Electric welding apparatus and method

An electric welding apparatus comprising a first consumable electrode and a second consumable electrode movable mechanically in unison along a welding path in a movement direction defined by the gap between the edges of two adjacent, mutually grounded first and second plates, a first power supply for passing a first welding current between said first electrode and said first plate, a second power supply for passing a second welding current between said second electrode and said second plate and a torch for directing said first and second electrodes toward said first and second plates, respectively, from first and second driven wire feeders, respectively, whereby said first and second electrodes are spaced from each other in a direction transverse to said movement direction and an insulator structure in said torch to isolate said electrodes electrically as they move toward said plates including an adjusting mechanism to move said electrodes relative to each other.

An electric welding apparatus comprising a first consumable electrode and a second consumable electrode movable mechanically in unison along a welding path in a movement direction defined by the gap between the edges of two adjacent, mutually grounded first and second plates, a first power supply for passing a first welding current between said first electrode and said first plate, a second power supply for passing a second welding current between said second electrode and said second plate and a torch for directing said first and second electrodes toward said first and second plates, respectively, from first and second driven wire feeders, respectively, whereby said first and second electrodes are spaced from each other in a direction transverse to said movement direction and an insulator structure in said torch to isolate said electrodes electrically as they move toward said plates wherein said first power supply is a surface tension transfer welder.

An electric welding apparatus comprising a first consumable electrode and a second consumable electrode movable mechanically in unison along a welding path in a movement direction defined by the gap between the edges of two adjacent, mutually grounded first and second plates, a first power supply for passing a first welding current between said first electrode and said first plate, a second power supply for passing a second welding current between said second electrode and said second plate and a torch for directing said first and second electrodes toward said first and second plates, respectively, from first and second driven wire feeders, respectively, whereby said first and second electrodes are spaced from each other in a direction transverse to said movement direction and an insulator structure in said torch to isolate said electrodes electrically as they move toward said plates wherein said first and second power supplies are both surface tension transfer welders.

An electric welding apparatus comprising a first consumable electrode and a second consumable electrode movable mechanically in unison along a welding path in a movement direction defined by the gap between the edges of two adjacent, mutually grounded first and second plates, a first power supply for passing a first welding current between said first electrode and said first plate, a second power supply for passing a second welding current between said second electrode and said second plate and a torch for directing said first and second electrodes toward said first and second plates, respectively, from first and second driven wire feeders, respectively, whereby said first and second electrodes are spaced from each other in a direction transverse to said movement direction and an insulator structure in said torch to isolate said electrodes electrically as they move toward said plates wherein said first and second power supplies are each short circuit welders for creating a succession of welding cycles each having a short circuit portion and a plasma arc portion with the plasma arc portion including in sequence a plasma boost segment, a tailout segment and a background current segment.