Alteration of welding to direct current. Homemade DC welding machine. How to remake an inverter transformer

Any welder knows about the advantages of a semiautomatic device over manual electric welding. Due to their high prevalence and low cost, MMA inverters are in the arsenal of many craftsmen. But with MIG welding, the matter is different - 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 will not be so difficult.

There are fundamental differences between MMA and MIG welding. To operate the semiautomatic device, you need carbon dioxide (or a mixture of carbon dioxide and argon) and an electrode wire, which is supplied to the welding site through a special hose. Those. the very principle of semi-automatic welding is more complicated, but it is universal and its use is justified. What is needed for the operation of a semi-automatic device:

wire feeder;
burner;
hose for wire and gas supply to the heating pad;
current source with constant voltage.
And to turn a welding inverter into a semiautomatic device, you need a tool, time and desire.

Training

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

Completely make a semi-automatic welding machine with your own hands.
To remake only the inverter - the feeding mechanism is ready to be purchased.

In the first case, the cost of parts for the feeder will be about 1000 rubles, excluding work, of course. If the factory semiautomatic device includes everything in one case, then the home-made one will consist of two parts:

Welding inverter.
Drawer with feeder and wire reel.

First, you need to decide on the case for the second part of the semiautomatic device. It is desirable that it be light and roomy. The feed mechanism must be kept clean, otherwise the wire will be jerky, in addition, periodically you need to change the spools and adjust the mechanism. Therefore, the box should be easy to close and open.

The ideal option is to use the old system unit:

neat appearance- it doesn’t really matter, but it’s much more pleasant when the insides of the homemade product do not stick out and the semi-automatic device from the MMA inverter looks good;
light, closed;
the case is thin - it is easy to make the necessary cutouts;
the gas valve and the wire feed drive operate on 12 volts. Therefore, a power supply from a computer is suitable, and it is already built into the case.

Now you need to estimate the size and location of future parts in the case. You can cut out approximate layouts from cardboard and check them mutual arrangement. After that, you can start work.

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

Burner

Homemade semi-automatic must be equipped with a burner. You can make it yourself, but it is better to buy a ready-made kit, which includes:

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

A normal burner can be purchased for 2-3 thousand rubles. Moreover, the device is homemade, so you can not 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 is the main task of the hose, to ensure the free flow of the wire to the torch. If it is soft, any kink will slow down the movement;
springs near the connector and burner - they prevent the hose from breaking.

Feeder

The electrode wire must be fed continuously and evenly - then the welding will turn out to be of high quality. The feed rate must be adjustable. There are three options for how to make a device:

Buy a fully assembled mechanism. Expensive, but fast.
Buy feed reels only.
Do everything with your own hands.

If the third option is chosen, you will need:

two bearings, guide roller, tension spring;
wire feed motor - a motor from wipers is suitable;
metal plate for fastening the mechanism.

One pressure bearing - it must 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;

Bearings are best placed on metal strips - one end is bolted to the main plate, and a spring with an adjusting bolt is connected to the other.

The made mechanism is placed in the body so that the rollers are located in line with the connector for the burner, i.e. so that the wire does not break. Before the rollers, you need to install a rigid tube to align the wire.

Implementation of the electrical part

For this you will need:

two automotive relays;
diode;
PWM controller for the engine;
capacitor with transistor;
idle solenoid valve - for supplying gas to the burner. Any VAZ model will do, for example, from the eight;
wires.

The wire and gas feed control scheme is quite simple and is implemented as follows:

when the button on the burner is pressed, relay No. 1 and relay No. 2 are activated;
relay No. 1 turns on the gas supply valve;
relay No. 2 is paired with a capacitor and turns on the wire feed with a delay;
wire pulling is done by an additional button bypassing the gas supply relay;
to remove self-induction from solenoid valve, a diode is connected to it.
It is necessary to provide for the connection of the burner to the power cable from the inverter. To do this, next to the euro connector, you can install a quick connector and connect it to the burner.

The semi-automatic device has the following sequence of work:

The gas supply is turned on.
After a short delay, the wire feed is switched on.

Such a sequence is needed so that the wire immediately enters the protective environment. If you make a semi-automatic without delay, the wire will stick. To implement it, you will need a capacitor and a transistor through which the engine control relay is connected. Operating principle:

voltage is applied to the capacitor;
it is charging;
current is applied to the transistor;
the relay turns on.

The capacitance of the capacitor must be selected so that the delay is approximately 0.5 seconds - this is enough to fill the weld pool.

After assembly, the mechanism needs to be tested, and the manufacturing process can be seen on the video.

Alteration of the inverter

To make a semiautomatic device from a conventional inverter with your own hands, you will have to slightly redo its electrical part. If you connect the MMA inverter to the assembled case, you will be able to cook. But at the same time, the quality of welding will be far from the factory semiautomatic device. It's all about the CVC - current-voltage characteristics. The arc inverter produces a falling characteristic - the output voltage floats. And for the correct operation of the semiautomatic device, a rigid characteristic is required - the device maintains a constant voltage at the output.

Therefore, in order to use your inverter as a current source, you need to change its CVC (voltage characteristic). For this you will need:

toggle switch, wires;
variable resistor and two constant;

It is quite easy to get a hard characteristic on an inverter. To do this, you need to put a voltage divider in front of the shunt that controls the welding current. For the divider, fixed resistors are used. Now you can get the necessary millivolts, which will be proportional to the output voltage, and not the current strength. There is only one minus in such a scheme - the arc turns out to be too rigid. To mitigate it, you can use a variable resistor, which is connected to the divider and the output of the shunt.

The advantage of this approach is that the arc stiffness adjustment appears - such a setting is only in professional semi-automatic machines. A toggle switch switches the inverter between MMA and MIG modes.

Thus, converting an MMA inverter into a semiautomatic device, although not an easy task, is quite feasible. At the output, it turns out a device that is not inferior to the factory ones in terms of its characteristics. But it is also much cheaper. The cost of such an alteration is 4-5 thousand rubles.

A semi-automatic welding machine can be homemade, made from an inverter. We must say right away that it is not easy to make a semi-automatic welding machine from an inverter with your own hands, but not impossible. Anyone who plans to make a semi-automatic device with their own hands from an inverter should study the principle of its operation, watch a video or photo on this topic if necessary, prepare necessary accessories and equipment.

How to convert an inverter into a semi-automatic

For work you will need:

FROMsemi-automatic welding circuit

Particular attention is paid to the alteration of the feeder, which feeds the wire into the welding zone, which moves along a flexible hose. To obtain a high-quality, neat weld, the speed of wire feed through the flexible hose and the speed of its melting must match.

Semi-automatic welding uses wire different diameter and from different materials, so it should be possible to control the speed of its supply. This is what the feed mechanism does.

The most common wire diameters in our case: 0.8; one; 1.2 and 1.6 mm. Before welding, the wire is wound on coils, which are attachments fixed with simple fasteners. The wire is fed automatically during the welding process, which significantly reduces the time technological operation and efficiency increases.

The main element of the electronic circuit of the control unit is a microcontroller responsible for the stabilization and regulation of the welding current. The current parameters and the ability to regulate them depend on this element.

We remake the inverter transformer

Do-it-yourself semi-automatic welding can be done by altering the inverter transformer. To bring the characteristics of the inverter transformer in accordance with the required, it is wrapped with a copper strip wrapped with thermal paper. Ordinary thick wire is not used for these purposes, because it will get very hot.

The secondary winding is also being redone. For this you need:

Wind the winding from three layers of tin, each of which is insulated with fluoroplastic tape.
The ends of the windings are soldered to each other to increase the conductivity of the currents.

In the design diagram of the inverter used for inclusion in the semiautomatic device, a fan must be provided to cool the device.

Setting

When making a semiautomatic device from an inverter, first de-energize the equipment. To prevent the device from overheating, place its input and output rectifiers, as well as power switches, on heatsinks.

After completing the above procedures, connect the power section to the control box and connect it to the mains. When the mains indicator lights up, connect an oscilloscope to the outputs of the inverter. Use an oscilloscope to find electrical pulses at 40-50 kHz. Between the formation of pulses, 1.5 μs should pass, and this is regulated by changing the magnitude of the voltage supplied to the input.

Oscillogram of welding current and voltage: on reverse polarity - on the left, on straight polarity - on the right

Check that the pulses that are reflected on the oscilloscope screen are rectangular, and their front is no more than 500 ns. If the parameters being checked are as they should be, connect the inverter to the mains.

The current that comes from the output must be at least 120A. If this value is less, it is likely that a voltage not exceeding 100 V is going into the wires of the equipment. In this case, the equipment is tested by changing the current strength (plus the voltage on the capacitor is constantly monitored). The temperature inside the device is also constantly monitored.

After testing, check the machine under load: connect a rheostat with a resistance of at least 0.5 Ohm to the welding wires. It must withstand a current of 60 A. The current supplied to the welding torch is controlled by an ammeter. If it does not correspond to the required value, the resistance value is selected empirically.

Usage

After starting the device, the inverter indicator should show the current value - 120 A. If the value is different, something is done wrong. Eights may appear on the indicator. Most often this is due to insufficient voltage in the welding wires. It is better to immediately determine the cause of this malfunction and eliminate it. If everything is correct, the indicator will correctly show the strength of the current regulated by special buttons. The current adjustment interval that provides the inverters lies in the range of 20–160 A.

Checking the correct operation

In order for the semiautomatic device to serve for a long time, it is recommended to control all the time temperature regime inverter operation. In order to control at the same time two buttons are pressed, and then the temperature of the hottest of the inverter radiators will be displayed on the indicator. Normal working temperature- no more than 75 ° C.

If there is more, in addition to the information that is displayed on the indicator, the inverter will emit an intermittent sound, which should immediately alert. In this case (or when the temperature sensor closes) electronic circuit will automatically reduce the operating current to 20A, and sound signal will go until the equipment returns to normal. An error code (Err), which is displayed on the inverter indicator, can also indicate a malfunction of the equipment.

When is a semi-automatic welding machine used?

A semiautomatic device is recommended for use when accurate, neat connections of steel parts are needed. With such equipment thin metal is boiled, which is important, for example, when repairing car bodies. Qualified specialists or a training video will help you learn how to work with the device.

A unit designed for welding products is considered to be a semi-automatic welding machine. Such devices can be various kinds and forms. But the most important is the inverter mechanism. It is necessary that it be of high quality, multifunctional and safe for the consumer. Most professional welders do not trust Chinese products, making devices on their own. The manufacturing scheme for homemade inverters is quite simple. It is important to consider for what purposes the device will be manufactured.

Welding with flux-cored wire;
Welding on various gases;
Welding under a thick layer of flux;

Sometimes, for a high-quality result and obtaining an even weld, the interaction of two devices is necessary.

Also inverter devices are divided into:

Single-hull;
double-hull;
pushing;
Pulling;
Stationary;
Mobile, which includes a trolley;
Portable;
Designed for beginner welders;
Designed for semi-professional welders;
Designed for professional craftsmen;

What will be required?

A home-made apparatus, the scheme of which is very simple, includes several main elements:

Mechanism with main function, responsible for controlling the welding current;
Mains power supply;
Special burners;
Convenient clips;
Sleeves;
Cart;

Scheme of welding using a semiautomatic device in a protective gas environment:

The master will also need:

The mechanism that provides the wire feed;
Flexible hose, through which the wire or powder will flow to the weld under pressure;
Bobbin with wire;
Special control device;

Principle of operation

The principle of operation of the inverter includes:

Adjustment and movement of the burner;
Control and monitoring of the welding process;

When connecting the unit to electrical network there is a transformation alternating current into permanent. For this procedure, you will need an electronic module, special rectifiers and a transformer with a high frequency. For high-quality welding, it is necessary for the future unit to have such parameters as the feed rate of a special wire, current strength and voltage be in identical balance. For these characteristics, you will need an arc power source that has current-voltage readings. The length of the arc must be determined by the given voltage. The wire feed speed is directly related to the welding current.

The electrical circuit of the device provides for the fact that the type of welding strongly affects the progressive performance of the apparatus as a whole.

Do-it-yourself semiautomatic device - detailed video

Created plan

Any scheme homemade device provides a separate sequence of work:

At the initial level, it is necessary to provide a preparatory purge of the system. She will perceive the subsequent supply of gas;
Then you need to start the arc power supply;
Feed the wire;
Only after all actions are completed, the inverter will start moving at a given speed.
On the final stage the seam should be protected and the crater filled;

Control board

To create an inverter, a special control board is required. On the this device the units of the device must be mounted:

Master oscillator, including a galvanic isolation transformer;
The node by which the relay is controlled;
Feedback blocks responsible for mains voltage and supply current;
Thermal protection block;
Block "antistic";

Enclosure selection

Before assembling the unit, you need to select the case. You can choose a box or box with suitable dimensions. It is recommended to choose plastic or thin sheet material. Transformers are mounted into the housing, which are connected to the secondary and primary reels.

Coil Matching

Primary windings are carried out according to parallel circuit. Secondary reels are connected in series. According to a similar scheme, the device is capable of accepting a current of up to 60 A. In this case, the output voltage will be 40 V. These characteristics are perfect for welding small structures at home.

Cooling system

During continuous operation, a homemade inverter can overheat greatly. Therefore, such a device needs special system cooling. by the most simple method creating cooling is the installation of fans. These devices must be attached to the sides of the case. The fans must be installed opposite the transformer device. Mechanisms are attached so that they can work on the hood.

If you decide to assemble a semi-automatic welding machine with your own hands from an inverter, a diagram and detailed instructions will become indispensable companions on the way to achieving your goal. The easiest way is to purchase factory semi-automatic devices such as Cedar 160, Kaiser Mig 300 with the required Ampere rating. But many tend to do everything with their own hands. It is not so easy, but if you want to achieve a positive result, you will be able to.

Mig, Mag, MMA welding requires the use of appropriate devices. Mig Mag is a semi-automatic welding, which is performed in an inert argon gas environment. Sometimes carbon dioxide is used for Mig Mag welding. MMA welding is called manual arc processing with electrodes on which a special coating is applied. If you are working with stainless steel, then MMA welding is carried out only with DC.

Since we are talking about how you can assemble a full-fledged inverter-based semi-automatic device with your own hands, you are not interested in MMA, but Mig Mag welding.

To assemble a home-made device, a worthy analogue for Kedr 160, Kaiser Mig 300, with your own hands, you will need a diagram, video instruction and necessary elements semi-automatic designs. These include:

inverter. Determine its welding ability by selecting the supplied current. Typically, craftsmen assemble devices capable of delivering 150 amps, 170 amps, or 190 amps. The more Amperes, the higher the ability of your welding device;
feed mechanism. We will tell about it separately;
Burner;
Hose for supplying electrodes;
Spool with special wire. This prefix is easily attached to the structure in any way convenient for you;
Control unit for your welding machine.

Now with regard to the feed mechanism for the semi-automatic and some important points.

He is responsible for supplying the electrodes with a flexible hose to the welding point.
The optimum feed rate of the electrode wire corresponds to the rate of its melting during do-it-yourself welding.
The quality of the hand-made seam depends on the wire feed speed.
It is recommended to make a semi-automatic with the ability to adjust the speed. This will allow you to adapt the semiautomatic device to different type used electrodes.
The most popular electrode wires have a diameter of 0.8 to 1.6 mm. It must be wound on a coil and charged the inverter.
If you provide fully automated feeding, you do not have to do it yourself, and therefore the time spent on welding activities will be significantly reduced.
The control unit is equipped with an adjustment channel, which is responsible for stabilizing the current.
The behavior of Ampere, that is, the semiautomatic current, is regulated by a special microcontroller. It performs its work in the pulse-width mode of operation. The voltage created in the capacitor directly depends on its filling. This affects the welding current parameters.

Semiautomatic transformer preparation

So that a do-it-yourself semi-automatic device works no worse than welding machine such as Cedar 160, Kaiser Mig 300, it is necessary to understand the features of preparing the transformer.

Wrap it with a copper strip. Its width should be 4 cm, and thickness - 30;
Before this, the strip is wrapped with thermal paper. Suitable material used in cash registers. It is not difficult to acquire such paper;
In this case, the circuit does not allow the use of ordinary thick wiring, otherwise it will start to overheat;
The secondary winding must be done by using three layers of tin at once;
Fluoroplastic tape is used to isolate each layer of tin from each other;
At the output, with your own hands, you will need to solder the ends-contacts from the secondary winding. This is necessary in order to increase the conductivity of the current;
Be sure to provide a fan in the inverter housing. It will serve as a blowing mechanism that reduces overheating of the equipment.

Inverter setting

There are no problems with the work of Kedr 160, Kaiser Mig 300. Kedr 160 and Kaiser Mig 300 are factory equipment, which has excellent specifications. These semi-automatic machines function perfectly, allow you to receive required amount Amperes - 160 Amperes, 170, 190 Amperes, etc. It all depends on how you set up the device.

But if you decide to remake the inverter and make it a semi-automatic device, then the idea of \u200b\u200bbuying a Cedar 160, Kaiser Mig 300 should be thrown aside.

After completing work with the transformer, you should move on to the inverter. If done correct settings the inverter itself, the alteration will bring the desired result. And therefore, a home-made semi-automatic device will function no worse than the finished device Kedr 160, Kaiser Mig 300.

Be sure to include high efficiency heatsinks used for rectifiers (input and output) and power switches. Without them, the device will not work properly.
Inside the radiator case, which heats up the most, a temperature sensor should be installed to trigger it in case of overheating.
Connect the power unit to the control unit and plug it into the working network.
When the indicator is activated, you should connect an oscilloscope to the wires.
Look for bipolar impulses. Their frequency is in the range from 40 to 50 kHz.
The time parameters between pulses are adjusted by changing the input voltage. The time indicator should correspond to 1.5 µs.
Watch the inverter output square wave on the oscilloscope. Edges should not exceed 500 ns.
When the device has passed the test, connect it to the mains.
The indicator built into the semiautomatic device should give out 120 amperes. The parameters can reach up to 170, 190 amperes. But if the device does not show this value, you will have to go in search of the causes of low voltage in the wires.
Typically, this situation occurs when the voltage is less than 100 V.
Now we are testing the semi-automatic welding machine by starting the machine with variable current. In this case, constantly monitor the voltage across the capacitor.
We complete the test by checking the temperature indicators.
Check how the device behaves in the case of a loaded state. Similar initial tests should be carried out with the Kedr 160 and Kaiser Mig 300. Although the Kedr 160 and Kaiser Mig 300 are factory semi-automatic machines from trusted manufacturers, it will never be superfluous to make sure that they are professionally suitable.
To test a homemade inverter or Kedr 160 with Kaiser Mig 300, you need to connect a 0.5 ohm load rheostat to the welding wires. Make sure that given element withstands a load of more than 60 amperes. The voltmeter controls the current parameters.
If the test of the semiautomatic device showed that the set current value and the controlled value are different, it will be necessary to change the resistance. Do this until you get a positive result.

Assembling a device that will act as a full-fledged analogue for Kedr 160 and Kaiser Mig 300 is not so easy, but possible. You yourself determine whether the semiautomatic device will produce 120 or all 190 amperes. Make it easier to choose a factory model. But they are also priced accordingly. The price of the same Kedr 160 Mig semiautomatic device is from 27 thousand rubles. But the decision is up to you.

The use of a semi-automatic welding machine makes it easier to work with metals. This technique can easily connect various alloys. You can make a semi-automatic welding machine with your own hands from an existing inverter, and homemade unit will be distinguished by versatility and functionality in use, allowing you to save on the purchase of industrial equipment.

Design features

A design feature of the semi-automatic welding machine is the constant supply of melted wire to the welding zone, which is used instead of metal electrodes. Wire feeding is carried out automatically, with the possibility of changing the speed of the flexible electrodes. The used welding wire will ensure constant contact of the surfaces to be joined, such material has a lower resistance compared to standard electrodes, which improves the quality of the connection.

Semi-automatic welding is versatile, which allows using this technology to weld metals of various characteristics, including stainless steel, non-ferrous alloys, aluminum and others. master correct technique semi-automatic welding is not difficult. Homemade devices are easy to use, so they can be recommended to ordinary homeowners. Depending on their variety, semi-automatic machines may have an additional nozzle for supplying gas, and the joining of metals is carried out in a protective environment, which makes it possible to exclude the subsequent formation of corrosion in the weld.

The inverters for welding offered today in stores are versatile, and many of them have an implemented two-in-one function. With low power and dimensions, a two-in-one semiautomatic device can work with refractory metals and thick metal blanks.

Many homeowners who often have to perform welding work decide to manufacture such equipment themselves. The advantages of homemade semiautomatic devices from an inverter include the following:

Among the shortcomings of this technology and the equipment itself, one can note the high cost of semi-automatic devices, which, with characteristics similar to those of an inverter, can have a price two to three times higher. It is not surprising that many homeowners decide to make equipment with their own hands, which can significantly reduce costs without losing the quality of the completed apparatus.

DIY manufacturing

The easiest way is to make a homemade semiautomatic device from an inverter based on a powerful power unit. You can make an inverter yourself or use it from the equipment at your disposal. For a semi-automatic device, inverters with a capacity of at least 150 amperes should be used.

There are schemes for reworking equipment that allow you to set the power that will be enough for semi-automatic welding. A device of this type will be difficult to implement, therefore, only experienced radio amateurs who can make truly complex equipment can be recommended to use low-power power units.

Craft quality equipment possible if you have a semi-automatic starting circuit on hand welding inverter. The characteristics of such a unit include the following:

Primary current - 8-12 A.
Supply voltage - 220 or 380 volts.
The open circuit voltage is 36-42 Volts.
Welding current - 40−120 amperes.
Voltage adjustment in plus or minus 20% increments.

it optimal parameters for a household welding semi-automatic device that will cope with metals of various refractoriness. Subsequently, using additional drawings to increase the power of the inverter, you can change basic characteristics, which allows the use of such equipment for domestic and industrial purposes.

Required Components

To make a semi-automatic garage welding machine with your own hands, you will need the following:

Torch prefix for the inverter.
Wire feeder.
Robust inner hose for welding wire.
Bobbin with wire.
Sealed gas hose.
Inverter control unit.

The easiest way is to place the inverter and the mechanical control unit in a separate box, for which they use blocks from an old computer. The presence of power in the system unit can significantly simplify the manufacture of equipment.

The roller mechanism for the wire can be made from a motor from a car windshield wiper. Under such a motor, a mechanism frame is designed, which is cut out of metal elements and welded or bolted together.

The burner and hose can be made independently from a gun from polyurethane foam and silicone. You can also purchase ready-made kits, which will ensure the safety of working with a semi-automatic device and simplifies its manufacture.

When making a wire feed mechanism, all the components used must be placed opposite each other, which will subsequently ensure a uniform supply of flexible electrodes. The rollers should be centered relative to the fitting in one slot, in the future this will allow you to smoothly change the wire feed speed. A diagram of the wire feed speed controller of a semi-automatic welding machine can be easily found on the Internet.

All used metal elements should be fixed on a sheet of plywood, thick plastic or textolite. Since electricity is supplied to the metal elements used, the grounding of each node should be checked. This will eliminate the possibility of short circuits, which can lead to serious damage to equipment.

Mechanics control scheme

A small electric motor and a broaching mechanism will be responsible for feeding the welding wire, the operation of which is controlled by a PWM controller. The quality of the welding performed will directly depend on the uniformity of the welding wire feed in working area. It is necessary to pay due attention to the correct manufacture of semi-automatic welding circuits.

A variable resistor of the controller is installed on the front panel of the inverter, after which they begin to assemble the relay for starting the motor and controlling the valve, which is responsible for supplying inert gas. The contact groups of the controllers must operate simultaneously when the start button on the burner is pressed.

The work of the gas supply must be adjusted so that the valve opens a few seconds before the wire begins to enter the welding zone. Otherwise, melting occurs in the atmospheric environment, after which the wire will begin to burn instead of the melt. It will be impossible to achieve a high-quality connection and a reliable welding seam when the wire burns.

To delay turning on the wire feed, you need to make a simple relay, which requires a capacitor and an 875 transistor. You can use the simplest relay from a car that connects to 12 volts on a computer power supply.

The valve itself can be used from various automotive locking devices. Easiest to change air valve from the car GAZ-24. You can also choose an electrovalve from a reducer from gas cylinders.

All available controls and the PWM wire feed controller of the semi-automatic welding machine are located on the front panel of the system unit. A ready-made inverter with a power of at least 150 amperes is connected to the control unit and the wire feed controller with gas. It remains to carry out a test run and, if necessary, make appropriate adjustments to the operation of the welding wire and shielding gas supply system.

During operation, the power unit of the inverter semiautomatic device will heat up, which can lead to damage to the inverter and control boards. Repair of the unit after such breakdowns will be extremely difficult. To avoid this, it is necessary to install temperature sensors and coolers inside the inverter and the system unit, which can effectively cool the operating equipment.

You can use an optocoupler, which is connected to a common control unit for the operation of the equipment. If the temperature inside the inverter is exceeded, the sensors will send appropriate signals to the executive relay, which will turn off the power supply until the device is completely cooled down.

Additionally, various coolers from old computers can be used to cool the system unit. Coolers will vary in size. You can choose a fan that will cope with high-quality cooling of the system unit, inside which there is an inverter and other automation. The cooler used is connected to a 12-volt power supply directly or through a thermal sensor, which, when the temperature inside the case rises, will send a signal to supply voltage. The control unit will turn on the fan, which guarantees rapid cooling of the body of the semi-automatic device.

Assembling a semi-automatic welding machine is not particularly difficult, so every homeowner can handle this job. It is only necessary to use a high-quality powerful inverter, and it is best to take a burner with a drive from industrial factory semi-automatic devices. This will greatly simplify the manufacture of equipment. On the Internet you can find various schemes execution of semi-automatic welding machines, which will not be difficult to implement. Such a device will differ in functionality and versatility in use..