1. Principle of inverter welding machine
Inverting and rectification are two opposite concepts. Rectification is the process of converting AC power into DC power, while inverter is the process of changing DC power to AC power. The arc welding power source using inverter technology is called inverter welding machine. The inverter process requires a high-power electronic switching device, and the inverter welding machine using the insulated gate bipolar transistor IGBT as the switching device becomes the IGBT inverter welding machine.
2. Working process of inverter welding machine
The three-phase or single-phase power frequency AC rectification is performed, and after filtering, a relatively smooth direct current is obtained, and the inverter circuit composed of the IGBT converts the direct current into an alternating current of several tens of KHZ, after being stepped down by the main transformer, and then subjected to rectification and filtering. A smooth DC output welding current is obtained.
Since the inverter operating frequency is very high, the cross-sectional area of the core of the main transformer and the number of turns of the coil are greatly reduced. Therefore, the inverter welder can largely save metal materials, reduce the size and weight, and greatly reduce power loss. What is important is that the inverter welder can adjust the output current in microseconds, so that the ideal control process required for the welding process can be achieved and a satisfactory welding result can be obtained.
Although the circuit is closed, it is because the circuit is closed so that the entire closed circuit and current are equal; but the resistance can vary from place to place, especially at the unfixed contact, which is physically The contact resistance is called. According to the law of thermal effect of current (also called Joule's law), Q=I square Rt knows that if the current is equal, the heat is higher in the part where the resistance is larger, and the contact of the metal body where the contact of the electrode is also connected when welding is welded. The contact resistance is the largest, and the electric heat generated at this part is naturally the most. The electrode is a low melting point alloy, which is naturally easy to melt. After the molten alloy electrode core is wetted on the object to be welded, it is cooled. Bond the welded objects together.
Since the inverter welding machine is a typical switching power supply (the output characteristics are very characteristic), the output power is large, and the working environment changes greatly, so the quality of the components is required to be good, so as to ensure stable operation and long service life.