Hello People!
This is my first Post here.
I have searched the internet in vain, trying to find out the electronics behind "Arc Balance Control", which is used on TIG welders for the welding of aluminium. I understand what it is and why it is used when TIG welding on aluminium, but I can't find any information about how the proportions of the negative to positive polarity of the AC square wave are actually adjusted. When the Tungsten electrode is energised with the negative phase of the square wave current, the arc penetrates the aluminium work, and when the electrode switches to the positive phase, any aluminium oxide is cleaned off the surface. Somehow, by turning an "AC Balance Control" knob from 20% to 80%, the proportion of electrode negative to electrode positive, that is to say the proportion of the negative to positive levels of the square wave, can be adjusted. My analog TIG welder has no adjustment for the frequency of the square wave, and I'm guessing it is about 60 Hz, and 50% of the time the wave is in the negative direction, and 50% of the time the wave is positive. So, within that given frequency, the proportion of the time spent in the negative wave and inversely in the positive wave, can be adjusted (balanced).
But, how is this proportional balance of the square wave controlled? What is the technology behind it? I can't find any information or circuit diagrams, so I am hoping that someone on this forum might please be able to shed some light on the subject, or direct me to some source or authority that can explain it to me.
One authority has suggested:
"Presumably it is a type of pulse width modulation operating on the AC waveform, with an adjustable duty cycle between the positive and negative portions. It may be implemented using a TRIAC with separate duty cycle setting for each polarity. It may be possible to create this waveform by stepping down the 50Hz mains waveform to a lower voltage, followed by a Triac-based duty cycle controller."
Hmm, a "Triac-based duty cycle controller"............. is that what the TIG Welding machines use to effect this "AC Balance Control"? If so, were can I get more information?
Previously, I have converted a mains-powered transformer MIG welder to run on DC from onboard 18650 Lithium batteries, and I would like to do the same kind of conversion (or build from scratch) for a TIG welder.
Hope some info is incoming.
Cheers,
Krisby.
This is my first Post here.
I have searched the internet in vain, trying to find out the electronics behind "Arc Balance Control", which is used on TIG welders for the welding of aluminium. I understand what it is and why it is used when TIG welding on aluminium, but I can't find any information about how the proportions of the negative to positive polarity of the AC square wave are actually adjusted. When the Tungsten electrode is energised with the negative phase of the square wave current, the arc penetrates the aluminium work, and when the electrode switches to the positive phase, any aluminium oxide is cleaned off the surface. Somehow, by turning an "AC Balance Control" knob from 20% to 80%, the proportion of electrode negative to electrode positive, that is to say the proportion of the negative to positive levels of the square wave, can be adjusted. My analog TIG welder has no adjustment for the frequency of the square wave, and I'm guessing it is about 60 Hz, and 50% of the time the wave is in the negative direction, and 50% of the time the wave is positive. So, within that given frequency, the proportion of the time spent in the negative wave and inversely in the positive wave, can be adjusted (balanced).
But, how is this proportional balance of the square wave controlled? What is the technology behind it? I can't find any information or circuit diagrams, so I am hoping that someone on this forum might please be able to shed some light on the subject, or direct me to some source or authority that can explain it to me.
One authority has suggested:
"Presumably it is a type of pulse width modulation operating on the AC waveform, with an adjustable duty cycle between the positive and negative portions. It may be implemented using a TRIAC with separate duty cycle setting for each polarity. It may be possible to create this waveform by stepping down the 50Hz mains waveform to a lower voltage, followed by a Triac-based duty cycle controller."
Hmm, a "Triac-based duty cycle controller"............. is that what the TIG Welding machines use to effect this "AC Balance Control"? If so, were can I get more information?
Previously, I have converted a mains-powered transformer MIG welder to run on DC from onboard 18650 Lithium batteries, and I would like to do the same kind of conversion (or build from scratch) for a TIG welder.
Hope some info is incoming.
Cheers,
Krisby.