Welding machine for operation from a weak network. Welding inverter for reduced voltage. What you can ignore

The provision of stable network power in cities and rural areas is fundamentally different. The use of modern household appliances with their high energy consumption has placed villages and holiday villages in conditions of equipment operating at low voltages in the public network. Any construction involves the use of metal compounds, so welding inverters operating at low network voltages will always be in demand far from cities. We will look at models of inverter devices operating in these conditions and ways to ensure their optimal performance.

The principle of operation of the inverter is based on the conversion of input alternating current with a frequency of 50 Hz and a voltage of 220/380 V into an output current of increased power. It provides a short circuit arc, as a result of which the metal melts at the junction of the parts. The equipment that achieves a stable arc effect is a welding machine. In the case of reduced input characteristics, it acts as a welding inverter operating at low supply voltages. These units are no different from conventional ones, except for the circuit design and the semiconductor elements used.

Devices for low voltage are characterized by a small influence of input parameters on the process caused by welding of parts. This occurs due to the fact that the built-in voltage stabilizer for the welding inverter operates, which smoothes out surges. Any inverter uses the output voltage to convert it into a powerful welding current in order to fuse metals into one whole in composition and strength characteristics. These units consist of the following blocks:

1. low-frequency rectifier that converts alternating voltage 220/380 V into direct current;
2. high-frequency transistor inverter that generates alternating current with a high oscillation frequency;
3. power transformer with a choke, which allows you to supply welding current to the inverter terminal;
4. a feedback system that regulates the output current, arc ignition, and stabilizes the output voltage;
5. optionally there is a rectifier, arc forcing and an anti-stick electrode function;
6. system of indication and control of operating modes, system of ventilation and protection from extreme welding conditions.

It is important that an inverter operating in reduced power mode especially needs effective cooling, so periodic cleaning of dust from the device’s cooling radiators is necessary.

Ensuring efficient inverter operation

Fluctuations in indicators in public power networks can be from 150 V to 270 V, with a rated power supply of 220 V. This occurs due to load imbalance between phases and outdated equipment, which does not have the ability to regulate stable parameters in the network. This situation is typical for rural areas and, unfortunately, is widespread. To ensure the operation of the welding inverter in such conditions, the following circumstances are necessary:

• the presence of an input voltage stabilizer for the welding machine, which must provide the power necessary for operation;
• engineering circuit solutions that allow the unit to perform its functions in conditions of changes in network values;
• the presence of a welding oscillator for effective ignition of a short circuit arc;
• selection of device parameters that provide optimal open circuit voltage for the welding inverter.

The input voltage stabilizer must provide power consumption ranging from 5 kW to 9.8 kW and operate in a wide range of surges in AC supply currents.

It should be noted that large dimensions, weight and high price do not make this equipment particularly popular. Therefore, the most popular are power supply stabilizers built into the inverter, which make it possible to reduce network instability by selecting semiconductor elements and their operating modes.

In the model range of many manufacturers there is no such device that cannot operate at least in the range from 190 to 230 V, and some units designed for the Russian market operate in a much wider range of input indicators. Since stabilizers for inverters are too expensive, when choosing a device you should focus on circuit solutions and high-quality components. It is necessary to ensure the presence of an oscillator, as well as the stability of the open circuit voltage during surges in the network.

It is important that the circuit contains semiconductor parts from well-known manufacturers and their load parameters; such a criterion should be decisive when choosing an inverter device.

There are German, Italian, Chinese and Russian devices on the inverter market that can stably perform their functions both when network parameters increase and decrease. We will look at some models in the budget and mid-price categories, which have the following qualities:

• wide limits of welding current adjustment;
• the presence of a hot start function;
• possibility of operation within a wide temperature range;
• continuous operation at maximum current;
• stable open circuit voltage;
• operation with input voltage from 150 V to 240 V or more.

The inverter device allows you to work with electrodes from 1.6 mm to 5 mm, allows you to cook at an input voltage of 150 V. Current adjustment - from 5 A to 200 A, ambient temperature - from -10 o C to +40 o C, has a hot start and provides an even, stable short circuit arc.

The welding machine Svarog ARC 160 operates stably from 160 V to 245 V input power supply with stable arc ignition and rated current from 20 A to 160 A. It supports welding mode with a tungsten electrode in a protective environment, but has a low duty cycle of 40%.

The Interskol ISA 160 inverter also operates at a reduced network value, producing stable current readings from 20 A to 160 A. Duration of operation at a maximum PV current of 100%, there are functions of hot start, anti-stick and arc force. It is in demand due to its stability, ease of use and unpretentiousness.

The Aurora PRO Inter 200 inverter continues to operate even if it drops to 140 V, has multi-level protection and produces a welding current from 20 A to 200 A. It is possible to use 5 mm electrodes at maximum current, its duty cycle is 60%, and a characteristic feature is the ability to connect a network extension cord up to 100 m long with a wire cross-section of at least 2.5 mm 2.

All these devices have a protection class of IP 21, weigh no more than 8 kg and have relatively low power consumption. Of course, if the network voltage is below 180 V, you cannot count on welding with a 5 mm electrode, but with a 3 mm electrode you can work at 150 V.

It is important that unstable conditions force the inverter to work in extreme mode, so before purchasing you need to make sure that there are workshops servicing your device.

Results

We examined the operation of welding inverters at low voltage in the electrical network. You can choose an expensive stabilizer, or you can choose a welding machine with optimal characteristics, the choice is yours, and it depends on the type of work and financial capabilities.

The times when huge welding transformers “ruled the show” are irrevocably a thing of the past and welding at home has become not a luxury, but an everyday task for the master. Thanks to the advent of innovative technologies, a compact and functional welding inverter with PFC (power factor correction module) has become more common among home craftsmen. In the material presented, we will reveal why the choice falls on welders with PFC and what their advantages are.

Advantages of welding inverters equipped with a PFC module

On professional forums, electrical engineering specialists argue until they are hoarse about the advantages of active and passive power correctors in devices and their ability to minimize electricity losses during its transmission from the power source. However, a practitioner is of little interest in theoretical jungle; it is enough for him to know that from a practical point of view, welding inverters that have a PFC function (PFC, power factor correction) have practically another additional voltage stabilizer at the input, so such a device is capable of:

• Use a significantly lower amount of current consumption without reducing the maximum welding current;
• Work on ultra-low voltage (drained networks), as well as when it changes abruptly. In this case, the range of voltage values ​​in the network can fluctuate quite significantly (from 90 to 240V);
• Work when connected via an extended portable cable;
• Work with gasoline or diesel generators, because a machine with a PFC does not load them like a regular welder.

The figure shows the current-voltage characteristic with and without the PFC module. A conventional inverter (without PFC) takes peak values ​​from the network, shown by the red line, and with the PFC module, consumption is transferred to a smooth sine wave, due to this there is no load on the network.

Along with this, the efficiency of the device increases sharply, reaching at least 85%. Correction of the PFC power factor allows you to achieve the highest possible power factor (up to 99.9% ideally), while no more than 1% of the total inverter power is spent on heating the conductors!

What to choose? Household inverters with PFC function

It should be noted that the cost of a PFC inverter with an active type of power factor control is, of course, slightly higher than that of conventional switching power supplies with a transformerless input, this especially affects the price of household models. Therefore, when purchasing a device, it is necessary to clearly outline its planned scope of activity.

Budget options for inverters are suitable if welding work will be performed only occasionally, and the material being welded will be simple steel. You should not think that such devices are completely primitive, for example, the welding inverter Svarog 160 PFC, despite its reasonable price, is capable of:

• Operate from a network with a voltage of 160-240V, that is, high-quality work with electrodes with a diameter of up to 3 mm is possible even with a significant voltage drop;
• Especially for amateurs, the device is equipped with the HOT START function, as a result of which, at the moment the electrode touches the welding workpiece, the value of the welding current briefly pulses, due to which the arc is ignited;

However, it will not be possible to weld aluminum using such equipment, since it is intended for welding work with direct current. Welders who work on this device praise its reliability, but among the many advantages they sometimes note a small drawback: difficult ignition of some brands of electrodes, and in particular UONI 13/55, but basically this inverter is enough for most household tasks.

If you are ready to spend money on functionality, be sure to pay attention to the Gysmi E200 PFC model. In addition to all the advantages of an inverter with a PFC, this device is equipped with an automatic arc extinction function, which allows you to complete a weld without defects such as cracks and a welding crater (deepening). The device can easily be reconfigured to the argon arc welding mode with a non-consumable electrode and the maximum welding current threshold is slightly higher than that of the model from the Svarog brand.

An Italian-made inverter falls into a slightly more expensive price range. Not only does the manufacturer allow the connection of extension “carries” up to 50 m long to the device, but he also prudently equipped the device with a reinforced housing. And most importantly, synergetic adjustment allows you to accurately adhere to a certain arc length; you just need to set the data on the thickness of the material. The Active 187 MV PFC model allows you to work not only with ferrous metal, but also with stainless and high-alloy steel, since it can also weld in an inert gas environment. When purchasing it, you can use any types of electrodes (including those with rutile and cellulose coating).

If you are a professional...

Industrial welding machines are capable of operating without failures or breakdowns in the most difficult conditions. Of course, they can hardly be called compact, because the weight of this equipment starts from 20 kg and you have to use a special cart to move the inverter around the facility.

The American company Lincoln Electric produces one of the most functional inverters - the Lincoln Electric Invertec 300TPX model, which has several argon arc welding modes and allows you to work with various metals. Innovative software allows, after determining the settings, to perform work in a semi-automatic mode. Low energy consumption and reduced energy dissipation in power cables are ensured by the PFC unit, and the low percentage of CO 2 emissions during the welding process allows us to call this device “environmentally friendly”.

Unfortunately, inverter welding machines cannot always work stably in household electrical networks. And, often, the reason for this behavior lies not in the welding machine, but in the electrical network itself, and its voltage of 220 V.

When connecting the welding inverter to 220V, be sure to check the actual voltage during operation of the device. Thus, the reduced voltage may be 170-180V, which for some inverters is not a working range. In this case, the power of the welding machine is reduced and is much less than the calculated power.

Therefore, in order buy a welding machine Inverter type that can operate in networks with low voltage (or rather, with a high voltage drop), it is necessary to pay attention to devices that are capable of operating at such values. Such a welding machine will lose power and will be able to weld at reduced voltage values.

When welding in weak networks, the value of the welding current can drop to 80-90A. With such values, the maximum electrode diameter that can be worked with is 2-2.5 mm, which is often very small. Most inverter welding machines operate with voltage deviations of 15%, that is, at 187-253V. Within these limits, even with sudden voltage surges, the devices continue to operate without any losses.

Therefore, if you are sure that the network in which you will work tends to lose voltage below 187V, pay attention to devices that are capable of operating at lower values. The most resistant inverters to low voltages are those with a built-in power factor correction device. This function in the instructions is abbreviated as “PFC - power factor corrector”. Therefore, if you see it in the description of a particular inverter, rest assured that the welding machine will be able to work without problems.

During operation, be careful, for example, when using extension cords longer than 15 meters, the voltage value is significantly reduced, and the output is much less than the calculated one. Therefore, try to avoid connections through extension cords, tees and other additional means. Use the device in close proximity to a power source.

Also, pay attention if you want to connect the welding machine to the generator. Firstly, this can significantly reduce the voltage in the generator itself, and secondly, it can negatively affect the operation of the device itself.

When choosing, it is important not only to focus on how much such equipment costs, but also to evaluate its reliability rating. Expensive models, although a priori of higher quality, can also present unpleasant surprises to their owners. Cases when a completely new inverter, which required large financial investments, fails after the first few starts are not that uncommon.

You should also not focus exclusively on budget models, which, as a rule, are produced in China and are not characterized by stable quality characteristics and high reliability indicators. If financial resources allow and the task is to purchase a reliable welding machine, it is better to pay attention to models presented by well-known world brands: EWM, Elitech, Blueweld, etc. It should be borne in mind that the cost of such inverters starts at $1,500, but it is adequate for the high quality and product reliability.

When choosing welding equipment, it is necessary to remember that not all models produced in Europe are able to operate efficiently and reliably from domestic electrical networks, which are not characterized by stable voltage and current. However, mid-price inverters produced by Russian and Chinese manufacturers are well adapted to such conditions. These devices are adapted to operate under voltage surges, and they have decent technical characteristics.

Inexpensive inverter devices

If you need a budget welding inverter, you can consider one of the options below. It should be said right away that the listed inverters are not distinguished by outstanding qualities and functionality and are not among the top three in terms of reliability rating. This is fully explained by their low price.

GERRARD MMA-200

If you are interested in one of the most, which nevertheless performs well in work, then the GERRARD MMA-200 will suit you best.

Among the technical characteristics of this device are the following:

• welding current control range – 20–200 A;
• duration of continuous operation at maximum current – ​​60%;
• supply voltage – 220 V (the device can operate with maximum supply voltage deviations of ±15%);
• weight – 5.3 kg;
• power consumption – 5 kW;
• dimensions – 445x180x271 mm.

Despite the fact that this welding inverter has a number of significant disadvantages associated with its configuration, the welds when using it are of high quality and reliable. The disadvantages of such a welding machine include the not very high reliability of the connectors for connecting power cables (they quickly become loose), and also the fact that it does not include a device with which it can be carried.

KAISER NBC-200

The equipment of this model is somewhat more expensive than the inverter discussed above, although in terms of their technical characteristics they differ little.

The welding inverter KAISER NBC-200 is characterized by the following parameters:

• the range in which the welding current can be adjusted is 20–200 A;
• period of continuous operation (at maximum current) – 60%;
• operation from a single-phase network with a voltage of 220 V (permissible voltage drops in the electrical network are ±15%);
• weight - 6.5 kg (larger weight, compared to the weight of the previous model, ensures better heat removal from the electronic components of the inverter);
• dimensions – 445x180x271 mm;
• power consumption - 6.7 kW (due to the higher power, the electrical wiring of this device heats up much more intensely than the previous model).

A serious disadvantage of the KAISER NBC-200 inverter is its low maintainability. After the warranty period has expired, this welding machine often has electronic boards that fail and must only be replaced. The cost of such repairs, if we talk about its feasibility, is comparable to the price of a new inverter.

Cedar 200

In the reliability rating, the inverter of this model is significantly higher than the two previous devices. This device costs a little more than cheap Chinese models, but in terms of quality and reliability it is in many ways superior to them. An important advantage of such an inverter is that welding work can be performed with its help even when the voltage in the network is too low (up to 140 V).

Cedar 200 has the following parameters:

• adjustment of welding current in the range from 20 to 200 A;
• period of continuous work performed at the maximum value of welding current – ​​60%;
• operating voltage range – 187–242 V (the microprocessor unit used in the inverter design allows welding work to be performed when the voltage drops to 140 V);
• weight – 5 kg;
• Dimensions – 320x123x220 mm.

As mentioned above, the reliability of the welding machine of this model is at a fairly high level, however, in some batches of inverters there may be specimens that are initially of low quality.

Professional inverter models

The top lines in the reliability rating are occupied by inverters designed for professional use. Even if we consider those professional series inverters that have technical characteristics identical to those of the models described above, they are distinguished from budget welding machines by a significantly lower number of operational failures, as well as expanded functionality. That is why such equipment can be used not only for performing manual arc welding, but also for joining parts in a shielding gas environment. Let's look at the characteristics of two inverters that rank high in the popularity rating among specialists.

Svarog 205

This inverter did not achieve the level of a professional welding machine in only one parameter - stability of continuous operation. If we evaluate this welding machine by cost, then it is quite expensive for home use, but quite affordable for a construction organization and even a small workshop. In fact, most often small production organizations, service stations and repair teams purchase them.

The warranty on Svarog inverters can be up to 5 years

The Svarog 205 inverter has the following technical characteristics:

• welding current control range – 10–180 A;
• duration of continuous operation at maximum welding current – ​​60%;
• the supply voltage of the electrical network is 220 V (the device can operate with voltage drops within ±15%);
• power consumption – 5.7 kW;
• weight – 5.8 kg;
• Dimensions – 336x120x198 mm.

Due to the high reliability of the inverter, it rarely requires repairs, but it should be borne in mind that the cost of such repairs is quite high.

Despite the fact that the country of manufacture of this model is China, it occupies a high position in the reliability rating. This is also evidenced by the fact that the inverter of this model is often counterfeited, so you should be very careful when purchasing it.

Fast and Furious 200

Among domestic inverter devices, this model occupies the top lines of popularity and reliability ratings. The high cost of such a device is compensated by the good maintainability of the inverter, the components of which are much cheaper than those of its foreign analogues.

This device is characterized by the following parameters.