Among novice welders who become familiar with the types of joining metals with an electric arc, the question arises: which is better, a transformer or an inverter? To choose the right device for yourself, it is worth understanding their design and differences, as well as the advantages and disadvantages. The future use of the equipment (the most frequent specific types of work and the time of their execution) also plays a big role. Below are the answers to each point in detail.

The most accessible means for electric arc welding is a transformer. A good device is capable of connecting metal elements with a thickness of 1.5 to 30 mm. It can also be used for cutting steel when the temperature from the propane-oxygen flame is not enough.

The welding transformer has a simple structure, including two windings. The first receives alternating voltage from an outlet or panel. The devices can be designed for both single-phase and three-phase networks. For this reason they come in large and small sizes. Thanks to electromagnetic induction, the current (A) increases significantly and the voltage (V) ) decreases. A current of 80 to 500 A is generated on the secondary winding. There are also more powerful models. The maximum for a transformer is 48 V at idle speed. This makes it safe to use when the welder comes into contact with the product being worked on.

This allows you to weld carbon steel, aluminum, and cast iron. Adjusting the current strength in large models is done by removing or bringing the windings closer. Small devices use step switching, cutting off part of the winding and reducing the voltage path.

Equipment advantages

Among the advantages of transformers, the following stand out:

• simple device and the ability to make repairs yourself;
• cheap cost of components;
• alternating current holds the arc well in a humid environment, so when welding pipes with leaking water, it is easier to weld;
• the ability to work as a transformer with electrodes with a diameter of 1.6 to 7 mm (large devices);
• high current strength (in portable models up to 300 A, and in stationary models more than 500 A), allowing you to weld thick metal;
• relatively cheap cost of store versions.

Disadvantages of equipment

The disadvantages of this welding equipment include:

• Step adjustment in small models. This does not allow you to accurately adjust the device to a specific metal thickness. For example, in mode “4” the current strength is not enough for full penetration, and in mode “5” burns already appear. To overcome the situation, welders use a spring located between the product and the ground cable, which creates additional resistance and reduces the current.
• Welding with a transformer is characterized by a stronger hum. This noise can become annoying to the welder throughout the day. To reduce its impact, the device should be placed away from the work site, but this requires longer cables.
• Spattering of molten metal occurs to a significant extent, which leads to excessive consumption of electrodes.
• Most machines can only lower the current to a certain value, usually around 80 A. This creates difficulties when welding thin sheet iron. In such situations, additional resistance must be used.

Features of inverters

The welding inverter is a more “advanced” device that has gained popularity recently. It significantly increases the frequency of the incoming voltage and converts it into direct current. This is achieved through the operation of a transformer in combination with capacitors, key transistors and diodes. Thanks to modern technologies, it was possible to achieve the minimum dimensions of the device, allowing them to be hung on the shoulder and work for a long time.

Equipment advantages

Inverters have the following advantages:

• thanks to direct current, there is less metal spattering, which saves consumables;
• the surface of the seam is smoother with fine scales;
• arc burning is calm and stable;
• the inverter can weld not only carbon steel, but also stainless steel and aluminum;
• the device supports work with electrodes with a diameter from 1.6 to 5 mm;
• compact models that fit into a small suitcase;
• current settings occur smoothly, which allows you to set any required value;
• thanks to the minimum current value of 20 A, it is possible to work with thin parts without additional resistance;
• energy savings (all inverters operate from 220V, and power consumption is 6-9 kW);
• Some devices are equipped with additional functions that make it easier to ignite the electrode and prevent it from sticking to the surface.

Cons of inverters

This equipment has few disadvantages. One of them is the higher cost relative to the transformer. But the device is completely worth the money. In the event of a breakdown, repairs are more expensive due to the numerous components. The complex electrical circuit makes it difficult to troubleshoot the problem yourself.

Semi-automatic machines based on transformers and inverters

In the creation of semi-automatic machines, a transformer or inverter is used as the main source of welding current, which melts the fed wire in a shielding gas environment. Their application has the following capabilities:

• A semi-automatic transformer is more suitable for welding carbon steel. Most often they are used in car body repair work. This is a cheap and reliable way to weld cracks in thin metal. The large size of the equipment allows it to be used in a workshop or workshop. The movement is carried out on a small trolley, where a gas cylinder is placed.
• The inverter semi-automatic machine has small dimensions and can be carried by hand, provided it has a long gas hose. Constant voltage makes it possible to weld carbon steel, stainless steel and aluminum (when installing wire of the appropriate composition). Although spattering on alloy metals is high, the welds are of high quality.

How to choose a device

The cost of transformers and inverters differs. But when choosing, it is necessary to proceed mainly not from the price of the equipment, but from future use. The transformer is perfect for personal use in the country or in a private home. They can be used to repair a fence, build a greenhouse in the spring, or weld a canopy that has fallen off a gate. Semi-automatic machines based on transformers are suitable for repair work on car bodies in your own garage.

An inverter is worth buying if you plan to do frequent welding work. It can be:

• heating welding;
• water supply;
• production of stainless steel containers;
• creation of new doors and gates.

The seams on such products will be of higher quality and more beautiful. Subsequent surface treatment is also reduced.

A semi-automatic machine based on an inverter can be purchased for regular work on the manufacture of tanks (for water, fuel, chemical media), filters, welding of stainless metals, or for a large service station.

Choosing welding equipment is easy when you understand its features and advantages for future work. It would be good if, before purchasing, you had the opportunity to cook with both devices and compare the quality of the result and your own feelings about ease of use.

In technical terms, welding inverters are the same welding machines, only more modern, running on semiconductors. Exactly the same technologies are used here as in semi-automatic machines; argon-arc and plasma cutting are performed in the same way, as well.

Undoubted advantages

Actually, an inverter is a power converter. Accordingly, the difference between a welding inverter and a conventional transformer is as follows:

• Its useful operating efficiency is between 80 and 90 percent, so when converting DC to AC and then AC back to DC, not much power is lost;
• In order to control the conversion processes, a processor is used, and, depending on the strength of the voltage, and sometimes its dips, the conversion coefficient changes, which makes it possible to maintain the output voltage at a constant level.

Welding theory

All that is required of the welder is to smoothly move the electrode along the line of the intended seam, without touching the metal, so that the electrode is a few millimeters from it. In reality, a simple theory turns into flour, since working in a mask with sparks flying into it does not make it easy execution.

Using a conventional transformer when touched results in a short circuit. In order to tear it off, some effort is required, otherwise the thermal protection is triggered or the transformer winding catches fire.

If an inverter is used, then the touch is almost imperceptible: the processor, which instantly reacts to the voltage drop, melts the electrode and can be removed from the part without any effort.

Among other cases when our clumsy actions are masked by a “smart” inverter, we note the practice when the electrode is deliberately kept in close proximity to the welding object. In this case, the processor stops receiving output voltage, and overheating can be avoided.

The undoubted advantage of the inverter is its low weight and size; it cannot even be compared with the previous transformer. And all because power conversion here occurs at 50-60 kHz.

The welding tool of the new millennium gives the impression of a good wizard, with it the welding process becomes simple, fast and convenient. And not only for professionals. Even a beginner can feel like such a professional, with an inverter in his hands.

Summarizing the above, we can note among the advantages of the tool the advantages of:

• very noticeable power density;
• significantly reduced weight;
• wide choice and simplicity of adjustments available on the body;
• convenient sizes, including for mobile transportation;
• minimum number of consumable electrodes;
• high performance;
• Possibility of welding in a horizontal plane, vertically and at an angle;
• advantages of welding various metals, including stainless steel, cast iron and non-ferrous metals;
• convenient compatibility with a wide range of electrodes;
• potential for modular repurposing.

Obvious disadvantages

Why have old welding transformers, with such an abundance of advantages of inverters, still not been written off to the notorious dustbin of history? The main reason why some potential consumers continue to use older, more familiar transformers is the price. The inverters that replaced them are at least twice as expensive.

The second of the shortcomings Visitors to various forums on the Internet are sure to mention the high process of tool decommissioning. Once the electronic board gets dirty, the unit refuses to work. Therefore, it constantly needs to be blown out with compressed air.

The small size of the new welding unit also has its downside. After all, it is extremely saturated with all kinds of electronics, the normal operation of which can be easily interrupted by capricious weather. “Smart” filling is more sensitive to both dampness and sub-zero temperatures. As soon as the temperature drops below zero, a number of budget models begin to malfunction, and branded products begin to malfunction at temperatures below – 15 degrees. And storing such equipment in severe frost conditions (in winter, in an ordinary Russian garage) reduces the reliability of the “delicate” instrument.

Problems also arise when working in dusty conditions. If the product is not blown out in time, its failure is just a matter of time.

Not everything is so simple with the welding itself. This applies to cutting thick metal. If the network voltage is unstable, which is quite common in rural areas, then the converter module may fail. Therefore, when characterizing the inverter as a new word in welding, it is hardly worth idealizing it too much. Yes, this is the best there is. But this is far from a panacea.

The next big disadvantage of the product is very expensive repair. After all, the operation of the inverter is based on a transistor IGBT unit, the price of which can be from a quarter of the cost to half of the nominal value of the entire product. Therefore, if the warranty period of the unit has expired, its “reanimation” will require significant financial investments. Part of the model range is far from the best maintainability. The lack of service centers can have a negative impact, especially in rural areas, where inverters are in demand on private farmsteads and, of course, in small farms.

The situation is also complicated because it is impossible to assemble an IGBT unit yourself, even if you have all the necessary microcircuits at hand. You need to buy a branded block. But there are budget models on sale, the design of which is limited by the presence of only one electronic board. In this case, a breakdown will cost not even 50, but 60 percent of the cost of the product.

Of course, all these problem areas are more than worth it, just remember the bulky transformers that spit melt and are inconvenient. Next to them, a mobile, comfortable, almost silent, energy-efficient inverter appears in a completely different light. And the quality of the result, even if a beginner gets down to business, turns out to be quite acceptable.

In the construction industry, both traditional welding machines and more technologically advanced ones - inverter ones - are used. What is the specificity of both? What is the difference between a welding inverter and a welding machine classified as a traditional unit?

What is a welding inverter?

This type of welding machine is characterized by the ability to convert direct electric current into alternating current. This unit contains the following main components:

• rectifiers - network and frequency;
• filter;
• frequency converter - the inverter itself;
• transformer;
• Control block.

This is how a welding inverter works.

Alternating current from the electrical network, which has a frequency of 50 Hz, is supplied to the network rectifier. After this, the current is correspondingly rectified and then smoothed through a filter. Next, it is fed to an inverter, in which it is converted into an alternating voltage with a high frequency - approximately several tens of kHz. Then, through a transformer, the current voltage is reduced to a level of about 50-60 V, while its strength increases to approximately 100-200 A. Then the current is rectified using a frequency rectifier - already during the arc welding process.

The frequency converter - inverter - can be adjusted by the welder, thereby ensuring optimal operating parameters of the unit. To do this, another functional element of the inverter welding machine is used - the control unit.

Main advantages of inverters:

• low weight and dimensions;
• high energy efficiency of welding;
• high welding precision.

Disadvantages of inverters:

• units in many cases require special storage conditions - in terms of temperature, air humidity;
• sensitivity to low temperatures;
• high price, high cost of maintenance and repair.

What is a traditional welding machine?

The “classic” welding machine is characterized primarily by its simplicity of design. Its main functional element is a transformer.

This is how a traditional welding machine works.

Alternating current from the electrical network is directed to the primary winding, as a result of which magnetization of the transformer core is formed. Then the current passes through the secondary winding - in it the magnetic flux forms an alternating current, characterized by a lower voltage compared to what is supplied to the primary winding. Its voltage depends on the number of turns on the secondary winding.

A traditional welding machine thus operates due to electromagnetic induction, which generates a high current strength - sufficient for welding, at a low voltage.

The main advantages of traditional welding units:

• no requirements for special storage conditions;
• lack of sensitivity to low temperatures;
• low price, inexpensive service.

Disadvantages of the corresponding devices:

• heavy weight and dimensions;
• not the most outstanding energy efficiency and accuracy.

Comparison

The main difference between a welding inverter and a traditional type welding machine is the presence of a current converter in the first device. In addition, the units under consideration differ in the following aspects:

• weight, dimensions;
• energy efficiency, welding accuracy;
• availability of requirements for storage conditions;
• sensitivity to low temperatures;
• prices, services.

It can be noted that, as a rule, the use of traditional machines requires a more highly qualified welder.

Having determined what the difference is between a welding inverter and a traditional type welding machine, we will reflect in a small table its main criteria in relation to the aspects discussed above.

Table

Welding inverter	Traditional type welding machine
Includes converter	Does not have a converter
Has small dimensions and weight	Has large dimensions and weight
May require special storage conditions	As a rule, does not require special storage conditions
Characterized by high energy efficiency	Characterized by relatively low energy efficiency
Characterized by high welding precision	Characterized, as a rule, by lower welding accuracy
Sensitive to low temperatures	Not too sensitive to low temperatures
Costs more, requires more expensive maintenance	Costs less, involves cheaper maintenance

Welding machines are becoming indispensable not only in industrial production, but also in everyday life. This is confirmed by the huge selection of household and semi-professional equipment. At the same time, among other types of equipment, inverter devices are becoming increasingly popular. What is the difference between an inverter welding machine and a conventional one?

Operating principle of a transformer welding machine

Modern transformer welding machines are reliable and unpretentious. They operate at a frequency of 50 Hz. Electric current is converted using a transformer. This happens as follows. First, a current of 220V is supplied to the primary winding of the transformer. It magnetizes the composite core, which creates an alternating magnetic field. As a result, an alternating current appears in the secondary winding, but its parameters are already different: voltage - 50-90V, current - 100-200A. The latter value directly depends on the number of turns in the secondary winding of the transformer. It is adjusted mechanically. An example of such a device is WESTER ARC 130.

Electric welding was first used in practice by the Russian inventor N.N. Benardos in 1881.

Advantages of transformers

Welding transformers have a number of advantages:

• They are inexpensive. With equivalent characteristics, a welding transformer costs half as much as an inverter.
• The devices have a simple and reliable design.
• They can be repaired even at home.
• They can operate at sub-zero temperatures.

Disadvantages of transformers

• Transformers are distinguished by their solid dimensions and heavy weight. They are not well suited for frequent movements.
• When working on alternating current, it is difficult to ensure high quality seams.
• Device efficiency is no more than 80%.
• The devices consume a large amount of electricity.
• They cannot be connected to the intra-house network.

Operating principle of a welding inverter

Serial production of welding inverters was established about 30 years ago. Their more accurate name is rectifiers with a transistor inverter. The main difference between welding machines of this type is the sequence of electric current transformations. In these devices, it has to change its characteristics several times. First, the current is rectified and becomes constant as it passes through the semiconductor. The next step is to pass it through a filter for additional smoothing. Then the current enters the inverter and is converted into alternating current with a frequency of about 100 kHz. After this, it enters a transformer, in which the voltage decreases and the current increases. It then goes into a high-pass filter and then into a rectifier. The output produces a direct current of the required parameters.

Due to such complex transformations, it was possible to reduce the dimensions of the welding machine. An example of such a device is ELITECH AIS 200 PNS.

Advantages of an inverter device

• The efficiency of the devices reaches 95%. Energy losses are minimal.
• The devices are characterized by increased electrical safety.
• They can be connected to a regular household network without consequences.
• The devices have a very wide range of current regulation. Thanks to this, it is possible to use different types of electrodes and select the required welding mode for metals.
• All operation of the devices is regulated by control circuits and microprocessors. This ensures easy ignition and stable arc retention.
• The voltage and current in inverter devices are adjusted smoothly.
• The devices are equipped with protection against surges in mains voltage.
• Welding can be carried out in any spatial position.

Disadvantages of an inverter device

• Their cost significantly exceeds that of welding transformers.
• The devices are sensitive to dust. It may be the cause of failure.
• Inverter welding machines do not tolerate high humidity and low temperatures. They need to be stored only at positive temperatures.
• If the operating rules are violated, the unit with power transistors fails. Replacing it can cost half the cost of the device. Repairing a device is a very expensive procedure.

As a result, the difference between an inverter and a transformer-type welding machine from the user’s point of view is the following: it is mobile, provides excellent quality of seams, and is convenient to work with. These functional advantages are provided by electronics and process automation. For the same reason, such devices are more expensive. Welding transformers are unique “workhorses”. They should be used when the device is not expected to move and high quality welding is not required.