The A-C arc progresses

ELECTRIC WELDING could be pictured very accurately to an electrical engineer as an attempt at maintenance and control of a short circuit. In resistance welding, whether spot, butt, roller seam, flash, or projection, it is an actual short circuit with definite resistance and low voltage drop. The arc is the maintenance of a short circuit in a very unstable medium, generally air, with a comparatively high voltage and nature conspiring to extinguish it. The “holding” of a metal arc is especially difficult as one electrode is continuously melting away into the other electrode called the “work.”