For lovers of welding craft there is a good tool - a welding inverter. And it is suitable not only for amateurs, but also for workers in more serious areas. The development of modern technologies has made it possible to make such a technique quite portable, especially if we compare the current models with the first prototypes. But in order to make the right choice, it is necessary to make a comparison of welding inverters and consider many nuances.
Diagram of the elements of the inverter welding machine.
Features and specifications
The welding inverter is the same welding machine, only modernized. First of all, it is much lighter than its counterparts. This technique has an inverter power supply that converts the alternating voltage of the electrical network to the voltage for welding.
The principle of operation of the welding inverter.
The principle of operation is as follows: alternating current coming from the mains with a frequency of 50 Hz, falls on the rectifier. The converted current is corrected using filters, after which it follows special high-frequency switching transistors, where it again becomes alternating, but already having a high frequency (from 20 to 50 kHz). After this, the value of the AC voltage drops to 70-90 V, and the current is gaining strength in 100-200 A, which is suitable for welding. High frequency gives the main advantage to welding inverters, if we make a comparison with similar power sources of a welded arc.
Unlike transformers, inverters convert high-frequency current into the required amount of welding current.Back to table of contents
Pros and cons of welding inverters
Like any other technology, such equipment has its positive and negative points.
Let's pay attention first of all to the positive sides:
- relatively small weight, as a result of which the inverter has small dimensions;
- there is the possibility of using electrodes of alternating and direct current, which is very important when welding non-ferrous metals or cast iron;
- it is possible to adjust the welding current for each welding separately, which is convenient for non-consumable electrode argon-arc welding;
- Hot start functions (designed to ignite the electrode with maximum temperature), Anti-Sticking (designed for short circuit cases, reducing the current to a minimum, which prevents the electrode from sticking on the instrument), Arc Force (to eliminate sticking, when the electrode tears off a drop of metal, increasing the current value to the optimal level);
- when working with such a technique, spattering of molten metal is minimal, which significantly increases the level of safety;
- the equipment easily copes even with those metal grades with which an ordinary transformer is difficult to handle;
- Such welders do not require significant knowledge and experience for their operation, while you can not worry about the quality of the seam.
Functional device welding inverter.
But, making a comparison, it is necessary to take into account the disadvantages:
- high cost, it is about 2-3 times the price of a conventional transformer;
- are sensitive to pollution, primarily to dust, experts recommend 1 time in 2 years to remove the case and clean all parts of the dust, but again, depending on the operating conditions, such cleaning may have to be done more often;
- sensitive to low temperatures: the recommended ambient temperature should not be lower than -15 °, in most cases the manufacturer will influence this characteristic; such a nuance can be clarified in the passport of the product or from the sales assistant;
- limited cable length: welding inverters have a cable length of 2.5 m, which may limit the work area, so in this case, you may need an extension cord.
When working with arc welding, the operator needs not only theoretical knowledge, but also practical welding skills.
Having made a comparison of inverters and other welding machines, immediately it is worth noting such a moment as the ease of ignition of the arc. The problem of the old technique is sticking of the electrode. This is due to the fact that there is a low voltage in the home electrical networks, and a transformer device such that the output and input voltages are proportional to each other. If the current is increased, then it will simply burn out. But in the device of the inverters this moment is provided, therefore both voltages are autonomous and the current keeps its indicator regardless of the power grid. Such a system prevents sticking of the electrodes, creating a stable arc.
The invertor welding machine is supplied with double insulation, therefore it is absolutely safe during electric welding works.
The second point to which attention should be paid: in old models with careless handling or insufficient experience, there was a chance of burning or under burning sheets of metal. This disadvantage is due to the variable value of the current. If the metal is not modified, it threatens with a low quality of the seam, and if, on the contrary, it is reworked, the joint will be weak, and bores and shells will appear on it. And the inverter converter has a current that is adjusted by a potentiometer.
The most difficult thing in welding is to control the arc. With proper work, welding seams is at an angle of 15 °. In this case, the side of the slope (in motion or against) does not matter. In addition, the electrode should move longitudinally, it should be moved and perpendicular to the joint. This is influenced by the arc length. Most electrodes operate in a short arc. With proper welding, the electrode, moving perpendicular to the seam, is at a distance from the surface equal to its two diameters. But due to the presence of direct current and its stable voltage, welding inverters do not depend on the arc length. In comparison with other devices, this greatly facilitates the work of the welder. However, he does not have to worry about the quality of the seam.
There are stages of work when the welded elements have a vertical arrangement, respectively, the molten metal begins to flow down. In this case, the work technique should look like this: the previous drop should cool down, after which, moving up, the next arc is set on fire. In the field of welding, this work has the name of tack. Even a newbie can handle this way.
If we compare the welding inverter and the more classical devices, then the first ones greatly facilitate the work, as they easily ignite the arc and control it, do not form sticking. When comparing, consider this parameter as well.Back to table of contents
Varieties of inverter welders
Classification of welding inverters.
The division of welding inverters was determined by the type of welding process. Therefore, there are the following types (comparison is carried out on them):
- MMA - inverters that work by manual arc welding;
- MIG / MAG - inverters operating in semi-automatic mode;
- TIG - inverters that are applicable in argon-arc welding;
- CUT - the inverters having plasma cutting for metals.
If we compare all the above-mentioned markings, it is worth noting immediately that each of the units has its own price and mandatory packaging.
The first type of inverter has wide application for domestic needs. They are a hand-held apparatus that has a minimum weight for such a technique. With the help of it, it is rather easy to cope with home welding, since its package includes the simplest electrodes. If it is necessary to replace one of the electrodes, this will not cause any special problems.
The second category is most often used in manufacturing, as it is already a more serious technique. Such equipment has more substantial dimensions, which affect its mass. The process of welding itself also has its own characteristics. In order for such an inverter to weld a seam, the catalyst for the arc is a special welding wire, which helps to carry out the entire process.
Characteristics of the inverter.
The third type of inverter works due to the formation of an arc with an inert gas, more precisely, it appears inside it. The properties of argon are such that chemically it does not react to the metal. Electrode sets can be of two types: melting and non-melting. For the manufacture of the first used tungsten. Such equipment is quite expensive and also requires certain skills in the work. Therefore, for home use it is not rational to purchase TIG welding inverters.
But the latest models are considered professional equipment. However, such devices are not used for welding. Their direct purpose is metal cutting. Although, by comparing them with conventional inverters, we can assume that the principle of their work is similar.Back to table of contents
Selection criteria for welding inverters
Having the goal to acquire the correct welding inverter, you should answer a number of questions for yourself:
Control of the welding inverter.
- what current to deal with;
- available network operating voltage;
- starting current indicator;
- equipment power;
- electrode cross section;
- idle voltage indicator;
- What are the limits for adjusting the voltage of the welding current;
- the size of the technique;
The answer to each of these questions will greatly influence the choice of hardware. The main thing is to remember that the most important feature of the welding inverter is the output of direct current, and not alternating. This is its main advantage, if compared to other similar equipment.
In order to choose the correct model of the inverter apparatus, it is necessary first of all to decide for what needs it will be used.
Therefore, there are professional and domestic models. In the first case, the equipment can easily withstand an 8-hour duty cycle, while household counterparts can work for about half an hour, after which they require a break of 60 minutes. Professional devices are intended for industrial productions where it is necessary to work in more severe conditions.
Reverse and direct polarity in the welding inverter.
For home use, you can opt for models that have a maximum current of 160 A, but only with the condition that the grid will produce a voltage of 210 V. If the home network has a tendency to lose constant voltage or it has low performance, then it’s better acquire an inverter unit at 200 A. But most often the standard voltage goes to 220 V and 380 V. For such conditions, welders up to 4 kW are suitable, because mini-transformers will be higher.
Speaking about household goods, it should be noted that inverters have a starting current in the range of 4 to 32 A. Although 16 A is enough for home use, this parameter will affect the choice of electrodes, which, in turn, have a diameter of 1, 6 cm to 8 cm. But in non-professional welding, it is recommended to use 20-mm electrodes.
As already mentioned, the inverters have a small weight and size, but this can also affect the power of the transformer. That is why in a small welder there can be no big power.Back to table of contents
Purchase welding inverter
If someone could think of making such equipment on their own, then this should be immediately abandoned. This is a very dangerous undertaking, and it will come out quite expensive from a financial point of view.
To date, you can make a purchase in several ways:
- the Internet;
- special shop.
The welding inverter Telwin Technology, despite the high price, is the most popular, as it has high technical characteristics and proven reliability in testing.
Experts recommend not to make a mistake with the acquisition, still on the spot to test it. Very often, manufacturers slightly overestimate their performance, but the reality is somewhat less. Many are accustomed to thinking that China is not capable of making high-quality products if compared to other manufacturers. Still, some truth in this.
For example, welding inverters of such companies may be labeled as 250 A, but in practice they reach a maximum of 160 A. Such irresponsibility often leads to the wrong components being selected for the device, and they, in turn, simply break the equipment. To avoid such deception, you can use a special ammeter, and if the seller has any resistance to such a test, you can with firmness say that he is trying to sell low-quality goods. But such a problem is clearly faced when they decide to purchase a product via the Internet.
As for the warehouse, in this case, of course, verification is much easier to implement. The shopping purchase is the most reliable, as in this case, the equipment is always a warranty card that will help to return or exchange the faulty equipment.
Scope of invertor svarochnik happens three types:
The KEMPPI welding inverter produced in Russia has been tested satisfactorily and meets all the necessary parameters.
The average price of household inverters is up to $ 300. most often it is Chinese production. The maximum current is 160 A, and the electrodes are supplied with a diameter of 1.6 cm and 2 cm. Working with such a unit, they get rough metal welding, although the arc indicator is quite large. A good alternative to such firms will be domestic producers.
But on the modern market, it is quite difficult to meet new equipment, most often these are devices that have already been in use. But despite this, such inverters make a better seam, and their cost is slightly lower, which saves money. If there is a need to purchase household models, it is better to turn your attention to Italian firms. Of course, their average cost is 300-500 cu. but the quality of the equipment is much higher in comparison with the Chinese counterparts.
Their main advantage is compliance with all stated requirements in the data sheet. That is, what labeling is worth, such a voltage will be issued by the inverter. If the device will have the correct configuration, it will be able to serve its owner from 15 (permanent use) to 30 years (intermittent use).
To compare household and professional welding inverters, it should be noted that the latter have very scrupulous control of the operating current strength. In addition, the current power itself can reach 500 A, which contributes just to the jewelry welding of the joints. Since such models are in the region of 1500-3500 cu, few can afford to have such equipment at home to use it from time to time.Back to table of contents
Possible failure of welding inverters
It happens that during operation the device may stop working. And the most common problems can be:
- lack of arc stability;
- strong splashing of metal;
- sticking of the electrode on the metal;
- no arc is created;
- no constant power;
- overheating device.
Some of the above troubles can be eliminated by yourself, but others will need professional intervention.
The principle of operation of the welding inverter.
If the current strength and the size of the diameter of the electrode do not match, then the arc will be intermittent. According to the standard, packaging with electrodes should be marked with a cross section, but if there is no such, then the following formula can be applied: the electrode diameter (mm) is multiplied by 4 A.
If during welding too high welding current is applied, it will cause metal spatter. Therefore, replacing the electrodes with a smaller cross section and lowering the amperage, you can get rid of this problem.
Such a problem as sticking occurs because:
- There is too low a voltage on the power supply.
- Cable length exceeds 40 m.
- Overheating of the cable or its plug, which may cause the insulation to melt. The consequence of this may be a short circuit.
To avoid problems with the cable, it is necessary to inspect it every time before starting work. The arc will not occur only if there is no current. Again, one of the reasons for this failure may be damage to the wires or the electrode does not come in contact with the clamp.
In case of interrupted power supply, it is necessary to check the circuit breaker, as it could burn out. Then it should simply be changed to a new one.
It is very important not to overload the device. Each model has its own cycle of work, which is specified in technical documents. But if there is a fault in the winding, then this also leads to overheating of the device. In this case, the device is better to entrust a professional repairman.Back to table of contents
Popular manufacturers and their models
The FUBAG welding inverter creates a high-quality, even weld when welding steel parts.
Leading positions in the welding equipment market are held by KEMPPI. It has found wide application in domestic production, as its inverters withstand our climatic conditions (heat and frost). Models are equipped with automatic adjustment of current, and they are also undemanding in the spare set. If there is a need to replace the electrode, the selection will not take long, as any manufacturer contacts KEMPPI.
There is a German representative - FUBAG. Very good models for working with a variable network, as they have stabilizers. This element allows you to operate the device with a mains voltage from 85 to 380 V. If you have to work with low-carbon, alloyed or stainless metals, then FUBAG IN 163 is specially designed for this purpose. It is equipped with automatic devices that independently adapt to the type of welding.
In this ranking there are Italian manufacturers - the company TELWIN. They have a huge range of household inverters and professional models. Household appliances are designed to work with a current of 160 A, although their small dimensions are not protected, that is, any mechanical damage or concussion can damage the equipment.
After analyzing all the above characteristics, in addition to them, you can make an additional comparison and select the appropriate device for your needs.