What is the current of the welding inverter?

Operating principle of a welding inverter - circuit and device

Both professional welders and home craftsmen appreciated the principle of operation of the welding inverter, so these devices are gradually replacing traditional welding transformers and rectifiers from the market. And soon the time will come when they will reign in the modern welding equipment market.

What is a welding inverter, why did they appear recently? It should be noted that the principle of inversion, and accordingly the welding unit itself, did not appear yesterday. The basic diagrams of the devices were developed in the 70s of the last century.

But welding instruments appeared in their modern form only recently.

Welding inverter device

Until recently, the inverter device was quite simple in terms of operation. Over time, engineers added electronics to it, which increased the functionality of the unit. The most interesting thing is that this does not make the price of the welding inverter higher. As the sales trend shows, it is gradually decreasing, which makes everyone happy.

Attention! The term "inverter" does not refer to the welding process. This is not a technique. This is the power source of the device.

https://www.youtube.com/watch?v=ZlOj3ebCsbw

What is the operating principle of an inverter-type welding machine?

• It operates from an alternating current network with a voltage of 220 or 380 volts and a current frequency of 50 Hz. Plugs into a regular outlet if we are talking about a household welding inverter.
• The welding current entering the inverter passes through the filter, where it is smoothed out and becomes constant.
• The resulting electrical energy passes through a block of transistors (with a high switching frequency), the result is again alternating current only with a higher frequency - 20-50 kHz.
• Next, the current voltage is converted, it is reduced to 70-90 volts at the inverter output. According to Ohm's law, a decrease in voltage results in an increase in current. At the output (at the end of the electrode) there will be a current equal to 100-200 amperes. This is the welding current.

It is the high frequency of current that is the main technical solution in inverter welding machines. It allows you to achieve maximum advantages over other power sources for the electric welding arc. In inverters, the current required for welding is achieved by changing the high-frequency voltage. In conventional welding transformers, this process occurs due to a change in the electromotive force (EMF) of the induction coil, which is the main part of the transformer.

It is the preliminary conversion of electricity that allows the use of small-sized transformer units in inverters. For comparison, we can give the following example. If you need to obtain a current of 160 amperes at the output, then for this you will need to install a transformer weighing 300 g in the inverter. The same current at the output of conventional welding transformers will be obtained if a transformer with a copper wire (coil) weighing 20 kg is installed in it.

Why is this happening? The main element of a transformer-type welding machine was the power transformer itself with primary and secondary winding coils.

It was the coil that made it possible to reduce the alternating voltage and obtain high currents at the output of the second winding, suitable for inverter welding of metals. A dependence appears from the voltage drop to the current increase.

In this case, the length of the copper wire on the secondary winding decreased, but its diameter increased. Hence the large dimensions of the welding machine and its heavy weight.

Schematic diagram of the inverter apparatus

In inverter-type welding machines, the opposite is true: they are small in size and weight. But how to obtain high-frequency voltage if its frequency in the network is only 50 Hz? The basic inverter circuit of the device, which consists of powerful transistors, comes to the rescue. They can switch with a voltage frequency of 60-90 kHz.

But for transistors to work, a constant current is required. It is obtained through the use of a rectifier. This block is a combination of two elements: a diode bridge, which rectifies the alternating voltage of the network, and filter capacitors, with the help of which smoothing occurs. The output of the rectifier produces a constant voltage of more than 220 volts. This is the first stage of voltage and current conversion.

The resulting voltage is the power source for the operation of the entire circuit of the device. And since powerful key transistors are connected to a transformer (step-down), they will switch at a high frequency. Accordingly, the welding unit itself will operate at such a high frequency. For all this to work (transform), it is necessary to install a large number of additional elements into the circuit.

To understand the circuit diagram of a welding inverter, you need to consider any model.

Power block

We will not repeat ourselves and tell you how an inverter welding machine works. Let's go through the nuances and elements of the device.

• Network rectifier. Its task is to turn alternating current into direct current.
• Noise filter. It is installed specifically to prevent high-frequency interference that appears during operation of the welding inverter from entering the power supply network.
• Inverter (converter). Essentially, this is a block of powerful key transistors, which are most often assembled using the oblique bridge principle. A radiator is required in conjunction with which heat is removed from the transistors. They are connected to a high-frequency transformer, where voltage switching occurs through its winding. Please note that voltage conversion (DC to AC) does not occur in the transformer itself. This responsibility is assigned to transistors. The main purpose of the transformer is to reduce the voltage to 60-70 volts. In it, a current with high voltage but low current flows in the primary winding. In the secondary, on the contrary, with low voltage, but with great force.
• Output rectifier. This is a diode bridge in which fast-acting diodes are installed. They can open and close in moments. The properties are very important because these elements rectify alternating high-frequency current. Simple diodes installed in the inverter would not have time to close and open. As a result, they would overheat, resulting in failure.

Attention! You need to know that the voltage on the capacitors installed in the filter will be greater than at the output of the diode bridge. The value is 1.4-1.5 times. With a stable network voltage of 220 volts, the capacitors will have a voltage of 310 volts. If there is a jump in the network, for example, to 250 volts, then inside the device in the capacitors the voltage will rise to 350 volts. This is why capacitors with a voltage rating of 400 V are used.

Here are the main elements of the power unit of the inverter welding machine. There is also a control unit, but it affects the ease of operation of the unit and its settings (manual or automatic).

Now you know what parts an inverter welding power source consists of. Let's repeat it again. This is a rectifier, an inverter assembled from transistors, a transformer that reduces the voltage, and a rectifier installed at the output. For novice welders, these elements mean nothing. And it seems like they don’t need to know about them. After all, working with an inverter is a pleasure.

• It's lightweight (thanks to the small transformer).
• Easily welds fairly thick metal parts (thanks to the high current and low voltage).
• The electrode does not stick to the metal surface (thanks to the “Arc Force” function).
• The process of igniting the electrode is simplified by supplying a high current to its end at the beginning of operation. This function of the welding inverter is called Hot Start.
• If a short circuit occurs when the electrode sticks, the voltage in the device drops sharply to a minimum. This protects it from failure.

So, we figured out the structure of the welding inverter, its circuit diagram, and how it works. It should be noted that there are several requirements for a working welding inverter (the operating principle is the same for all models), two of which are the length of the power cable no more than 15 m and the frequency of maintenance - at least twice a year. Basically, it needs to be cleaned of dust.

Source: https://svarkalegko.com/oborudovanie/nikakoj-magii-ili-kak-rabotaet-svarochnyj-invertor.html

Starting current of welding inverter

Inverters, or they are also called converters, are popular welding machines that are powered by autonomous generators (power plants) produced by manufacturers in a wide range.

Which generator is suitable for welding? What criteria or parameters should I pay attention to when selecting a generator model? How to competently and correctly select it? The reader will receive answers in this article.

The generator for the welding inverter is selected based on a very important characteristic of the converter - its power consumption. But this is not always enough, because...

not all characteristics of the power source are compatible with the data specified in the inverter data sheet.

Features of choosing a generator

Particular attention must be paid to such an important characteristic as the rated power of an autonomous generator. It should be selected with a large margin and directly depends on the specific model of the generator; you can find out more about the new products of gasoline generators at the link - http://www.tiberis.

ru/collections/generatory-elektrostancii-agregaty-benzinovye. It has been practically proven that for generators running on diesel fuel, it should be 50% higher than the power consumed by the inverter. For generators running on gasoline, this figure is within a wider range - 15 ÷ 25%.

The discrepancy between the operation of these two units is the result of the difference in the nature of their load. In an inverter it carries a capacitive component; in a generator it is designed for active-inductive consumers. As the current strength of the welding machine increases, the voltage increases and this occurs due to the capacitive component.

The generator develops current feedback, which should compensate for the voltage from the load. As a result, there is a large increase in voltage in the inverter module, which sometimes leads to damage to the equipment or it stops working altogether.

It is for this reason that generators with increased power are used for inverter-type welding machines. These can be generators of any type, but they must satisfy this important

requirement. If the generator power is not enough, then it is better to use an external electrical network when carrying out welding work to turn on the inverter unit. But in many cases this is not feasible. If there is no electrical network, you must use only an autonomous generator.

Power calculation

When calculating the required power that a power plant must have, it is necessary to use the technical characteristics of the converter. They must be indicated in the manufacturer’s passport of a specific model. Usually the passport indicates the limits of current regulation - from minimum to maximum. Based on this, the power (maximum) of the welding converter is calculated.

When calculating power, a special formula is used that helps to quickly make the necessary calculations. Take the maximum welding current of the inverter and multiply it by the welding arc voltage. The result obtained is divided by efficiency. inverter (the efficiency value is taken from the passport data). The result will be the maximum power of the converter.

But one feature must be taken into account - the inverter is usually never used to operate at maximum power. It operates at average power, which is calculated taking into account the on-duration (ON). The PV value is indicated in the product passport. Now all that remains is to multiply the resulting inverter power by PV. The result will be the average power of the device.

https://www.youtube.com/watch?v=ZlOj3ebCsbw

In conjunction with generators, it is best to use welding inverters that operate at reduced voltage; you can learn more about such devices on this website.

The calculation looks like this:

For example, the initial data for the inverter is as follows (we take the values ​​from the passport):

• regulation limits: I= 10 ÷ 180 A;
• U arc – 25 V;
• efficiency – 0.85;
• PV – 40% (0.4).

We substitute the data to calculate the maximum power of the converter:

180 x 25 / 0.85 = 5294.12 W or 5.3 kW

Determine the required average power:

5294.12 x 0.4 = 2117.65 W or 2.1 kW

It remains to calculate the required generator power. To do this, multiply the inverter power by the following coefficients:

•  1.5 - in case of choosing a diesel generator;
•  1.15 ÷ 1.25 – in case of choosing a gasoline-type generator.

In numbers, in relation to our example, it looks like this:

Power for generator:

2.1 x 1.5 = 3.15 kW,

2.1 x (1.15 ÷1.25) = 2.4 ÷2.6 kW

All these formulas are correct if the power consumed by the inverter is indicated in kW. But many manufacturers of high-quality generators indicate the power value in another unit of measurement - kVA. This is especially true for imported generators. The calculation then needs to be carried out taking this feature into account. Conversion from one unit to another is carried out using the following formula:

1kW = 1kVA x power factor

The power factor of inverters does not exceed 0.7 and is usually indicated in the passport.

By applying the above formulas, you can calculate the maximum permissible current the inverter can operate at.

Selecting a generator for a welding inverter of a certain model, for example, for the widely used welding converters Svarog ARC 205 (J96), Resanta SAI-190, Kemppi Minarc Evo 150, EWM Pico 162, is not at all difficult, using all of the above.

Let's just say one thing - any model that meets the specified requirements will do. For example, German generators of the Fubag and Huter models are suitable for Svarog and Resant, and Endress (Germany) is suitable for Kemppi and EWM.

More details about this assortment can be found in the online hypermarket http://www.tiberis.ru/.

Useful tips for choosing a generator for welding

In order for the power plant and inverter to work efficiently and serve for a long time, it is necessary:

• always select the brand of generator for a specific inverter model based on power and do not forget that it should be overestimated;
• turn on the inverter after the generator reaches a stable operating mode, and turn it off before turning off the generator.

Source: https://steelfactoryrus.com/puskovoy-tok-svarochnogo-invertora/

Welding inverter

One of the ways to create permanent connections from metal is electric arc welding. For many years, transformer-type generators were used to perform this operation. Their main drawback is their size and weight characteristics. For example, a VD 306 brand unit weighs about 150 kg.

With the development of semiconductor equipment and the emergence of elements such as thyristors, it led to the creation of devices that have all the characteristics of transformers, but weigh several times less, only a few kilograms, for example, Resanta SAI 250 weighs only 5 kg - a welding inverter or an inverter welding machine.

Arc welding

Design and main characteristics of inverters

Inverter devices have a completely different electrical circuit, based on the use of semiconductor devices such as diodes, thyristors, and transistors.

As already noted, inverters entered the practice of welding not so long ago, at the end of the twentieth century. The operation of devices of this type is based on the principle of voltage shift. This solution allows you to increase the strength and frequency of the current. It should be noted that the device of the inverter used for the work contains a rather complex circuit, within which the following processes are implemented:

Inverter welding machines

1. The alternating current supplied to the inverter is converted to direct current. The change in current parameters occurs in the device, which is assembled using a diode bridge.
2. The resulting current is transmitted to the inverter, which plays the role of a high-frequency pulse generator. In the transistor unit, the reverse conversion of direct current to alternating current occurs. But the resulting current has a significantly higher frequency than that coming from the power supply.
3. High frequency current is supplied to the transformer. This device reduces the voltage and simultaneously increases the current. Since the transformer, which is used to work with high-frequency currents, has small dimensions, all this affects the overall weight characteristics of the inverter.
4. After passing through the transformer, alternating current with new parameters is supplied to the rectifier, where it is again transformed into direct current, which is used for welding.

Welding with an inverter for beginners

It should be noted that inverter devices, unlike transformer-type devices, consume half the amount of energy. In addition, the parameters of the current that comes from the device ensure that the welding arc will have stable ignition and combustion during welding.

Technical parameters of devices

Welding inverters have a number of specific characteristics by which one can judge its technological properties. These include the following parameters:

Welding inverter design

1. The type of current that is generated at the output of the rectifier.
2. The amount of voltage that is used to supply electricity. Manufacturers produce products that operate on 380 and 220 V. The former are used for professional welding, the latter for work at home.
3. Current size, this parameter has a direct impact on the size of the electrode that will be used to perform the weld.

Technical parameters of welding inverter

1. Unit power, this parameter provides information about the current and strength that will form the welding arc.
2. Open circuit voltage, this parameter shows how quickly the welding arc will be produced.
3. The range of electrode sizes that will be used for welding.
4. Dimensional and weight characteristics of the inverter welding machine and the size of the welding current at the output. The lower the last indicator, the smaller the device, but accordingly such a device has lower performance characteristics.

Pros and cons of inverter welding

Inverter devices show efficiency in the range of 85 - 95%, I must say that this is a high figure among electronic equipment. The circuit used allows you to adjust the level of welding current from several amperes to hundreds, or even thousands.

For example, an inverter of the MMA brand, it is 20 - 220 A. Inverters can operate for a long time. The power supply can be controlled remotely. The undoubted advantages of inverters include their small size and weight characteristics, which allow the device to be moved at the welding site. The design of the devices uses double insulation, ensuring electrical safety.

Technological advantages

The use of inverters allows the use of electrodes of any brand that work with both direct and alternating current. Devices of this type can be used for welding with a non-consumable electrode in a shielding gas environment. In addition, the design of this equipment makes it easy to automate welding processes.

Tungsten electrodes for argon arc weldingElectrodes for resistance welding

Welding can be performed using a short arc, thus reducing energy losses and increasing the quality of the weld; in particular, there is virtually no welding spatter on the surface of the parts being welded. By the way, the use of inverters allows you to produce seams in any spatial configuration.

Microprocessor

Microprocessors are used to control modern welding inverters, and this ensures a stable connection between voltage and current.

Inverters are somewhat more difficult to repair than traditional transformer units. If some control elements located on the board fail, repairs can cost about a third of the cost of a new welding inverter.

Inverters, unlike other types of equipment, are very susceptible to dust. That is, such devices must be serviced more often. Operation of an inverter welding machine is also limited by low temperatures. In addition, there are some restrictions on storing the inverter at sub-zero temperatures. This is fraught with the formation of condensation, which can lead to a short circuit on the board.

When selecting welding equipment, the consumer must decide what tasks it will be needed for.

If it is used for repairing body parts, then it should have some parameters, and if it is used for the production of metal structures, then it should have different parameters. But in any case, the devices must meet a number of requirements, in particular, functions such as hot start, anti-sticking and some others must be implemented in a home device. This is how inverters differ from traditional devices.

A fan must be installed in the design of this type of device. In addition, the circuit must be protected from power surges. In principle, a device with such parameters can work both in a home workshop and in industrial production conditions.

Which welding machine is better

The choice of device is for the most part a purely individual matter. And everyone chooses a device according to their needs, but we can say that devices with a welding current range of 200 - 250 A allow you to perform the most complex work and process parts of different thicknesses.

Welding inverters can be classified by the size of the welding current. Manufacturers produce three types of devices:

• 100-160 A – low-power;
• 160-200 A - average;
• 200-250 A - powerful.

There is a relationship between the size of the current and the dimensions of the device. When choosing a device for use at home, you should be guided by the tasks that they have to solve.

The weakest devices can be classified as devices of the lowest level; many use them to gain work skills. Devices that are classified as middle class are among the most popular and allow you to perform a wide variety of work, from assembling a fence and manufacturing quite complex metal structures. The most powerful devices are mostly used for production purposes. They are used for working with rolled metal of large thickness.

Electrodes for manual arc welding

Most inverters are designed to work with coated electrodes. But they can also be used to work with welding wire. To do this, a device is installed on the device that feeds the wire into the welding zone. The wire is fed through the welding gun, and the gas mixture is also fed through it, protecting the working area from exposure to atmospheric air.

Additional functions in inverters

Modern inverter devices implement some options that significantly facilitate the welder’s work:

1. Hot start - often novice welders, and not only them, have difficulty igniting and maintaining the arc in working condition. At the moment of ignition, the current rises to the required level and immediately after ignition returns to operating parameters. The process of changing the current occurs completely automatically, without the participation of the welder.
2. Another problem that plagues beginners is electrode sticking. There are several reasons for this, but there is only one solution - reducing the level of welding current. This operation is also performed automatically.

1. Arc forcing allows you to make seams in different spatial positions.
2. Reducing the no-load voltage to a level that is safe for the worker and his surrounding people.

Like any technical equipment, welding inverters have a number of technical parameters that determine their capabilities.

Inverter welding machines provide the generation of welding current in the range from 100 to 250 A.

After converting the current supplied from the electrical network to 220 V, a current with a voltage of 50 - 90 V and an operating frequency of 20 - 50 kHz is obtained at the output of the device. Maximum voltage must be used to ignite the arc, but this creates a safety hazard for the welder and surrounding people. Therefore, after finishing work, the voltage drops to a safe level.

Maximum current operating mode

An important indicator of the operation of any welding machine is the operating time. It may be called PN or PV. This indicator indicates how long the device will operate with a ten-minute welding cycle before shutting down.

In other words, if the duty cycle is 50%, this means that the effective operating time will be 5 minutes, if the indicator is 70%, then the time will be 7 minutes. This indicator must be reflected in the technical documentation included in the delivery of the welding machine.

Recommendations for the use of household inverters

An inverter designed for welding is a complex engineering device that is equipped with many levels of protection.

Equipment of this class demonstrates stable operation and, at the same time, requires careful treatment and timely maintenance.

Before purchasing the device, it is advisable to carefully study the instruction manual.

Welding inverter instructions

When working with an inverter, you must follow a few simple safety rules:

1. All conductive hoses must not be damaged, the connection terminals must be securely fixed in the device.
2. If the device is designed with a fan and it does not rotate when turned on, operation of such a device is unacceptable.
3. When working with the device, you must use personal protective equipment.

Source: https://stankiexpert.ru/spravochnik/svarka/svarochnyjj-invertor.html

What current does a welding inverter produce?

In a private home and country house there is always a need to cook something. In order not to contact professionals for small details (and not to pay them), you can buy an inexpensive welding machine and learn it yourself.

To acquire these skills, it is recommended to purchase DC welding machines, and in particular, welding inverters. They have small dimensions, weigh little, and with their help you can get a high-quality seam even without much experience.

What is equally important, in this category there are good devices at a low price (5-10 thousand rubles). Therefore, welding with an inverter for beginners is the best that the market can offer today.

What is a welding inverter and how does it work

This device was called an inverter because it converts alternating current of a 220 V network with a frequency of 50 Hz into high-frequency oscillations, and then into direct current. At the same time, the device has a high efficiency: about 85-90%, and even under fairly heavy loads the counter “winds” a little. In any case, you won’t have to pay crazy bills. The consumption will be slightly higher than without welding, but not by much.

This small box is an inverter welding machine

Most inverter welding machines operate from a 220 V household network (there are also devices from 380 V). And this is one of their advantages. Moreover, they have practically no effect on it, i.e. do not reduce tension. Rest assured about your neighbors: they won’t even know that you are welding.

The second important advantage is that they can work more or less normally at reduced voltage. Of course, you need to look at the specifications, but at 170 V, most of them still allow you to work with a 3 mm electrode.

This is very important especially for rural areas, where low voltage is the norm rather than the exception.

What’s also good for beginners is that it’s easier to get and hold an arc when using inverter welding. And in general, according to many, it cooks “softer” and has a “lighter” arc. So if you want to learn how to cook, try inverter welding first.

Inverter Welding Basics

First, let's look at the design of the welding inverter. We won’t look at the “stuffing”; we’ll look at what’s on top and what we’ll have to use.

What does an inverter welding machine consist of? (To enlarge the picture size, right-click on it)

This device is a small metal box, which, depending on the power, weighs from 3 kg to 6-7 kg. The case is usually metal; some manufacturers make ventilation holes in it for better cooling of the “filling” (mostly the transformer). There is a belt for carrying, and sometimes there is also a handle: the belt is put on the shoulder if the work requires movement.

One of the panels has a power button or toggle switch. The front part contains power and overheat indicators. There are also knobs for setting voltage and welding current. Also on the front panel there are two outputs - “+” and “-” to which working cables are connected. One cable ends with a clothespin clip, which is attached to the part, the second - with an electrode holder. The power cable connector is usually located at the back. That's all, actually.

When purchasing an inverter, make sure that the cables are long enough and flexible: this makes it easier to work with. It is the insufficiently long and rigid working cables that have the most complaints from users of the popular brand of inverter welding machines “Resanta”.

The general principles of working with an inverter welding machine are described in this video.

Welding with an inverter for beginners

As with any electric welding, the melting of the metal occurs due to the heat of the electric arc. It occurs between the welding electrode and the metal being welded. To create an arc, they are connected to opposite poles: “+” is applied to one, “-” to the second.

When connecting the electrode to the “minus” and the part to the “plus”, the connection is called “direct”. If “plus” is applied to the electrode, the connection is reversed. Both options are used when welding, but only for metals of different thicknesses: reverse - for welding thin metals; straight - for welding thick metals (more than 3 mm thick). But this is not an immutable rule; sometimes they do the opposite.

Direct and reverse polarity of connection on the welding inverter

What causes this division in practice? Physics of the process. When an arc occurs, the electrodes move from minus to plus. And at the same time they transfer their energy to the positively charged surface, increasing its temperature. Therefore, the element that is connected to the positive output heats up more.

When welding metals of sufficient thickness, they need to be heated well so that they melt and the weld is of high quality. That’s why they give “+” to them. Thin metal, on the contrary, can burn out due to overheating and a “minus” is attached to it, warming up the electrode more, from which more molten metal flows into the seam.

You can weld metal correctly with an inverter only if you have good control over the electrode. To do this, you need to take the holder correctly. How to do this, watch the video.

How a seam is formed during welding

To make the basics of welding with an inverter clearer, let’s look at what happens when a seam is formed. To begin with, let us clarify that a welding electrode for welding metals consists of a metal core and a coating - a special coating that protects the welding area from contact with oxygen contained in the air. Read more about electrodes for inverters here.

Now about the welding process itself. An electric arc is formed when the electrode core and metal come into contact (read how to ignite an arc below). At the same time, the coating begins to burn. It partially melts, turning into a liquid state, and partially turns into gases. These gases surround the welding zone - the weld pool.

They prevent oxygen from the air from “breaking through” to the molten metal. The part of the coating that has become liquid covers the molten metal, creating a second layer of protection. After cooling, it turns into slag, which crusts over the seam. And at this stage, the slag protects the still hot metal from oxygen.

How does inverter welding work?

But slag and protection are far from the only process that occurs and that needs to be controlled. When welding, it is necessary to ensure that the junction of two pieces of metal is heated evenly and sufficiently. Both parts should melt to the same distance from the edge. To ensure uniform heating, you need to maintain the same distance from the tip of the electrode to the part.

This is not very easy to do: the electrode melts during welding, and particles of its molten metal are transferred into the seam by the arc. Therefore, you have to gradually move the electrode holder closer to the part. But this is not the end of the electrode welding technique. You also need to “write out” some shapes with its tip - zigzags, circles, Christmas trees, etc. They allow you to make the seam wider and fuse two parts together.

The most common electrode movements are shown in the photo below.

Source: https://vi-pole.ru/kakim-tokom-varit-svarochnyj-invertor.html

How much power does a generator need for inverter welding?

How much power does a generator need for inverter welding?

Inverter welding is becoming popular day by day. The ability to weld at reduced voltage in the mains and from a generator has made welding inverters an indispensable tool for welding in everyday life.

To figure out which generator to choose for inverter welding, you need to take into account not only the power of the inverter. The choice is strongly influenced by the welding current, which is selected taking into account the use of various electrodes.

Welding is inherently a short circuit, so most generators react accordingly to the connected welding machine. If the generator is of insufficient power, then when welding with an inverter it will always go into protection, in simple words, turn off. To prevent this from happening, you need to correctly calculate the power of the generator to connect the welding inverter.

A generator for welding must be powerful and reliable, otherwise it will quickly fail. Today, there are various types of generators, synchronous and asynchronous, as well as inverter ones (see the website mmasvarka.ru). To connect a welding inverter, you need to purchase only an asynchronous generator running on gasoline or diesel fuel.

Now, as for the power of the generator, it, as mentioned above, should be selected with a small margin ( 20-25% ) so that the generator does not go into protection when connecting welding. The power of the generator should be selected based on the power of the welding inverter connected to it. You can find out the power of the inverter in its documentation. However, one should not confuse kW and kVA , since these are completely different values.

How to convert kVA to kW

• kVA is the rated power of an electrical appliance;
• kW - active power.

Very often, in the passport for a welding inverter, the power is indicated not in kW, but in kVA, so you need to be able to convert kVA to kW. To do this, just use the following example, where 10 kVA * 0.8 = 8 kW . Thus, after the necessary calculations, it becomes clear exactly how much the welding inverter consumes in the load.

In this case, you need to take into account the welding current that the inverter produces. The higher the welding current, the more the inverter will create a load on the power grid or work at the limit of its capabilities. Therefore, if you need to cook with 3 or 4 mm electrodes from a generator, then you need to be prepared for the fact that a 2.5-3 kW generator will be absolutely unsuitable for these purposes.

Inverter current and generator power: what do you need to know?

Therefore, when choosing a generator for a welding inverter, you should also take into account the maximum current strength. So, for example, if the maximum current strength of the welding inverter is 180A, then you need to multiply them by 25V, not forgetting about the efficiency. Most often, the efficiency of an inverter for welding is 85%, so you can safely take a value of 0.85.

Using this calculation: 180A*25V/0.85=5294 W , it becomes clear that the generator power for a 180A inverter must be at least 5.5 kW. However, ideally, you need to take a generator with at least a 25% power reserve if you have to cook with inverter welding quite often. Therefore, the figure regarding the generator power automatically increases to 6.6 kW and is optimal in this case.

Many people wonder whether it is possible to weld using inverter welding from a 2.5 kW generator . The answer is yes, it is possible, but only for a short time and using for this purpose electrodes no more than 2 mm in diameter, with a current strength on the welding inverter of 30-40A, maximum.

In any case, you must understand that by connecting your inverter to a generator, you can easily cause it to fail, since welding requires high power and loads.

Source: https://mmasvarka.ru/kakoj-moshhnosti-nuzhen-generator-dlya-invertornoj-svarki.html

What power generator is needed for a welding inverter?

What kind of generator is needed for a welding inverter?

“Which generator to buy for inverter welding” is the question asked by most people who dream of mastering electric welding if they do not have the opportunity to connect a welding inverter to a household power supply. At the same time, if you buy any generator you come across, it won’t work, since it must meet a number of requirements, including being suitable in terms of power.

Welding is essentially a short circuit. Therefore, the generator will react accordingly to a short circuit. Not only will it constantly turn off when welding, but there is also a risk of the inverter failing. Therefore, you need to approach the choice of generator consciously. And if we don’t go into the types of existing generators, we can only say that only a synchronous type generator is suitable for welding with an inverter.

In addition, it is better to give preference to a generator with a copper alternator winding than one with aluminum. Generators with copper winding are more reliable in operation, they are able to carry loads much better. Well, we’ll talk about other parameters that influence the choice of a generator for welding with an inverter below, in this article from the construction magazine samastroyka.ru.

What kind of generator is needed for a welding inverter?

A generator for inverter welding must meet a number of the following requirements:

• Have a sufficient power reserve (about 20%);
• Be a synchronous type;
• Be compatible with inverter equipment.

When choosing a generator for welding, you must be guided by the following points:

• Inverter power consumption;
• The current required for welding;
• The diameter of the electrodes (depending on the thickness of the metal being welded).

It is precisely these nuances that you need to be guided by when choosing a generator for a welding inverter. At the same time, the power of the generator comes first, so that’s where we’ll start.

How much power does a generator need for inverter welding?

The selected generator for welding must have a power no lower than that of the inverter, but on the contrary, slightly higher, taking into account the required margin of 25%. Typically, the power of the generator and welding inverter can be found in the technical data sheet. At the same time, you should not make mistakes in the units of measurement, since very often the power of electrical appliances is indicated not in kW, but in kVA.

kW is active power, and kVA is the apparent power of an electrical appliance. If the power of the welding inverter is indicated in kVA, and you need to convert it to kW, then it is enough to use the following formula for calculation: where 10 kVA * 0.8 = 8 kW.

At the same time, you need to understand that the welding inverter will not always operate at full power, and here everything largely depends on the required current strength. And since the efficiency of the inverter for welding and the arc voltage always have a constant value, then calculating the power of the generator for welding is not so difficult.

The efficiency of the welding inverter is 85%, and the arc voltage is 25V.

Knowing these parameters, you can independently calculate how much power a generator is needed for inverter welding, based on the strength of the welding current. If the inverter for welding has a maximum current of 160 Amperes, and you need exactly this current for welding, then the power of the inverter will be equal to: 160A * 25V / 0.85 = 4705 W. Considering the required power reserve for the generator, which is at least 25%, you can easily calculate its optimal power: 4705 W + 25% = 5881 W, which is almost exactly 6 kW.

From all of the above, it becomes clear how exactly the current strength of the welding inverter affects the required power of the generator. Consequently, by reducing the current on the inverter, it will be possible to use a generator of much lower power, for example, 2.5 or 3 kW.

Here everything depends on the diameter of the welding electrodes and the thickness of the metal being welded.

For example, using electrodes up to 2 mm, you can weld from a 2.5 kW generator, the power of which will be quite enough for the welding inverter to produce the required current for welding.

Source: https://samastroyka.ru/kakoj-nuzhen-generator-dlya-svarochnogo-invertora.html

How to choose the right generator for a welding inverter | Tiberis

“Which generator is suitable for welding” is a question that often arises among people who have decided to seriously engage in welding on their own and at the same time do not have the opportunity to connect the welding machine to the network. It’s easy to get confused, especially after we see a huge list of available models on the online store page.

It would seem that it is very difficult to understand this diversity, especially if you have a liberal arts education behind you. In fact, any of us can choose the right generator for a welding inverter; to do this, you just need to know a few small but very important nuances. They will be discussed in this article.

What points must be taken into account when choosing a generator?

As befits a serious unit, each generator for inverter welding has a huge number of different technical characteristics, among which it is very easy for a beginner to get confused. But for the right choice, only five of them are most important:

It is these parameters that you should pay special attention to in order to use the generator for a long time and safely.

Generators differ by type into synchronous, inverter and asynchronous, as well as a symbiosis of asynchronous and synchronous Duplex series (manufactured by Endress); synchronous or Duplex series generators are suitable for welding . Inverter engines, as a rule, have insufficient power and are not designed for high starting loads. You can find out more about the types of generators in a separate article here.

Generator power for welding - what is the reserve for?

In most cases, the power of the welding inverter and generator is indicated by the manufacturer in the technical data sheet. Therefore, even a child can easily find these values ​​and compare them. The main thing is not to confuse the power units kVA and kW, as well as the declared rated and maximum power of the generator.

It should be remembered that when buying a generator, you need to choose a model that has 25-50% more power than the inverter you have. This is explained quite simply - constant operation of the generator at the limit of its capabilities will very quickly disable it and will not make it possible to use the full potential of the welding machine.

https://www.youtube.com/watch?v=ZlOj3ebCsbw

If for some reason you do not have information about the power of your welding inverter, you can calculate it yourself using a simple formula:

Maximum current * arc voltage / efficiency of the welding inverter - maximum power.

In this case, you only need to know the value of the maximum current, since the other two components are almost always constant (the arc voltage is 25V, and the inverter efficiency is 0.85).

For example, if your welding machine has a maximum current of 180 Amps, then approximately its power is:

180A*25V/0.85=5294 W, which means that in this case, the optimal value for the generator will be a power of 5294 W + 25% reserve = 6617.5 W, or if converted to kW - 6.6 kW. In this case, the Huter DY8000LX gasoline generator model will be one of the best options.

Welding current - it must be taken into account

Another good news is that you can very well use a generator for inverter welding, which has less power than your inverter. However, in this case, you will have to use it with some restrictions, namely, reduce the current strength to an acceptable value.

Take, for example, the case if you decide to purchase a 4 kW generator model.

We use the same formula as when determining power, but in reverse order:

Power*Efficiency/Arc Voltage = Current or 4000*0.85/25 = 136 A

Thus, on a 4 kW generator you will be able to weld on your welding inverter without any noticeable loss of quality with a current of up to 130A.

Electrode diameter - a label that is easy to remember

Another important nuance that should be taken into account is the correspondence of the electrode diameter to the minimum power of the generator. These data are approximate and fit into a simple table:

Electrode diameter (mm) Minimum generator power (kW)

2	2,5
3	3,5
4	4,5

That is, if you plan to carry out welding work with a 4 mm electrode, then the minimum power of the generator for welding should be at least 4.5 kW and higher.

Which generators are suitable for working with a specific welding machine?

You have read the main rules for choosing a generator for welding in the previous sections. Using them, you can safely start purchasing a power plant. But to make it easier for you to navigate the assortment, let’s take a closer look at the most popular inverters for household tasks and determine which generators are most suitable for them.

For inverters Svarog

Unpretentious and inexpensive Svarog inverters stand out among other brands with a long five-year warranty. Buyers also often prefer them due to their low price, so purchasing budget options for Huter and Fubag generators seems like a completely reasonable decision.

The welding inverter Svarog REAL ARC 200 (Z238N) will work perfectly in tandem with the Huter DY6500L generator. This high-quality and useful unit can successfully operate on natural gas, which significantly increases the efficiency of the generator.

For Resanta inverters

The popular inverter manufacturer Resanta also produces products intended for the mass consumer. A distinctive feature of this brand is the compact size and light weight of welding machines.

For the household welding inverter Resanta SAI-190, you can use the BRIMA LT 8000 B gasoline generator, which, in addition to this purpose, will, if necessary, serve you as a backup power source at the dacha or in a country house.

For Kemppi inverters

Finnish Kemppi inverters have proven themselves worthy when working in harsh natural conditions and in production. They are rightfully the leader in sales among imported premium models. They are bought by people who know how to value real quality and reliability.

In addition to the popular model of the Kemppi Minarc 150 welding inverter, you can safely purchase the Fubag BS 5500 generator, which is characterized by very low fuel consumption, a durable frame and reliable overload protection.

For EWM inverters

Products of the famous German brand EWM appeared on our market back in Soviet times. From then until now, EWM inverters have brought real pleasure to the people who work with them. Such a device needs an excellent generator.

Therefore, for the EWM Pico 160 welding inverter, the Fubag BS 7500 A ES generator seems to be a worthy partner, which is equipped with a powerful engine, an AVR unit and is equipped with a spacious fuel tank for long-term operation without refueling.

Useful tips for choosing a generator

There are several other useful tips based on the recommendations of welding professionals that will be useful to you when purchasing a generator for an inverter welding machine.

1. generators with a power of up to 10 kW on a gasoline basis . They are most widely represented in this segment. And more powerful power plants run on diesel fuel.
2. The power reserve of a gasoline generator, at least 15-25%, greatly facilitates ignition of the arc. For power plants running on diesel fuel, it is desirable to have a larger reserve - up to 50%.
3. The most functional are power plants equipped with cast iron sleeves. Their minimum service life is 1500 hours . Aluminum blocks can withstand significantly less load - up to 500 operating hours.
4. Inverters with the abbreviation PFC in the name have a built-in power factor corrector in their circuit design, so they can operate at reduced voltage and are excellent for operation from a generator, for example the Svarog ARC 160 PFC model.

The information provided in the article is intended for conventional welding inverters, which are often used in domestic conditions.

For professional equipment (semiautomatic welding machines and inverters designed for argon-arc welding), certain problems may arise when operating from a generator. Many manufacturers explicitly state this in the user manual. Therefore, it is highly advisable to consult with specialists before purchasing in order to avoid serious consequences.

It is quite possible to select a generator for a welding inverter yourself, using common sense and our advice. And for complete confidence, contact the consultants and managers of our welding hypermarket, who will tell you which generator is suitable for welding in each specific case. Our specialists have the right answers to the most tricky and difficult customer questions!

Source: https://www.tiberis.ru/stati/vybor-generatora-dlya-svarochnogo-invertora

Advantages and disadvantages of AC welding machines

In the twentieth century, the AC welder was the most common metal welding device in construction and industry. This is explained by the simplicity of the design of the device.

In short, it is a power step-down transformer, the secondary winding of which has several terminals. Depending on what kind of metal needs to be welded, what thickness, what electrode, the welder chooses one or another output of the secondary winding.

Types of devices

Welding machines operating using alternating current are divided into the following types:

• equipment for manual electric arc welding using separate electrodes coated with flux;
• equipment for manual argon electric welding using non-consumable tungsten electrodes;
• semi-automatic equipment that performs welding in a protective and inert gas environment using an electrode wire;
• resistance welding equipment.

In the international classification, electric arc welding is designated MMA-AC or MMA-DC, in the case of manual electric welding with single electrodes, and argon welding with non-consumable electrodes is TIG.

Transformer-based design

The size and shape of a regular welding machine looked like a household washing machine on wheels, only even heavier. The closed magnetic circuit was located vertically. Below was the primary winding of the transformer.

The secondary winding was movable. It was attached to the nut of a vertical screw with a tape thread. On the housing cover there was an eye bolt with a handle.

When the handle was rotated, the nut with a secondary winding moved along the screw, changing the magnetic flux passing through the coils. Thus, the welding electric current was adjusted.

To move the apparatus, there was a handle on the lid; to connect the wires of the welding chain, there was a clamp on the side wall. All walls had slotted holes for cooling the transformer.

Speaking about such devices in the past tense, it means that now most people use AC and DC welding inverters. Welding equipment based on a power transformer is practically not used.

In order for the weld to be of high quality, a steeply falling current-voltage characteristic of the transformer is required. This is achieved in two ways. First option: in a transformer with normal magnetic leakage and a separate reactive coil (choke), the welding process is adjusted by changing the gap in the choke core.

Second option: adjustment is carried out by changing the gap between the primary and secondary coils. In this case, a change in the electric current over a wide range does not lead to a change in the arc voltage, which has a positive effect on the quality of the seam.

Resistance welding equipment

In resistance welding machines at the time of the welding process, in low-power devices the welding current reaches 5000-10000 A, in powerful devices it reaches 500 kA. Therefore, high demands are placed on transformers.

They are step-down transformers with a number of design features:

• to obtain maximum electric current, the secondary winding is made of one turn;
• The primary winding is made on a disk core in the form of separate sections. Dividing the coils into sections is necessary to regulate the electric current, and the disk is for uniform cooling;
• The secondary winding is made in the form of parallel-connected copper disks. To protect them from moisture, they are filled with epoxy resin;
• Air or water cooling is provided.

Resistance welding machines are mostly single-phase with armor-type cores. Since the quality of welding strongly depends on the duration of the welding pulse, the switching equipment is quite complex - a price to pay for accuracy.

The devices experience heavy mechanical loads, up to 400 starts per minute, so they are subject to additional requirements for structural strength.

Low-power resistance welding machines have a welding current of up to 5000 A, weigh about 20 kg and weld metal up to 2.5 mm thick. Widely used at home and small workshops.

Inverter design

Inverters are sometimes called DC welding machines because during their operation, the first stage is the conversion of alternating voltage to direct current.

Inverters are actively replacing transformer-based devices due to their light weight, compact size and high performance.

The welding inverter consists of a high-voltage rectifier diode bridge and a low-pass filter, a frequency generator in the range of 30-70 kHz, high-voltage power switches, an isolation capacitor and a step-down transformer. It performs the function of a low-frequency alternating current to high-frequency converter.

A voltage of 220 V 50 Hz is supplied to the rectifier bridge, where it is rectified, the filter reduces ripple and is supplied to electronic switches made on bipolar transistors with an insulated gate or field-effect transistors.

At the output of the keys, thanks to a control unit based on a frequency generator, a signal with a frequency of 30-70 kHz is obtained. Passing through the separating capacitor, the electric current gets rid of the constant component and enters the primary winding of the step-down transformer.

The output of the secondary winding produces high-frequency alternating current, which is used for welding. Essentially, AC welding inverters are designed as switching power supplies without a rectifier unit at the output .

Due to the rapid transition through zero, AC inverter welding machines have a stable, uniform arc, which has a positive effect on the quality of the seam.

Using an inverter allows you to get a small-sized device with high power. A disadvantage of the inverter can be considered its high sensitivity to voltage surges.

Advantages and disadvantages

Manual arc welding with alternating current works on the basis of a power transformer, which has a simple, reliable and inexpensive design. It can work in almost any conditions and for a long time without interruption.

The disadvantages include the low productivity of welding work and the need for constant removal of slag. The welding seam is worse than that produced by DC welding.

Argon welding using an alternating current machine with non-consumable electrodes produces a weld of the highest quality, allows you to weld large-section metal, and there is no spatter.

The disadvantages include the need to use additional equipment in the form of gas cylinders and low productivity.

Electrodes and features of work

Electrodes for welding with alternating current have been developed for a long time and have a wide variety. When using inverters, it was necessary to create new electrodes due to the specifics of high-frequency alternating current.

The most widely used electrodes are the ANO, OZS, and MR brands. They are used for welding carbon and low alloy steels. They ensure easy ignition of the electric arc and uniform maintenance of it, and easy removal of slag. Can be used for AC and DC welding machines.

The peculiarity of alternating current welding is to change the polarity of the current flowing through the electric arc. Due to the fact that at a frequency of 50 Hz the time of transition through zero is quite long, the arc almost goes out and turns out to be uneven.

This often leads to porosity of the seam and a decrease in its quality. When using high-frequency alternating electric current, this disadvantage is practically overcome.

The use of constant allows you to obtain welds of higher quality due to the uniform release of heat in the weld pool. With direct current, the arc starts at lower voltage and is easier for the welder to maintain.

Source: https://svaring.com/welding/apparaty/svarochnyj-apparat-peremennogo-toka

Which is better: an inverter or a welding transformer?

Beginning welders are often faced with a choice: what equipment to purchase for work. Knowing the difference between an inverter welding machine and a conventional one, it will be easier to choose a welder. Transformers and high-tech inverter converters have pros and cons. The devices differ in power indicators, functionality, and dimensions.

What is a regular welding machine?

The classic current source for generating an electric arc is a transformer. The welder lowers the mains voltage, and the current increases accordingly. Such equipment was used for manual welding everywhere until the beginning of the 21st century.

The operating principle of the transformer is based on the magnetic induction method. Electric current passing through the first winding magnetizes the core. An electromagnetic field arises, and under the influence of waves an electric current is formed in the wire of the secondary transformer winding. The output voltage depends on the number of secondary turns. The equipment generates high-ampere current with parameters necessary for welding.

Welding transformer layout

Advantages and disadvantages of welding transformers

First, about the advantages of transformer devices:

• simplicity of the device, the scheme of operation is clear to the student;
• maintainability, in case of breakdown the transformer can be repaired independently;
• the ability to work for a long time is ensured by low sensitivity to overheating during operation;
• impact resistance – the risk of mechanical damage during transportation is minimal;
• accessible service;
• low price;
• versatility, the device is used for welding various metals;
• there are no special storage requirements, the transformer is resistant to high humidity and dust.

The disadvantages of traditional welders are obvious:

• when the network sags, the transformer turns off; a stable voltage is needed for power supply;
• lack of precise adjustment of current parameters, large adjustment steps, difficult to set up equipment for welding thin-walled workpieces;
• heavy weight, it is difficult to move the equipment independently;
• significant dimensions;
• high power consumption.

It is worth considering that most transformers operate from a three-phase network. Beginners working with a transformer have problems with arc ignition and sticking. Seams are difficult to form without experience.

What is a welding inverter

The operating principle of the inverter is also based on the induction method; in fact, it is also a transformer converter, only equipped with electronics. The main difference between an inverter welding machine and a transformer one is the presence of semiconductors. The inverter converter is a new generation device, a modern version of classic equipment. Through the use of power electronics, the size of the converter was significantly reduced.

For stable operation of semiconductor elements, the device has a fan. With built-in tunnel-type ventilation, it is possible to protect microcircuits from dirt and dust. A whole class of welding equipment has been created based on inverter converters. It is customary to call an inverter a welder only for manual arc welding; devices operating in TIG, MIG/MAG, and FLUX welding modes are considered semi-automatic.

Welding inverter layout

Advantages and disadvantages of inverters

The device is convenient. There are no problems with igniting the arc thanks to the “easy start” fiction. The electronics maintain stable combustion during voltage surges, and the current is easy to regulate. The difference in setup between an inverter and a transformer is significant. With low energy consumption, it is possible to obtain high-frequency alternating or high-ampere direct current, necessary for the formation of an even seam.

So, the main advantages of the inverter:

• light weight;
• compactness, this largely explains the popularity of inverter power supplies;
• additional functionality that improves the quality of welds;
• ease of setup;
• ability to connect to a standard network (only professional models have an additional input for power supply from a three-phase 380 V network).

Now about the disadvantages, they also exist:

• high price;
• sensitivity to overheating, the inverter must be turned off periodically to prevent the semiconductor unit from overheating;
• increased requirements for operating conditions: equipment should be protected from high humidity, increased dust, low temperatures (professional models are made in a protective case);
• low mechanical strength, the inverter must be handled with care.

Despite all the disadvantages, inverter equipment is gradually replacing traditional transformers.

Which welding machine is better: inverter or transformer

Deciding what is best for welding metal in your own garage or home is not difficult. Comparative characteristics of power supplies will help. First, about the similarities: both are necessary for converting electric current, obtaining operating current parameters, only inverters are equipped with electronic converters.

A short example will help you compare the dimensions of inverter and transformer welding machines. To generate 160 A, you need a transformer weighing 20 kg or an inverter weighing 2.5 kg. The inverter has the highest power, however, transformers have high efficiency.

A transformer unit is more difficult to master; special knowledge and skills will be required to set it up. Inverter devices are easier for beginners. Reduces the risk of uneven seams due to built-in functions:

• Hotstart improves arc ignition when the welder is turned on;
• Arcforce prevents the electrode from sticking when a drop falls, forcing the electric arc;
• Anti-stick protects against overload during a short circuit, the arc does not go out.

The capabilities of the inverter are wider; you can obtain a constant electric current of the required strength. High-frequency or pulsed alternating is similar in action to constant.

Transformer welders do not have such a concept: intermittency; the operating mode is indicated on each inverter. If the efficiency is 50%, every half hour the unit is turned off for 15 minutes.

It is impossible to say unequivocally which welder is better. Or rather, such a conclusion makes no sense. Much depends on the working conditions, the nature of the workpieces being welded, and the skill of the welder, finally.

Inexpensive inverter devices are well suited for a summer house and garage, in cases where there is no extensive work experience and they are used a couple of times a year. But you should not forget about storage: protect from high humidity, dust and low temperatures.

Other types of welding equipment

A rectifier differs from a transformer apparatus by the presence of semiconductors that rectify the electric current, and welding capabilities are expanded. When changing poles, you can shift the area of ​​maximum heating:

• with straight polarity, the electrode heats up more;
• in the reverse case, the workpieces to be welded are in the welding zone.

The difference between semi-automatic machines is the use of welding wire, which is fed into the heating zone automatically. Semi-automatic devices are created on a transformer and inverter basis. The transformer semiautomatic device with gas equipment is used in auto repair shops and in production; there are no special requirements for storage and transportation conditions. The inverter is more capricious and is necessary for working with thin metal, stainless alloys, and aluminum.

Separately, there are generators that convert the mechanical energy of the engine into electric current. Such devices produce direct and alternating current, operate on mains power and liquid fuel.

Welders prefer transformer devices for large volumes of work. For beginners, it is advisable to purchase small inverter models. Auto repair shops typically require a variety of equipment.

Source: https://svarkaprosto.ru/oborudovanie/chto-luchshe-invertor-ili-svarochnyj-transformator

Main characteristics of the welding inverter

Essentially the same characteristic of the operating current range. Sometimes, due to illiteracy or malicious intent, the diameter of the electrode is indicated, which will not be able to cook with the stated maximum current. Sometimes it’s the other way around: the maximum diameter of the electrode is indicated, which clearly does not reach the value of the declared welding current.

The latter option is occasionally a glimpse into the conscience of deceptive suppliers. They indicate the short-circuit current as the maximum current. But the maximum working diameter of the electrode is still indicated honestly.

Welding current type: direct (DC) or alternating (AC)

Cooking with constant (or direct, in English - DC) current is simpler: it is easier to hold the arc. Therefore, 99.9% of modern MMA inverter machines produce constant welding current.

But among transformers, previously the majority were AC devices.

Alternating current (in English - AC) is used for welding non-ferrous metals. But not with MMA devices, but with TIG devices. Therefore, an MMA welding inverter that produces alternating current is a rarity.

No load voltage

After turning on the device, until the arc is ignited, the voltage at the tip of the electrode is significantly higher than during operation. And the higher it is, the easier it is to ignite the arc. But standards prohibit open-circuit voltage levels on devices delivering direct current above 100V.

To further reduce risks, the so-called VRD blocks. A device equipped with a VRD has only a few volts at the tip of the electrode before the arc starts. And only when you touch the metal, the no-load voltage is restored to the level necessary to ignite the arc.

All electrodes always indicate the polarity of the connection, the type of welding current (direct or alternating) and the minimum level of open circuit voltage required for ignition. For the vast majority of widely used electrodes, it does not exceed 60V.

The open circuit voltage, as well as the welding current, depends on the input voltage level. The lower the voltage in the power supply, the lower the open circuit voltage. Therefore, as the supply voltage decreases, ignition of the electrode becomes more and more difficult.

Duty cycle, also known as PV (on period), also known as PN (payload)

PV is indicated by two numbers. The first is current strength. The second is the percentage of time. For example, “130A-50%” means that this device with a current of 130A can cook half the time. And the same amount of time will remain idle, waiting for cooling to operating temperature.

If measurements are carried out at the maximum current of the device, the first digit is omitted, leaving only the percentage indicator.

For example, if a device with a rating of 160A has the entry “30%” opposite “PV”, this means that with a current of 160 amperes it can operate 30% of the time, and 70% will cool down.

That's right. It only remains to add that the domestic GOST R IEC 60974-1-2004 does not establish a single mandatory method for measuring the PN indicator for MMA devices. “The standard does not apply to limited-duty manual arc welding power supplies that are designed primarily for non-professional use.”

The European methodology, set out in the EN60974-1 standard, suggests measuring on a load stand at an ambient temperature of 40C only until the first shutdown due to overheating. The result obtained is referred to a 10-minute period. It turns out that the thermal protection worked after 3 minutes, the cycle of the device at this current is 30%.

Methodology of the TELWIN concern. To date, it is used by most Chinese manufacturers (those that generally conduct such tests on their cars). The Italian concern itself, when measuring the PV of its devices using its own method, modestly indicates “TELWIN” after the indicator. The vast majority of Chinese manufacturers do not do this.

Finally, there is a Russian, also known as Soviet, methodology. In essence, it is closer to the TELWIN method: all intervals during the control period when the device was working are summed up. But the segment is taken not 10, but 5 minutes. And - most importantly - the device is first put into overheating protection mode, after which measurements begin.

As a result, the same device produces completely different percentages using all 3 methods! Naturally, the most modest “numbers” are obtained using the European method, and the most impressive ones – up to 2 times or more – using the Telwin method.

Version: IP protection class

The IP protection class indicates the performance of electrical devices in relation to solid objects (first digit) and liquids (second digit).

You can determine the degree of protection of the device visually. If a device with IP21 has all the ventilation slots completely open, then with IP22 they are already covered on top with protruding visors. And on a device with IP23, these visors almost completely cover the cracks.

The degree of protection IP24 and higher is technically difficult and makes no sense.

Version: insulation class (heat resistance)

Many materials lose their working properties when heated above a certain temperature. To standardize materials according to this criterion, a classification of insulation based on heat resistance has been introduced. Almost all welding inverters using IGBT transistors have insulation class H, which corresponds to a maximum heating temperature of 180C. The previous “step” - class F - means a heating limit of 155C. Above class F is only class C, indicating a possible heating temperature of over 180C.

Operating temperature

Like internal heating, external heating and especially cooling impose certain operating limitations. Most inverter welding machines are suitable for operation in the range from 0C to +40C. If the device is suitable for use in cold weather, its limit value must be indicated: minus 20C or minus 40C.

Author of the text: Yu. Shklyarevsky.

Source: https://www.kuvalda.ru/blog/articles/raznoe/osnovnye-harakteristiki-svarochnogo-apparata-mma_2.html