It is hard to imagine the construction industry or mechanical engineering without the use of welding. It is divided into two types: direct and alternating current.
Using direct current produces a better weld. This is due to the absence of zero current values, which means that the arc burning becomes more stable, spatter from the burning electrode decreases, metal penetration is deeper, and the strength characteristics of the weld improve.
In addition, only DC welding can be used with materials such as cast iron, high alloy steels, nickel and copper alloys, titanium.
To convert alternating current having a frequency of 50 Hz into direct current, a welding rectifier is used. It uses semiconductor valves and special control devices in the transformer. There are various types of such products. Each of them has in its design a rectifier unit, a ballast unit for protective and measuring equipment and a power transformer.
The welding rectifier is used formanual arc welding, when the electrodes melt, and pulsed arc welding, in which the pulse contributes to the separation of a drop of metal from the wire electrode.
For the convenience of mechanical welding, a special welding rectifier VD of a transformer type has been created, which has a remote mode switch. Such converters are characterized by the main technical solutions:
- in one range, the current adjustment for welding is smooth;
- magnetic wedge movable shunt, horizontal design, provides mechanical adjustment of the weld, simple structure;
- transformer windings are made of copper;
- no moving windings;
- air cooling;
- ignition is easy, the arc burns steadily;
- insulation class - N;
- current connectors are safe and open quickly;
- under installation conditions, this type of welding rectifier is easy to move.
Sometimes at home it becomes necessary to perform welding work. In this situation, there are two options - buy a ready-made machine or make your own welding rectifier with your own hands.
The main element of a homemade rectifier is a transformer designed to convert AC voltage in the network and provide the required value and quality of the welded current. It can be connected to a network with a voltage of 220 V, and at the output it must provide 40-70 V.
Next, you need to solder a network wire of about 2.5 square millimeters in diameter and about 5 meters long to the transformer terminals, for convenient movement of the welding machine. The wire is best used in double insulation.
The next step is to prepare the cables for welding. For this purpose, it is better to use soft wires with rubber insulation, at least two meters long. At the end of one cable we attach a “ground” clip (sometimes you can use a car “cigarette lighter”), on the other cable - an electrode holder.
Now the welding rectifier needs to be assembled. It depends on how convenient the device will be during operation. During operation, it will heat up, which means that the case must be made with ventilation holes. For ease of transportation, we attach handles to the case and install wheels. It is possible to install additional elements in the form of hooks, washers, corners for laying wires and cables.
