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Ultra Pulsing

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  • Ultra Pulsing

    I'm away from my 200DX for a couple weeks but I was thinking about the pulser because of another thread here and it occurred to me that you might be able to use the pulser as an independent polarity amperage control in AC mode. This is going to be kind of hard to explain, but I'll try to get the idea across...

    Any respectable AC TIG machine lets you adjust the AC balance: this lets you adjust the time per cycle that the machine is EN and inversely the time per cycle that the machine is in EP. But more advanced machines let you also adjust the amperage for each side of the AC cycle. So you could have the EN portion of the cycle put out 100A and the EP portion put out, say, 50A. The Dynastys don't have this option as a panel control, but I was thinking and I think you might be able to do this with the Dynastys anyway by using the pulser in AC mode.

    Before I go on, I might at that I'm not a good enough welder at this point to need this kind of control, but I thought this might work and I want to know...

    For instance (and these values are arbitrary) if you setup the machine to AC at 100Hz at 50% balance, couldn't you then enable the pulser and set it to 200Hz at 50% peak time? This would, in effect, allow you to set the EN amperage and EP amperage independently by adjusting pulser's amperage and background amperage, wouldn't it? As long as the pulsing frequency was exactly twice that of the AC frequency, the pulser would switch the amperage twice per AC cycle, and you could even adjust the pulser's peak time to correspond to the AC square wave balance.

    This is assuming a few things, however. First, it assumes that the pulser and the AC polarity switcher are running from the same clock, or that the two clocks are sync'd to the same counter. If not, then the two might drift apart. But if they are, they would stay locked.

    Also, it assumes that the machine would always start welding in either EN or EP and that the pulser always started at either normal amperage or background amperage. For this to work, the starting mode of each section (pulser, AC switcher) needs to be consistent and known (and figured out).

    Then I noticed that the AC frequency range on the Dynastys is 20-250Hz and the pulser's frequency range is, well look at that, 10-500Hz. This means that if this idea is valid, you could use this technique with ANY AC frequency. Further inspection of the specs show that you could also use this technique with any AC balance setting from 30% through 95% - almost the entire balance range. Sweet!

    Perhaps this is something that is already known and applied, but if not I'd like to verify that this works. Does anyone own an oscilloscope that could work with me in investigating this? I could rent one if not, and probably will if nobody gives me any convincing evidence that this will not work.

    Any comments/ideas, though? Techies?

  • #2

    I was just thinking and I errored in my pulser setting...

    Since I'm trying to align the pulser's high state to the EN portion of the AC cycle, the pulser would need to be set at the same PPS as the AC frequency, not twice the AC frequency. So the idea still works.

    If the AC frequency was 100Hz, you would need 100 PPS, not 200 PPS, on the pulser side, still assuming that the pulser and the AC switcher are sync'd. The AC balance and the pulse time would still need to be set at the same value.

    And if the output starts on EN and the pulser starts at HIGH, you would only be able to get a combined output that has an EP amperage LESS than the EN amperage which is generally what you'd want with this type of control. If either the pulser OR the output polarity starts the other way, you would only be able to get a combined output that has an EP amperage MORE than the EN amperage, not so useful, I would think...


    • #3
      aphexafx, I also like to figure out new ways to use equipment, but I am not sure of the advantages you would get by doing what you are thinking...please enlighten me. Best Regards, Paul
      More Spark Today Pleasesigpic


      • #4
        That makes my head hurt to try to figure it out, but it sounds like you could be onto something. I bet Dyn88 could tell us something or explain why it would or wouldn't work. He seems like the scientific type.
        Zeb's Welding and Machine