your board for repair or replace it with a purchased new one. The same should be done if there are suspicions about the serviceability of all other modules or blocks of the welding machine.
In conclusion, we recall that the repair of any welding units(and inverters, in particular) is considered a rather complicated procedure that requires certain skills and the ability to handle complex measuring equipment.
If you have the slightest doubt about your professionalism, you should use the help of specialists and give them the opportunity to return the faulty device to work.
Welding inverter provides good quality welding, creating the welder the most comfortable conditions for work. However, these advantages lead to an increase in the complexity of its design. This can cause various malfunctions of the welding inverter and reduce its reliability.
Inverter repair features
Unlike conventional welding machines, which are electrical products, the welding inverter is electronic device. Therefore, diagnostics and repair of inverter welding machines are carried out by checking the working condition of diode bridges, transistor connections, zener diodes and other parts that are part of electronic circuits. In this case, you need to have the skills to handle oscilloscopes, voltmeters, multimeters and other measuring instruments.
Home hallmark in repairing a welding inverter, it is difficult to determine the nature of the breakdown and detect a failed part. Therefore, very often it is required to diagnose all the nodes of the electrical circuit.
Based on the foregoing, we can conclude that it is necessary to have minimal knowledge in the field of electronics and be able to understand the design electrical circuits. If such skills and abilities are absent, then take on self repair such a device is not recommended, so as not to waste extra time and effort.
The principle of operation of the inverter
The principle of operation of inverter devices is the sequential (step-by-step) conversion of the incoming electric current signal:
- the process of rectifying incoming mains currents using a special rectifier;
- the process of converting rectified currents into alternating high-frequency signals;
- the process of lowering currents with high voltage to the welding voltage occurring on the power transformer;
- transformation alternating current with high frequency in D.C. that occurs with the help of the output rectifier.
To perform such operations, the design of the welding inverter has several modules with electronic stuffing. The main module is the input current rectifier. Then comes the control board, on which the transistors (keys) are located, and it ends with a rectifier for the output signals.
However, in devices different manufacturers having different models, the layout of the units of the unit can be very diverse, but the installation of the main components will always be unchanged.
Therefore, knowing the basic principle of operation of such units and the location of the main modules of their design, it is possible to diagnose possible malfunctions and perform the necessary repairs.
Types of basic faults
When a welding inverter fails, the first thing to do is to check its transistors, since they are one of the most weaknesses such units. Initially, a visual inspection of the transistors should be carried out. It is very easy to identify such a broken part: it has a broken or cracked case with burnt out leads at the solder points on the board. This part needs to be replaced immediately.
New transistors should be installed on a special thermal paste. It will provide heat dissipation from the transistor to a radiator made of aluminum. But very often a visual inspection does not allow you to identify faulty elements, then you should perform a “ring” with a multimeter.
Replacement of defective elements is carried out according to precisely specified parameters. In some cases, analogues of parts can be supplied, while the required parameters can be determined from the datashift. If replacing the burnt transistors did not help, you need to proceed to further diagnostics.
AT normal mode work, transistors cannot fail just like that, most likely, this is due to the incorrect operation of other elements. Most often it is the driver. It is checked with an ohmmeter. If defective parts are found, they must be soldered and replaced with similar parts.
Then the input and output current rectifiers, which consist of diode bridges, are checked. They are mounted on a radiator and are reliable components of welding inverters. But they can also fail. Checking their performance is checked using a voltmeter.
Control board failure
It is best to check diode bridges by soldering wires from them and then detaching them from the board. This can alleviate further work and will not cause doubts when it happened short circuit the entire inverter circuit.
Verification occurs according to a fairly simple algorithm. It is necessary to "ring" the entire group of parts. If at the same time a “shorty” is revealed, then you should search for a broken diode. After its detection, the diode should be carefully soldered and replaced.
If after carrying out all the above steps, the welding machine still does not work, the control board should be tested. It controls the operation (management) of the keys. The reliability of the operation of all equipment will depend on the reliability of the operation of such a board.
To perform a competent and qualified repair of the inverter, it is necessary to check for the presence of the necessary signals that make it work. These signals must be fed to the gate busbars of the key module. You can perform a similar check using oscilloscopes.
Periodically, high heating of the inverter housing may occur. This may be due to violations of the rules for using the unit and the wrong choice of the value of the current used for welding. It can also occur if the electrodes are incorrectly selected or the unit is running for too long. To avoid such difficulties when using the inverter, it is necessary to observe optimal modes works that are registered in the technical passport.
Inverter malfunctions that occur can be eliminated on your own, but this can only be done if you have the necessary diagnostic tool and experience in using it. Otherwise, it is better to seek help from specialists.
Malfunctions of welding inverters are most often caused by either illiterate or careless operation, since these are quite reliable devices and there is simply nothing to break. However, there is also the fault of the manufacturer, who installed a low-quality part, or carried out poor installation.
Let's try to summarize typical faults welding inverters and ways to eliminate them.
1. Unstable arc burning or strong metal spatter during the welding process.
This may be the result of an incorrectly chosen . Recommendations for the selection of the manufacturer indicates on the pack of electrodes. If this information is not available, use the simplest formula: 20 to 40 amps of current must be applied to 1 mm of stick electrode thickness.
2. Sticking of the electrode even with the existing "anti-stick" function.
Most often it is caused by too low voltage in the supply network, and if a welding machine with reduced voltage is possible, the latter will fall below the minimum when the load is connected.
Another reason for sticking is poor contact in panel jacks. To eliminate it, it is enough to tighten the fasteners or fix the inserts.
The voltage drop may be due to the use of a power extension cable with a wire cross section of less than 2.5 mm, which again leads to a decrease in the effective supply voltage of the welding machine. In addition, the reason may lie in an extension cord that is too long. It should be noted that with a cable length of more than 40 meters effective work impossible - too big losses.
The cause of sticking can also be the burning of contacts in the connections of the supply circuit, which again leads to a significant “drawdown” of the voltage.
3. No welding, although all indicators work.
The first cause of the malfunction is overheating of the welding inverter. In the presence of control lamp or indicator, their glow may not be noticeable if the welding inverter does not have an overheating sound signal.
Transistor damaged due to overheating in a welding inverter
Working transistor in a welding inverter
The second reason is a break in the welding cables, or spontaneous disconnection.
The third is the failure of control parts. To eliminate the cause, you will have to open the case and first visually inspect the filling for damaged parts. Sometimes the reason lies in poor-quality soldering - it is enough to re-solder the parts.
4. Power off when welding.
It is most often caused by a malfunction of the switch itself or by a mismatch of its rated current. The switch must be capable of withstanding up to 25 A.
5. Lighting up of the indicator of an overheat.
Excessive load, especially when either thick layer dust inside the case. If the cooling fan fails, the welding inverter will usually not turn on, although this may depend on the specific model.
Of course, in a short article it is impossible to detail all the reasons and possible faults welding machines. However, careful attention to the welding inverter used can prolong its “life” for a long time, and bring joy to the owner from work.
Welder on a run-in after repair. Thermal control:
Radical repair of malfunctions of the GYS 3200 welding inverter:
An inverter welding machine, like any other equipment, sooner or later may fail. And if this happens, then the problem can be solved in two ways: give the device to service center, whose specialization is the repair of inverter welding machines, or try to fix the problem yourself.
Before repairing the welding inverter, make sure that it is disconnected from the mains.
Having mastered the necessary information, you can fix some malfunctions with your own hands, without resorting to the help of masters. This will of course save you cash. However, it can also take a lot of time. Consider how to repair welding machines with your own hands and what malfunctions are most common.
Features of welding inverters and their repair
Inverter welding machines make it possible to perform high-quality welding with maximum comfort, while having minimal skills in working with it.
The welding inverter is characterized by a more complex, but less robust design than welding transformers and rectifiers. The inverter, unlike its electrical predecessors, is a rather complex electronic product. If the inverter device stops working, then the first thing to test is whether the diodes, stabilizers, transistors and other elements of the electrical circuit are working. inverter welding. To do this, you must be able to use a voltmeter, multimeter and oscilloscope.
Inverter welding has its own characteristics when carrying out repairs. For example, it often happens that it is not possible to immediately identify a non-working part and you have to check each element of the apparatus circuit. Therefore, in order to qualitatively repair the inverter, it is very important to own at least basic knowledge in electronics and skills in working with electrical circuits. If you do not own this knowledge, then it is better to give the inverter for repair to specialists. Otherwise, you will simply waste time and energy, or even aggravate the situation.
Each inverter must be accompanied by an instruction that lists possible malfunctions and recommendations for their elimination. Back to index
Diagnostics of malfunctions of welding inverters
In the power supply of the welding inverter, capacitors most often fail.
Before you start repairing inverter welding, you should know what the main types of malfunctions are.
First, a visual inspection of the device is carried out.
If there are places with damaged contacts, the parts must be disconnected, cleaned and connected back.
The terminal block is one of the most vulnerable places of the inverter welding machine. The welding cable is connected to it.
A high current rate and poor contact lead to heating at the junctions of the wires, which can be critical for the device.
There are several groups of all malfunctions of inverter welding machines:
- faults that occur when wrong choice operating mode of welding;
- breakdown or malfunction of the electronic parts of inverter welding.
In both cases, welding is either difficult or impossible at all. There are several factors that contribute to the occurrence of malfunctions.
Diagnosis should be carried out sequentially, starting with simple operations and ending with complex ones.
When testing the welding inverter control unit Special attention it is necessary to pay attention to the induction coils of the voltage regulator.
The reasons for the malfunction of the electrical circuit can be:
- moisture ingress into the device (operation of the device during precipitation);
- dust accumulated inside the body of the apparatus leads to a disruption in the normal cooling of the electrical circuit elements (usually this occurs during constant operation at construction sites);
- overheating of the inverter as a result wrong mode work.
Back to index
The main types of breakdowns of welding inverters and their elimination
Basically, breakdowns of welding inverters are the result of exposure to any external factors or errors in setting up and operating the devices.
Scheme of the main elements of the welding inverter.
The most common faults:
- Unstable burning welding arc or excessive spatter of the electrode material. The reason is the mismatch between the current type and diameter of the electrode and the welding speed. The required current strength can be found in the recommendations of the electrode manufacturer, which are indicated on the packaging. If this information is not specified, then you can use the formula for calculating the current: 20-40 A per 1 mm of electrode diameter. When the welding speed decreases, the current value must also be reduced.
- Adhesion welding electrode to metal. This may be due to several reasons. In most cases, this happens due to the fact that the device is connected to a network with insufficient supply voltage. This may also be due to poor contact between the device modules in the panel sockets. You can fix this problem by tightening the fasteners and fixing the boards well. Voltage may drop at the inverter input when using a mains extension cord with a wire size of less than 2.5 mm2. An excessively long extension cord can also cause a voltage drop (with a wire length of 40 m or more, the operation of the device is practically impossible, since there are large current losses in the circuit). The electrode can stick due to oxidation or burning of the contacts in the circuit, which can also lead to a voltage drop. This problem can also be encountered with improper preparation of materials to be welded (the contact between the electrode and the workpiece deteriorates if there is an oxide film on it).
- Lack of welding when the inverter is on and the indicators are working. The reasons for this in most cases are overheating of the machine and spontaneous disconnection or damage to the welding cables.
- Spontaneous shutdown of the inverter. When the transformer is connected to the network, its protection is activated and the device turns off. The cause may be a short in the circuit between the wires and the case. Protection can be activated when there is a short circuit between sheets of magnetic wire or turns of coils and a breakdown of capacitors. Remedy: disconnect the transformer from the mains, find defective element and repair it - replace the capacitor, restore the insulation, etc.
- High current consumption with little or no network load. Possible reason- closing the turns on the coils. The problem is fixed by rewinding or adjusting the insulation layer.
- The reason for the shutdown welding work mains voltage may become the wrong choice circuit breaker. It should be rated for current up to 25 A.
- Stopping the inverter during long welding. This is most likely due to overheating. When the allowable temperature is exceeded, protection is triggered. Wait 20-30 minutes and continue working.
- The transformer can hum strongly, which is accompanied by overheating of the device. One of the reasons is the loosening of the bolts that tighten the sheet elements of the magnetic wire. The reason for this may be a malfunction in the core fastener, and an overload of the transformer, and a short circuit between the welding cables. Check and retighten all bolts, repair the core fastening, re-insulate the welding cables.