The Weldman “H” series heavy duty energy efficient inverter power sources deliver constant current (CC) DC welding power using proven IGBT power transformation technology. These machines render excellent performance for stick welding with various types of electrodes and also for scratch-start TIG application. When coupled to the high frequency TIG control unit WERT301, various TIG features are available. Heavy duty welding at high current is achieved due to careful design and layout of power components and cooling arrangement. The power source is highly energy efficient.