How to make a choke for a semi-automatic welding machine

How to wind a choke for a welding machine - Metalworker's Guide

Almost every master has at least once thought about how to make a choke for a welding machine with his own hands.

Today, a fairly large number of different devices are sold that can be used in small-scale production.

This can be a device that operates on temporary or continuous current, a semi-automatic welding machine, or a product using electrodes. However, a high-quality device is very expensive, and budget analogues quickly become unusable.

Diagram of an AC welding machine with a separate choke: 1 – primary winding, 2 – core, 3 – secondary winding, 4 – choke winding, 5 – fixed part of the choke core, 6 – moving part of the choke core, 7 – screw pair, Dr – regulator current.

To assemble a homemade welding fixture, you will need to select and build all the necessary elements, including the throttle.

Benefits of using a throttle

Single-phase bridge rectification circuit (a). Graphs of voltage and current in the transformer (b), voltage and current in the load (c).

A welding choke is a device for regulating the current used to perform welding work. The element is needed to compensate for resistance that may be lacking. It can be connected to the re-winding of the transformer structure.

This makes it possible to shift the phases between the passing current and its voltage, as a result of which it is easier to ignite the electric arc at the beginning of work. It will burn evenly, and therefore it is possible to obtain a weld of good quality.

If you do not use the choke, problems may occur during welding.

The choke may consist of a semi-automatic design or a welding device that involves the use of electrodes. A semi-automatic machine with a throttle practically does not splash metal during operation. The welding process will be much smoother than without a choke.

The weld seam can be welded to a significant depth. The advantages of such an element are beyond doubt. It can be mounted not only on a homemade device, but also on a factory-made device. This is especially true for budget options that are prone to malfunctions.

This can significantly facilitate work on such structures and improve the quality of the weld.

What available tools can be used

Power supply diagram for an inverter welding machine.

To build a choke for welding with your own hands, the first step is to prepare the material. In this case, you can use almost any unused electrical devices.

The design is an ordinary core with a wound wire. For this purpose, you can use a transformer structure that was previously mounted in an old TV. The entire winding will need to be dismantled.

The core can be used to wind wire, the length of which is calculated in advance.

If possible, you can use parts that were installed in the lantern bulbs. Old windings should be dismantled, as they are often faulty. During the process of winding the wires, they will need to be installed in their original place.

To wind the inductor, you can use any core with a cross-section of approximately 12-15 cm. You will need to make a non-magnetic part between its elements. To do this, attach an insulation gasket approximately 0.6-1 mm thick.

Smooth current regulation can be achieved through the installation of movable windings of a transformer design. By changing the distance between the windings, you can change the magnitude of the magnetic flux and resistance in the repeat winding.

Current conversion in a welding inverter.

To weld with continuous current, an element must be connected to the winding at the output of the transformer structure to convert the temporary current into a continuous one. This device is called a rectifier. The current may not be continuous, but pulsating. It is possible to reduce ripple only by increasing the capacitance of the capacitor device.

To be able to adjust the arc current using a choke, 3 rectifiers must be connected between the output of the transformer structure and the point.

Elements that will be needed to construct the throttle:

• electrical design;
• wires;
• transformer;
• lantern lamp;
• cardboard for insulation.

Manufacturing diagram of a welding choke.

Before winding the wire, you will need to insulate the yoke. To wind the choke, you can use aluminum or copper wire. In the first case, its cross-section should be approximately 36-40 mm, in the second, the recommended cross-section is 25 mm. Instead of wire, you can use a copper busbar 4-5 mm thick. If you plan to use an aluminum part, it must be thicker.

The wire needs to be wound in an amount of 30-35 turns, the bus is wound in 3 layers. If an element from a lantern light bulb is used as the core, then winding should be done only on one side part along the entire length until the window is filled. The winding direction cannot be changed. Each layer must be isolated from the previous one.

It is recommended to impregnate the elements with bakelite varnish.

During the winding process, taps should be made through the same number of turns. The contacts must be strong, since they will bear a significant load.

Installing a throttle has a positive effect on the operation of a semi-automatic device or an ordinary homemade device. For a device that operates on temporary current, it is recommended to use a device together with a structure for rectifying the current. In this case, it will be possible to use almost all possible electrodes.

A do-it-yourself choke for welding can also be installed on a device with a step-down transformer design. The element must be connected to the secondary circuit of the transformer for welding.

This will make it possible to build a proprietary semi-automatic welding device, which is very expensive. The throttle should be accurately calculated according to the formula that is in the documentation supplied with the device.

This product will have a transformer design with good dissipation and excellent performance.

It is important to configure the choke for an inverter or any other device correctly.

Stepwise adjustment of the welding arc current can be achieved by switching on an ohmic resistance at the output, which is a nichrome spiral, through the same number of turns of which taps should be made with contacts that can withstand any load. The disadvantage of this method is that in this case the thread will become very hot.

When the welding choke setting is successful, you can begin welding work.

Existing methods for adjusting welding arc current

Scheme for welding thin metal using an inverter.

You can adjust the arc current by changing the air gap. The transformer device can be in the following modes:

1. Idling. Temporary voltage is supplied to the input of the transformer device. In the repeat winding, an EMF is initiated, but there is no current in the output circuit.
2. Load mode. In the process of igniting the arc, it will close the output circuit, which consists of re-winding the transformer device and the inductor winding. A current will flow, the value of which can be determined by the resistance of these windings. The degree of impact will depend solely on the size of the gap in the rod.
3. Short circuit mode. The electrode touches the parts being connected. A temporary magnetic flux must be created in the core of the transformer structure. An emf should be initiated in the re-winding. The current in the circuit will be determined by the resistance value of the inductor and the winding of the transformer device.

The resistance will increase as the gap increases. This should lead to a decrease in magnetic flux. Eventually the arc current will increase. This method allows for smooth adjustment of the current, so it is recommended to use it.

The disadvantage of the moving system is that if the metal vibrates, the coil will become unreliable during the passage of temporary current. In this case, the adjustment can be made in steps. To do this, the choke should be made so that there is no gap in the wire.

  Operating principle of an inverter welding machine

It is not difficult to build a welding choke with your own hands. To do everything correctly, you will need to follow the technology, prepare all the necessary elements and follow the sequence of actions.

Source: https://ssk2121.com/kak-namotat-drossel-dlya-svarochnogo-apparata/

Choke for a welding machine: why you need it and how to assemble it yourself (instructions and diagram)

Recently, electric welding has become extremely popular in the professional sphere and at home, but we all know how many problems welders face.

The current market segment of electrical engineering offers a lot of machines for welding using an electric arc, starting from small and not very powerful welders for the home and performing small volumes and tasks, and right up to huge industrial machines with high productivity, which are sent directly from shops to huge factories.

But such a problem as sudden, and most importantly uncontrollable voltage drops, is known to professionals and home craftsmen.

These problems cannot be affected by overly expensive equipment or the type of application, this is a typical welder’s scourge, such little things drive even experienced craftsmen crazy, and a beginner will simply turn away forever from working with welding that does not cope with its functions. This phenomenon affects the arc and seam formation becomes more difficult.

But such a problem is in the past, because there is such an innovation as a choke, it makes the cooking process much easier, and most importantly, makes it safer in many ways.

It is introduced into the welding process chain, and welding is ready for comfortable operation. Beginners, of course, are not aware of current, what a choke is and how it is useful, how it works, how to make it at home. This article will shed light on all your questions and more.

General statements

So why do we need a choke on a welding machine? Perhaps we can do without it? Yes, of course you can, but for effective and comfortable welding it is simply necessary.

This is a small element that is connected to the circuit, and it provides stable, uninterrupted, smooth heating of the arc.

At the second stage, it maintains this stable state, and the metal does not fly away in all directions, which often happens and, incidentally, can lead to severe burns.

During operation, the seam comes out neat, the machine is adjusted more accurately and can even weld difficult elements, but of course, a lot also depends on the professionalism of the master in whose hands the welding fell.

The principle of the robot is easy and understandable to everyone: the inductor passes current through itself, keeping it away from the welding machine.

And then this stored current replenishes those same voltage surges, which allows welding to work stably. Another choke with magnetization allows you to provide the necessary resistance if the voltage suddenly goes up.

Buying a choke for a welding machine in stores is not a cheap pleasure, yes, of course, you can look for something more budget-friendly, but will it work well?

You can do it at home yourself, for this you will need very little logic, time, and inexpensive materials that you probably have lying around in the garage.

The inductor design is a core with two coils with a cross-section designed for use with a constant current value.

So, unfortunately, we can’t make a choke that would be suitable for different welding machines, it’s a pity, but it’s a fact. A small part will obviously not be able to handle a strong welder.

So it is advisable to know in advance the number of skeins, which will be useful for working with different voltages.

Current adjustment

An example of a choke for a welding machine, assembled by yourself

And how can we make our seam neat and, most importantly, durable? That's right, we need to regulate the current well.

There are several methods for this:

1. Stabilization, in which we increase and decrease the distance between the elements and the welding machine. This is the best known method. That is, that the current strength was less, we must separate the cut transformer core. The induction will drop, and the current will creep down behind it. If your device is large, then this is a plus since it is easier to control the current on it, since the control interval depends on the scale of the available size in the body of the device.
2. Control of current on the transformer winding. This method simply ignores part of the coil, which increases the voltage, because the path that the current overcomes becomes smaller. Well, that is, if this very path becomes larger, then the path needs to be extended.
3. But it can also be controlled using a steel spring to which we attach the terminal in series. This method could be good because it doesn't adjust the current much, but there is a caveat. This method is extremely unsafe, since the overcooked spring ends up at the master’s feet. If you value your health and don’t want to get fried, this method is not for you.

Such a coil will solve almost all your problems with voltage stabilization. In fact, it is always ready to make up for the lack of this voltage, or to take away the excess so that it can be used again later.

The main thing is that the unsafe hot spring will no longer lie at your feet, because safety should come first, especially with such difficult work, the adjustment will be made by the throttle on the welding machine, and the master may not think about it.

Using the throttle

Welding transformers are the best basis for creating a choke at home. This has been proven in practice more than once.

It easily, but smoothly heats our arc, at any current, so it is suitable for ordinary summer residents, as well as for working in factories and concerns with voltage surges.

You can also take a choke for a welding machine along with a rectifier. A pair of inductor and rectifier has the ability to increase the electromotive force of self-induction.

For example, if we are talking about semi-automatic devices, then this pair can strike an arc even at a large distance from the metal.

Homemade choke

So let's start building a choke for a welding machine at home; for this we will need to know how to wind a coil. In order to do everything in the best possible way, quickly and efficiently, we must have a good understanding of how the throttle works.

You learned everything you need about the functions and design of the throttle from the previous sections, of course, if you were careful.

We have also written a small instruction for you, using which you will definitely be able to build a wonderful device. Let's start our simple work on a very useful device:

1. First of all, let's find an old transformer; it will serve as an excellent base for us. Experts in this matter advise using parts from TCA 270-1 televisions; it should become our core. Such little things are always not difficult to find in spontaneous markets, or you were lucky and your grandmother had a TV of the right model lying around, but if not, then the Internet will certainly not deny you an abundance of junk.
2. Next, we must obtain the necessary parts from the transformer; for this we must get rid of the fasteners, often they are on top and, of course, get our coil.
3. Next, you must form gaskets for the induction passage that will be glued to the previously mined element.
4. Now a difficult and painstaking stage awaits us, but the result of our entire work greatly depends on it; we must wind the wire. We need a wire, preferably made of aluminum, with a cross-section of at least 36 millimeters. Next we apply 25-26 turns on each side. If you have found all the parts we recommend, then everything should come out very clearly and neatly. The insulation between the turns is also very important; you can make it with paper, and of course varnish it with insulating lubricants.
5. Wind the cord in one direction on both coils, otherwise there is a risk that at the end the cords will point in different directions, jumpers will not appear between the taps that connect the coils, and the input and output will not be positioned correctly.
6. But if it already happens that you wound so that the wires point in different directions, it’s not a problem - we need to attach a diagonal jumper between the upper and lower taps. Here the second pair will serve as the entrance and exit.
7. It is recommended to integrate a choke into the welding after the diodes.

But if even after all our manipulations the voltage jumps, then you just need to remove a couple of turns from the coil.

Bottom line

Congratulations, if you have mastered all our tips, then you will certainly be able to make a choke for a welding machine with your own hands. It was not difficult at all, it took a little perseverance and technical savvy.

But at the end you will receive a high-quality device (of course, if you did everything correctly), of course you will be proud that it was made by yourself, and you can even teach it to one of your friends or relatives.

Tell us about how you made your throttle, what problems arose, what the result was, show the article to your friends. Peace and new heights to everyone!

Source: https://prosvarku.info/prisposobleniya-i-detali/drossel-dlya-svarochnogo-apparata-svoimi-rukami

Do-it-yourself choke for a semi-automatic welding machine

Electric welding is widely used in large industries and small workshops. Devices for joining metals with an electric arc also vary in size and power.

But they all have one possible problem in common - a voltage drop interferes with the ignition of the arc and the welding. It can also be difficult to adjust the required current value for a specific metal thickness. To solve all this, a choke is used as part of the equipment.

What it is? How does it function? How to make a throttle for your device yourself?

What it is?

It is quite possible to make a choke for a welding machine with your own hands. It consists of a core and two windings with a specific cross-section, designed to operate with a specific current value. A choke from a large welding equipment will not fit a small unit, and vice versa, a small model will not be effective on a large welding machine.

The choke receives and accumulates current from the step-down transformer, which facilitates smooth ignition of the electrode. During welding, the arc burns more softly and the metal of the weld pool is less splashed. If the incoming voltage is too high, the inductor takes over part of the resistance function. This allows you to more accurately tune the machine and weld thin metal.

The advantage of a homemade throttle

To weld metal of various thicknesses, several methods are used to adjust the current:

• Changing the distance between transformer elements. Welding machines have two windings, between which electromagnetic induction occurs. Due to this, Volts decrease and Amps increase. If the current is too high for normal welding on a given thickness of material, then the windings are separated from each other using a threaded screw. This dissipates induction and reduces current. The degree of adjustment depends on the length of the screw and the size of the device body. The wider the settings for this parameter, the larger the welding unit itself.
• Step adjustment on the transformer winding allows you to cut off part of the coil, allowing the current to flow along a shorter path. To reduce the force of the welding arc, set the longest voltage path possible. But this depends on the number of turns of the step-down transformer.
• A resistance made of a steel spring with terminals attached at a certain interval allows you to regulate the current strength in small “steps”, but has a significant drawback in the form of rapid overheating of the resistance, which is constantly under the welder’s feet.

The introduction of a choke into the circuit solves all these problems at the same time. This small electrical device partially compensates for the missing resistance, so there is no need to use large transformers with wide adjustment parameters. The current adjustment occurs smoothly without steps, and there is no hot spring under your feet.

Application

A self-made choke interacts well with transformers. Since alternating current is characterized by crackling and splashing of metal, adding this element to the circuit will allow you to cook more gently. This is especially felt when working on heating pipes, where water continues to leak from the system.

The choke for a welding inverter and semi-automatic device is also useful in facilitating rapid ignition of the arc. For example, if the inverter should produce 48 V no-load, then when the voltage in the network drops or surges, this value will be even less.

When you need to weld with an MP-3 electrode, the optimal current value for which is 70 V, and at 48V it ignites with difficulty, then in the event of a voltage drop it will be very difficult to initiate an arc.

As a result, planned welding work will have to be postponed until normal voltage is restored.

The choke, in combination with a rectifier, is capable of producing a self-induction emf, which penetrates the air space and easily ignites the electrode. In the case of a semi-automatic machine, this facilitates easy start of work at the slightest approach of the wire coming from the nozzle to the product.

Combining two functions (resistance compensation and arc stabilization), this device allows you to weld thin metal under conditions of surge voltage. Thus, devices with a choke are widely used for welding car bodies at service stations, or stainless steel thin containers.

DIY choke

To know how to wind a choke correctly, it is important to understand its structure. Although it is simple, following each part carefully step by step will ensure a quality result. For a semi-automatic machine or inverter used in a private home or country house, a choke made as follows is suitable:

1. An old transformer is used as a basis. The optimal model is a boost element on a tube TV marked “TSA 270-1”. Similar ones can be found in elderly friends' garages. The dimensions of its internal part are ideal for a welding machine for home use.
2. The transformer is disassembled by cutting off the bolts to release the coils. Or you can rotate the row of heads at the top of the device and remove the coils directly.
3. It is necessary to install gaskets on empty horseshoes that will form an inductive gap of the choke. They can be made from cardboard with a sheet thickness from 0.8 to 1.0 mm. The spacers are glued to the base of the horseshoe.
4. The winding is made with soft aluminum wire with a cross-section of 36 mm. Each coil should have 24 turns. Using the specified core from an old TV, you can make three layers of eight turns each. Between layers it is necessary to perform high-quality insulation with paper and bakelite varnish. This is done due to the device’s ability to generate self-induction emf, which appears when the arc breaks. Then the discharge follows the path of least resistance and breaks through the air, which renews the burning of the electrode. If the least resistance is between the turns of the winding, then a breakdown will occur there, which will lead to damage to the element.
5. The wire must be wound in one direction on each coil. Thanks to the same direction, you will get a structure on which at the top there will be a jumper between the taps connecting the coils, and at the bottom there will be an input and an output.
6. If an error was made during winding and the coils turned out to be opposite in the direction of winding, then you can get out of this situation by installing an oblique jumper between the upper and lower taps diagonally. The second pair of taps forms the inlet and outlet.
7. It is recommended to install the inductor in the circuit after the diodes. A cable from the diode bridge is connected to the input, and a ground cable supplied to the product is attached to the output.

Throttle check

After assembly, the device is tested. To do this, it is necessary to weld on metal whose thickness will be used most often in everyday work. The current strength is checked, which should be sufficient for good penetration, but without burn-through.

It is also necessary to pay attention to the behavior of the welding arc, its stability, moderate crackling, and smooth combustion without excessive spatter. Easy ignition of the electrode and good arc characteristics will indicate proper assembly. If the current strength has dropped significantly, then it is worth rewinding the device and removing several turns of the winding on each coil.

The introduction of a choke into the circuit of a semi-automatic device, inverter or conventional transformer makes it easier to work with the device. It becomes more convenient to apply sutures, and the electrode ignites smoothly and stably. This is especially practical in the private sector, where power surges are commonplace. It is easy to make a homemade device following the sequence given in the article.

Source: https://steelfactoryrus.com/drossel-dlya-svarochnogo-poluavtomata-svoimi-rukami/

DIY choke for a welding machine

A choke is the industrial name for an electrical element such as an inductor. This device has a wide range of applications, in particular, a powerful choke can be used to improve the performance of a semi-automatic machine or inverter for welding.

Principle of operation

The main property of an inductor, which is a magnetic circuit wound under certain conditions around a ferromagnetic core, is the stabilization of current strength over time.

Simply put, voltage applied to the coil causes a smooth increase in current output. Changing the polarity leads to the same smooth decrease in current.

The main factor is the condition that the current passing through the inductor cannot sharply increase or decrease. This is precisely what determines the value of using a choke for welding - resistance compensation allows you to avoid sudden jumps in amperage.

This allows you to protect against accidental burning of the workpieces being welded, reduce spattering of the melting metal and accurately select the current parameters for welding for a given metal thickness. The chances of getting a good weld using a welding choke are much higher.

The parameter that determines the current change coefficient is inductance. It is measured in H (henry) - in 1 second at a voltage of 1 V, only 1 A can pass through a choke with an inductance of 1 H.

The number of turns on the coil directly affects the amount of inductance. It is directly proportional to the number of turns squared. But if you need to make a welding choke with your own hands, then it is not necessary to calculate the exact number of turns.

Since the parameters of welding machines for household use are mostly standard and well-known, a welder will only need to use the instructions below to make a choke with his own hands.

Purpose

In an inverter for welding, a choke is needed to create an electric arc on the electrode. Ignition occurs when a certain voltage level is reached.

The welding choke increases the resistance, which shifts the phases between current and voltage and allows for smoother ignition. This fact in itself often allows one to avoid burning through the workpiece, especially if parts made of thin sheet metal are welded.

A smooth change in current makes it possible to avoid damaging the workpiece by abruptly applying too much power, to optimally set the arc temperature and, accordingly, to prevent metal spattering while maintaining the required processing depth.

Another valuable property is its partial protection against unstable voltage in the network.

A choke for a welding inverter greatly facilitates ignition of the electrode, which should light up at a higher voltage than the inverter produces.

An example is the MP-3 electrode, which must have a voltage of 70 V to ignite. An output choke for welding can make working with this electrode much easier for an inverter, which produces only 48 V at idle.

This occurs due to the phenomenon of self-induction. The device induces EMF (electromotive force), which causes air breakdown and flashing of the welding arc, as soon as you bring the additive a few millimeters from the metal surface.

The choke for welding is connected to the secondary winding of the transformer in the machine. It can be used in devices of any type - both home-made and factory-made, operating on any principle - inverter, with a step-down transformer, and the like.

Materials for production

The choke for retrofitting a semi-automatic device or inverter can be assembled with your own hands, using structural elements from old equipment - tube TVs, old street lamps and other devices that have a transformer.

Structurally, it consists of a core made of a material that conducts a magnetic field, but does not conduct electric current, or is reliably insulated, and three layers of windings separated by a dielectric.

As a basis for the core, either a special material is suitable - ferrite, which has these properties, or a yoke (horseshoe) from an old transformer. Winding of the device for welding is done with aluminum or copper wire with a cross-section of 20-40 mm.

If aluminum is used, the wire cross-section must be at least 36 mm; copper wire can be thinner. A flat copper busbar with a cross-section of 8 mm is suitable.

The dimensions of the core should allow winding approximately 30 turns of a busbar of a given section, taking into account dielectric spacers. A core from the step-up transformer of the Soviet TV TCA 270-1 is recommended.

Sequencing

When the necessary tools and materials are prepared, you can begin to manufacture the throttle for welding. The algorithm of actions is as follows:

1. disassemble the transformer, clean the coils from traces of old windings;
2. make gaskets from fiberglass, cardboard impregnated with bakelite varnish, or other suitable dielectrics, which will subsequently play the role of an inductive (air) gap. They can simply be glued to the corresponding surfaces of the coils. The thickness of the gasket should be 0.8-1.0 mm;
3. wind a thick copper or aluminum wire onto each coil. You should focus on a round wire made of aluminum with a cross-section of 36 mm or copper with a similar ohmic resistance. Each “horseshoe” is covered with 3 layers of 24 turns each;
4. lay a dielectric material between the layers - fiberglass, cardboard impregnated with bakelite varnish or another dielectric. The gaskets must be reliable, since a choke of this design is prone to self-breakdown between windings. If the resistance between the windings is lower than the air resistance between the electrode and the additive, then a breakdown will occur between the windings, and the welding device will be irreversibly damaged.

Winding must be done evenly, without overlaps, strictly in the same direction, so that the “bridge” between the coils is on one side of the future inductor, and the input and output contacts are on the other.

In case of an error, the jumper can also be installed askew. It is important that its installation turns coils with different winding directions into coils with the same direction in fact.

Power on and check

The choke for welding is connected to the system between the diode bridge and ground - a contact that connects to the material being welded. The output of the diode bridge is connected to the input of the inductor, to the output of the assembled inductor - respectively, a ground contact.

The entire assembly for welding must be tested on a piece of metal of the same chemical composition and thickness with which it is planned to carry out most of the welding work in the future. Quality indicators are:

• easy electric ignition;
• arc stability;
• relatively weak crackling sound;
• smooth combustion without strong splashes of melt.

Please note that the introduction of this element into the design of the welding machine leads not only to stabilization of operation, but also to a slight drop in current strength . If the inverter or semiautomatic device begins to cook worse, it means that the current strength has dropped.

The choke needs to be disconnected and a few turns removed from each coil. The exact number of turns in each specific case is selected empirically.

Source: https://svaring.com/welding/prinadlezhnosti/drossel-dlja-svarki

Making a choke for a welding machine with your own hands

A step-down transformer is the basis of a simple welding machine. A more complex welding machine is one that has a rectifier at the output that converts alternating voltage into direct voltage. Such welding machines are called rectifiers.

There are three types of transformers: toroidal, rod and armored, the differences between them can be seen in the figure above.

The most complex is the welding machine, which first converts the input power frequency of 50 Hz into a direct voltage, like rectifiers, and then converts it into an alternating voltage, the frequency of which is measured in kilohertz. This is an inverter.

Only someone who is well versed in radio electronics and the element base used there can make an inverter with their own hands. For this specialist, there is no need to explain why the inductor is needed and where its place is in the circuit. It would be advisable to explain to an unprepared person what a transformer and a rectifier for it are.

Calculation of the cross-section of the wires of the primary winding of the transformer

Diagram of a welding transformer.

The theory of transformers is complex in that it is based on the laws of electromagnetic induction and other phenomena of magnetism. However, without using complex mathematical apparatus, it is possible to explain how a transformer works and whether it can be assembled independently.

The transformer can be manually wound on a metal core assembled from transformer steel plates. It is easier to wind on a rod or armored core than on a toroidal one. You should immediately note that the image clearly shows the difference in the thickness of the wires: the thin wire is located directly on the core, and a larger number of turns is clearly visible in it. This is the primary winding. The thicker wire with fewer turns is the secondary winding.

Without taking into account the power losses inside the transformer, let's calculate what the current I1 should be in its primary winding. The ideal network voltage is U=220 V. Knowing the power consumption, for example, P=5 kW, we have:

I1 = P:U= 5000:220=22.7 A.

Based on the current in the primary winding of the transformer, we determine the diameter of the wire. The current density for a household welding transformer should be no more than 5 A/mm2 of wire cross-section. Therefore, for the primary winding you will need a wire with a cross section of S1 = 22.7:5 = 4.54 mm2.

Using the cross-section of the wire, we determine the square, its diameter d without taking into account the insulation:

d2=4S/π=4×4.54/3.14=5.78.

Taking the square root, we get d=2.4 mm. These calculations were performed for copper wire cores. When winding wires with an aluminum core, the obtained result must be increased by 1.6-1.7 times.

For the primary winding, copper wire is used, the insulation of which must withstand high temperatures well. This is fiberglass or cotton insulation. Rubber and rubber-fabric insulation is suitable. Wires with PVC insulation should not be used.

How to independently and beautifully create a living room design?

Calculation of the cross-section of the wires of the secondary winding of the transformer

Diagram of a transformer with primary and secondary windings.

The voltage at the output of the welding machine transformer in the absence of a welding arc (idle mode) is usually 60-80 V. The higher the idle voltage, the more reliably the arc is ignited. The welding arc voltage is usually 1.8-2.5 times less than the no-load voltage.

Attention. It is necessary to constantly remember that in the absence of an arc the voltage at the transformer output is life-threatening.

For welding in everyday life, an electrode with a diameter of 3 mm is usually used, which is sufficient to provide an arc current of approximately 150 A. With an open circuit voltage of 70 V, the arc voltage will be approximately 25 V, and the power consumption P of the welding machine must be at least

Р=25×150=3750 W =3.75 kW.

It is advisable to design the transformer for higher power, that is, higher welding arc current. For example, with an arc current of 200 A, the power consumption will be approximately 5 kW. This is the power the transformer should be designed for.

The single-phase voltage in the house should be 220 V, but it can vary by ±22 V. This is one of the reasons why the arc current may change and will need to be adjusted.

The cross-section of the wire in the secondary winding of the transformer is determined based on the current density equal to 5 A/mm2. For a current of 200 A, the wire cross-section is 40 mm2, that is, it can only be a busbar that is wound with layer-by-layer insulation. Based on existing standard sizes, you can select the required tire both in length and cross-section.

Typical sizes of copper busbars produced by industry:

Manufacturing diagram of a welding choke

• length from 0.5 to 4 m with intervals of 0.5 m;
• width from 2 to 60 cm with intervals of 1 cm (with widths from 4 to 10 cm) and with intervals of 5 cm (with widths from 10 to 60 cm);
• thickness from 3 to 10 mm.

You can also use a stranded wire, the cross-section of which corresponds to the calculated value. To increase the cross-section, the wire can be folded in half or three. For aluminum wire, the cross-section must be increased by 1.6-1.7 times.

For a choke that is connected at the output of the transformer, the cross-section of the wire must be the same as in the secondary winding of the transformer.

Rectifier for welding machine

Electrical circuit of a welding machine rectifier.

To weld with direct current, an AC-to-DC converter must be connected to the output winding of the transformer. Such a device is called a rectifier, which is why a welding machine with this device is called a rectifier.

The top graph represents the sinusoidal voltage at the output of the transformer secondary winding. The horizontal t-axis is the time axis. The time interval between zero voltage values ​​is determined by the oscillation period. It consists of positive and negative half-cycles.

It can be seen that the current is not constant, but pulsating. The only way to reduce ripple is by increasing the capacitance of the capacitor.

To regulate the arc current, the choke must be connected between the transformer output and point 3 of the rectifier.

Methods for regulating welding arc current

Let's consider one of the methods of regulating the welding arc current, based on the use of a choke in the secondary winding of the transformer. The arc current is regulated by changing the air gap provided in the core on which the busbar is wound.

Let's consider three modes in which a transformer can be.

Diagram of no-load and short circuit of a transformer.

1. Idle mode. Alternating voltage is supplied to the input of the transformer. An emf is induced in the secondary winding, but there is no current in the output circuit.
2. Load mode. As a result of ignition of the arc, it closes the output circuit, consisting of the secondary winding of the transformer and the inductor winding. A current flows, the magnitude of which is determined by the inductive reactance of these windings. If there were no choke, the current would be maximum. The degree of impact depends on the size of the air gap in the rod on which the winding is wound.
3. Short circuit mode. This is the moment the electrode touches the parts of the workpiece being welded. An alternating magnetic flux is created in the transformer core, and an emf is induced in the secondary winding. The current in the circuit is determined by the inductive reactance of the inductor and the secondary winding of the transformer.

As the gap increases, the resistance increases. This leads to a decrease in the magnetic flux and, accordingly, to a decrease in the inductive resistance of the choke coil and the total resistance of the circuit. The arc current increases. This method allows you to smoothly regulate the current.

Transformer assembly diagram.

However, the moving system has the disadvantage that as a result of the vibration of the metal when passing alternating current through the coil, it becomes not very reliable.

You can, sacrificing the smoothness of the adjustment, make it stepwise. To do this, it is necessary to make the choke so that there is no air gap in the magnetic core. During the winding process, taps must be made through a certain number of turns. In this option, the current can be adjusted in steps, through contacts that must be made powerful in order to carry a current of hundreds of amperes.

There is another reason why the throttle must be turned on to create normal manual welding conditions.

The characteristic of the dependence of arc voltage on its current is called falling. An inexperienced welder will have to believe that such a relationship is useful when welding if it is difficult to maintain a constant distance between the electrode and the parts being welded. To provide such a characteristic, the inductive reactance of the secondary winding of the transformer alone is not enough. The immediate task of a choke for a welding machine is to add the missing resistance.

How to make a choke and wind it correctly?

To wind the choke coil, you can use a UI series magnetic core. Table 1 shows the dimensions corresponding to the maximum values ​​of parameters a and b.

Table 1.

Name	a, mm	b, mm	c, mm	d, mm	e, mm	f, mm	h, mm	i, mm	k1, mm	k2, mm	Holes, mm
UI 90	90	120	90	30	30	30	7,8	60	15	105	4
UI 120	120	160	120	40	40	40	11,0	80	20	140	4

Before winding, it is necessary to insulate the yoke. During the winding process, its direction does not change. The next layer is isolated from the previous one with cotton insulation. You can use fiberglass or cardboard designed for insulation. The insulating gasket is impregnated with bakelite varnish. If conclusions are drawn during winding, they should be marked immediately.

The welding arc current can be adjusted stepwise by turning on a load ohmic resistance at the output in the form of a nichrome spiral, with periodic taps. However, this method is inconvenient due to the possible high heating of the filament (even red hot).

For smooth adjustment, movable windings of the transformer are created. By changing the distance between the primary and secondary windings, they change the magnitude of the magnetic flux and, consequently, the resistance in the secondary winding of the transformer.

But for a welding machine used in everyday life, the most suitable method is a smooth adjustment using a throttle.

Source: https://moyakovka.ru/instrumenty/drossel-dlya-svarochnogo-apparata.html

Options for making a choke for a welding machine with your own hands - Tool Build

A choke is the industrial name for an electrical element such as an inductor. This device has a wide range of applications, in particular, a powerful choke can be used to improve the performance of a semi-automatic machine or inverter for welding.

Choke with voltage booster for semi-automatic welding machine

> Repair > How to make a semi-automatic machine from an inverter with your own hands

A good owner must have a semi-automatic welding machine, especially owners of cars and private property. You can always do small jobs with it yourself.

If you need to weld a machine part, make a greenhouse, or create some kind of metal structure, then such a device will become an indispensable assistant in your personal household. Here a dilemma arises: buy or make it yourself. If you have an inverter, it’s easier to do it yourself.

It will cost much less than buying in a retail chain. True, you will need at least basic knowledge of the basics of electronics, the availability of the necessary tools and desire.

Making a semi-automatic machine from an inverter with your own hands

Structure

It is not difficult to convert an inverter into a semi-automatic welding machine for welding thin steel (low-alloy and corrosion-resistant) and aluminum alloys with your own hands. You just need to have a good understanding of the intricacies of the work ahead and delve into the nuances of manufacturing. An inverter is a device that serves to lower the electrical voltage to the required level to power the welding arc.

The essence of the semi-automatic welding process in a protective gas environment is as follows. The electrode wire is fed at a constant speed into the arc burning zone. Shielding gas is supplied to the same area. Most often - carbon dioxide. This guarantees a high-quality weld, which is not inferior in strength to the metal being joined, while there are no slags in the joint, since the weld pool is protected from the negative influence of air components (oxygen and nitrogen) by shielding gas.

The kit of such a semi-automatic device should include the following elements:

• current source;
• welding process control unit;
• wire feed mechanism;
• shielding gas supply hose;
• carbon dioxide cylinder;
• torch gun:
• spool of wire.

Welding station design

Semi-automatic Sanych

To make the transformer, Sanych used 4 cores from TS-720. The primary winding was wound with copper wire Ø 1.2 mm (number of turns 180+25+25+25+25), for the secondary winding I used an 8 mm2 busbar (number of turns 35+35). The rectifier was assembled using a full-wave circuit. For the switch I chose a paired biscuit. I installed the diodes on the radiator so that they would not overheat during operation.

The capacitor was placed in a device with a capacity of 30,000 microfarads. The filter choke was made on a core from TS-180. The power part is put into operation using a TKD511-DOD contactor. The power transformer is installed TS-40, rewound to a voltage of 15V. The roller of the broaching mechanism in this semi-automatic machine has a Ø 26 mm. It has a guide groove 1 mm deep and 0.5 mm wide. The regulator circuit operates at a voltage of 6V.

It is sufficient to ensure optimal feeding of the welding wire.

How other craftsmen improved it, you can read messages on various forums dedicated to this issue and delve into the nuances of manufacturing.

Inverter setup

To ensure high-quality operation of a semiautomatic device with small dimensions, it is best to use toroidal type transformers. They have the highest efficiency.

The transformer for operation of the inverter is prepared as follows: it must be wrapped with a copper strip (40 mm wide, 30 mm thick), protected with thermal paper, of the required length. The secondary winding is made of 3 layers of sheet metal, insulated from each other. To do this, you can use fluoroplastic tape. The ends of the secondary winding at the output must be soldered. In order for such a transformer to operate smoothly and not overheat, it is necessary to install a fan.

Transformer winding diagram

Work on setting up the inverter begins with de-energizing the power section. Rectifiers (input and output) and power switches must have radiators for cooling.

Where the radiator is located, which heats up the most during operation, it is necessary to provide a temperature sensor (its readings during operation should not exceed 75 0C). After these changes, the power section is connected to the control unit. When switched on.

The network indicator should light up. You need to check the pulses using an oscilloscope. They should be rectangular.

Their repetition rate must be in the range of 40 ÷ 50 kHz, and they must have a time interval of 1.5 μs (the time is adjusted by changing the input voltage). The indicator should show at least 120A. It would not be superfluous to check the device under load. This is done by inserting a 0.5 ohm load rheostat into the welding leads. It must withstand a current of 60A. This is checked using a voltmeter.

A properly assembled inverter when performing welding work makes it possible to regulate the current in a wide range: from 20 to 160A, and the choice of operating current depends on the metal that needs to be welded.

To make an inverter with your own hands, you can take a computer unit, which must be in working condition. The body needs to be strengthened by adding stiffeners. An electronic part is mounted in it, made according to Sanych’s scheme.

Wire feeding

Most often, such home-made semi-automatic machines provide the possibility of feeding welding wire Ø 0.8; 1.0; 1.2 and 1.6 mm. Its feeding speed must be adjusted. The feeding mechanism together with the welding torch can be purchased at a retail chain. If you wish and have the necessary parts, you can do it yourself.

Savvy innovators use an electric motor from car wipers, 2 bearings, 2 plates and a Ø 25 mm roller for this. The roller is installed on the motor shaft. Bearings are attached to the plates. They press themselves against the roller. Compression is carried out using a spring.

The wire passes along special guides between the bearings and the roller and is pulled.

All components of the mechanism are installed on a plate with a thickness of at least 8-10 mm, made of textolite, and the wire should come out in the place where the connector connecting to the welding sleeve is installed. A coil with the required Ø and grade of wire is also installed here.

Pulling mechanism assembly

Burner

You can make a homemade burner with your own hands, using the figure below, where its components are shown clearly in disassembled form. Its purpose is to close the circuit and provide the supply of shielding gas and welding wire.

Homemade burner device

However, those who want to quickly produce a semi-automatic gun can buy a ready-made gun in a retail chain along with sleeves for supplying shielding gas and welding wire.

Balloon

To supply shielding gas to the combustion zone of the welding arc, it is best to purchase a standard type cylinder. If you use carbon dioxide as a shielding gas, you can use a fire extinguisher cylinder by removing the speaker from it. It must be remembered that it requires a special adapter, which is needed to install the reducer, since the threads on the cylinder do not match the threads on the neck of the fire extinguisher.

Semi-automatic with your own hands.

You can learn about the layout, assembly, and testing of a homemade semi-automatic machine from this video.

A do-it-yourself inverter semi-automatic welding machine has undoubted advantages:

• cheaper than store-bought counterparts;
• compact dimensions;
• the ability to weld thin metal even in hard-to-reach places;
• will become the pride of the person who created it with his own hands.

Source: https://stroyka.ahuman.ru/drossel-s-voltodobavkoj-dlja-svarochnogo-poluavtomata/

How to make a choke for a welding machine with your own hands?

Almost every master has at least once thought about how to make a choke for a welding machine with his own hands.

Today, a fairly large number of different devices are sold that can be used in small-scale production.

This can be a device that operates on temporary or continuous current, a semi-automatic welding machine, or a product using electrodes. However, a high-quality device is very expensive, and budget analogues quickly become unusable.

Diagram of an AC welding machine with a separate choke: 1 – primary winding, 2 – core, 3 – secondary winding, 4 – choke winding, 5 – fixed part of the choke core, 6 – moving part of the choke core, 7 – screw pair, Dr – regulator current.

To assemble a homemade welding fixture, you will need to select and build all the necessary elements, including the throttle.

How to make a choke for a welding device

Manufacturing diagram of a welding choke.

Before winding the wire, you will need to insulate the yoke. To wind the choke, you can use aluminum or copper wire. In the first case, its cross-section should be approximately 36-40 mm, in the second, the recommended cross-section is 25 mm. Instead of wire, you can use a copper busbar 4-5 mm thick. If you plan to use an aluminum part, it must be thicker.

The wire needs to be wound in an amount of 30-35 turns, the bus is wound in 3 layers. If an element from a lantern light bulb is used as the core, then winding should be done only on one side part along the entire length until the window is filled. The winding direction cannot be changed. Each layer must be isolated from the previous one.

It is recommended to impregnate the elements with bakelite varnish.

During the winding process, taps should be made through the same number of turns. The contacts must be strong, since they will bear a significant load.

Installing a throttle has a positive effect on the operation of a semi-automatic device or an ordinary homemade device. For a device that operates on temporary current, it is recommended to use a device together with a structure for rectifying the current. In this case, it will be possible to use almost all possible electrodes.

A do-it-yourself choke for welding can also be installed on a device with a step-down transformer design. The element must be connected to the secondary circuit of the transformer for welding.

This will make it possible to build a proprietary semi-automatic welding device, which is very expensive. The throttle should be accurately calculated according to the formula that is in the documentation supplied with the device.

This product will have a transformer design with good dissipation and excellent performance.

It is important to configure the choke for an inverter or any other device correctly.

Stepwise adjustment of the welding arc current can be achieved by switching on an ohmic resistance at the output, which is a nichrome spiral, through the same number of turns of which taps should be made with contacts that can withstand any load. The disadvantage of this method is that in this case the thread will become very hot.

When the welding choke setting is successful, you can begin welding work.

How to make a choke for a DC welding machine

Welding with direct electric current is widely used not only in large-scale industries, but also in home workshops.

The modern market offers dozens (if not hundreds) of machines for welding using an electric arc, ranging from compact low-power welders to industrial high-performance units.

Regardless of the type of equipment used for electric welding, they all have one problem in common - an uncontrolled voltage drop, which makes igniting the arc and forming a seam difficult.

To solve this problem, craftsmen came up with a choke, which is introduced into the circuit with welding equipment. Beginner welders will immediately have many questions: “What is this part and how does it function? How to make a throttle for your device yourself? How to calculate the throttle correctly? In this article we will try to answer these and many other questions.

general information

What is a throttle for? This small part, connected to a circuit, ensures smooth ignition of the arc and maintains its stability even with voltage fluctuations, in addition, the metal practically does not spatter, the weld is of higher quality, you can fine-tune the device and weld thin metal without any problems.

The principle of operation is simple: the choke passes current through itself, accumulating it from the welding machine. The accumulated current is used to compensate for the lost voltage. Also, the bias choke provides the required current resistance if the voltage is too high.

It is not at all necessary to buy a throttle in a store, especially since it is far from a cheap purchase. This unit can be made independently.

Its design consists of a core and two windings with a cross-section designed to operate with a certain value of direct current.

This is why it will not be possible to make a universal choke, because a small part cannot cope with a powerful welder, and vice versa. So it is important to correctly calculate how many windings will be needed to work with a particular voltage.

Throttle application

A choke for DIY welding works best on welding transformers. Our practice proves this. The choke quickly ignites the arc even with a significant loss of current, so it can be used without problems in the country or in a workshop with unstable voltage.

A separate feature is the ability to use a choke in conjunction with a rectifier. The inductor + rectifier combination is capable of increasing the electromotive force of self-induction. In the case of a semi-automatic machine, such a set of equipment allows you to easily ignite an arc even at a considerable distance from the metal surface.

Instead of a conclusion

Now you know how to make a choke for a welding machine with your own hands and use it in your work. You can easily assemble a homemade choke on your own, knowing the basic laws of electrical engineering. Tell us about your experience with throttle design in the comments and share this article on social networks. Good luck!


Source: https://svarkaed.ru/oborudovanie-dlya-svarki/detali-i-prisposobleniya/kak-sdelat-drossel-dlya-svarochnogo-apparata-postoyannogo-toka.html