Its structure is very simple, it is a high-power transformer. Welding machine can be divided into two types according to the type of output power, one is AC power supply, the other is DC power supply. They use the principle of inductance, inductance will produce a huge voltage change when switching on and off, and use the high voltage arc generated by the instantaneous short circuit between the positive and negative poles to melt the solder on the electrode, so that they can achieve the purpose of atomic bonding.

Electric welding machines are widely used. Welding machine is an indispensable tool for large shipbuilding enterprises, industrial and mining enterprises and various construction enterprises. Electric welding machine is used for material welding, and it is electrified in use.
In particular, some small construction units purchase cheap electric welding machines in order to save cost. It is easy to cause electric shock, fire and desoldering when used in the harsh environment of construction site, which will endanger personal safety and property safety. Due to a bad welding quality, it is possible to collapse the building project.

Advantages of DC welding machine: the most important is that the arc is relatively stable during DC welding, because the current is not zero point, it can maintain arc combustion under a very small current, and basically can apply all kinds of welding rods; the welding penetration is large, and at the same time, it is relatively energy-saving. Disadvantages of DC welding machine: DC is easy to bias arc, the current can not be too large.