| 摘要 |
PURPOSE:To obtain always stable welding current by changing over the current value of a main power supply device according to the welding current set to meet welding conditions and suppressing the fluctuation of the welding current from the output current of an auxiliary power supply device. CONSTITUTION:The total current of the welding current from the variable iron core type main power supply device 1 and the current for suppressing fluctuation from the SCR type auxiliary power supply device 2 is detected by a current detector 3 and is compared by a comparator 5 with the welding current set in a setter 4 to meet the welding conditions. The deviation signal thereof is inputted to a commander 6 which outputs a command voltage V to control the firing phase of a thyristor switch of the power supply device 2, thereby making constant the welding current outputted to an electrode 7. On the other hand, the command voltage V is inputted to a means 8 for controlling the change over of the current. An upper limit signal generator 11 outputs the command voltage VU corresponding to the upper limit value of the current regulating range of the auxiliary power supply device 2. A lower limit signal generator 12 outputs the command voltage VL corresponding to the lower limit value of the current regulating range of the auxiliary power supply device.
|
