| 摘要 |
PURPOSE:To offer the groove detecting method and device of high speed and high accuracy by detecting the arc current immediately before a short circuit at short circuit time or by detecting the current of only the prescribed period at the arc generating time. CONSTITUTION:The above-mentioned device connects a partial pressure resistance 7a between a welding cable 1a and return wire 1b and connects the detecting terminal of this resistance 7a to the input terminal of a comparator 7b. The circuit 7 detects the welding voltage, discriminates the arc generating time or short circuit time and outputs an arc generations signal only at arc generation time. An analog signal 8 is turned on at the time when an arc generation signal is impressed on a control input terminal 8a and inputs to the input terminal of a sample holder circuit 9 via a switch 8 the output signal of a current detecting circuit 6. Therefore the switch 8 is made ON during the arc generation and the current detecting signal of the circuit 6 is impressed on the capacitor 9c of the circuit 9 via the switch 8 to charge the signal voltage at arc generation time. And at short circuit generation time the switch 8 is made OFF and the signal of the arc generation time before short circuit generation is held by the capacitor 9c. |
