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  1. CDRIVE

    Help for test uc3845

    The datasheet includes a transformerless test circuit. http://www.ti.com/lit/ds/symlink/uc3845.pdf Chris
  2. CDRIVE

    Electric load controller high voltage capacitor

    Harald, thanks for the explanation. Alec, thanks for the sim but I'm not surprised at the results. That 10uF cap is going to be working its ba!!s off! :eek: Chris
  3. CDRIVE

    Electric load controller high voltage capacitor

    Question: Why do you need such a relatively large cap across the AC Mains? Chris
  4. CDRIVE

    Electric load controller high voltage capacitor

    It would seem logical that high current would occur when the IGBT turns on. This is going to require an extremely low ESR cap. The problem here is most AC caps designed for AC motor application are actually 2 electrolytic caps wired in series +[ ]- -[ ]+ or -[ ]++[ ]- . As far as I know...
  5. CDRIVE

    Small DC TIG welder remote switch needed

    EEK! :eek: That's the absolute worst time I can imagine for it to shut down! That alone would be a damn good reason to replace that thing with a 120V box fan. This way it can be wired to the power cord. Then you'd be good to go with your switch wired in series with the Pot's switch. They're not...
  6. CDRIVE

    Small DC TIG welder remote switch needed

    Ed, reading this was like a Maxwell Smart moment. You know those little exchanges between him and the Chief. When the Chief says " Did ya get that Max? " and Max would say " Not quite Chief ". You know how the rest of the dialog goes.. :confused: Anyway, on the up side I did comprehend the HV...
  7. CDRIVE

    Small DC TIG welder remote switch needed

    More relevant would be the current delivered between the electrode and the work but you could fry your DMM measuring it. Chris
  8. CDRIVE

    Small DC TIG welder remote switch needed

    I was hoping that it was a 120VAC 60Hz fan. I guess it was too much to hope for. My next suggestion was going to be hard wiring the fan across the AC mains so it's always on when plugged in. Then I was going to suggest breaking the Pot Switch circuit and inserting your foot switch in series...
  9. CDRIVE

    Small DC TIG welder remote switch needed

    I just reread the above post. I'm not familiar with inverter arc welders so I can only speculate. What I think is this. An arcing contact is actually a rapidly intermittent connection. This is what actually generates the arc. When the electrode is stuck it is no longer an intermittent...
  10. CDRIVE

    Small DC TIG welder remote switch needed

    Is the stuck electrode feature something different than the overload feature? Or are you saying that when overload occurs it also sounds the Piezo until the electrode is unstuck? If that's the case it kinda puts the relay option in the undesirable category. Chris
  11. CDRIVE

    Small DC TIG welder remote switch needed

    Yes, that's why I asked you to remove the jumper, turn the Pot to minimum but not OFF and test the arc. My guess is it produce a small arc similar to when you jumped the Pot wiper. This only reinforces my opinion of Ed's approach. Energize the overload relay coil and kill the output entirely...
  12. CDRIVE

    Small DC TIG welder remote switch needed

    OK, I just want to wrap my head around this. Your results are somewhat as expected but not 100%. I expected no arc at all. What I expected was the same results that would be produced when without jumping anything and the Pot is set to 0, while not tripping the switch. Do you still get a small...
  13. CDRIVE

    Small DC TIG welder remote switch needed

    I meant this test. Make sure the Pot's at mid range. It insures that this test can't pop anything because the opposite fixed un-shorted terminal will always see some resistance between it and the wiper. Chris
  14. CDRIVE

    Small DC TIG welder remote switch needed

    Ah, I see but why does it stand proud like that? Also, have you tried my last posted test yet? Chris
  15. CDRIVE

    Small DC TIG welder remote switch needed

    Hey Ed, after examining the photo closer I see (what appears to be) a center pin on the Pot switch. Now I'll admit that I've never (in over 58 years) seen an integral SPDT Pot switch. This pin is connected to the Pot wiper. See what the "?" is pointing to. Chris
  16. CDRIVE

    Small DC TIG welder remote switch needed

    My Apologies! So you did. I guess that Vodka save didn't improve my reading comprehension. :D Though I like Ed's approach of tapping into the overload relay coil I think I should mention some points about your previous attempt to break the wiper connection. Since breaking the wiper...
  17. CDRIVE

    Small DC TIG welder remote switch needed

    Ed, when you leave this earth donate your eyes to science. They're amazing! It's either that or I've long forgotten what I used to be able to see. :( Chris
  18. CDRIVE

    Small DC TIG welder remote switch needed

    I've just read Ed's post and your reply. I would be remiss if I didn't state that your reply pissed me off just a tad. Finding out (NOW!) that you've messed with the Pot before this topic was created is a real A$$ burner! Also I assume you realize the Pot's mounting ears (as Ed pointed out)...
  19. CDRIVE

    Small DC TIG welder remote switch needed

    Well I've spent most of my morning coffee time watching youtube inverter welder vids and searching through endless google image schematics until my eyes threatened to bleed. Here's your next two tests.. Measure the resistance of the two outer terminals of the Pot when at extreme CCW (0)...
  20. CDRIVE

    Small DC TIG welder remote switch needed

    I think I found it! Is it the lower left corner of the board bottom photo? If I'm right I don't think the switch is switching the mains. Chris
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