The Large power compent, MOSFET filed-effect transistor, is used to convert 50/60HZ power frequency into hign frequency(for example, 100KHz above). Then, Produce large power DC source by reducing the voltage, rectifying the current, and applying pulse-width modulation(PWM) technology. The width dimension of the main transformer is significantly decreased and the efficiency is increased by 30% above. Has the auto-compensation function to mains voltage fluctuation, powerful ability in anti-fluctuation of mains, welding current stable and reliable. Automatic over-voltage and over-current protection function Good Arc Force compensation Reliable performance, small dimension, low weight, high efficiency, and energy saving Acidic and alkaline welding rods of various brands can be used for welding All black metals such as low carbon steel, mild carbon steel, and alloy steel structure. With quick protection circuit for over current, protect IGBT against break down effectively, suitable for continuous work Mainly applied for welding carbon steel, low alloy steel, stainless steel etc. in various welding postion. The welder rated current more than 350A is suitable for welding in shipbuilding, car, bridge, and steel structure etc. Industries.