The welding machine is a special kind of transformer,The difference is that the voltage drop is small when the transformer is connected to the load, and the voltage drop is large when the welding machine is connected to the load, which is mainly realized by adjusting the inductance of the magnetic flux and the series inductance. The working principle of ordinary welding machine and transformer is similar, step-down transformer. At both ends of the secondary coil are the welding workpiece and the welding rod, which ignite the arc at the high temperature of the arc and weld the gap between the workpiece and the welding rod.

Welding transformer has its own characteristics, that is, it has the characteristics of voltage sag. The voltage drops after the electrode is ignited; when the electrode is short-circuited due to adhesion, the voltage will also drop sharply,The reason for this phenomenon is the core characteristics of welding transformers. The adjustment of the working voltage of the welding machine, except for one220/380In addition to the voltage conversion, the secondary coil also has a tap conversion voltage. At the same time, through the adjustment of the iron core, the magnetic circuit can be shunted as much as the iron core enters, and the lower the welding voltage is. Although the circuit is closed, but because the circuit is closed, so the entire closed circuit and the current is equal everywhere; but the resistance varies from ground to ground, especially at unfixed contacts, which is called contact resistance in physics.

In fact, the principle of electric welding is: we commonly used220Vor380VThe industrial power supply reduces the voltage and increases the current through the voltage reducer in the welding machine. The huge amount of heat generated by electricity is used to melt steel, which has a higher degree of fusion with iron. In addition, the coating of the outer layer of the electrode plays a very important role. The electrode used in manual arc welding consists of a coating layer and a core layer,When welding, the silver electrode acts as an electrode, on the one hand, it plays the role of conductive arc, so that a continuous and stable arc is generated between the silver electrode and the base metal, and the necessary heat is provided for melting and welding. On the other hand, the silver electrode is added to the weld as a filler metal and becomes the main component of the weld metal. Therefore, the composition and quality of the silver electrode will directly affect the chemical composition, mechanical properties and physical properties of the weld metal. In addition, the silver electrode has a great influence on the stability of the welding process, the appearance quality of the weld, and the welding productivity. The core is the metal core of the electrode. In order to ensure the quality of the weld, the content of various metal elements in the weld core is strictly regulated.

Non-coated silver electrodes cannot be used for arc welding,This is because the arc stability is very poor, the spatter is large, and the weld formation is not good. After long-term practice, it is gradually found that coating some mineral raw materials on the outside of the core material can greatly improve the performance of the electrode.