Inverter - what is it: all about welding inverters
Inverter, which replaced conventional welding transformers, Is a modern electronic device, characteristics of which allow to use it for performance of welding works on various technologies. In addition to the main characteristics, inherent welding machines of transformer type, inverters have a number of additional features, which makes their use more convenient and significantly expands their technical capabilities. Due to this, such equipment can be used just as successfully as in production, and at home.
Inverter welding "Svarog" ARC-200
How the inverter type welding machine works
Due to its technical characteristics, the inverter can be used to perform welding with electrodes of different types. Distinguish such device compact sizes, as well as light weight, which makes it very mobile, in contrast to heavy and large transformers. Convenient and that, that such a welder st can produce as a constant, and alternating current.
To understand, what are the advantages of the inverter, it is necessary to understand that, how it works. The basis of this device, which began to gain mass popularity only at the beginning of the XXI century, laid down a completely different principle compared to the operation of a conventional welding transformer.
Schematic diagram of the welding inverter "Arc-200" (click to enlarge)
AC, supplied to the inverter from the normal electrical network, straightens first, passing through a diode bridge, which is equipped with an electrical circuit of the device. After rectification, direct current is supplied to power transistors, which convert it back to a variable, but has a high frequency. To reduce the voltage of high-frequency alternating current and get the welding current of the required strength, a transformer is used in the electrical circuit of the inverter.
Because the reduction of high-frequency current is not carried out on this principle, as in a conventional welding machine, it is not necessary to use dimensional transformers, quite a compact device. After reducing the voltage and increasing the current to the required value it is fed to the output rectifier, in which it becomes permanent.
Inverter controls on the example of the device "Fast and Furious" (click to enlarge)
Use of high frequency current, produced by the inverter, not only allows you to significantly reduce the size of the device, but also has a positive effect on the combustion process of the welding arc, characterized by high stability. This welding machine has a high efficiency, as in it energy is not spent in vain on heating of transformer iron.
Simplified scheme of operation of the welding inverter
So, any inverter device consists of the following structural elements, as:
- rectifier, assembled on the basis of a diode bridge (this block of the electrical circuit is responsible for the rectification of alternating current, coming from the mains);
- the inverter itself, which is a generator of high-frequency electrical pulses (the basis of this unit are transistors, opening and closing with high frequency);
- humiliating transformer, which solves the problem of reducing high-frequency voltage and, accordingly, increasing the strength of the welding current;
- output current rectifier, having a high frequency (such a rectifier, as well as the input unit, assembled on the basis of a diode bridge);
- special electronic unit, is provided for control of operating modes of the inverter device.
Technical capabilities of inverter devices
Any inverter, being a welding machine, serve for, to ignite the welding arc and keep it burning in a stable state. Due to the peculiarities of its design, the inverter device perfectly copes with this task. In addition to the main function, modern models of inverters are endowed with a number of additional options, which make their use as convenient and comfortable as possible. These include:
- "Hot start" (this option allows you to ignite the welding arc faster, which is carried out by applying an additional electrical pulse to the electrode);
- "Arc Fast and Furious" (this feature assumes, that at sharp approach of an electrode to a surface of welded details force of welding current automatically increases, which prevents the electrode from sticking in this situation);
- "Anti-stick" (this option works as follows: when the electrode sticks, electric current ceases to be supplied to it; it begins to act only then, when the electrode is detached from the surface of the connected parts).
The front panel of the BIMARK-170 welding inverter
Some models of inverter devices are also equipped with overheating indicators and the option of automatic shutdown in that case, if overheating still occurred. This useful feature protects such an expensive device, what is an inverter, from burnout and, Consequently, from costly repairs.
Additional options, described above, especially useful for novice welders, as they allow to minimize the impact of the level of qualification of the specialist on the quality of welding.
Types of inverters in the modern market
Welding inverters, presented in the modern market, can be divided into two main types.
Household
Such a device, as a household inverter, designed to perform periodic welding work. These devices are inexpensive, but they can be exploited from time to time, they are not intended for intensive daily work. Such inverters are optimal in that case, if you sometimes need to perform simple and short welding work. Most of these devices are made in China.
Professional
Such equipment is designed for daily multi-hour use, its design was originally designed for active operation. The cost of these inverters, naturally, quite large, but it is adequate to their qualitative characteristics.
Semi-professional inverter devices are also available on the market, located on the technical characteristics and cost between household and professional equipment. In addition to the above types, there are universal devices, which are also called combined. Their universality lies in that, that with their help it is possible to carry out welding on various technologies. Such inverter equipment due to its wide functionality also belongs to the category of professional.
Technical characteristics of inverter devices
Choosing an inverter, primarily focus not on its value, and its technical characteristics. From that, how correctly they will be selected, depends, whether you can use such a device to perform those tasks, for which it is acquired.
The most important characteristic of any welding machine (and the inverter is no exception) current is considered, which allows you to get such equipment. This setting affects that, how thick the part you can cook with an inverter device. It makes no sense to overpay for a powerful device, if you plan to use it only for welding thin parts of ferrous metal.
Dependence of welding current and used electrodes on the thickness of the metal
An important parameter is not only the maximum value of welding current, but also its minimum value. Sheet metal welding is performed at the minimum current. It is also necessary to take into account that, how the welding current is regulated - stepwise or smooth circuit. Current regulation with smooth circuit, naturally, is more convenient.
This parameter has a key effect on the ease of ignition of the welding arc, as no-load voltage. The higher it is, the easier the arc will ignite.
Type of electric current, which powers the inverter device, - another parameter, which must be taken into account. Inverters are presented on the modern market, which can operate from the mains with voltage 220 and 380 St.. Naturally, that it is more expedient to choose the equipment for household use, running on mains voltage 220 V.
Advantages and disadvantages of inverters
The high popularity of inverters is due to a number of advantages, which they own.
- Inverters have high power and a wide range of welding current control.
- Even when performing work by a specialist who is not very highly qualified, inverter devices allow to obtain high quality welds, reliability and attractive appearance. - Inverters are compact in size and light in weight.
- Devices of this type have a high efficiency and, Consequently, economically consume electricity. - The molten metal is sprayed very slightly during inverter welding, which helps to save consumables and the formation of neat welds.
- Undoubted universality of inverter devices, so they can be used to perform welding on various technologies.
There are inverters and disadvantages, to the most significant of which are the following.
- Inverters are quite expensive, if you compare them with conventional welding transformers.
- In case of failure, inverter devices are very expensive to maintain.
- Inverters, the basis of the design are complex electronic circuits, very critical to dust, high humidity and low temperatures. That is why the scope of such devices is quite limited. For their trouble-free operation it is necessary to create special conditions and devote a lot of time to their maintenance (dust cleaning, etc.).
- Wires can be used in conjunction with inverter devices, whose length does not exceed 2,5 meters. Such short wires are also among the factors, which seriously limits the scope of inverters.
In general, if you weigh the pros and cons of using inverters to perform welding, the benefits will be much greater. The design of the equipment provides fast ignition of a welding arc and its stable combustion in the course of performance of works, and due to their technical capabilities, inverters allow you to get quality, reliable and accurate connections with electrodes of any type.
