Single-phase welding current power sources for mechanised carbon dioxide welding

The Study of Welding Power-Arc System Stability Based on DFCD

“…The Experimental Analysis of the WPSS [9] [10] Test conditions: Wire grade is for ER-50-6; the wire diameter d is 1.2mm; inductance L is120µH; the welding current If is 250A, the welding voltage U y is 34.5v the speed of automatic welding is 42cm/min;the rate for wire feed is about 3.85m/min;the height for welding torch is 15 mm; the flow for gas CO 2 is 14l/min; the welder is KR-II-350 for Panasonic ,a intelligent detection system of welding process. [11] The above test, the figure a) and c) corresponds to the total resistance R toa from the external circuit , the figure b) and d) corresponds to the total resistance R 'toa from the external circuit , and R toa > R' toa , the remaining test conditions are consistent. From the view of welding current waveform, compared the figure a) and b),the a) is small fluctuations in the waveform, indicating each current error ,which is due to interference factors ,decay faster until to be eliminated, the time t* required is less, these reflected that the distortion is very weak in the law waveform, indicating a larger is the WPSS corresponding to the strong R toa ; the other hand, in the diagram b),the corresponding to the R' toa , the WPSS is accordingly weak.…”

“…Based on the formula ( 7), ( 8), ( 9), then the ( 10) is born: 11) k' w is the coefficient of the WPSS. In the equation ( 11), I f is the welding current on the static equilibrium, which is the same to the parameters from the welding process specifications (WPS); the △I' f (t) is the actual DFCD, is also for the deviation of the welding current relative to the point A 1 or B 1 c orresponding to I f on the time t, as shown in Figure 2, that is say that the dynamic deviation of current is relative to the actual WPS.…”

“…Based on the formula (11), if KW >0, then k' w ﹥0, therefore, the Optimal conditions of WPSS is k w >0, it is that at the A0, the slope of the characteristic curve 2, which is from arc volt-ampere, is greater than the characteristic curve 1.…”