Welding rectifier and its device

It is difficult to imagine a building industry or engineering without the use of welding. It is divided into two types: on a constant and alternating current.

The use of DC provides a better weld. This is explained by the absence of zero current values, which means that the burning of the arc becomes more stable, the spraying from the burning electrode decreases, the penetration of the metal turns out to be deeper, the strength characteristics improve on the welded seam.
In addition, with materials such as cast iron, high-alloy steels, nickel-copper alloys, titanium, only DC welding can be used.

To convert an alternating current having a frequency of 50 Hz to a constant, use a welding rectifier. It uses semiconductor valves and special regulating devices in the transformer. There are various types of such products. Each of them has in its design a rectifying unit, a start-up unit for protective and measuring equipment and a power transformer.

The welding rectifier is used for manual arc welding when melting of the electrodes occurs, and pulse- arc welding, in which the pulse facilitates the separation of the metal droplet from the wire electrode.

For the convenience of mechanical welding, a special welding rectifier WD of transformer type has been created, which has a remote mode switch. Such converters are characterized by the basic technical solutions:

• In one range, the current regulation for welding is smooth;
• Magnetic wedge-shaped movable shunt, horizontal version, provides mechanical adjustment of the welded seam, has a simple design;
• Transformer windings are made of copper;
• There are no moving windings;
• Cooling in air;
• The ignition is easy, the arc burns steadily;
• Insulation class - H;
• Current connectors are safe and quickly open;
• In the mounting conditions, a welding rectifier of this type is easy to move.

Sometimes at home, there is a need to perform welding work. In this situation, there are two options - to buy a ready-made device or independently to make a welding rectifier with your own hands.

The main element of the self-made rectifier is a transformer designed to convert an alternating voltage in the network and to provide the necessary value and quality of the welding current. It can be connected to a network with a voltage of 220 V, and at the output it must provide 40-70 V.

Further to the transformer's terminals, you need to solder a network wire of approximately 2.5 square millimeters in diameter and about 5 meters long, for convenient movement of the welding machine. Wire is better used in double insulation.

The next stage is the preparation of cables for welding. For this purpose it is better to use soft wires with rubber insulation, at least two meters in length. At the end of one cable we attach a clothespin "mass" (sometimes you can use a car "cigarette lighter"), on the other cable - the electrode holder.

Now the welding rectifier needs to be assembled. It depends on this, how much the device will be convenient for operation. When working, it will heat up, which means that the housing must be made with ventilation holes. For ease of transport on the body we attach the handles and install the wheels. It is possible to install additional elements for the laying of wires and cables in the form of hooks, washers, corners.