| 摘要 |
PURPOSE:To prevent the plunging of a consumable electrode into weld zones on accouut of its inertia and the generation of a globular lump at the leading end of the electrode in a welding machine for welding under feeding of said electrode by changing the output voltage of a welding power source at the end of welding to a pulse form within a period when it is maintained low. CONSTITUTION:When the signal during working from a starting circuit 13 is annihilated at the end (b) of welding, a control circuit 18 interrupts the output immediately and therefore an electric motor 20 is decelerated quickly and stops after the time DELTAt. On the other hand, a circuit 9 changes over and transmits the output of a reference voltage setter 8 from the same setter 7. Delay switching circuits 14, 15 start clocking and the latter times out after the time t2 and the former after the time t1(t1>t2). Upon timing out of the circuit 15, a delay switching circuit 16 starts timing. During the time of t2 after the time (b), the low voltage of the setter 8 is supplied to the welding power source and the voltage E2 lower than that during welding is supplied to a torch 3 and the work 4. During the time of the set time t3 of the circuit 16 after this, the output is supplied to a switching circuit 11, and the voltage Ep corresponding to the set value of a setter 10 in lieu of the setter 8 is outputted. Thereafter, the circuit 11 supplies the voltage E2 until the t1 times out. |
