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Discussion Starter #1 (Edited)
3 phase shop equipment question...

Hey, any of you all running any three pahse shop equipment off 220 single phase with a rotary phase converter? Any one have any luck running a 3 phase welder? I just bought a huge 3 phase DC Welder from surplus inventory where I work. Just wondering if I built a big enough rotary 3 phase converter if I am going to be able to get it to run or if I should just look into selling it.

Let me know :)

Thanks,
 

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phase converter

yeah, that would work, but thats gonna be a big converter. It will proably work good with the motor-generator set too, as the momentum of the motor will allow it to start an arc and hold it good. BUT...its noisy cuz the m/g set will run even while your not welding An electronic one will probably not work.
 

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Discussion Starter #3
I realize that a solid state one will probably not work, but I am thinking I will be able to pick up a 10-15hp 3 phase motor for the rotary converter. From all of the research I have done on the net this should be sufficient to run the 20amps per leg that the welder will require. W/ a m/g set 3 phase actually generated or is it still the 220 single phase but just time aligned differently... I am not sure if I am asking this correctly, because I am not an electrition, but I am try to get an idea what wire size and disconnect I am going to have to run to the shop. The welder is 220 3 phase 58 amps. Am I correct in my thinking in that the phase converter is actually generateing a third of my power? I realize I am a little off topic and I appologize, but this should be some good info for lots of people since you can get used 3 phase shop equipment for very reasonable prices. Thanks again!

Jason
 

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the generator will create the 3rd leg. Remember, depending on the motor, you may have to excite it to get it to start generating. I see you say 20 amps per leg??? a 58 amp welder requires 58 amps per leg...so there for you will need a single phase motor that draws in the range of 80 amps per leg...that is a BIG ASS MOTOR. (You match the horse power ratings, thats all you have to remember, not the current ratings.)

Just a little info...

PS. a 3 phase welder may work on single phase, but the arc may not be as stable, and its capacity will be reduced to .707 (if I remember correctly)
 

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I would just sell the welder and take all of the money you would have put into making it work on on single phase and buy something suited for single phase. You say it takes 58A at 220V so you are looking at a 300-400 Amp welder. WTH do you need something that big for? As well anything that big is probaly going to be pretty old and inefficent on it's own, let alone running it through a phase converter. You might as well get out the vaseline for the electric company right now because you are going to get fawked on your bill.
 

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Welders are not good candidates for rotary phase converters because of the variable amount of amps that they draw depending on operation conditions. The size of static converter that it would take would cost more than a single phase welder.

Sell it and get a single phase unit.

Single phase or three phase, these old transformer type boxes draw impressive amounts of current at idle, so remember to turn it off between welds or the bill will eat you up.
 
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