WELD ELECTRODE TRACKING SYSTEM

摘要

A constant voltage source (AVC) is used to supply welding current to a laterally oscillating weld torch, and abrupt changes in the arc voltage occurring when the torch electrode approaches the sidewall of the welt joint are used as a signal to reverse the lateral travel of the torch across the weld joint. A stepping motor is used to move the torch first to the right a predetermined number of steps with the AVC operative and, after completing this number of steps, the arc voltage is sampled for averaging. The torch is then moved back to the original lateral position and thence to the left the same number of steps with the AVC on. At the end of the lateral travel, the arc voltage is again sampled for averaging and the two averaged arc voltage samples are compared for adjusting the lateral original position of the torch.