| 摘要 |
PURPOSE:To obtain a stable arc in a wide welding current range from low to large current with substantially no generation of spatters by superposing respectively optimum pulse current on approximately specified base current in the stage of a short circuit and in the stage of an arc by the detection signals for the short circuit and the arc so that the short circuit is executed forcibly. CONSTITUTION:The voltage transformed to a prescribed voltage by a transformer 3 and rectified to DC by a current rectifier is applied through a current limiting element 5 and a power feed chip 7d to an electrode 7c and the arc 7d is generated between said electrode and a base metal 7a when said voltage is outputted. The electrode 7c is fed at a constant speed and the arc voltage 9 is detected in this stage. The value set in a reference signal generating circuit 11 and the detected 9 value are compared by a discriminating circuit 10 for the short circuit and arc, by which the short circuit is discriminated. The circuit 10 applies a start to a circuit 13 for generating pulse current signal of the short circuit when the short circuit is decided. The circuit 12 applies the signal to the circuit 13 upon lapse of the preset delay time after the signal from the circuit 10 is applied thereto. The circuit 13, when applied with the signal from the circuit 12, outputs the preset waveform signal to a driving circuit 6 which impresses the pulse current for the short circuit from the element 5. |
