Will high frequency TIG damage nearby computer? - Page 2
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  1. #21
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    I have a Dynasty 200dx 6 feet away from my plasma table and it's computer...which is old and running Windows XP.

    Never any problems running a program but the tig will 'turn off' the usb mouse and keyboard, and unplugging/plugging is the only thing that will get them working again.

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    Computers are made to not emit any radio interference, not direct, not through the PSU, nowhere. That shielding works both ways, what cannot get out also cannot get in.

    So the culprit was indeed probably a cable going to something else, and the "something else" may not have been as shielded as it needed to be.

    Or, as often happens, the computer cover gets put back, but not with all the parts that originally held it, so it no longer functions as a good shield. I see computers with missing covers etc from time to time, and obviously they are not shielded in that condition.

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    I had a watch that would freeze up for a bit when using my Syncrowave 200. And a device with a very long, extended USB cable that would sometimes lose connection and need the port reset after I did a bunch of TIG welding. So I would say that it's possible.

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    Quote Originally Posted by bob View Post
    I was doing a bit of tig welding about 6 feet from computer that was drip feeding the EDM. Machine stopped didnt think much about it restarted and kept welding. Stopped again but this time no joy. Computer had red light on and was beeping. Took it in motherboard bad. Old computer so maybe a coincidence just wondering if the tig fried the computer?
    Bob
    I used to have a Fronius TPS 4000 welder. It would do Tig, Mig, Stick, pulsed Mig and Tig and synergistic welding. Fronius has wire fed tig torches, so I asked Fronius USA if I could use that on my machine, to which they responsed that the TPS models have sophisticated electronics that will not permit high frequency Tig because it would damage the electronics.

  5. #25
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    Quote Originally Posted by bob View Post
    I was doing a bit of tig welding about 6 feet from computer that was drip feeding the EDM. Machine stopped didnt think much about it restarted and kept welding. Stopped again but this time no joy. Computer had red light on and was beeping. Took it in motherboard bad. Old computer so maybe a coincidence just wondering if the tig fried the computer?
    Bob
    It MOST CERTAINLY CAN.

    If things are shielded well, and your HF component isn't overly strong, and there's plenty of ferrite choke material in the right spots, you MIGHT have it 'tight enough' to keep HF RFI out of the inside. As others noted, good shielding from inside out, is reciprocal to good shielding outside in, but with one caveat:

    Good shielding at low emmission levels, and at controlled spectrum, is entirely irrespective of high emmission levels and uncontrolled spectrum. A tuned cavity, carrying a large component of a primary frequency, will exhibit internal resonance overtones. That cavity, being used as a source for 3rd harmonic oscillator multiplication, will keep it's fundamental tightly inside, and pass on only the desired harmonic when the coupling stub passing on to the next cavity is tight... but if you overdrive the fundamental, there will be large quantities of spurious harmonics, and a substantial amount of energy will appear on the outside of the cavity, even if it's grounded-to-heck.

    Which is probably much more science than you wanted to know...

    But the easy way to get an answer, particularly for anyone who says otherwise, is through simple empirical investment. Set it up, run it, and see if it blows up. If it blows up, you'll know. If it doesn't, you'll know.

    This will NOT be a 'final answer', though- It may fry immediately, it may last a long time. The HF energy generated from your TIG, REGARDLESS of wether it's a modern inverter OR an old-school transformer machine, is enormous. Take a 3-block walk down the street with an AM radio while your buddy is working the torch, and you'll hear it.

    Transformer machines do NOT generate '60hz' RF... they generate wide-band HF... although it is usually through the 60-cycle waveform that the HF generator instigates RF, the spark-gap oscillator does a remarkable job of creating a 'Christmas tree' of HF noise, and that frequency spectrum changes based on spark point gap and the HF generator circuit's loading capacitance. It is consequently, High, and Wide.

    What people don't realize about RF ingress into electronics, is that it doesn't take much to blow stuff. All it takes, is enough to destabilize a feedback point in some circuit, to send that circuit straight to the moon. A switch-mode power-supply, for instance, has a reference feedback line from it's output, back to it's controls. Superimpose some HF on that circuit, even if it ISN'T sensitive to that specific frequency, will cause devices, particularly solid-state, to become rectifiers which will build a charge onto such lines, and cause a loss of regulation.

    GOOD power supplies... really high quality ones... will have substantial loading and snubbing to mitigate the effects of incoming noise.

    Cheap ones don't have squat.

    The switch-mode supplies my company uses, are of the cheap variety. Strike an arc with a stick within 90 feet, and they go berzerk, and fry a pair of video cameras immediately.

    Roll your dice:
    Just because it doesn't happen, doesn't mean it cannot.
    Just because it HAS happened, doesn't mean it will.


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