Classification of arc welding machines that utilize electric arc heat to melt and join metal materials. Includes covered electrode arc welding machines (stick welders), semi-automatic welding machines, and automatic welding machines, used in manufacturing heavy structures such as construction machinery, shipbuilding, bridges, piping, and general fabrication. Classified by power source types including AC/DC inverter, thyristor, and engine-driven types, selected based on welding current range and duty cycle. Distinguished from TIG welders, MIG/MAG welders, and plasma welders by different welding methods, primarily using covered arc welding electrodes.