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Need to simulate a floating ground

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milw sales

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I have a plasma cutter(DC output) that was designed to be used with an engine generator welder. The floating ground is brought back to the generator/welder. I don't have the generator & just want to run this on 220AC line voltage. The floating ground point can't be connected to an earth ground without tripping the GFI. Can I use something to take the place of the generators mass which is possibly an air ground? Please keep replys simple.
 

betwixt

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As the weld is probably 'live' I can't see it is possible to ground it at all. I suspect the solution is to disconnect the ground wire so the GFI doesn't work then wear insulated rubber boots!

Brian.
 

milw sales

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That is what I am basically doing now Brian. I have the first contactor bypassed because it wont get control voltage no matter what I do. In doing this I have no protection for the delicate electronics though & I had hoped to be able to use the circuit protector board. Is there some way to simulate the generator ground that is not an actual earth ground. In a floating ground the wire is brought back to the power source. Is there any way to get this partial ground that the generator appears to be Brian? Thanks, Randy
 

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The only way I can think of is to actually isolate the supply, in other words use an isolating transformer on the incoming 220V AC so no current can flow directly from either wire to anywhere else, then connect the real ground to the output side. With the GFI on the incoming AC, it will still provide over-current protection but with no path to anywhere except the transformer primary it should never see any ground current, even if one side of the welder power is shorted directly to ground. Such isolating transformers are easy to obtain in regions of the World where 220V is normally used but if you are in a 115V/60Hz country you might find it more difficult.

Brian.
 

milw sales

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Thanks, That may be just the ticket here. I will be searching for one of these, Randy
 

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