Parallel inverter welders anyone?

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Does anyone know if you can parallel two dc inverter welders the same way you do two transformer base units.  I have a couple of powcons I was thinking of running in parallel (@ about 200amps each for 400 amps total) off a 200 amp panel.  I have used 3-phase transformer welders in this configuration, but never inverter based units and never on a single phase line.  The need to hotrod...what can I say. Smithboy...if it ain't broke, you ain't tryin'.
Reply:smithboy: I've done that to arc gouge before. Don't know what if any long term effects this would have. Although I did gouge for a few days.  revpol
Reply:Thanks for the info.What type/brand of inverter did you use?  Were they just hooked positive to negative between the two welders?Smithboy...if it ain't broke, you ain't tryin'.
Reply:I just gave this some thought.  I've heard of inverters being synched together.  A friend of mine has a couple of generator/inverters that do this.  Given that the AC wave has to be coupled, I believe the oscillators on them are synched together.  In this case, you want to parallel a power source that's already been rectified.  I'm not sure how the electronics that control the power supply would respond, but I bet this could be done with a few diodes to prevent an unbalanced condition.  The only issue is that you're going to need some uncommonly beefy (200A+) diodes with very low series resistance.  You could parallel a few diodes together to get a greater current carrying capacity, but then you need a power resistor with a very low value to keep the current balanced between those.  If you're serious, I've got a friend that I'll be seeing later today that's an EE and owes me a favor as I've been doing some welding for him.  I can run it by him and come up with a schematic.  What I'm envisioning is pretty straightforward, but he'll be able to tell me if there are any issues that I'm unaware of.-Heath
Reply:I spoked to my EE buddy last night.  He confirmed my theory that it shouldn't be any more complex than using a couple of very beefy xener diodes on the positive side of each power supply.-Heath
Reply:Thanks Halbritt,I have some big diodes from a junk inverter welder, but I am not sure what their rating is.  I'll check to see what I have on hand and maybe this is possible with no out-of-pocket expenses...always a good thing.  I am serious about this, but I am also really out of my league (electronically speaking) here.  However, that has never stopped be before.  I might be back for more help, but I will document the process for posterity and for the coroner's inquisition if necessary.  I always have to remind myself that the theory of evolution DOES NOT state that smarter creatures survive to pass on their genes, just those creatures that are able to adapt.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Using the diodes should minimize the possibility that something could go awry and kill one of your welders.  Following that, the only remaining issue is one of controlling the power supplies.  Hooking up a wire feeder and getting remote voltage control to both supplies would require some thought.  Though, if I remember correctly, your setup leaves the contactor in the power supply always on?-Heath
Reply:Oh...I was only going to use them (300ssX2) for plasma cutting and stick welding.  No wire feeding.  Do these look like they might be beefy enough? Attached ImagesSmithboy...if it ain't broke, you ain't tryin'.
Reply:They do look beefy enough.  They might be in the 400-500A range, but I can't tell the scale really well.  Can you get a part number off of them?-Heath