CO2 WELDING-Power Source
Normally, a power source with constant potential characteristics is used for CO2 welding as it has the ability to self regulate the welding arc. The positive polarity of the power source is always connected to the consumable wire electrode and the negative polarity is connected to the work piece. Transformer - Rectifier (T-R sets) type which were in use earlier is now being fastly replaced by more advanced inverter power sources. The Transformer - Rectifier sets used to contain a variable inductance in series to limit the rate of raise of the short circuit current and thereby reduce the spatter loss. However, the advent of the thyristor and transistor power sources has obviated the need for inductance control, the rate of rise of current is now controlled electronically. The welding voltage in these modern power sources can be adjusted both from the panel as well as from a remote pendent.