Paralleling

[roeder]

Hello...

I've read a bit about running welding power sources in parallel to increase available amperage, and I was wondering if anyone here has any experience with that.

Can two identical inverter sources run parallel? Or does in have to be a traditional transformer?

Thanks in advance for any feedback.

[roeder]

By the way I understand the different procedures for DC rectifier sources and AC sources, I was wondering if paralleling would damage an inverter source somehow.

Thanks

[roeder]

Anyone? Anyone? Bueller?

[HAWK]

roeder,

It looks like Farris is out. According to the Miller catalog, page 43 of the 2003 edition, the CST-250s can be paralleled for increased amperage to achieve Air Carbon Arc Cutting and Gouging. I don't know about other inverters, but you probably can. I would call Miller technical concerning the specific power sources you are considering running in parallel. I do feel sure that they would have be be identical units in order to maximize output performance without damaging the machines. You sure don't want to damage the IGBTs in the inverters. They probably do not cost a lot from the manufacturer, but by the time they get to us they are ridiculous! You are looking at approximately $900 each. If your inverter has 2 IGBTs, you could almost buy a new unit rather than repair. Info to think about.

Good Luck

[HAWK]

roeder,

Just an after thought: When you parallel your power sources what amp draw will you have on your input supply? Miller only mentions paralleling machines (inverter or classic transformer) with 3 phase input. I'm sure inverter type machines have a maximum current draw, (for example 50 amps), and may not be able to achieve maximum rated output on single phase input power. How efficient would it be to parallel 2 singlle machines when neither could attain rated output?
Do you have access to 3 phase power or single phase that can sustain high amp draw for continuous duty cycles of 5-6 minutes per usage interval?

If you find anything concrete, I'd like to know. I do not have the need for such high current applications at this time, but this type information is good to know. I have and use up to 325 amps output on a 60% duty cycle for carbon arc gouging and cutting in small amounts where time constraints do not allow for plasma cutting set up. I also use this higher amperage for .035 mig spray arc and 5/64" flux core applications. What are you doing that requires 400-500 amps in a shop enviroment? Most of my buddies that run that type of amperage are welders for the railroad (Norfolk & Southern) doing track repair. Carbon arc with 1/2" rods is the way to go! It's a definite rush to do if you have not had the opportunity. A #14 FIXED shade is inorder with maximum body protection. Stike that arc and hear a tremendous buzz, see a almost blinding light (sometimes 2 #14 FIXED glasses back to back are necessary), and sometimes the big engine drives will even jump due to the sudden current demand place on them! I think I'll stick to 300 [email protected] 100% or 325 amps @60%. Somebody stonger and younger with real enthusiasm can have the back breaking ox work! I have enough headaches keeping up with what I have in the MRO and pipe business. In reality I don't push more than 200 amps most of the time. But in those times when the job requires it, there is nothing like cranking it up and doing it!

Good Luck