| 摘要 |
PURPOSE:To reduce generation of spatter and generate arc surely by providing a short-circuit detecting circuit and an arithmetic circuit and controlling welding current basing on differential voltage between set voltage and welding voltage. CONSTITUTION:In the case where welding current exceeds the set value when short-circuiting, welding current is controlled by a controlling circuit 34, and peak value is limited. During the period of arc generation, a Q output signal L is outputted from the short-circuit detecting circuit 38. At the same time, a current detecting signal H is outputted from a welding current detecting circuit 36, and a transistor 44 makes off operation and compensating voltage V2 is generated from a pre-amplifier 42. Accordingly, a pre-amplifier 20 adds compensating voltage V2 to set voltage Vs and compares with welding voltage Vf, and outputs large controlling voltage Vo to a driving circuit 30, and controlling voltage corresponding to the controlling voltage Vo is outputted to a controlling circuit 34. Accordingly, welding current is controlled by the controlling circuit 34 until welding current becomes below a specified value at the time of arc generation and decrease of current becomes gentle. |
