| 摘要 |
PURPOSE:To maintain always a torch angle in an optimum reference condition by oscillating an arc forward of a welding direction and turning a torch in such a way that the difference between the arc voltage during oscillation and the arc voltage during non-oscillation is made equal to a reference value. CONSTITUTION:The arc voltage waveform passed through a low-pass filter 12 and the arc voltage during non-oscillation are inputted to a differential amplifier 16 and the pulse-shaped arc voltage waveform only during the oscillation period is inputted to an integrator 17. The integrator 17 calculates the area of the pulse waveform which is stored in storage devices 18, 19. If a torch angle theta is not equal to the initial reference value, the output S from the device 18 attains the value different from a reference value S0 and the torch is corrected and driven to the reference torch angle by a torch angle correcting motor (theta motor) 21. |
