Cases and bags for welding inverters. Box for welding kit made from a canister. Collecting materials and tools

A welding inverter has become an indispensable attribute of a professional or amateur welder. With the help of welding equipment, soldering or cutting of the alloy is done, and the suitcase for the welding inverter is designed to store the main units and components designed to work with alloy surfaces. For those who are constantly engaged in welding, the priority quality of work will be the comfortable placement and placement of the main parts and components that are intended for welding work.

Application of inverter case

Box for welding kit from a canister

Hello, readers of this site. Today I will tell you how I made a convenient box for transporting a welding machine from a plastic canister.

Most of the time I live in a city apartment. I have a workshop in the basement under a nine-story building, where I do my hobby - homemade things. There I can do everything except welding work - firstly, there is a 10-amp circuit breaker installed in the electrical panel, which can be knocked out if the electrode gets stuck (And the electrician has the key to the panel). Secondly - fire safety! And thirdly (and most importantly), the ventilation there does not allow welding.

Therefore, in order to perform welding work, I go to the country house or to a private house. And since I’m always short on time, most often, after work, I pop into the basement, grab everything I need, and go.

I use this welding inverter “Gerard-MMA200”.

He has served me faithfully for many years. I kept it in its “original” box. But the problem with all factory packaging, as you know, is that once you take out its contents, it is almost impossible to put everything back in! )))). Fortunately, a “souvenir” welder’s shield was supplied with the device! Without it, the device fit easily. But only him!

And so, I arrived at the dacha. I lay out the tool in anticipation of interesting work. . And then it turns out that I forgot my mask.

Another time I took both a mask and welding. but I forgot the electrodes. Next time I took everything except the cutting wheels. ))))).

It was events like these that gave me the idea to make some kind of box that would hold the entire set - a welding machine, a mask, wires, electrodes, clamps, a hammer. In short, grab one box, throw it in the car - and don’t forget anything! )))))

And I began to think about what I could make one out of! My choice fell on this 30-liter canister, of which I have quite a lot:

Having estimated, I came to the conclusion that this is exactly the volume I need. (To be honest, it wasn’t this particular canister that went under the knife. I just forgot to take a picture of the one I cut.))))

As a result, I ended up with a box, which you can see in this video (it was filmed crookedly, but sorry):

And now I will tell you in detail how I did it.

I needed:

1. Plastic canister 30 l. 2. Blind rivets with a diameter of 4.8 mm of different lengths. 3. Loops 2 pcs. 4. Chest latches 2 pcs. 5. Strips of tin. 6. Cuttings of PVC pipes. 7. Trim of linoleum. 6. M5 washers enlarged.

So, let's begin. At first I wanted to do a horizontal layout. But, after thinking about it, I came to the conclusion that, firstly, I would significantly lose the rigidity of the structure, and secondly, I was still going to carry it by the handle (i.e., vertically), and therefore it would be better if the tool was laid out will be done in the same position.

So I took the canister and cut off the top part:

These are just strips with a curved edge. Left over from something, I don’t remember. If necessary, they could be easily cut and folded.

I took a narrower strip and riveted it around the edge of the cut top part, using a regular rivet gun and pop rivets. At the same time, I slightly pushed the double-folded edge of the tin beyond the cut:

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Feeder

The electrode wire must be fed continuously and evenly - then the welding will be of high quality. The feed speed must be adjusted. There are three options for making the device:

1. Buy a fully assembled mechanism. Expensive, but fast.
2. Buy feed reels only.
3. Do it all yourself.

If the third option is chosen, you will need:

• two bearings, guide roller, tension spring;
• motor for feeding wire - a motor from windshield wipers will do;
• metal plate for fastening the mechanism.

One pressure bearing - it should be adjustable, the second serves as a support for the roller. Manufacturing principle:

• holes are made on the plate for the motor shaft and for mounting bearings;
• the motor is fixed behind the plate;
• a guide roller is put on the shaft;
• bearings are fixed at the top and bottom;

It is best to place the bearings on metal strips - one edge is bolted to the main plate, and a spring with an adjusting bolt is connected to the other.

The completed mechanism is placed in the housing so that the rollers are located in line with the burner connector, i.e., so that the wire does not break. A rigid tube must be installed in front of the rollers to align the wire.

Case for welding inverter

A welding inverter has become a mandatory attribute of a professional or amateur welder. Welding equipment is used to solder or cut metal, and the case for the welding inverter is designed to store the main units and components designed to work with metal surfaces. For those who are constantly engaged in welding, the priority quality of the work will be the convenient location and placement of the main parts and components that are intended for welding work.

Application of inverter case

Disadvantages of the Resanta inverter model 220

Almost all specialists and organizations specializing in sales of welding equipment, judging by the reviews, blame the fact that among the inverters of the model in question there is a rather large percentage of defects. Thus, there is data according to which out of 10 Resanta model 202 welding machines, 1–2 are not completed until the end of the warranty period and fail.

Faulty parts that caused an overload to occur

If you encounter a malfunction such as overheating of the inverter, then you can remove it without the help of others or with the help of service professionals. Quite often, overheating is associated with poor contacts between the elements of the electrical circuit, and this problem can be eliminated by revising them. The situation is much more difficult when the electrical components of the inverter fail. In some cases, replacing such components at a price can be comparable to the price of a new device.

A huge drawback of inverters of this model is that the actual values ​​of the welding current that they generate may diverge from the passport data by 15–20%. Almost always, this does not reduce the efficiency of using welding equipment, but nevertheless worsens its multifunctional capabilities.

Problems listed in the instructions for the welding machine

The Resanta model 202 inverter is not very effective when working with parts whose thickness exceeds 10 mm. In such cases (even with the introduction of electrodes with a diameter of 5 mm), there can only be a surface melting of the alloy, and effective heating of the parts being connected does not occur over their entire thickness.

In general, reviews of the inverter of this model and the opinions of experienced professionals indicate that such a device is comfortable and reliable in operation, allowing for high-quality and careful welded joints.

Features of industrial cases

The industry produces several options for boxes for welding inverters, but most equipment users believe that making a case with your own hands would be an excellent option. By the way, some developments of do-it-yourself welding inverter cases have become the basis for industrial production, which have gained popularity among welding specialists.

Industrial series have convenient compartments and sections for storing tools and other auxiliary components and parts. As a successful example of industrial production, we can point out the 18″ FIT case series, which has the following parameters:

• External overall size - 450*240*200 mm.
• The inner part of the case is 440 (390 mm internal working part) * 225 * 180 mm.

Appearance of FIT case 18″

The side handles used in this design allow the usable volume of only 390 mm. The height of this design is 180 mm, with a size of 145 mm allocated for the direct construction of the box, and 35 mm belongs exclusively to the closed part of the body in the form of a lid. The weight of this design is about 2.5 kg. As practical experience shows, this option is excellently used as a case for the welding inverter Resanta, Torus, etc. The only drawback is considered by many to be the inability to fully accommodate wires and cables provided for the design of inverter welding equipment.

Factory case of the Resanta welding machine

In any case, for some models it is still possible to “squeeze” cables, holders, and wires inside the box structure. The inside of the cover has a special recess that allows you to accommodate a pack of electrodes and the necessary minimum of protective equipment.

Unlike homemade options, which have to be made from handy materials, the welding inverter inside the case will not “dangle”, but tightly holds the main body of the inverter equipment. An additional advantage of serial production of the case for the Paton welding inverter will be a special varnish coating that will not change its appearance regardless of the condition of the main inverter welding equipment.

Preparation

Manufacturing a semi-automatic welding machine at home begins with planning the work. There are two options for making MIG welding from an inverter:

1. Completely make a semi-automatic welding machine with your own hands.
2. Only remake the inverter - buy a ready-made feeding mechanism.

In the first case, the cost of parts for the feeding device will be about 1000 rubles, excluding labor, of course. If a factory semi-automatic machine includes everything in one case, then a homemade one will consist of two parts:

1. Welding inverter.
2. Box with feeding mechanism and wire reel.

First, you need to decide on the body for the second part of the semi-automatic device. It is desirable that it be light and roomy. The feeding mechanism must be kept clean, otherwise the wire will feed jerkily; in addition, the reels must be changed periodically and the mechanism adjusted. Therefore, the drawer should be easy to close and open.

The ideal option is to use the old system unit:

1. neat appearance - it doesn’t really matter, but it’s much nicer when the insides of the homemade product don’t stick out and the semi-automatic machine made from an MMA inverter looks good;
2. light, closes;
3. the body is thin - it’s easy to make the necessary cutouts;
4. The gas valve and wire feed drive operate on 12 Volts. Therefore, a power supply from a computer will do, and it is already built into the case.

Now you need to estimate the size and location of future parts in the body. You can cut out approximate layouts from cardboard and check their relative position. After this, you can begin work.

The best option for electrode wire is a 5 kg coil. Its outer diameter is 200 mm, inner diameter is 50 mm. For the axis of rotation, you can use a PVC sewer pipe. Its outer diameter is 50 mm.

Burner

A homemade semi-automatic machine must be equipped with a burner. You can do it yourself, but it’s better to buy a ready-made kit, which includes:

1. Burner with a set of tips of different diameters.
2. Supply hose.
3. Euro connector.

A normal burner can be purchased for 2-3 thousand rubles. Moreover, the device is homemade, so you don’t have to chase expensive brands.

What to look for when choosing a kit:

• what welding current is the torch designed for;
• the length and rigidity of the hose - the main task of the hose is to ensure free flow of wire to the torch. If it is soft, any bend will slow down the movement;
• springs near the connector and burner - they prevent the hose from breaking.

Advantages of industrial designs

Considering that welding work is classified as complex and responsible, the presence of additional accessories and items intended for mobile carrying or long-term storage plays an important role in this. The advantages of industrial designs are as follows:

• The front part of the box body, bottom and back wall are made of a metal base.
• The side walls, as well as the closed part of the top in the form of a lid, are made of impact-resistant plastic with a suitable varnish coating.
• The service life is at least 5 years.
• The movable tray mechanism, as well as the built-in organizer components, are used to accommodate basic accessories and additional spare parts for inverter equipment.
• Universal and strong locks made of chromed metal add not only aesthetics, but also reliably protect the drawer from intentional opening.

An industrial case is more expensive than a do-it-yourself welding inverter box, but at the same time, you can use this device as a full-fledged working tool for storing and carrying a welding inverter.

Features of self-assembly of a case for a welding inverter

To assemble a box for a welder yourself, you need to have minimal knowledge of mathematics, in particular geometry, in order to correctly cut the structure and make a useful accessory for temporary storage of inverter equipment.

How to make a semi-automatic machine from an inverter?

Any welder knows about the advantages of semi-automatic welding over manual electric welding. Due to their widespread use and low cost, MMA inverters are in the arsenal of many craftsmen. But with MIG welding it’s a different matter – these devices are more expensive. But there is a way out - you can make a semi-automatic device from an inverter with your own hands. If you delve into this issue, the matter turns out to be not so complicated.

Units suitable for modernization

The most important parameter of any welding machine is the current-voltage characteristic (CVC), which ensures stable arc burning at different arc lengths. The correct current-voltage characteristic is created by microprocessor control: the small “brain” of the inverter changes the operating mode of the power switches on the fly and instantly adjusts the parameters of the welding current. Unfortunately, it is impossible to reprogram a budget inverter in any way - the control microcircuits in it are analog, and replacement with digital electronics requires extraordinary knowledge of circuit design.

However, the “skills” of the control circuit are quite enough to level out the “crookedness” of a novice welder who has not yet learned to hold the arc stably. It is much more correct to focus on eliminating some “childhood” diseases, the first of which is severe overheating of electronic components, leading to degradation and destruction of power switches.

The second problem is the use of radioelements of questionable reliability. Eliminating this drawback greatly reduces the likelihood of breakdowns after 2–3 years of operation of the device. Finally, even a novice radio engineer will be quite capable of implementing an indication of the actual welding current to be able to work with special brands of electrodes, as well as carry out a number of other minor improvements.

Changing the current-voltage characteristic of the inverter

To change the I-V characteristic of an inverter, there are many circuits, but the simplest way to do this is as follows:

• assemble the device using a choke from a fluorescent lamp according to the diagram below;

• to connect the assembled device, you will need to assemble another block according to the following diagram;

• To prevent the overheating sensor from triggering on the inverter, an optocoupler must be soldered to it (in parallel), as shown in the following diagram.

But if the welding current in the inverter is controlled using a shunt, then you can assemble a simple circuit of three resistors and a mode switch, as shown below.

As a result, converting a welding inverter into a semi-automatic machine will cost 3 times less than a ready-made unit. But of course, to independently assemble the device you will need to have certain knowledge in the radio business.

Improved heat dissipation

The first drawback that plagues the vast majority of inexpensive inverter devices is a poor heat removal system from power switches and rectifier diodes. It is better to begin improvements in this direction by increasing the intensity of forced airflow. As a rule, case fans are installed in welding machines, powered by 12 V service circuits. In “compact” models, forced air cooling may be completely absent, which is certainly nonsense for electrical equipment of this class.

It is enough to simply increase the air flow by installing several of these fans in series. The problem is that the “original” cooler will most likely have to be removed. To operate effectively in a sequential assembly, fans must have an identical shape and number of blades, as well as rotation speed. Assembling identical coolers into a “stack” is extremely simple; just tighten them with a pair of long bolts along diametrically opposite corner holes. Also, do not worry about the power of the service power supply; as a rule, it is enough to install 3–4 fans.

If there is not enough space inside the inverter housing to install fans, you can install one high on the outside. Its installation is simpler because it does not require connection to internal circuits; power is removed from the power button terminals. The fan, of course, must be installed opposite the ventilation louvers, some of which can be cut out to reduce aerodynamic drag. The optimal direction of air flow is towards the exhaust from the housing.

The second way to improve heat dissipation is to replace standard aluminum radiators with more efficient ones. A new radiator should be selected with the largest number of fins as thin as possible, that is, with the largest area of ​​​​contact with air. It is optimal to use computer CPU cooling radiators for these purposes. The process of replacing radiators is quite simple, just follow a few simple rules:

1. If the standard radiator is isolated from the flanges of the radio elements with mica or rubber gaskets, they must be preserved when replacing.
2. To improve thermal contact, you need to use silicone thermal paste.
3. If the radiator needs to be trimmed to fit into the case, the cut fins must be carefully processed with a file to remove all burrs, otherwise dust will accumulate on them abundantly.
4. The radiator must be pressed tightly against the microcircuits, so you first need to mark and drill mounting holes on it; you may need to cut a thread in the body of the aluminum base.

Additionally, we note that there is no point in changing the piece heatsinks of separate keys; only the heat sinks of integrated circuits or several high-power transistors installed in a row are replaced.

Mechanical control circuit

To achieve good quality seam when welding, it is necessary to ensure wire feed at a certain and constant speed. Since the motor from the windshield wiper is responsible for the feed speed of the equipment, a device is needed that can change the speed of rotation of its armature. For this, a ready-made solution is suitable, which can also be purchased in China, and it is called a PWM controller.

Below is a diagram from which it becomes clear how the speed controller is connected to the engine. The controller regulator with a digital display is located on the front panel of the case.

Next, you need to install a relay that controls the gas valve. It will also control the engine start. All these elements must be activated when the start button located on the burner handle is pressed. In this case, the gas supply to the welding site should be ahead (by about 2-3 seconds) of the start of wire feeding. Otherwise, the arc will ignite in the environment of atmospheric air, and not in the environment of the protective gas, as a result of which the electrode wire will melt.

A delay relay for a homemade semi-automatic machine can be assembled based on an 815 transistor and a capacitor . To get a pause of 2 seconds, a capacitor of 200-2500 uF will be enough.

The solenoid shut-off valve is placed in any place where it will not interfere with the operation of the moving parts, and is connected to the circuit according to the diagram. You can use an air valve from GAZ 24 or buy a special one designed for semi-automatic machines. The valve is responsible for the automatic supply of protective gas to the burner. It turns on after pressing the start button located on the semi-automatic burner. The presence of this element significantly saves gas consumption.

Next, after installing all the components in the housing, the attachment to the inverter for semi-automatic welding will be ready for work.

But as already noted, the current-voltage characteristics (CV) of the inverter are not suitable for full-fledged operation of a semiautomatic device. Therefore, in order for a semi-automatic attachment to work in tandem with an inverter, minor changes need to be made to its electrical circuit.

Welding current indication

Even if a digital current setting indicator is installed on the inverter, it does not show its real value, but a certain service value, scaled for visual display. The deviation from the actual current value can be up to 10%, which is unacceptable when using special brands of electrodes and working with thin parts. You can get the actual value of the welding current by installing an ammeter.

A digital ammeter of the SM3D type will cost around 1 thousand rubles; it can even be neatly built into the inverter housing. The main problem is that measuring such high currents requires a shunt connection. Its cost is in the range of 500–700 rubles for currents of 200–300 A. Please note that the type of shunt must comply with the recommendations of the ammeter manufacturer; as a rule, these are 75 mV inserts with an intrinsic resistance of about 250 μOhm for a measurement limit of 300 A.

The shunt can be installed either on the positive or negative terminal from inside the housing. Typically, the size of the connecting bus is sufficient to connect an insert about 12–14 cm long. The shunt cannot be bent, so if the length of the connecting bus is not enough, it must be replaced with a copper plate, a pigtail of cleaned single-wire cable, or a piece of welding conductor.

The ammeter is connected with measuring outputs to the opposite terminals of the shunt. Also, for the digital device to operate, it is necessary to supply a supply voltage in the range of 5–20 V. It can be removed from the fan connection wires or found on the board at points with potential for powering control chips. The ammeter's own consumption is negligible.

Application area and technical properties

The Resanta SAI-220 welding inverter is a device operating from a single-phase electronic network with a voltage of 220 V. A constant current is generated at the output of the device, which is used to perform electric arc welding using consumable coated electrodes. If you need to weld parts of small thickness, then such a device can even be connected to an ordinary household outlet (naturally, provided that the electrical panel is equipped with machines that can withstand the current consumed by the device).

Although all Resanta brand inverters are manufactured in China, the circuits, system and design of these devices were developed in Latvia. The name of the brand was immediately invented, which is now perfectly clear to welders in almost all countries of the world. Among the technical features of the welding machine in question, the following should be highlighted:

• welding current control range – 10–220 A;
• supply voltage value - 220 V (permissible differences in supply voltage can be 10% on the positive side (242 V), 30% on the negative side (154 V));
• the current consumed by the device at peak overload is 30 A;
• open circuit voltage – 80 V;
• rated operating voltage – 28 V;
• ON duration (DS) when working at the highest welding current (220 A) – 70%, at a welding current of 10–140 A – 100%;
• diameters of the electrodes used are 1.6–5 mm;
• protection class – IP 21;
• inverter weight – 4.9 kg.

The required value of welding current for the SAI-220 machine is set in accordance with the diameter of the electrode

In addition to the inverter of the designated model, its modification is presented on the market - Resanta SAI-220 PN. The difference between the Resanta SAI-220 PN inverter and the basic model is that it allows you to do excellent welding even at an even lower voltage - 140 V. In addition, the design of the Resanta SAI-220 PN has a digital indicator of the welding current, which does the job it is the most comfortable. Naturally, the cost of the Reasant SAI-220 PN welding machine is slightly higher than the cost of a basic inverter.

Interesting read: Homemade magnetic corner for welding

Front panel of the Resanta SAI-220 inverter with a digital screen and a transparent protective shield

It is worth taking a closer look at such a noticeable parameter of the device in question as the on-time period (OP) or the period of continuous operation (PO - overload duration). As mentioned above, for the inverter in question it is 70% when operating at the highest welding current and 100% at a current in the spectrum of 10–140 A. This means that if you are going to do welding at the highest current, then for a period equal to 10 minutes, you will need to create a break for 3 minutes, and the other 7 you can work quietly.

Such a break is needed so that the electrical circuit of the device, the elements of which are actively heated during the welding process, cools down. Otherwise, the device may automatically turn off if the thermal protection is triggered, or simply burn out. If you apply a current whose strength is in the range of 10–140 A, then there is no need to interrupt the operation of the equipment.

Increasing duty cycle

The on-time duration in the context of welding inverters is more reasonably called the load duration. This is the part of the ten-minute interval in which the inverter directly performs work; the remaining time it must idle and cool.

For most inexpensive inverters, the actual PV is 40–45% at 20 °C. Replacing radiators and an intensive airflow device can increase this figure to 50–60%, but this is far from the ceiling. A PN of about 70–75% can be achieved by replacing some radioelements:

1. The capacitors around the inverter keys must be replaced with elements of the same capacity and type, but designed for a higher voltage (600–700 V);
2. Diodes and resistors from the key harness should be replaced with elements with higher power dissipation.
3. Rectifier diodes (valves), as well as MOSFETs or IGBT transistors, can be replaced with similar, but more reliable ones.

It is worth talking about replacing the power switches themselves separately. First, you should rewrite the markings on the element body and find a detailed datasheet for a specific element. According to the passport data, choosing an element to replace is quite simple; the key parameters are the limits of the frequency range, operating voltage, the presence of a built-in diode, type of housing and current limit at 100 °C. It is better to calculate the latter yourself (for the high-voltage side, taking into account losses on the transformer) and purchase radioelements with a maximum current reserve of about 20%. Of the manufacturers of this type of electronics, International Rectifier (IR) or STMicroelectronics are considered the most reliable. Despite the rather high price, it is highly recommended to purchase parts from these brands.

Homemade welding machine

Assembling an inverter for welding is easy, since there are many schemes. It is possible to make welding from a computer power supply and knock down a box for it, but you will end up with a low-power welder. Details about creating a simple inverter from a computer power supply for welding can be found on the Internet. An inverter for welding using a PWM controller such as UC3845 is extremely popular. The microcircuit is flashed using a programmer, which can only be purchased at a specialized store.

To install the firmware, you need to know the basics of the C++ language; in addition, it is possible to download or order ready-made program code. Before assembly, you need to decide on the basic parameters of the welder: the maximum permissible supply current is no more than 35 A. With a welding current of 280 A, U of the supply network is 220 V. If you analyze the parameters, you can conclude that this model exceeds some factory models. To assemble the inverter, follow the block diagram in Figure 1.

The power supply circuit is simple, and it is quite easy to assemble it (Scheme 1). Before assembly, you need to decide on the transformer and find a suitable housing for the inverter. To make a power supply inverter you need a transformer. .

This transformer is assembled on the basis of a ferrite core Ш7х7 or Ш8х8 with a primary winding of wire with a diameter (d) of 0.25..0.35 mm, the number of turns is 100. Several secondary windings of the transformer must have the following parameters:

1. 15 turns with d = 1..1.5 mm.
2. 15 turns with d = 0.2..0.35 mm.
3. 20 turns with d = 0.35..0.5 mm.
4. 20 turns with d = 0.35..0.5 mm.

Before winding, you need to familiarize yourself with the basic rules for winding transformers.

Scheme 1 - Inverter power supply diagram

It is advisable not to connect parts by surface mounting, but to make a printed circuit board for this purpose. There are many ways to make a printed circuit board, but you should focus on a simple option - laser ironing technology (LUT). The main stages of manufacturing a printed circuit board:

After manufacturing the transformer and printed circuit board, you need to begin installing the radio components according to the power supply circuit of the welding inverter. To assemble the power supply you will need radio components:

After assembly, the power supply cannot be connected and tested, since it is designed specifically for the inverter circuit.

Winding the output choke

One of the simplest and at the same time most useful additions to a welding inverter will be the winding of an inductive coil that smoothes out the DC ripples that inevitably remain when the pulse transformer is operating. The main specificity of this idea is that the choke is made individually for each individual device, and can also be adjusted over time as electronic components degrade or when the power threshold changes.

To make a choke you will need nothing at all: an insulated copper conductor with a cross-section of up to 20 mm 2 and a core, preferably made of ferrite. Either a ferrite ring or an armored transformer core is optimally suited as a magnetic core. If the magnetic core is made of sheet steel, it needs to be drilled in two places with an indentation of about 20–25 mm and tightened with rivets in order to be able to cut the gap without any problems.

The choke begins to work starting from one full turn, but the real result is visible starting from 4–5 turns. During testing, turns should be added until the arc begins to stretch noticeably strongly, preventing separation. When it becomes difficult to cook with separation, you need to remove one turn from the coil and connect a 24 V incandescent lamp in parallel with the choke.

Fine-tuning the throttle is done using a plumber's screw clamp, which can be used to reduce the gap in the core, or a wooden wedge, which can be used to increase this gap. It is necessary to ensure that the lamp burns as bright as possible when igniting the arc. It is recommended to manufacture several chokes to operate in ranges up to 100 A, from 100 to 200 A and more than 200 A.

Advantages of using an inverter of this model

As with almost all models of modern inverter devices, this welding machine has a number of options that ensure the highest quality welded joints. Thanks to these options, a very important problem is also solved - the impact of the welder’s qualifications on the properties of the joint being created is minimized.

These options, which are very familiar to almost all welders, include:

• automatic shutdown of the device in this case if parts of the circuit diagram overheat (this function is possible due to the presence of a special temperature sensor);
• “Hot start” is a function that ensures quick ignition of the welding arc due to the automatic supply of high current to it;
• “Anti-sticking” is a function that automatically turns off the welding current at the moment when the edge of the electrode is welded to the surface of the parts;
• “Arc force” is a function that automatically increases the welding current when the arc length shortens and makes it possible to prevent electrode sticking.

The power of the device allows you to make welding seams with electrodes up to 5 mm, but the current consumption for all this is about 30 A

The welding inverter under consideration provides enhanced protection of parts of the circuit diagram from overheating. This protection is provided by several design features:

• the presence of two fans at once, improving the cooling process of the device;
• the highest resistance of electrical circuits to overheating;
• introduction of a temperature sensor that automatically turns off equipment at the moment of overheating.

The strong handle and fastened belt add convenience both when carrying the unit and during operation.

The undeniable advantages of the inverter of this model also include the following.

• The exceptional mobility of the inverter is ensured not only by its light weight, but also by the presence of a comfortable shoulder strap, with which the device can be carried to any space where welding needs to be carried out.
• The housing and other elements of the inverter are highly resistant to mechanical damage, which can be caused by impacts, falling or overturning of the equipment.
• The welding machine of this model is distinguished by its exceptional compactness (130x310x190 mm) and mobility.
• If desired, you can order an inverter package that includes a special suitcase with a handle, in which it is convenient to store and transport not only the device itself, but also all the necessary cables.
• The inverter system allows for its effective operation even at fairly low ambient temperatures (down to –20). But when welding at low temperatures, you should strictly monitor the heating and cooling modes of the equipment.

Characteristics and materials

For use at home, homemade inverters are required, connected to a 220 V power supply . The welder, powered from a 380 V network, is also easy to assemble. Domestic inverters must meet the following requirements:

• voltage – 220 V;
• input current 32 A;
• output current strength at 250 A.

To build an inverter welding machine with your own hands, prepare the following materials:

• fasteners;
• sheet metal;
• thermal paper (cash tape is suitable);
• radio components for forming electrical circuits;
• copper strips or wires;
• textolite;
• mica;
• fiberglass fabric.

Organizer for welding machine

pogranec 17-12-2017, 10:09 11 743 Devices

Those who use a welding machine know how inconvenient it is to store and carry it because of the wires. A DIY master decided to make an organizer for a welder. Below we will consider what came out of this and what he used for this

Tools and materials:

Welding machine; - Metal strip; - Drilling machine; - angle grinder; - Metal corner; - Metal rod; - Bending machine; - Vise; - Clamp; - Tape measure; - Spray paint; - Magnet; - Fasteners; - Stainless steel tube; Step one: hooks Marks a 3*30 mm metal strip. Drills an 8mm hole. Cuts off plates. Cuts four rods from 8 mm reinforcement. Inserts them into the holes in the plate and scalds them. Bends the edges of the plates at 45 degrees. From the reinforcement he makes two more hooks with an angle of 90 degrees. Cuts two strips, drills a hole and welds the hooks. Makes another semicircular plate for a magnet. Step two: frame The master made the upper part of the frame from a 10 mm metal rod. Cuts two rods and bends them in a U shape. The craftsman makes the lower supporting part from a 30 mm corner and a strip. Cuts off two corners. Weld a strip at the ends. Moreover, on one side there is a strip with a hook. Welds a U-shaped frame to the bottom. Welds a plate with a hook onto one U-shaped frame, in its middle part. The result is a hook at the bottom and top of the frame; the power cord will be wound around it. He welds the hooks on the sides of the frame; welding cables will be wound around them. He welds the eyelet under the magnet. Step three: painting and assembly Cleans the seams and paints the surface. Makes a fork holder from plastic. Screw a holder to the eye on one side and a magnet on the other. Installs the welding machine. Wraps cables around hooks. Secures the tube for electrodes in the upper part. The organizer is ready. The entire manufacturing process can be seen in the video.

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Features of operation

Before assembly, you should familiarize yourself with the operating features of the inverter, which are similar to the functioning of a computer power supply . The device operates in the following order:

• the incoming alternating voltage is converted to direct voltage;
• 50Hz input current is transformed into high frequency current;
• the output voltage decreases;
• the output current is corrected and the frequency required for welding is maintained.

Transformer equipment is large and heavy due to the following features. Arc welding is performed using current. The secondary winding to attenuate the voltage and increase the current is arranged from a minimum number of revolutions, the cross-section of the conductor is taken to be the maximum possible.

The use of the inverter principle reduces the volume and weight of units by an order of magnitude due to an increase in frequency to 60-80 kHz.

To implement such a conversion, it is necessary to use field-effect transistors communicating with each other at exactly this frequency. To power them, direct current is used, directed from a rectifier, the role of which is performed by a diode bridge. To correct the voltage, capacitors are required. From the transistors, the current is supplied to the transformer, which is a compact coil.

Conversion and modification into an inverter semi-automatic machine is possible. It has similar characteristics to a transformer, but its weight and dimensions are smaller .

Device and principle of operation

The welding inverter is designed so that it is suitable for both home use and enterprise use. With small dimensions, it is capable of ensuring a stable burning of the welding arc and even using a welding current that is significantly higher than that of an ordinary welding machine. It uses high-frequency current to generate a welding arc and is an ordinary switching power supply (the same as a computer one, only with higher current), which makes the circuit of the welding machine simple.

The basic principles of its operation are as follows: input voltage rectification; conversion of rectified U into high-frequency alternating current using transistor switches and further rectification of alternating U into high-frequency direct current (Figure 1).

Figure 1 - Schematic design of an inverter-type welder.

When using high-power key transistors, direct current is converted, which is rectified using a diode bridge into high-frequency current (30..90 kHz), which makes it possible to reduce the dimensions of the transformer. A diode rectifier allows current to flow in only one direction. The negative harmonics of the sinusoid are “cut off”.

But the rectifier output produces a constant U with a pulsating component. To convert it into a permissible direct current in order to ensure the correct operation of key transistors operating only on direct current, a capacitor filter is used. A capacitor filter is one or more high-capacity capacitors, which can significantly smooth out ripples.

The diode bridge and filter make up the power supply for the inverter circuit. The input of the inverter circuit is made using key transistors that convert DC U into high-frequency AC (40..90 kHz). This transformation is needed to power a pulse transformer, the output of which produces a high-frequency current of low U. A high-frequency rectifier is powered from the outputs of the transformer, and a high-frequency direct current is generated at the output.

The device is not very complicated, and any inverter welder can be repaired. In addition, there are many schemes by which you can make a homemade inverter for welding work.

Diagnostics and preparation for work

The description of the welder diagnostic procedure looks like this:

1. Supplying 15 V to the PWM together with turning on one convector allows you to prevent overheating and practically eliminate noise.
2. To stabilize the voltage, turn on a relay that short-circuits the resistor after connecting to the mains.
3. Make sure that the relay is activated, short-circuiting the resistor 3-5 seconds after connecting to the PWM. After testing the relay, make sure that there is a rectangular pulse signal on the board.
4. Supply 15 V to the diode bridge to test its normal operation. When operating at idle, the current should not exceed 100 mA.
5. Verify that the phases are correctly positioned using an oscilloscope.
6. When the current gradually increases through the resistor on the lower switch, there should not be more than 500 V.
7. Welding should begin after 10 seconds or after heating the radiators.

I make cable holders

The sequence of work is as follows:

• I cut pieces from a steel strip for holders, the size is selected arbitrarily.
• I drill a hole with a diameter of 8 mm in the middle; a steel rod with a diameter of 8 mm will subsequently be inserted and welded into it.
• I bend two corners from a rod with a diameter of 8 mm; they will be used as holders for the power cable.
• I cut off the curved elements; the length of both sides was 30 mm.
• I cut four pieces of 8 mm rod, 30 mm long. They are carefully inserted into pre-prepared plates and welded.
• I process the surface with a grinding wheel to level it to perfection. I round the corners and slightly bend the ends.

Service

When servicing the inverter, it is necessary to periodically clean the internal elements from dirt and dust using a vacuum cleaner or dry rags, especially if the device had to stand for a long period without use.

It is necessary to constantly monitor the performance of the temperature sensor. In the event of a breakdown, this element cannot be repaired but must be replaced.

It is necessary to periodically monitor the quality of connections and correct them if necessary. Malfunctions can be determined both visually and using a tester.

General information

Transformer welding machines are relatively inexpensive and easy to repair due to their simple design. However, they are heavy and sensitive to supply voltage (U). When U is low, it is impossible to carry out work, since significant changes in U occur, as a result of which household appliances may fail. In the private sector, there are often problems with power lines, since in the former CIS countries most power lines require cable replacement.

The electrical cable consists of twists, which often oxidize. As a result of this oxidation, an increase in the resistance (R) of this twist occurs. Under significant load, they heat up, and this can lead to overload of power lines and transformer substation. If you connect an old-style welding machine to an electricity meter, then when U is low, the protection will be triggered (“knock out” the machines). Some people try to connect the welder to the electricity meter, breaking the law.

Such a violation is punishable by a fine: electricity is consumed illegally and in large quantities. In order to make work more comfortable - not to depend on U, not to lift heavy objects, not to overload power lines and not to break the law - you need to use an inverter-type welding machine.

Preparing elements for the frame

Now you need to make blanks for the structure frame:

• To begin with, I bend two U-shaped blanks from a rod with a diameter of 10 mm. Their length depends on the model of your device, so it makes no sense to give exact dimensions.
• From the corner I cut two blanks for the lower part of the frame. The length is selected individually.
• I cut three elements from the strip according to the width of the future structure.
• In two previously cut strips, I drill holes in the middle with a diameter of 8 mm.
• I insert the previously bent elements into the holes and weld them, this will be a holder for the power cable.

Assembling the structure

The assembly process is performed in the following sequence:

• One of the lower plates is accurately and accurately aligned with the corner and tacked at 1-2 points.
• Another flat plate is placed on the second side, after which a second corner is placed and the base is welded, do not forget to control the geometry of the product.
• Welding areas are immediately carefully processed to perfect smoothness.
• The first curved workpiece is exposed. It is important to place it correctly; the lower ends will serve as legs, so the distance from the edge is selected so that the welding machine fits inside.
• The second element is positioned in exactly the same way, after which everything is welded along the entire joint.
• Cable holders and a handle in the upper part are welded, I also placed a special element for attaching the container with electrodes, but this is not necessary.

Painting and finishing the design

We complete the assembly and perform the following work:

• All joints and welds are inspected again, and if necessary, they are processed with a grinding disc until they are perfectly smooth so that everything is safe.
• Metal elements are first treated with primer and then painted. The easiest way to use the compounds is in aerosol cans; they are easy to work with and the surface dries very quickly.
• On the side where the power cable is located, I attached a nylon plug holder, just took a piece of a suitable size and drilled two holes in it to fit the size of the plug, it turned out very convenient.
• I attached a magnet to the inside of the holder under the fork; it is very convenient because a welding hammer is fixed to it, which will always be at hand and at the same time it will not be difficult to take it during the work and you will not have to disconnect or unscrew anything.
• I also made a tube for the electrodes, for this I took pieces of stainless steel pipes and made the structure shown in the photo above. There are two hooks welded on the tube to hang it on the handle and carry it along with the device. If you, like me, work outside a lot, then the tube will help keep the electrodes dry in any weather.
• All elements are inserted and the structure is ready for use. Now it is easy to carry or transport in a car, everything you need is collected in one place.

Tuomas Soikkeli from instructables.com shared his experience

October 8, 2022

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