How to make homemade welding transformers. How to properly connect a welding transformer Connecting a welding transformer in a summer cottage

The typical design of a welding machine for electric arc welding includes two main parts: a power source, which receives voltage from the mains, and a welding unit. The welding unit, in turn, consists of a holder, the electrode itself and the neutral wire.

When the electrode briefly touches the place of the future connection, a spark jumps at this place (a breakdown occurs) in the gap from the air. This is where welding begins directly. The welder must have time to remove the heated end so that it does not stick to the metal surface. At the same time, you need to keep this minimum distance between the electrode and the metal, which allows you to maintain the electric arc.

Electric arc- this is a fairly long-lasting electrical discharge that occurs between the area of the future weld and the end of the electrode. The welding area is also called the arc zone. At the cathode region a temperature of over 30000C is formed. At the same time, the potential difference remains relatively small, only 20 - 25 V.

During arc formation, the air gap first breaks down with electrons. Afterwards, in a split second, the process stabilizes in the arc gap. Next comes the ionization of gas molecules by electrons, resulting in ionic conductivity. The arc combustion is stabilized with the help of melting and evaporating coating of the electrodes.

During welding, under the influence high temperature, the electrode begins to melt. A drop of molten metal appears at its end: it breaks off and falls onto the metal surface of the part. Within 95% of the total mass of the electrode is transferred to the metal, the rest turns into steam and splashes. , electrode diameter, arc length and other factors affect the rate of droplet formation and their size. The shell that covers the electrodes forms a slag to hide the metal droplets. As a result, drops of metal passing through the arc do not close the arc gap.

The operating procedure of a typical welding transformer and its connection diagram

The main power source for the entire welding system. With its help, the single-phase mains voltage is reduced from 220V to a working value for welding of the order of 50 - 80V. Non-standard operating conditions require the greatest power output from the transformer during welding work. The design of the welding transformer involves the passage of large currents through it.

For improvement technical characteristics welding machine uses additional devices:

To improve arc stability, ballast resistance is used. It is made of nichrome wire, which has good resistivity. The location of the electrode with less accuracy in relation to the metal is allowed;
For stable operation of the device from alternating voltage, a choke is used. At the same time, the weight of the welding machine increases significantly and use is possible mainly only in stationary conditions;
Rectification using diode bridges. The welding arc with constant current burns more stably, and the quality of the seams is higher.

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 the 380 W welding machine is the cause of sudden voltage surges, which leads to failure 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 machine 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 wire cross-section must comply with the rule: 1 sq. mm for every 8 A;
total length of supply wire– 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 requirements and standards when connecting guarantees subsequent safe and efficient use equipment.

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?

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.
Resistant to power surges. Since in the power supply network there often occurs both a sharp drop and a sharp rise in current voltage.
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.

Read also:

How to use it correctly.

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:

Define required power devices for performing welding in accordance with what will be welded.

Using the current regulator knob, adjust the position of the transformer core. These actions decrease or increase the current strength.

If necessary, set the switch on the unit body to the 380 V position

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.

You will probably find an instruction manual included with it. Having carefully studied it, you will find that only a few general phrases are said about the correct inclusion. Is it really that simple? Plug the plug into the socket and that's it? Alas, no.

An inverter-type welding machine is a complex device with its own nuances and features. By thoughtlessly plugging it into a household outlet, you risk losing the device itself or the wiring in the house. So how to connect a welding inverter correctly?

In this article we will briefly describe how to connect a welding machine to a 220 Volt home network and what should be taken into account.

Before you learn how to properly wire a welder, you need to make sure that the wiring in your home can handle the welding job. Inspect the sockets, how old are they? If the outlets have not been replaced for more than 25 years, most likely all the wiring in the house is also old. This is not critical if it can withstand high current values. But often old wiring brings nothing but problems. You are unlikely to be able to use modern welding wires with the machine if the power supply in the house is far from ideal.

You don't need to be an electrician to understand what will happen if you connect a powerful modern welder to old sockets. At best, you will be left without electricity. In the worst case, all your neighbors will be left without electricity, and your electrical appliances will simply fail.

In a word, check first whether your wiring can withstand the load. If you find that it can't, don't despair. This problem can be solved. We'll talk about this later. In the meantime, below is a diagram of connecting the welding machine.

Application of a current generator

So, you checked your wiring and it turned out that connecting a 220V welding machine is simply impossible. What to do in this situation? You can use a third-party current generator.

And at this moment, many immediately begin to remember that they keep an old gasoline generator in their dacha, which more than once saved them from sudden power outages. On the surface, the use of such generators seems like a pretty good idea, but in practice everything is different. Often everything gasoline generators weak and incapable long time provide voltage more than 5 kW.

As you understand, connection welding inverter to a low-power gas generator is simply pointless. To find out how much power you need, simply multiply the amperage you'll be cooking with by the voltage.

Let's take the most popular situation: you are welding with a 3 mm electrode with a current of 120 Amps and a voltage of about 40V. We multiply 120 by 40, we get 4.8 kW. This is the minimum power that a gas generator must provide. But in the calculations we did not take into account the efficiency of the welding machine, which is less than 100%. To ensure uninterrupted operation of the inverter you need at least 6 kW.

In general, a gas generator is a choice for those who no longer have any opportunity to get additional source current Ideally, before purchasing an inverter, you should check all the wiring and, if it is unsuitable, buy a welder with a built-in generator. Yes, these models are expensive and very bulky. But this is the most convenient solution to the problem.

If this solution is inconvenient for you, then you can buy a special current stabilizer for the welding machine. It connects directly to the welding inverter. This solution is suitable for a more or less stable power grid.

Use of extension cords

The topic of extension cords does not relate to connecting a welding machine, but these two issues are related. The fact is that if you select the wrong extension cables, the voltage may drop and the efficiency of the welding machine may decrease.

Why are extension cords needed? After all, the kit already contains quite long wires, usually up to 2.5 meters. At first this may be enough, but over time you will want more freedom for your actions. Especially if the device is heavy, and you need to move around the entire summer cottage or cook at height.

Therefore, we decided at the same time to tell you about connecting extension cables. First of all, remember that they cannot be used thoughtlessly. You need to accurately calculate what cross-section the extension wire should have. The maximum power that the wire can withstand will depend on this.

Let's give a simple example, using the same numbers from the previous example. Let's say we need a welding current of 120A. Wire cross-section 2.5 sq. mm. gives us 16A. Accordingly, for welding with a current of 120A, we need a wire with a cross-section of at least 12 sq. mm. We recommend choosing extension wires with a spare cross-section. Also remember to untangle them before welding so that it cools better. And don't forget about grounding. This is the simplest safety rule.

Before welding, at a minimum, you need to understand how the welding machine is connected to the existing network, as well as what conditions must be observed.

To quickly and efficiently connect the welding machine, you should follow the current operating instructions for devices of this class.

Of greatest interest from the point of view of the features of this process is the connection of a welding inverter, most often used at home.

The connection diagram for an inverter welding machine is quite simple and allows the device to operate in a cyclic (intermittent) mode, which allows for maximum welding efficiency. Before plugging into a socket, you still need to read the connection instructions, check the network parameters, completeness of the equipment and the external integrity of all its parts.

Options for connecting the inverter to the network

The instructions should clearly describe how to properly connect the welding machine, and also stipulate the procedure for its safe connection to the current electrical network. The need to check traffic jams and circuit breakers installed in the power supply circuit.

The fact that in old houses aluminum wiring does not allow working with currents above 10 Amperes should also be taken into account. Therefore, before connecting converters to the network, it is necessary to find out their rated power and current consumption.

When assessing the power taken from the network, one should not forget that when the device is turned on, there is a sharp surge in the starting current, the value of which can exceed the rated value several times.

Before connecting the device and welding work, the operator must fulfill the following requirements of the operating instructions:

remove foreign electrical devices (computers, transmitters, measuring instruments) from the device body;
when working with inverter equipment workplace must be freed from all other obstructions;
The rooms in which the welding unit is located must be equipped with a forced ventilation system.

To avoid emergency situations, before connecting the welding machine for the first time, it is recommended to test it in various welding modes.

Turning on the device (operating instructions)

When considering the operating conditions of a welding inverter, first of all, you need to pay attention to the following points:

the normal duration of the current load should not exceed 5 minutes;
in practice, the so-called “three-minute cycle” is usually used, which is two-thirds of the full load;
If strong heating of the case is detected, the device must be turned off until the causes of the overload are determined.

Welding using an inverter machine requires careful preparation, since when working with equipment of this class, possible dangerous situations. Before starting welding work, the operator must fulfill all the requirements of the operating instructions, including choosing the appropriate current mode and electrode type.

Connecting the inverter to the network and putting it into operation is allowed only after meeting safety conditions, including the use of sockets and plugs of the appropriate standard.

When operating a welding machine, you should use special coated electrodes (MMA type).

The thickness of MMA electrodes is selected based on the mode and type of metal to be worked with. Typically, the thicker the metal, the greater the current required and, accordingly, the diameter. The most common ones used at home are 2 and 3 mm electrodes.

Before starting welding, make sure that the electrodes are dry. The wire going to the torch is connected to the minus terminal, after which the gas hose is connected to the reducer located on the cylinder if welding is performed in a protective environment.

When connecting via an extension cord, you need to pay attention to the cross-sectional diameter of its cable. The cross-section must be at least 1.5 square meters. mm for working with current up to 16 A. The wire must be completely untwisted so that there is no inductance, which, after connecting the welding machine, will create additional resistance.

Launch Mode Features

The inverter is put into operation by pressing the “Start” button, which leads to a state of complete readiness for welding procedures. To start welding in a protective gas environment after connection, just slightly unscrew the torch valve, install the desired electrode and “strike” it on the workpiece to be welded.

When considering starting an inverter, the following must also be considered. The fact is that any inverter device is equipped with a soft start device that prevents the failure of the electronic elements of the circuit from a surge of current.

Despite such protection, current surges when turned on can reach values of the order of 40 Amperes, which are dangerous not only for the outlet, but also for the existing electrical network due to the strong “sag” of voltage.

During current surges within the above limits, the mains voltage may decrease (“sag”) from 220 to 130-140 Volts.

It is recommended to connect the power supply circuit of the device to the terminal contacts located directly on the distribution panel, where the grounding bus is also supplied separately. For a machine installed in input device, such voltage surges are less dangerous.

The situation with inrush currents is significantly simplified when linear rather than phase voltages are used to power the inverter. However, this option can be implemented only for devices designed for 380 Volts and provided that the house is connected to a three-phase network (generator).

When considering the features of putting an inverter device into operation, one should not forget the features of adjusting its load current, which is carried out automatically (using a special control unit). Setting elements that set the control limits are located on the front panel of the device.

Compliance with the instructions for connecting pulse converters is mandatory for all models of welding devices without exception. Only if the starting conditions for inverters are met is it possible to maintain their functionality and guarantee high efficiency of the welding process.