Answer: The arc welding machine is a device that provides electric energy for the arc load and ensures the stability of the welding process. In the commonly used arc welding section, the voltage is about 20-40V, and the current is in the tens to thousands of amperes. Therefore, there must be an energy transmission and voltage transformation device between the industrial power grid and the welding arc, which is the arc welding machine. Its basic principle is to reduce the voltage of the power grid to a voltage suitable for arc work, and can transmit a large current.