welding shop welding equipment mma400 Welding shop welding equipment mma400, use powerful IGBT switchs and adrranced inrrerter control technology. Use PWM control technology and Constant Current (CC) output control, welding current can be exactly controlled. Continuous adjustment on welding current in large scale. Excellent arc characteristics, Stable arc, good welding performance and high quality. With anti-stick,hot start,arc force,strong compensation capability. Minimizing