| 摘要 |
1,088,511. Automatic control systems. WELDING RESEARCH, Inc. Jan. 20, 1965 [Sept. 21, 1964], No. 2462/65. Heading G3R. An automatic welding control system includes apparatus for sensing the position of the welding electrode with respect to the workpiece and apparatus for changing the welding current, arc voltage and/or welding speed in dependence upon a position error signal, which parameters determine the weld penetration, whereby the weld penetration is maintained constant. As shown, the arc voltage between a non-consumable electrode 10 and a workpiece 11 is maintained constant by a conventional electrode positioning system 16 to 25, the changes in electrode position being detected by sensing apparatus 30 to 35 to produce an error signal at a potentiometer 38. The output of the welding current source 12 is controlled by a signal derived from a potentiometer 40 associated with a supply source 41 to 46 and after a predetermined time delay produced by the operation of a relay system 49 to 60, to this control signal is added the position error signal from potentiometer 38; the welding current is then controlled in dependence upon this error signal. Thus, if the positioning system 16 to 25 causes the electrode 10 to move away from the workpiece 11 in order to maintain a desired arc voltage, then a position error signal will arise at potentiometer 38. This error signal, applied to the current source 12, will cause the welding current to increase whereby the weld penetration will also increase so that the electrode 10 will move toward the workpiece 11 and tend to return to its original position as is required to hold the weld penetration constant. In other embodiments, the welding current is maintained constant and the position error signal is used to modify the arc voltage control system Fig. 2 (not shown), or the welding speed Fig. 5 (not shown). In another modification Fig. 3 (not shown) the system is arranged to provide an arc length which varies inversely with current below a certain value to maintain constant weld penetration at constant arc voltage, and a constant arc length with current above the said value. |
