Connection and operation of the welding machine. Connection of a 380V welding machine diagram

Connecting a 380V welding machine: how to connect a 380V welding machine

Today we will talk about how to independently connect a 380V welding machine for its further use. It’s worth warning right away that if the welding machine will be used at home, it is very important to know what load the machines in the electrical network of your house or apartment can withstand. And only after that choose an inverter of the desired type and power. When choosing a welding machine, of course, you need to take into account many important characteristics. We will describe the main points that you must pay attention to when choosing this rather expensive equipment. It is important to choose a unit that can be used to perform a maximum of tasks, but also that the cost corresponds to the stated parameters. So, what is it worth focusing on?

1. Current consumption power. For example, in order to carry out welding work at home, a welding unit with a power of up to 5 kW is sufficient. Buying a device with a higher energy consumption threshold will be a waste of money.
2. Resistant to power surges. Since in the power supply network there often occurs both a sharp drop and a sharp rise in current voltage.
3. What network voltage range is the connected welding machine designed for?

After assessing all of the listed parameters, as well as some other important conditions, you will already know how to properly connect the welding machine to the power supply. We will try to help a little with this and describe the technical key points.

Connecting equipment for welding work

Schematic diagram of the connection of the primary windings of the welding machine for voltage: a) 220 V; b) 380 V (secondary winding not specified).

At its core, a welding machine is a source of inverter welding current and a welding arc. It is clear that this arc occurs between the electrode and the metal. And the welding machine itself acts as a converter. To determine the permissible power of the equipment for the type of electrical wiring in the room, you need to multiply the voltage value in the network by the maximum current value, which is indicated on the machine input panel of the unit for this type of work. To connect the 380 V unit itself, the output contacts must be correctly connected to it.

It is important to establish grounding to avoid electric shock when welding.

The connection diagram for welding equipment used in everyday life will be as follows:

1. Determine the required power of the device to perform welding in accordance with what will be welded.
2. Using the current regulator knob, adjust the position of the transformer core. These actions decrease or increase the current strength.
3. If necessary, set the switch on the unit body to the 380 V position
4. Connect the two supply ends to the “phase”, and the third end to the “zero”.

Remember: the thick ends define the exit, and the thin ends define the entrance.

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Using cord extensions for the welding unit

As standard, such devices have a power cord ranging from 1.8 m to 2.5 m in length. But this length of the power cord may not be enough to carry out welding work on metal surfaces. But how to connect the welding unit in this case?

In such situations, extension cords are used. But using them uncontrollably is quite dangerous; preliminary calculations are required. So, with a wire cross-section of 1.5 sq. mm, the maximum current that can be passed through such a wire is 16 A.

An important detail is that the extension cord must always be unrolled. This is due to the fact that this way the wire does not overheat under load and cools down faster, which reduces the risk of fire.

In addition, in this state no additional inductive reactance is formed.

By following these simple requirements, you will be able to properly connect the welding machine and weld safely.

expertsvarki.ru

How to connect a 380 volt welding machine

Welding is a responsible and potentially dangerous process, during which many factors must be taken into account, technology and safety rules must be observed. Incorrect connection of a 380 W welding machine is the cause of sudden voltage surges, which leads to failure of household appliances, “sticking” of the electrode and accidents.

Wiring and socket requirements

According to the principle of operation, a welding machine is a current converter into a welding arc. The operating current range (equipment power) is the main characteristic of the device, which determines its technical parameters. It must be consistent with the building's electrical capabilities. To determine this, the network voltage is multiplied by the maximum permissible current value (indicated on the input panel). Compare the obtained value with the data in the equipment data sheet.

From a 220 V household outlet, you can only power an inverter device, which is a more advanced device with many settings and safety parameters. In this case, it must have a built-in refractory fuse or circuit breaker. In old houses, the wiring is designed for a maximum current of 10 A, and when the device is started, there is a jump to 40 A - in such buildings you need to connect to the panel.

A transformer device, which is designed to operate from 380 V, is connected only through the electrical panel. If the wiring is weak, it is recommended to use a gas generator.

Unit connection sequence

The general connection diagram is performed in the following sequence:

• Carry out the necessary calculations and make sure that connecting the equipment for welding to the building network is acceptable.
• Check the machines and the condition of traffic jams, make sure there are no bugs.
• Set the operating voltage required for specific work depending on the complexity, volume and type of metal. The setting adjusts the position of the transformer core.
• Turn the device switch to the 220 V or 380 V position.
• If it is possible to connect to 220 V, insert the plug into the socket.
• To connect the welding machine to a 380V network, two supply ends are supplied to the “phase”, the third – to the “zero”. It is recommended to use an industrial socket and appropriate plug.

Using extension cords

The maximum length of the device cord is no more than 2.5 m; it is not enough for large-scale work. In this case, the use of an extension cord is allowed to connect the welding unit. When choosing it, you must comply with the following requirements:

• The cross-section of the wire must correspond to the rule: 1 sq. mm for every 8 A;
• The total length of the supply wire is no more than 10 m.

During operation, the cable must be completely unrolled to prevent overheating and the formation of inductive reactance. Intermediate connections must be avoided - large current losses occur through them. The use of damaged wires is strictly prohibited.

Compliance with the requirements and standards during connection guarantees the subsequent safe and efficient use of the equipment.

Video on the topic: How from 380 you get 220 and where to connect the grounding

specnavigator.ru

How to connect a welding machine to a network at 220, 380: setup

To ensure that the welding process is as safe as possible and that no serious problems arise during it, you should figure out how to connect the welding machine. This requires taking into account several basic factors, such as location. Type of device, location of ventilation, etc. Ventilation is one of the most important considerations when placing an inverter, as they are highly susceptible to overheating. You also need to pay attention to contact with dust. Thus, connecting a welding machine can be a daunting process for beginners.

Connecting the welding machine begins with checking the network parameters. It must match the one indicated on the body of the equipment, since otherwise it cannot be used. Here it is necessary to observe the correct connection devices. Here it is necessary to use grounding and phase wires, which can consist of one phase or two phases and a neutral.

If the model has a function for self-regulating the input voltage, then it should be placed in a position whose value will correspond to the network voltage. A fixing screw is usually used to secure the position.

The device is connected to the network using an ordinary plug. It must be in good condition and meet temperature standards, as heating will occur during operation. The plug must have a ground to which a special cable is connected. You also need to connect the ground cable to the appropriate terminal. The connection should occur close to the future seam, but at a safe distance. A special clamp is used to secure it to a metal surface.

Step-by-step instructions for connecting a welding machine

If you do not know how to connect the welding machine, then you should follow the sequence of steps below. Naturally, before connecting, you need to once again check the integrity of the device itself, the functionality of the components, and also find out the operating voltage. To connect you should have the following things:

• Welding machine;
• Extension;
• Adapter.

The step-by-step connection sequence is as follows:

• Preparing a plug for connection, which must have a certain set of parameters corresponding to the required thermal throughput;
• Select an outlet that has a fuse or circuit breaker;
• The return cable is connected to the terminal;
• The cable with the holder is connected to the electrode using a clamp.

Only after completing all these procedures can the equipment be connected to the network. Almost all models have short wires, so to connect them you need to use an additional extension cord. The wire in it must be large enough to withstand the specified voltage level.

Connection features depending on the type of device

Naturally, a mini welding machine and a large professional model will have their own characteristics. If you need to connect a welding inverter with two phases, then the wires will be connected in an individual sequence. The first wire is put into phase immediately. The second wire is connected to the neutral output. The third wire is connected to the protection.

If you have to connect a three-phase device, then there is no longer a mandatory sequence. One of the main rules on how to connect a welding machine is to connect the first two wires to any phases, and one to the protection.

It is very important for specialists to know all the features of connecting various devices, especially such as a welding transformer. If this particular technique is used, then a number of special requirements must be taken into account. After all, the transformer is designed to work in a wide range of welding current parameters. This leads to a sharp surge in current in the network. Because of this, the circuit breaker may turn off or the socket may burn out. This type of equipment is connected to the panel.

Failure to comply with the above rules can lead to serious damage to equipment and also pose a risk to the life and health of people. Pre-inspection not only helps to avoid unnecessary injuries, but also ensures good, stable welding conditions, not to mention fire hazards.

Connecting an inverter welding machine is the simplest of the entire series, since most of them simply plug into a regular outlet without additional terminals, grounding, etc. The only question that may arise is how to connect the welding wires to the welding inverter. Here, too, everything is extremely simple, since the holder is placed on one terminal, and the clamp on the second. Most models even indicate the corresponding icons so that there is no confusion.

Possible connection problems

When the welding machine has been correctly configured, problems may still occur. One of the most common problems is the strong hum of the transformer, which is often accompanied by overheating of the windings, so that even forced and natural ventilation cannot cope. The cause of the problem here lies in the turn short circuit that occurs in the primary winding. The only solution to this problem is to rewind the winding, which can pass partially or completely.

When the welding machine is connected to the network, they may produce too high a current. This is also the reason for the short circuit, but this time its location is the secondary winding or the regulator winding. To correct the situation here, rewinding or eliminating the short circuit is also required.

If, when necessary, reduce the current value, nothing comes of it and the regulator spins in vain, then there is clearly a problem with the regulator terminals.

From time to time, a hum may occur on the device, which is not typical for normal operation. This situation may occur due to a weakened spring or due to a broken wire.

It may occur that the device does not turn on. Here you need to check all the connection contacts, since a contact may be broken, something may be disconnected, and so on. All inspections must be carried out only when completely disconnected from the network.

Thus, you should know not only how to connect an inverter welding machine, but also how to deal with its problems.

Video: connecting the welding machine to the generator

svarkaipayka.ru

Connecting the welding machine | Electricdom.ru

A welding machine is a voltage and current converter that are necessary to produce an arc between the electrode and the metal. Manufacturers of welding machines try to create the best possible conditions for the specialist during his work.

First of all, the welding current range (figuratively speaking, the power of the device) plays a role in the work. For welding fences, gratings and other structures, an electrode of up to 4 mm is sufficient, and the welding current in this case will fluctuate between 180-220 A. Ux.x also plays a role. (open circuit voltage), the higher it is, the easier it is to ignite the arc. Usually it is 35-80 V. But many devices already have an arc ignition function, which is convenient. If the machine has a function for rectifying the welding current, the seam will be of better quality and smoother.

The welding machine has a knob for adjusting the current (the core of the transformer is adjusted), the current decreases or increases. There are fewer turns on the secondary winding of a welding transformer than on the primary winding, this is necessary to increase the current.

When connecting the welding machine, you need to look at what voltage it is designed for; if it is both 220 V and 380 V, you need to switch the corresponding switch.

To connect a 220V welding machine to a 380V network, you need to connect the power supply to one wire per phase, the other to the neutral, and the third wire to the protective neutral conductor to protect the housing. To connect a 380 V household welding machine to the machine (you need to make sure that the machine’s rated current is sufficient for the operation of the welding machine), connect the supply ends to any two phases, and also connect the third wire to the protective neutral conductor to protect the housing. If you can’t see where the input and where the output of the welding transformer is - thick welding ends (output), thinner ends (input). In fact, a certain number of turns are simply added to the primary winding of the transformer and the supply voltage is increased from 220 to 380V.

Welding transformer NORDIKA 3200 is designed for manual arc welding with alternating current of low-carbon and low-alloy steels. The device is equipped with a fan and overheating protection, equipped with cables, an electrode holder, a grounding terminal, a mask, a brush and a hammer. Manufacturer: TELWIN.

Characteristics: Supply voltage, 220-380 V Power consumption, 3.5 kW Maximum current consumption, 16 A No-load voltage, 48 V Welding current, 55-190 AD Electrode diameter, 2-4 mm Weight, 20 kg Dimensions, 650x325x425 mm

On a core made of transformer steel, there are two windings - primary and secondary. In devices of this type, one winding is fixed statically, and the second moves relative to the first along the core. It is this movement that regulates the current strength.

To determine the permissible power of the welding machine for a specific electrical wiring, you need to multiply the mains voltage by the maximum current value indicated on the input panel.

When the current (welding) on ​​the secondary winding of the transformer increases, the voltage decreases, the power must remain the same (property of the transformer).

www.electricdom.ru

Connecting the welding machine and operating rules

In order to use the welding machine correctly and safely, it is necessary to ensure its connection in accordance with all the features of handling this equipment. It is important to connect the welding machine correctly.

Attention must be paid to every little detail, including the choice of power cable for the device. To work with a welding machine, you must have experience, since this equipment is potentially dangerous; you cannot start work without experience and protection.

Rules for connecting a welding machine

To use welding correctly, you must follow all the requirements and recommendations for turning on the welding machine:

1. The first thing to do is check the frequency and voltage. The data is indicated by the manufacturer on the equipment housing. They must match the network indicators. The connection itself can be made in one of several ways: using two phases, one phase and neutral, using separate grounding.
2. If the model of welding equipment allows it, you must immediately select the required voltage for the supply network. The switch is fixed in the selected position. It is important to determine which network will work with, otherwise the device will fail.
3. To connect, you must use a plug whose characteristics comply with all standards. Plugs can be easily purchased either separately or together with extension cables, which makes connection much easier. The plug must have a grounding lug, through which the connection will be made. A regular socket is no longer suitable; you must use a special fuse; you can also use an auto switch to make the connection simple and safe.
4. The welding machine is turned on by means of a return ground cable, which is attached to the terminals at the required operating point. In this case, the distance from the future seam should be as minimal as possible. The cable holder must be fixed to a special fragment of the housing using a reliable clamp.
5. Before you begin connecting to the network, you must re-check that all plugs and cables are connected securely and firmly. If there is poor contact, this may cause the equipment to stop, creating a dangerous situation.

Before you start working, you need to prepare gloves and a special welding mask with eye protection. This is a mandatory condition, since a high-temperature arc is formed during welding. It can seriously damage your eyes if you don't protect them.

Wiring for welding machine

If the welding machine will be used at home, then you must immediately check what type of wiring is installed and inspect the sockets. This happens due to the fact that weak wiring can lead to failure of the welding machine. Typically, in older homes, outlets are rated at 10 A, which may not be sufficient for welding work. In this case, the use of special generators may be required. It is necessary to inspect the condition of the meter; under no circumstances should there be so-called bugs on it.

If these requirements are not taken into account, then when the welding machine is turned on, a sharp voltage surge may occur, and the light may well go out not only in the apartment, but throughout the entire house. Strong drops of up to 150 V lead to the fact that welding becomes impossible, and vibrations occur in the room, which are dangerous for any electrical equipment and lighting fixtures.

Can I use an extension cord?

When connecting the welding machine, it is important to use the correct power cord; its length should be up to 1.8-2.5 m. Therefore, the question arises whether an extension cord can be used if required. There are no special restrictions, but you cannot use such equipment uncontrollably. This requires a calculation; it is not recommended to connect the extension cord without it.

You need to start with the cross-section of the electrical cable. For a product of 1.5 m², you can use a current with a maximum value of 16 A. For equipment with a cable cross-section of 2.5 m², the current value is already higher - up to 25 A. It is necessary to take into account what type of welding equipment will be used, what conditions for its applications exist. Manufacturers of welding machines themselves indicate all the necessary values; all that remains is to purchase an extension cord that meets all the requirements.

When using an extension cord, it is necessary to completely unroll the wire so that it cools quickly and easily and does not form inductive resistance. It is important to use grounding; operational safety depends on it.

Sometimes it becomes necessary to extend the cable near the entrance of the welding machine. It is better not to make intermediate connections; you should use a whole multi-core cable with the required cross-section. For a current of 140 A, the cross-section should not be less than 35 mm². It is best to use copper conductors with a diameter of 7 mm or more.

Welding generator or gas generator?

For proper use of the equipment, it is important to choose a generator. It often happens that when the voltage drops during welding, the process stops and becomes impossible. Many people make the mistake of using a gas generator for work, which will provide power to the welding equipment. Its power is small and it is simply not able to provide high-quality work.

You cannot use generators whose power is less than 5 kW, as they will not withstand the required voltage.

The output voltage value will be very different from the total power.

When using a 3 mm electrode, the current is 120 A, the voltage should be 40 V. The output power will be 120x40 = 4.8 kW. If the efficiency of the welding inverter is 0.8-0.9, then the input power should be 4.8/0.8/=6 kW. It is important to remember that an inverter-type welding machine is sensitive to any voltage surges at the input. If normal operating conditions are not ensured, the equipment will quickly fail.

If the network is weak, then it is better to use a welding machine that is connected not to a gas generator, but to an electric generator. The Champion DW 180 AE model is perfect here, for which a welding current of 180 A is possible. If necessary, you can use a special AC stabilizer, which is mounted in front of the welding equipment. The cost of such equipment is significant, but its use is necessary for high-quality work and safety.

For safe use of the welding machine, it is important to ensure that it is turned on correctly. To do this, you need to follow fairly simple recommendations, use only correctly selected cables for connections, and, if necessary, purchase a generator to power the device.

moyasvarka.ru

Connecting the welding machine

electric-220.ru

How to connect a welding machine: requirements

Until recently, the question of how to connect a welding machine was asked only by professional welders. Today this topic worries a large army of amateur craftsmen. Modern manufacturers have significantly expanded the scope of the concept of “household appliances and tools”. Now this list includes machines and devices for various purposes. Among this variety there is also a welding machine.

Connecting a welding machine can be a problem for those who purchased such a tool for the first time or asked it from a neighbor. You need to connect it correctly so that during operation you do not damage the electrical wiring, sockets, and the device itself. The equipment passport, as a rule, does not contain such recommendations.

Types of welding machine

You need to decide on the type of “welder” before starting work. There are two types of apparatus: inverter and transformer. The inverter welding machine is lightweight and compact and is equipped with many protections and adjustments. There are different models, differing in power and output current, designed for real “pros” and for “dummies”. Light weight (up to 5-6 kg) and modest dimensions allow such devices to be used as portable ones. You can simply hang them on your shoulder and work in the most difficult conditions. The device confidently cooks with electrodes with a diameter of up to 4-5 mm, and the price is quite reasonable.

The only drawback is maintainability. In the event of a breakdown, without knowledge of modern electronics, you will not be able to fix it yourself. Important advice for beginners from professionals - the “inverter” cannot be placed on the ground. Be sure to place a wooden or plastic board under the device.

Transformer welding machines are based on a traditional scheme: a network transformer with copper windings. Hence the solid dimensions, decent weight and corresponding price. The undoubted advantages of such devices include the ability to work with metal of almost any thickness and ease of repair.

Solving everyday problems that occur when using a welding machine at home and in the country. Practical experience in using various types of welding machines.

The snow is gradually melting and the summer season is quickly approaching, which for many is associated with construction or the hassle of arranging a summer cottage. One of the indispensable devices in a summer resident’s household has long been welding machine, especially since prices for household welding machines have dropped to 4-7 thousand rubles that are affordable for everyone.

If you bought a welding machine for the first time or borrowed it from a neighbor, then the question naturally arises - how to turn it on correctly? To turn it on correctly means to turn it on in such a way as not to damage the sockets and wiring when using the device for its intended purpose, not to burn the device itself, and to carry out the welding process.

Unfortunately, the passport for the welding machine provides only general recommendations on work-rest cycles, i.e. it talks about the need to take breaks during the welding process and nothing or almost nothing is said about the correct connection to the 220 V network.

What types of welders are there?

Let's talk about the nuances in detail. First of all, determine which one you have and which one type of electrical outlet. Welding machines can be divided into two large groups: transformer and inverter. much lighter and more compact, have soft start devices, many adjustments and protections. With output currents of up to 140 A, they can be plugged into a 16 A power outlet without any problems.

Welding inverter

Of course, inverter welding machines also have a transformer, but it operates at frequencies of 50-100 kHz, so it is very compact. The weight of a modern inverter welding machine is only 2.5-3 kilograms, and the dimensions are approximately 300x190x130 mm. An example is welding inverter “Fubag IR160”.

It has a MMA welding current range of 5-160 A. Welding current at 25% load is 160 A. Open circuit voltage is 65 V. Electrode diameter is 0.6-4.0 mm. Power factor 0.92. Productivity 85%. Air forced cooling.

Dimensions (LxWxH) 340x120x240 mm. Weight 5 kg. Price from 5118 rub. Typically, such inverters are equipped with convenient plastic cases.

Welding transformer

Transformer welding machines, as a rule, are less modern devices and have fewer adjustments and protections. Since the transformer operates at 50 Hz, it is much bulkier and heavier. An example is welding machine "Telwin Bimax 4.195 Turbo".

Welding current range 30-160 A. Power 2.3-5.2 kW. The diameter of the welding electrode is 0.6-1.2 mm. Dimensions 600x340x430 mm, weight 28 kg, price 11,800 rubles! When you plug it into the network, a surge of current occurs, which can burn out the electrical outlet or turn off the circuit breaker. Therefore, such devices are better using a special socket. For example, a very common socket for a three-phase electric stove RShVSh 40 (40A, 380V) is suitable.

Wiring is different

Before using a welding machine, look at what outlets and wiring are installed in your home. If the house is old enough, there may be outlets rated for a maximum current of 10 A. The wiring to these outlets is usually rated for the same current. Look at the traffic jams or the machines, and see if there are any bugs.

Welding is a very responsible process and must be approached seriously, otherwise you risk leaving yourself and your neighbors without electricity. By the way, if there is an overhead power line to your house, then the welding machine can load it so that the voltage “falls” below 150 V. This will lead to the fact that you will not be able to cook normally, and voltage fluctuations will occur in the network, dangerous for electrical appliances and electric lamps

Direct and reverse polarity when working with a welding machine on video:

How to use extension cords?

Typically, the welding machine has a network cable of no more than 1.8 - 2.5 meters. Therefore, when performing welding work, extension cords are used. Uncontrollably. Here you need to check and calculate everything in advance. The wire in the extension cord must be of sufficient cross-section. If the cross-section of the wire is 1.5 square millimeters, then the maximum current for which it is designed is 16A, 2.5 square millimeters - 25A.

Choose the wire cross-section with a margin and always unroll the wire from the extension cord, because... in this case, it cools better and no additional inductive resistance of the coil with the wire is formed. Don't forget to use grounding for your safety.

If you need to extend the wires at the output of the welding machine, it is better not to make intermediate connections. You need to buy a multi-core solid cable of the required length. The cable cross-section for current up to 140A must be at least 35 square millimeters, i.e. The cross-sectional diameter of the copper core must be at least 7 millimeters.

Gasoline generator or welding generator?

As mentioned above, due to a voltage drop in the power line, welding is simply impossible. In this case, many try to use a low-power gas generator to power the welding machine. This is the wrong approach if the generator has a power of less than 5 kW. The output voltage of a low-power generator is highly dependent on the load power.

When welding with a 3 mm electrode, the current reaches 120A, at a voltage of 40 V. The output power is 120x40 = 4.8 kW. Even with an inverter efficiency of 0.8-0.9, the input power should be 4.8/0.8=6 kW. By the way, inverter welding machines are very sensitive to voltage surges at the input and can fail.

Therefore, with a “weak” network it is better to use welding machine combined with an electric generator. For example, Champion DW 180 AE, welding current up to 180 A, weight 110 kg, price from 42,000 rubles. There is another option, this is to use it in front of the welder. True, if the network is very “weak”, such a solution will not help or you need to choose a stabilizer with a large range of adjustments, but it itself costs from 30,000 rubles.

conclusions

If possible, we told you about the problems that arise when using welding at home and in country life. In our opinion, you better choose for welding inverter welding machine. It will pay for itself faster, and learning how to use it is much easier and more enjoyable. I hope now you know how to properly connect a welding machine. If we missed something, write and share your experience, and we will tell others about it. We wish you success!

Electric welding equipment must be reliably grounded. There are special bolts on the transformer casings with the inscription “Earth”. In addition, the terminals of the secondary windings of welding transformers are grounded. Welding transformer connection diagram shown in the figure.

Connection diagram of the welding transformer to the welding station: 1 - welding station, 2 - three-core hose cable with a grounding conductor, 3 - welding transformer, 4 - regulator, 5 - housing grounding clamps, 6 - single-core hose cable, 7 - electrode holder, 8 - grounding wires

Before starting at the transformer it is necessary to check the compliance of the voltage of its primary winding with the supplied mains voltage. Before switching on the transformers, the welding circuit must be open.

Transformers should be connected to the supply network with separate switches.

The distance from the network to should be as short as possible. The cross-sections of wires connected to the secondary circuits of transformers or to the terminals of welding generators are selected according to the table.

To supply current to the electrode holder, insulated flexible wires are used in a protective hose with a length of at least 3 m. Their cross-sections are selected according to the table.

Load standards for flexible welding wires connected to the electrode holder.

The return wire for connecting the product being welded to the source of welding current can be steel busbars of residual cross-section, various steel structures, the structure being welded itself, etc. It is not allowed to use grounding networks as a return wire, as well as metal structures of buildings, equipment, etc. d.

Voltage drop in supply connecting welding wires no more than 5% of the network voltage is allowed. If this condition is not met, the cross-section of the wires must be increased.

Useful tips for using welding transformers

Maintenance of welding transformers is simpler than welding generators, and care for them comes down to ensuring reliable grounding of the housing, keeping all contacts in good condition and periodically checking the insulation resistance of the windings, especially when the installation is operating outdoors.

During operation, the following malfunctions may occur in welding transformers:

• strong humming and heating of the windings due to a turn short circuit in the primary windings. Damage is eliminated by partial or complete rewinding of the windings;
• The transformer produces a very high current due to a short circuit in the secondary winding or in the regulator winding. Eliminate the malfunction by eliminating the short circuit in the windings or rewinding them;
• the welding current does not decrease when the regulator operates, which can be caused by a short circuit between the regulator terminals;
• The regulator hums abnormally when welding; this may occur due to a malfunction of the drive or due to weakening of the spring tension;
• strong heating of contacts in connections due to broken electrical contact; The malfunction is eliminated by reassembling the heating connections, cleaning and tightly fitting the contact surfaces and tightening the clamps to failure.

A welding machine is a necessary tool for construction and performing a number of works, but it is difficult to imagine this unit without a welding transformer. However, a way out of this situation was found long ago - the creation of a homemade welding transformer.

What do you need to know before starting?

A number of characteristics affect the operation, so you need to familiarize yourself with them in more detail to create your own transformer. You should start with the number of phases and network voltage. These parameters indicate the voltage at which the work is carried out. As for homemade device options, 220 V is often used for them, although some can use 380 V. This is important when performing calculations.

Another important indicator is the rated welding current. The possibility of using cutting and welding tools depends on this value. In self-made devices, this parameter does not exceed a value of 200 A. This is quite enough, and an increase in this indicator results in an increase in the weight of the unit, which is inappropriate in this case.

When the device is operating, there must be current control limits. To work with metal of a certain thickness, a certain current strength is also necessary, otherwise it will simply melt. To avoid this, there is a regulator. Often the limits depend on the need to use electrodes of a certain diameter.

Figure 1. Diagram of a simple welding transformer.

In home-made designs they range from 50-200 A. As for spot welding machines, here the value is higher, 800-1000 A.

The diameter of the electrode used is also of certain importance. The rated current also depends on it. So, for example, when using thick electrodes, the current should be high, and when using thin electrodes, it should be small. This also applies to the thickness of the metal being processed.

For a contact welding machine, that is, spot welding, the diameter value is important. It is necessary to note that in this case there are two values: the diameter of the electrode and its cone-shaped part.

The next indicator is called the rated operating voltage, which is the output voltage after the input voltage has been reduced. This value is no more than 80 V. Transformers for arc units have a rated voltage from 30 to 70 V. This value for spot welding is 1.5-2 V. It is necessary to note that this parameter is an unchangeable value, and is set from the very beginning.

The key characteristic is the nominal operating mode. This indicator indicates the time during which the transformer can be used without interruption and during which it is able to cool down. For homemade devices, this value is 30%. That is, when operating the unit for 10 minutes, 7 of them will be spent cooling the device, and 3 minutes will be the entire work process.

Figure 2. Diagram of a welding transformer with regulators.

The following indicators are secondary, since they practically do not affect anything. But knowing them, you can determine the efficiency of the device. We are talking about output and power consumption. During calculations, you need to know the value of the power used. In addition, the smaller the difference between the second and first indicators, the better the device.

For arc units, it is also necessary to take into account the no-load voltage. If this parameter is high, then it will be easier to cause an arc. However, it must be taken into account that the indicated value has its own limitation, equal to 80 V, which is associated with the safety of the worker using the unit.

Device diagram

Creating a circuit is an important part, especially if you need to make a transformer yourself. The circuit is not complicated, but if difficulties arise, it is recommended that you familiarize yourself with GOST 21.614, which contains graphic symbols for electrical equipment. The simplest diagram is the one shown in Fig. 1. But the development of this direction is undergoing changes, as a result of which more complex parts can be seen in homemade mechanisms, such as regulators and diode bridges. A similar diagram is shown in Fig. 2.

As for arc devices made by hand, a toroidal transformer is most often used. It has a high rated current and efficiency, and the weight of the unit is light. The remaining characteristics are also higher than when using a P-shaped core.

A transformer for spot welding has a more complex circuit. It includes thyristors, capacitors and diodes. This allows you to better adjust the operating time and amperage. For a unit of this type of welding, the diagram is shown in Fig. 3.

Performing calculations

Figure 3. Transformer diagram for spot welding.

The transformer is represented by a core and two windings, which are responsible for the technical parameters of the product. Therefore, for calculations, you should know the parameters of the primary and secondary windings, their voltage, rated current and a number of other characteristics.

For calculations you need to know the following parameters. First you need to find out the voltage of the primary winding, which is the voltage at which the unit operates from the network. This value is 220 or 380 V.

It is also necessary to find out the rated voltage of the secondary winding, which is aimed at reducing the incoming one. This value should not be more than 80 V; it is needed to excite the welding arc. It is necessary to take into account both the diameter of the electrodes and the thickness of the metal with which the work will be carried out. In this case we are talking about the rated current of the secondary winding.

The reliability of using a welding unit depends on the cross-sectional area of ​​the core. For operation, values ​​from 45 to 55 sq.m. are recommended. cm. The current density in the winding is responsible for electrical losses. As for hand-made versions of products, for them this figure is 2.5-3 A.

To clearly show how the calculations are done, let's take our values ​​and use them for the formula. So, for example, the network voltage will be equal to the value U1 = 220 V, and the voltage for the secondary winding is U2 = 60 V. As for the other values, the rated current is 180 A, window area So = 100 cm², core cross-sectional area Sc = 45 cm², current density in the winding is 3 A. Based on the data presented, you can calculate the power of the device, which will be equal to P = 1.5*Sс*So = 1.5*45*100 = 6750 W.

It is necessary to note that in this case the value of 1.5 is used for transformers with a Sh and P core. As for the ShL and PL cores, this value is 1.7 for them, and for toroidal ones it is 1.9.

After this, you need to determine the number of turns in each winding. The result is K = 50/Sс = 50/45 = 1.11. The last value is the number of turns per 1 volt. In this case, it should also be noted that the number 50 is suitable for Sh and P cores. For ShL and PL the value is 40, and for toroidal ones - 35. After the previous calculations, you can find out the maximum current value on the primary winding. For this there is a formula where you need to insert the obtained values: Imax = P/U = 6750/220 = 30.7 A.

Next, you need to calculate the turns using the formula Wx = Ux * K. For example, for the secondary winding, a similar formula and result will look like this: W2 = U2*K = 60*1.11 = 67. The last value shows the number of turns required.

Assembly of the structure

As an example, a transformer with a U-shaped core is shown. The process of creating a structure begins with the manufacture of a frame for the windings. To do this, you will need PCB plates. The parts needed for the boxes are cut out of them.

As for the boxes themselves, they will have two lids located in the upper part, on each of them you need to make the slots necessary for the walls in the amount of four pieces. The cross-sectional area of ​​the core will be equal to the internal area of ​​the indicated slots. However, it should be noted that it is necessary to make a small increase, which will be required for the walls of the boxes.

After completing the assembly of the frame, it is insulated, then you can begin to create the winding. It is recommended to use wires that have heat-resistant insulation. After winding one layer, it is insulated, then winding of the next layer begins. It should not be forgotten that after a certain number of skeins it is necessary to make taps. After completing the winding, you need to install the top insulation. Copper bolts are fixed at the ends of the bends.

Then they begin to assemble and blend the magnetic circuit. For this purpose, special iron is used. Old metal plates are suitable for the core, or you can purchase new ones. After completing the assembly, you need to check the device with a tester.

At the last stage, you need to make a diode bridge, then install the regulator. Diodes KBPC5010 and B200 are suitable for the bridge. Their number depends on the rated current. If the unit has a similar parameter of 180 A, then for the device you need to take 4 diodes, since one is designed for 50 A. The diodes are attached to the aluminum radiator, then the connection is made simultaneously with the tap choke. Then the housing is assembled into which the transformer will be placed.

Manufacturing of a toroidal transformer

These homemade welding structures have more advantages than a W or U-shaped transformer. As a result, it is more profitable to make such a unit. To make the structure yourself, you need to use parts from old devices.

The work includes the following provisions. First you need to roll the metal plates with a round object, such as a bottle. After this, one of the plates is twisted into a ring; the element must be secured with self-tapping screws. This creates a mandrel for the plates.

Then the plates are laid, work should begin from the edge, gradually moving inward. It is necessary to lay those plates that have not yet been rolled in, which is associated with a significant internal diameter. After the required number of these elements has been collected, the plates are pressed. Gradually the internal diameter will decrease, so you can start using the rolled elements.

This creates the first ring for the magnetic circuit of the product. It is necessary to prepare the second mandrel required for the next magnetic circuit ring. In this case, the actions are similar; installation is carried out as in the case of the first ring. It is important to note that there should be no gaps between the plates. You need to take time to press the plates.

After completing the steps, you need to use a hammer to tap the end part of the rings. Then you will need epoxy glue, which is used to soak both rings. The glue must first be diluted with a solvent. Both rings are glued together.

Now you need to determine the height of the core. It should be noted that it can vary, depending on the thickness of the plates used. In this case, a core with a height of 14 cm is used. As a result, its area will be 56 square meters. cm, which, adjusted for gaps, will ultimately amount to 50 sq. cm.

Next, you need to isolate the element. To do this, circles are cut out of cardboard and placed on the core. The finished part is wrapped with black electrical tape, which has a rag base, and then with masking tape.

The transformer is ready for the next stage. On a shuttle made of chipboard, you need to wind the wire of the primary winding, and the end of wire No. 1 is wrapped with a panel. Then a shuttle is inserted through the hole in the torus, each turn is pressed. Each turn needs to be distributed over the core.

After winding, the first row is wrapped with electrical tape, then the second row is wound, not forgetting to make bends. After this, you need to check the no-load current. The ammeter should show a value in the range of 0.2-1.2 A. In this case, the actions were performed correctly.

End No. 2 is also wrapped using a panel. Next, the primary winding is insulated. Then the secondary winding is wound, only in this case the shuttle will not take part. Upon completion of the work, this part is insulated, two circles need to be cut from the PCB, and two holes are drilled to secure the windings.

It is worth noting that it will not be possible to manufacture and assemble the structure the first time.

But carefully performing calculations and installation, the end result will please you.

Answer:

Any electrical equipment, including a welding transformer, must be very reliably grounded. Welding transformers have specialized grounding bolts, which are located on the casings and are usually marked with a corresponding inscription. Also, this device must have grounded terminals of the secondary windings of the transformer.

The figure shows a diagram of connecting the transformer unit to the welding station. Number 1 shows the welding station, then from the welding station under number 2 there is a cable with a grounding conductor (three-core), then under number 3, in fact, the transformer unit itself. The number 4 denotes the control unit (most often a saturation choke), the fives denote the grounding clamps of the housing, and the six denotes the hose cable (single-core). The number 7 represents the electrode holder and the number 8 represents the ground cables.

Before you start the welding machine for the first time, you must check the voltage on the first winding. It must correspond to the voltage supplied from the network (220 or 380 Volts). Make sure that the circuit is open before turning on the transformer unit.

Try to reduce the distance from the power supply to the transformer unit to a minimum. There is a specialized table that allows you to select the correct cross-section of the power cable. In this case, it is very important to ensure that the voltage in the electrical network and the supply connecting wires matches within 5%. If the voltage drops below this indicator, you will have to increase the cross-section of the cable.

You should also pay close attention to the wires that are connected to the electrode holder. Typically, flexible insulated cables protected by a protective hose are used for this purpose. The length of such a wire must be at least three meters. The cross section is selected in accordance with another table.

During operation of the welding transformer, you should constantly monitor the grounding condition, keep the device connections in good condition, and test the insulation resistance of the primary and secondary windings.