Comparison EnerSol EWM-160AD vs EnerSol EWM-160AMD

The type of welding machine determines the features of its design and purpose.

— Transformer. The simplest type of welding machine. The principle of operation in this case is as follows: the input mains voltage is fed directly to the transformer winding, which lowers it to the open circuit voltage (see below). In addition to alternating current, transformers can also cook on direct current — in such models, the simplest rectifier with a stabilizer is usually used; when using alternating current, its frequency remains the same as in the network. The main advantages of transformers are high reliability combined with low cost and simplicity of design. At the same time, the functionality of such devices is rather limited — in particular, of the types of welding, there are rarely any other than manual arc welding (see "Type of welding"); and the quality of work is relatively low due to the instability of the current supplied to the electrode. Yes, and the weight of transformers, compared with inverters, is quite high. In general, this type of welding machine is intended mainly for simple work that does not require high precision.

— Inverter. A type of welding machine designed to overcome some of the major disadvantages of transformers, such as heavy weight and uneven seams. The key difference between inverters is that the current to the winding of the step-down transformer is not supplied...directly from the network, but through special control circuits (which, in fact, are an inverter in the narrow sense of the word). When passing through these circuits, the current is first converted to direct, and then back to alternating, but with an increased frequency of the order of tens of kilohertz (for comparison, the frequency of household alternating current is 50 Hz), and this high-frequency current is already supplied to the winding. This made it possible to significantly reduce the dimensions of the transformer coils and thus reduce the weight and dimensions of the entire device — many inverters can be safely carried on a shoulder strap. A high frequency provides a much more stable arc and a quality weld both when welding with alternating current and when using direct current (for both options, see the “Welding Current” paragraph for more details). In addition, this scheme allows the use of almost all modern types of welding (see below). Among the disadvantages of inverter devices, one can note the high cost due to the complexity of the design. However, if you need a device for high-quality professional welding, you cannot do without an inverter.

— Semiautomatic. This term refers to a type of welding transformers (see above), in which the welding process is partially automated. The electrode for a semiautomatic device has the form of a thin wire (usually not thicker than 1.2 mm) wound on a coil; during operation, this wire is fed to the nozzle automatically, as it is consumed. This is much more convenient than with conventional welding — after all, the operator does not have to control the length of the electrode himself and adjust it manually, the electrode itself has to be changed much less often, and semi-automatic welding also has some other advantages (for more details, see "Type of welding"). Otherwise, semiautomatic devices are completely similar to conventional transformers.

— Semi-automatic inverter. As the name implies, this category includes inverter-type machines with an electrode supply system typical for semi-automatic machines. For more details, see the relevant paragraphs above, but here we note that this option can be called the most advanced among modern general-purpose welding units.

Among the main types of welding can be called manual arc (MMA), semi-automatic (MIG / MAG), argon-arc (TIG), spot (SPOT), spot (STUD) and plasma cutting (PLASMA) welding.

— MMA. Welding using an electric arc and a consumable electrode with a special coating. The electrode is fed and moved manually by the welder. Shielding gas supply is not provided; protection of the weld pool from air can be carried out due to the combustion of the coating deposited on the electrode. This welding technology allows the use of the simplest equipment, it is undemanding to the quality of the current and the design of the welding machine. On the other hand, the quality of the resulting weld is highly dependent on the skills of the welder, the productivity of the process is relatively low, and this technology is poorly suited for non-ferrous metals — its main purpose is the welding of steel and cast iron.

— MIG/MAG. Partially automated welding in an inert (MIG) or active (MAG) gas environment. The gas enters directly to the place of welding through the burner and, when the arc burns, forms a protective sheath that covers the weld pool from exposure to air. And the term "semi-automatic" means that filler material in the form of a thin wire is also automatic...ally supplied to the place of work (but you need to move the burner manually). The choice between inert and active gas is made depending on the materials being welded — for example, the first option is usually used with non-ferrous metals, the second with steel. Such welding provides a much better quality of the seam than manual welding, and also increases the convenience and speed of work — in particular.

— TIG. Manual welding with a non-consumable electrode in an inert gas environment. With such welding, the electric arc melts only the edges of the parts to be joined, and the final seam is formed from them, without using the electrode material (in some cases, additives in the form of pieces of metal of the appropriate shape can be used). To protect the seam from exposure to air, a protective gas, usually argon, is supplied to the heating point. TIG welding is well suited for stainless steel as well as copper and aluminium alloys. It allows you to create a more accurate seam than the same MMA, and more precisely control the process. On the other hand, this technology is quite demanding on the skills of the welder, and the speed of work is relatively low.

— SPOT. Electric welding, carried out due to the point impact of high currents. It is used for connecting thin sheets of metal (mainly up to 3 mm), as well as for attaching pins and studs to a flat base. When connecting sheets of metal, two electrodes with a relatively small diameter tightly press the workpieces against one another, after which a current is passed through them with a force of the order of several kiloamperes; the metal at the point of contact is heated to the melting point, which ensures the connection. When attaching pins and studs, the role of one of the electrodes is played by the pin itself, the role of the second is played by a flat base. SPOT type welding is very popular in car manufacturing and car service: it is in this way that some elements of car bodies are connected, and it can also be useful for straightening. There are unilateral and bilateral. The first uses a single electrode, which is pressed against the workpiece with force. The main advantage of this option is the ability to work with surfaces that are accessible only from one side — for example, car doors. Actually, one of the main areas of application for one-sided SPOT welding is a car service, in particular, straightening car bodies and other car surfaces. The second welding (two-sided) involves the use of a pair of electrodes that compress the junction from both sides, like a vice. This variant is better suited for work with thick parts or where a high reliability of the connection is required — due to the compression described, it is easier to achieve the desired depth of the weld pool. On the other hand, its use requires access to both sides of the workpiece. Note that some models of welding machines are able to work according to one and the other scheme; this makes the device very versatile, but may come at a cost.

— STUD. Spot welding technology using a lifting (pulling) arc. Mainly used for flat base plus stud connections. The welding process itself takes place in the following way: the stud is pressed against the base; the current is switched on; the pin rises; an arc ignites between it and the base, which melts the surface of the base; the hairpin is lowered into the melt; the current is turned off, the metal freezes. STUD welding involves the use of mechanized welding torches with a spring or hydraulic system that raises and lowers the stud, and an inert gas or flux is used to protect the joint from atmospheric air.

– PLASMA. Cutting metal using a stream of heated plasma — a highly ionized gas. To do this, gas (inert or active) is supplied to the place of work, which, due to the influence of an electric arc, is ionized, heated and accelerated. The plasma temperature can exceed 10,000 °C, and the speed is 1,000 m/s, which makes it possible to work with almost any metals and alloys, including refractory ones. At the same time, cutting is carried out quickly, the cut is clean and neat, and the cutting depth can reach 200 mm. The main disadvantage of plasma cutting is the high cost of equipment.

The voltage supplied by the welding machine to the electrodes. As the name suggests, it is measured without load — i.e. when the electrodes are disconnected and no current flows between them. This is due to the fact that at a high current strength characteristic of electric welding, the actual voltage on the electrodes drops sharply, and this does not make it possible to adequately assess the characteristics of the welding machine.

Depending on the characteristics of the machine (see "Type") and the type of work (see "Type of welding"), different open circuit voltages are used. For example, for welding transformers, this parameter is about 45 – 55 V (although there are higher voltage models), for inverters it can reach 90 V, and for semi-automatic MIG / MAG welding, voltages above 40 V are usually not required. Also, the optimal values \u200b\u200bdepend on type of electrodes used. You can find more detailed information in special sources; here we note that the higher the open-circuit voltage, the easier it is usually to strike the arc and the more stable the discharge itself.

Also note that for devices with the VRD function (see "Advanced"), this parameter indicates the standard voltage, without reduction through VRD.

The minimum diameter of the welding wire that the machine can work with.

Wire electrodes are used in semi-automatic models (see "Type"), mainly for MIG/MAG welding (see "Type of welding"). The thinner the electrode, the better it is suitable for delicate work where a small thickness and width of the seam is required. Specific recommendations on the diameter of the wire for a particular task can be found in special sources.

The maximum diameter of the welding wire that the machine can work with.

Wire electrodes are used in semi-automatic models (see "Type"), mainly for MIG/MAG welding (see "Type of welding"). Specific recommendations on the diameter of the wire for a particular task can be found in special sources, but here we note that a large electrode thickness is important for rougher jobs that require a thick seam and a large amount of material. In general, the wire is noticeably thinner than traditional electrodes. The standard option here is considered to be a maximum diameter of 1 mm, smaller values ( 0.8 mm and 0.9 mm) are found mainly in low-power devices for fine work, and 2 mm or more — on the contrary, in advanced performant units.

The location of the wire feed spool.

The wire is used in semi-automatic welding (see "Type of welding"); the coil on which it is wound can be located both outside the device and inside. There is no fundamental difference in the design of the feed mechanism, in efficiency and in other operating parameters between the "external" and "internal" models, they differ mainly in the features of storage and transportation. For example, the built-in coil increases the size and weight of the entire device, but it does not need to be carried separately.

The type of MIG/MAG welding hose provided in the design of the welding machine.

Recall that MIG / MAG is welding in a special gas environment (inert or active); see "Welding type" for more details. And the welding sleeve can be described as a special hose connecting the torch to the machine (more precisely, the torch is usually part of the sleeve). Through such a hose, both the wire and the shielding gas are supplied to the welding site.

The sleeve for welding in modern MIG / MAG devices is most often made removable and fastened to a standard socket, known as a europlug. The advantages of this design are obvious: for storage, transportation or just long breaks in work, the hose can be removed and compactly rolled up so that it does not take up extra space or get in the way. In addition, if necessary — for example, in case of damage or in case of unsuitable length — the standard sleeve can be freely replaced with another one.

The non-removable design is much less common, as it is less convenient. Nevertheless, this option also has its advantages: fastening the sleeve to the device is as reliable as possible and at the same time inexpensive.

The length of the electrode holder cable supplied with the device.

As the name implies, this cable is used to connect the clamp for the welding electrode to the machine. The longer such a wire is, the more freedom the welder has in moving, the farther he can go without moving the machine itself. On the other hand, excessively long cables create problems in storage and transportation, and often during operation (you need to look for a place where to place the excess wire). Therefore, when choosing, you should proceed from what is more important for you: the ability to move away from the device or the overall compactness. As for specific numbers, most often the length of this wire varies from 2 to 3 m, but in some models it can reach 5 m.