Electric arc welder that provides non-sticking arc initiation and thereafter maintains the arc

摘要

An electric arc welder has a current-conducting means which can supply welding power to an arc along a first volt- ampere curve, has a second current-conducting means which can be paralleled with the first current-conducting means to supply welding power to that arc along a second and distinctly-different volt-ampere curve, has a voltage-sensing circuit which senses the arc voltage, and has a control circuit which automatically and virtually-instantaneously shifts the supplying of welding power from a point on the first volt- ampere curve to a point of essentially-equal potential on the second and distinctly-different volt-ampere curve when the voltage-sensing circuit senses that the arc voltage has fallen below a predtermined value. That control circuit will subsequently shift the supplying of welding power from a point on the second and distinctly-different volt-ampere curve to a point of essentially-equal potential on the first volt-ampere curve when the voltage-sensing circuit senses that the arc voltage has risen above that predetermined value. In this way, a welding wire or welding rod can be continually advanced toward a weld puddle in a work piece, and the welding power which is supplied along the second and distinctly-different volt-ampere curve will transfer the tip of that welding wire or welding rod to that weld puddle without "shorting" and thereby extinguishing the arc.