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Welding from a Listeroid/ST generator rig

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highroad281:

--- Quote from: 38ac on March 03, 2021, 11:41:15 AM ---It was unfortunate that all my pictures were lost when the photo host shut down this the reason for the vanishing posts here.  No pics equals rest of post worthless. That being said an enterprizing individual happened to save all of my rants so there is hope at some point they will be available with pictures.

--- End quote ---

I’m aware that this is a cold topic but since I haven’t seen anyone else offering this up I figured I would. Maybe someone has and I missed it.  In that case please disregard the following.

Some years back I collected a both 6/1 and 12/2 clones with intent to go through them and build a back up gen.  I thought at the time that I’d like to have a hard copy of 38ac’s Indian build thread to work from, so I saved it to a doc.  Now that the kids no longer require constant supervision I’m hoping to pick back up on these projects and was quite dismayed to find the content gone, and myself unable to locate the doc that I had saved! 

Well, after a few days of searching usb drives I have finally just found it. 

With permission from the original author I’d be happy to share, drop me a pm.  Better yet if there is a way for a moderator to restore the content to the WOK from the doc that would be better still.

I’m positive that I also saved the twin build, and others (possibly timing, and balancing) threads too but unfortunately I think those are now lost to me.  If anyone happens to have the twin thread content to share I’d be especially grateful.

Best,
Neal

cobbadog:
G'Day Neil,
That is a very kind offer and hopefully those who need it will contact you.

Something I would suggest providing the Admin approve is a new topic for listing all these manuals so they are easily found and looked up. Then anytime needs the information simply go to this new thread and find them there.

Is this possible to do please Admin?

olNick:
Hi,

After cooking an expensive inverter welder connected to "cheesy" generators, I found that what kills them, at least in my case is the sudden voltage drop that occurs when striking a real arc (120-150A), tacking is ok...

This AC drop is enough to momentarily lose the 12V logic voltage so the welder is running w/o the control circuit, i.e. no PWM of the current.

I believe that it's a tossup as to which IGBT side clamps ON, thus full current, thus meltdown.

Maybe this could be remedied w/ a supercap or something in the control voltage PS.

Never, ever had a problem w/ my "real" 2 cyl DEUTZ, 6KVA, avr controlled generator. If anything it runs a lot sweeter when I'm wleding away....

Anyway, my 2c,

nick

cobbadog:
Tghis site and another one I know of have a dedicated generator section with some very clever people to offer help with the right answers. Sorry I have no idea about generators but enjoy reading the problems and ways to fix.
Possibly duplicate the thread in the generator section or ask in that section to have a look at this and post a link of this in that section. If that makes any sense.

BruceM:
Oldnick, I think your assessment of the failure is interesting and quite possibly spot on.  Adding  large electrolytic capacitors on the 12V might be the simple solution.  But it is a very poor inverter-welder design that doesn't protect it's critical IGBT or Mosfet gate control from voltage sag.  Even if it did work admirably with a stronger AC supply.  All power electronics designers are not created equal; it's like any other professional, a brilliant minority and the rest barely getting by. 

I'm in the latter group.  I popped a couple MOSFETs in my own home-hobby inverter design last week when I accidentally applied a hard short to the 120V (transformer stepped down) while testing a current/voltage/power smart sensor for a water chiller project. The 230V AC breaker didn't pop in time, and the DC fast blow fuse for that H-bridge blew but not quite fast enough, apparently.  This is the first failure ever of my inverter.  I never tested it for an overload/ short on the 120V side, only 230V.  Luckily it's all my own design so the repair was $8. in parts and a lost day.

I'm adding a fuse on the 120V side to protect me from future senior moments.  If it was a commercial design,  I'd add a microcontroller and circuitry watching the real time current to shut down the waveform generator in real time, safely as soon as a peak load exceeded the safe limit for peak current and/or time at peak.  Fuses are too crude. 

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