| 摘要 |
1,186,735. Automatic control systems for arc welding. AIR REDUCTION CO. Inc. June 22, 1967 [June 30, 1966], No.28916/67. Heading G3R. A control system for arc welding equipment using a non-consumable electrode provides an unvarying control signal to the arc length control equipment so long as a predetermined relationship is maintained between arc voltage and at least one other arc parameter, the control signal being obtained from simultaneous and continuous input signals. In the D. C. system shown, the arc length is made independent of changes in arc current by feeding to the automatic voltage control device 64, which controls the position of electrode 52 through a conventional adjusting means 56, signals representative of arc voltage and arc current which are opposed to one another and which provide a substantially constant resultant input to the device 64 over a desired operating range of arc currents. The Specification gives typical values of the resistor R and current ratio k of saturable inductors 58, 60 suitable to provide the required compensation of the two signals over the desired range, operation of the system for changes in arc current and/or arc voltage being discussed, Fig. 1 (not shown). The operation of the current signalproducing circuit comprising members 58, 60, 70, 74 is also described. In another arrangement, Fig. 3 (not shown), the current signal-producing circuit comprises a resistor (R) connected in the electrode-workpiece circuit and supplying an inverting amplifier (80) whose output, together with the arc voltage signal, is supplied to the automatic voltage control device. The invention may be applied to an A. C. welding system and to systems wherein the device for adjusting the arc length is of the automatic current control type, e.g. when the arc length varies more rapidly with changing arc current than with changing arc voltage. Compensation for parameters other than arc current may be achieved by providing for the arc length adjusting device additional control signals representative of these parameters. |
