The selection of welding equipment is a crucial process. To acquire the really necessary equipment, you need to understand the principles of its operation, the types and purposes for which each type of device is intended. These aspects are discussed in detail below. After reviewing the main features and nuances of equipment, you will understand how to choose a welding machine correctly.
Classification of welding machines.
Varieties of welding equipment
First of all, it is worth noting that welding machines of any type are equipped with a power unit. Power units convert the received energy in different ways (depending on the category of equipment). There are devices that receive the necessary voltage directly from special batteries or fuel generators.
Each category of electric arc devices has its own technical characteristics, advantages and disadvantages.Back to table of contents
Inverter welding machines
Such equipment is one of the latest achievements in the field of creation of welds. His release was adjusted in the 80s. XX century. Equipment with a transistor inverter allows you to change the properties of the resulting electricity several times. First of all, the current is straightened, having made its way through the semiconductor, and then it is stabilized by a special filter. Electricity with a default frequency (50 Hz) is converted into alternating current with huge frequencies that reach several tens of kHz. This process is called inverting.
The design of the welding inverter.
Inverted current is supplied to the mini-transformer, which reduces the degree of its voltage and increases the power. Then a high-pass filter and a rectifier create an electric arc that transmits a stabilized current to the electrodes.
The main advantage of the welding inverter is the conversion of electricity into high-frequency current, which gives an undeniable advantage in weight and size. In addition to creating high frequencies, inverters have the following advantages:
- Increased power supply performance (efficiency 80-95%) with a relatively small loss of electricity. This allows you to power the equipment through a simple outlet and save on electricity.
- The ability to use the equipment for a long time in uninterrupted mode.
- Wide adjustment range of the electric current. This allows the use of many different electrodes, including the thinnest ones.
- Smooth adjustment of electric current and voltage.
- The principle of the functioning of the equipment is based on microcircuits and processors that allow you to quickly ignite the electric arc and maintain its stability.
- The device is protected from power surges in the mains.
- High-quality welded joints are obtained. In the process of their formation, molten splashes are minimal.
- There is the possibility of welding particularly hard structures.
- Safety of work with the equipment at a very high level.
Welding inverter control
To choose the inverter welding machine correctly, you also need to know about possible shortcomings. First of all, it should be noted that such equipment is expensive. Its cost exceeds the transformer equipment several times. Repairing possible inverter malfunctions also severely hits the wallet. For example, if a node of power transistors fails, you will need to lay out at least 1/3 of the total price of the device for its restoration.
Such equipment needs careful maintenance and regular inspection before and after completion of work. The fact is that the device is equipped with a ventilation system, which easily draws metal dust inside. It can disrupt the performance of expensive equipment, so it should be cleaned with a blower or a special brush.
In operation, the equipment relies on its electronic base, which is highly sensitive to humidity and cold. Under the influence of steam condensate may form, which causes a circuit during operation. Therefore, it is necessary to observe strict storage rules for welding inverters. They should be located only in a dry place, protected from the cold. It is not recommended to use the equipment in winter in open space.
Welding inverters have a modular control, which greatly simplifies the process of their operation by a person who does not have the necessary qualifications.
Scheme of the welding transformer.
If the device is used by a professional welder, it can be used to complete the task in a short time, not to mention the high quality of the result.
Inverters have a small mass and relatively small dimensions, so this equipment is almost indispensable at sites where you need to move a considerable distance several times a day. Of course, for the personal comfort and benefits of inverter welding equipment will have to spend a considerable amount of money.
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Today this type of welding machine is the most popular, especially in Russia. This is due to the fact that transformers have a low cost, simple design and a satisfactory level of reliability. The equipment operates on a standard 50 Hz due to a transformer that converts electricity. Electricity is collected by mechanical control of the magnetic flux in the core. Receiving energy from the mains, the core is magnetized, thus creating a variable type electric current with reduced voltage (from 220 to 55-85 V) and increased power. After that, he is sent to create an electric arc.
The power of the current on the transformers is controlled by shifting the winding on the core. The closer the windings are, the greater the current.
Transformers have advantages:
- low price of the equipment (almost 3 times less than similar equipment of the inverter type);
- the simplest design that allows you to repair yourself;
- durability and simplicity, because there is no electronic filling.
Welding machines, rectifiers
This kind of welding equipment is quite similar to the classical devices. It operates on electric current from the network without changing its frequency. The current is collected on the windings of the transformer, where its voltage decreases. The main feature of such devices is the supply of converted electric current by passing rectifiers of silicon or selenium through the nodes, as a result of which a direct current flows to the electrodes.
Welding rectifier circuit.
For this reason, the arc of rectifiers is fairly stable, there are no sudden drops or interruptions in it.
Welding rectifiers have a complex structure. In certain situations, the device must be cooled with the help of coolers. Often, devices of this type are equipped with additional microthrottles that contribute to the change in the properties of the resulting electric current. It is stabilized by filtration. Rectifiers are often equipped with special devices for protection and stabilization.Back to table of contents
Such equipment operates according to the principle of melting of a special wire under the influence of gas, which is fed into the welding area and creates a high-temperature bath there. Gas completely displaces oxygen from the bath, forming a protective aura from the air for the welded joint. This process requires the use of helium, carbon dioxide, argon, as well as their combination.
A semi-automatic welding machine is a device consisting of a power supply unit with constant electric current, a welding supply unit, a controller, a container with gas and equipment for its supply. The semiautomatic device is configured by changing the power of the electric current, the speed of wire feeding, the replacement of the composition of the mixture used or the gas itself.Back to table of contents
How to determine the type of welding machine when buying?
If you select equipment for non-production use, it is recommended to purchase machines with power that operate on the basis of a standard mains voltage of 220 V. Some devices for welding are quite sensitive to voltage drops and may come to malfunction after the next jump. For this reason, inverters are equipped with a protective system with fuses. In addition, for unstable power grids perfectly suitable devices designed to work with alternating voltage (for example, EWM Pico 162 works at 132-253 V).
Industrial equipment is capable of producing a current of 300 A and above. For applications in other areas, devices that give 200-250 A are quite suitable. This is enough for working with metal with a thickness of up to 6 mm. The thickness of the electrode in this case will be 4 mm. If the voltage in your power supply often jumps, it is recommended to purchase a device with a backup power, that is, with frequent use of a 3 mm electrode, it is better to purchase equipment rated for 4 mm.
All properties of the purchased equipment depend on your needs. If you have not yet decided on them, it is recommended to look closely at devices with a flexible configuration. The Stanley Super 180 welding machine meets these requirements. It operates at low voltage, and it is possible to change the amperage.