Abstract
With the development of "Inert Gas Arc Welding", the superposition of high frequency pulses to the welding current has become an indispensable practice. But, on the other hand, there is an urgent necessity to arrest the disturbing radio noise from the apparatus.
The contradiction has not yet been overcome complety. The authers studied the problem from the standpoint to find the most effective pulse shape and timing and to reduce the necessary pulse energy for maintaining the arc. The authors obtained following results:
1) The effect of the frequency of the pulses:
The lower the frequency the better the arc maintaining and starting action.
2) The effect of pulse duration:
The longer the duration the better the action, and the direct current component is very effective.
3) The polarity:
The polarity effect is not evident.
4) The timing:
The effective timing period of the pulse is not limited to the close neighbourhood of the zero of the arc current, but practically has an allowance about ±10°electrical angle.
This may seem contradicatory to the customary theory. But, the existence of the relatively broad allowance makes the apparatus very feasible.
From these results, the authors confirmed the possibility of obtaining an apparatus superior to convensional apparatus from the standpoint of noise reduction.
