ARC LENGTH DETECTOR, ARC LENGTH DETECTING METHOD, TORCH HEIGHT CONTROLLER, TORCH HEIGHT CONTROL METHOD, AUTOMATIC WELDING DEVICE AND AUTOMATIC WELDING METHOD

摘要

PURPOSE:To realize arc length detection and control of the torch position and welding conditions with high accuracy by comparing an electrical signal corresponding to the extracted torch position with a set signal from a reference torch position setter and executing control so that this output deviation signal attains zero. CONSTITUTION:A prescribed signal is superimposed on a welding arc 5 by an oscillation means 6. An arc sound is detected by a microphone 7 and an arc sound pressure level is extracted based on its output signal. The arc length is extracted by an arc length extraction means 11 from the relation between the sound pressure level and the arc length-the arc sound level stored in advance. The electrical signal corresponding to the extracted torch position is compared with the set signal from the reference torch position setter and control is executed so that this output deviation signal attains zero. By this method, welding control hardly influenced by an arc phenomenon is executed.