| 摘要 |
PURPOSE:To enhance an effect of the automatic welding by detecting a welding current value at the groove width center through a differentiation circuit and comparing it with a preset proper reference criterion value to control the welding speed and performing the one-side welding of members with the inferior groove accuracy. CONSTITUTION:The plug power of test from a DC constant voltage welding source 17 is connected with a gas shielding nozzle 14 through a shunt 23 and a welding current value I is allowed to flow thereto, by which the output voltage Ei is generated from the shunt 23. This output voltage Ei is converted into a differential output voltage value Ed by the differentiation circuit 24. The converted differential output voltage value Ed is compared with a reference voltage value Es from a proper reference circuit 19 by a comparator 18 to obtain the differential voltage + or -DELTAE. Further, the compared differential voltage + or -DELTAE is amplified by an amplifier 20 and the speed of a welding carriage motor 22 is controlled by an electric power output circuit 21, by which the positional relation between weld metal and the gas shielding nozzle is properly controlled continuously with the proper voltage value as a target to perform the welding as aimed at.
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