| 摘要 |
PURPOSE:To improve the control responsiveness to abrupt and large fluctuations of welding conditions in a welding machine which detects the presence or absence of short circuiting and sets arc outputs, by setting detection time intervals according to the average change rate of welding current which is removed of high frequency components. CONSTITUTION:The control loop consisting of 1-6 in the constitution block diagram of a welding output control system is the same as that in the prior art, except that it is so constituted that the sampling time by a setting part 7 changes according to the change rate of the welding current. The value of this change rate, that is, the quantity of change, is detected with a detecting part 8, where it is removed of high frequency components with a low pass filter of about 10Hz cut-off frequency in order to derive the average current from, for example, a pulse-like welding power source. Then, if the welding current value changes considerably and is decreased on account of an extreme increase in the projecting length of, for example, a wire, the sampling time is set low and the increase or decrease of the output within this short time is judged in a selection part 2. |
