Rules for selecting welding machines

Which welding machine to choose for the house? In order to deal with this issue, it is necessary to imagine what welding regimes are, and what devices are used for these modes. The use of different welding regimes for processing different materials is given in the table.

Electric welding machines are of three main types:

• Lowering welding transformers that perform AC welding. They have a broken magnetic circuit, due to the adjustment of the magnetic gap, the welding current changes. These units are very reliable and are effectively used for welding in MMAAC mode. Used for welding of carbon steel, when the quality of the welded joint is not required.
• Welding rectifiers operate in MMADC mode, that is, rectified current. With the help of these units you can cook carbon and stainless steel, as well as aluminum alloys. The quality of the weld is much higher.
• Welding inverters, operating depending on the model in all modes presented. These are universal devices that carry out welding of any materials with high frequency current.

Most amateur masters involved in welding from time to time prefer inverter devices. Their higher price is more than compensated by convenience and versatility. However, if you are more interested in a low price, you can choose a conventional welding transformer.

Selection of the reducing welding transformer

The main characteristic that should be considered when selecting a welding step-down transformer is its operating voltage. Welding transformers can operate from a three-phase network or single-phase 380/220 V network. Combined models that can be connected to both a three-phase network and a phase-to-phase voltage between two phases are more universal, and the voltage is 220 V.

The second parameter is the power of a welding transformer. Models with a power of ~ 380 V have a higher power and cause less distortion in the network, but not all have the ability to connect to a three-phase network. The declared power of the transformer must not exceed the maximum permissible power of your network.

When selecting, also consider the range of operating currents and the dimensions of the electrodes used. For the welding of carbon steel, a range of currents of 80-160 A is sufficient, electrodes are usually used from 1 to 6 depending on the thickness of the blanks.

The weight and dimensions of the welding transformer are important if you plan to move it. Since all welding machines of this type are very heavy, it is better to give preference to the unit equipped with wheels and a handle for the convenience of movement.

Choosing a welding rectifier

Welding rectifiers operate on a pulsed rectified current, which increases the stability of the arc, reduces the formation of metal spatter, and reduces the consumption of electrodes. In general, the use of rectified current makes it possible to obtain a more even and thin weld, which is important for decorative elements.

Welding rectifiers can operate on both a three-phase and single-phase alternating current, with rectifiers connected via a three-phase or single-phase bridge circuit. Connection on a three-phase circuit gives greater stability of arc burning and more power, but, again, it is necessary to be guided by the possibility of connection to a three-phase network of ~ 380 V.

When choosing, attention should be paid to the range of welding currents, the convenience of regulating the regimes, and the thickness of the electrodes used. Regulation of modes and welding current in rectifiers is usually carried out stepwise.

Selection of the welding inverter

The welding inverter is a universal machine, thanks to a wide range of welding modes it is very popular with masters of various profiles. Its price is higher than that of other welding machines, but the dimensions, weight and power consumption allow using inverters for welding in any conditions.

What should I look for when choosing a welding inverter? The main parameter, as in the previous cases, is the supply voltage of 380 V or 220 V, with three-phase inverters of high power. The power also depends on the service life: at equal loads, a more powerful inverter will be less heated and will last longer.

The second important parameter is the range of welding modes and current. Choose it according to the table, depending on the thickness of the metal.

For the inverter used in domestic and private construction, a range of 60-160 A is sufficient. A smooth adjustment will allow more accurate selection of the welding current and improve the quality of the weld.

Another parameter that has a value is the on-time duration, which determines the ratio of the time of continuous operation to the time of use of the unit at the maximum current conditions. The higher this value, the longer the welding inverter can operate without overheating. In practice, the required duration of the switching-on time can be calculated from the ratio of the welding time to the technological pauses in operation for changing the electrode or preparing the parts. For example, with a declared turn-on time of 80%, the welding time will be 4 minutes with a mandatory pause of 1 minute. In practice, there are much more pauses, but the safety margin of the unit does not hurt.

Also important is the availability of additional functions, the most popular of them:

• Hotstart, or "hot start" - an abrupt increase in current at the initial moment of welding, which facilitates the process of arcing;
• Antistick - an option that sharply reduces the current when sticking the electrode and allowing it to be easily removed from the weld metal;
• Arcforce, or "afterburner arc" - used in welding vertical seams, improves the quality of the seam.

These options are implemented in almost all modern models of inverters.

All welding machines are equipped with two cables with crocodile clips, an electrode holder for the electrode. And also terminals for connection to the welding machine. When buying, pay attention to the length of the cables - it should be at least 2 meters.

When choosing any welding machine, it is also important to look at the warranty period, the availability of after-sales service and the proximity of service centers. The country of manufacture does not have much importance, many Chinese models outperform European analogs in terms of functionality, while at the same time have a lower cost and at the same time are very reliable.

Thus, in this article we have considered what kind of welding machine to choose, and how to learn how to cook electric welding - read on our website.