1 vs. 3 phase

[ridesideways]

It isn't that I don't think there is a difference between machines, its that I don't think most people are good enough at it to make much of a difference. Most people think they can tell the difference between beer brands, blind taste tests say otherwise.

exactly. the placebo effect is rampant here, especially if someone thinks they could tell in a blind test if an inverter is running off 1 or 3 phase. hahahah... not going to happen.

[Fishy Jim]

exactly. the placebo effect is rampant here, especially if someone thinks they could tell in a blind test if an inverter is running off 1 or 3 phase. hahahah... not going to happen.

The inverters max power is greatly reduced on single phase. Without ever looking at the machine, I think you could get a really good idea which input power was being used by simply turning up the heat as high as it goes and seeing which melted more metal. Same machine, same operator, same input voltage = vastly different output based on input being single or three phase.

Now if you were intending to limit the test parameters to a given welding current within the range of both phase types, then I would agree with you.

I don't have any 3ph tig experience, but my inverter mig supply is every bit as silky as the 3ph transformer migs I've run.

[seattle smitty]

I hope I don't get held responsible for the acrimony that followed my asking about the effects of three-phase power on the welding arc . . . I'm new here, and don't want to make waves. I would like to ask Iron Head (I can't get through with a PM) about those SA-200s you found for $250 each. Did they need a bunch of work? I've been web-searching, and so far the SA-200s I see are well into four figures.

[FusionKing]

I hope I don't get held responsible for the acrimony that followed my asking about the effects of three-phase power on the welding arc . . . I'm new here, and don't want to make waves. I would like to ask Iron Head (I can't get through with a PM) about those SA-200s you found for $250 each. Did they need a bunch of work? I've been web-searching, and so far the SA-200s I see are well into four figures.

IMO you need to have one on the back of your truck and then people start coming out of the clear blue and telling you about where others are sitting.
Like when you're at wally world or wherever.
Doubtful your first one would be a killer deal.

[cliff huxtable]

Jimmy, You have alot of experience runing 3 phase MIGs?

[KB Fabrications]

The inverters max power is greatly reduced on single phase.

This is at best misleading and in reality, completely untrue. For instance, the maximum output of my Dynasty 350DX is 350 amps whether it be single or three-phase power. That said, the duty cycle is reduced when running single phase input power but not the max output amperage. Furthermore, the newest version of the 200DX (which I have) has identical output amperages/duty cycles between 230V single phase and 3 phase input power.

[Fishy Jim]

Here's your 350 *right off the website this minute:

Input Power

208-575 V, 3- or 1-Phase Power
Rated Output

3-Phase: 300 A at 32 V, 60% Duty Cycle
Single-Phase: 225 A at 29 V, 60% Duty Cycle

Same duty cycle, lower output current.

Here's the 200's literature. Same thing - output on single phase 70A lower.

http://millerwelds.com/pdf/spec_sheets/AD4-8.pdf

[MAC702]

Did you just post "rated outputs" in a discussion about maximum outputs?

And your Dynasty 200 link is a July 2004 product guide. He was very specific that he was discussing the latest generation of Dynasty 200, so I'll see what else I can find.

[MAC702]

Even with that July 2004 link you provided for the Dynasty 200, if you ignore the "rated outputs" and go straight to the volt-amp curves, you'll find the exact same max output from three-phase or single-phase.

[MAC702]

Looking at the product spec sheet for the Dynasty 350 CLEARLY shows EQUAL maximum outputs for single- and three-phase.

This is where you say "Oops! You're right guys, I was looking at the wrong thing; sorry!" But somehow I'm sure you'll Obama your way out of it.

[KB Fabrications]

Looking at the product spec sheet for the Dynasty 350 CLEARLY shows EQUAL maximum outputs for single- and three-phase.

This is where you say "Oops! You're right guys, I was looking at the wrong thing; sorry!" But somehow I'm sure you'll Obama your way out of it.

My thoughts exactly.

[KB Fabrications]

Here's your 350 *right off the website this minute:

Input Power

208-575 V, 3- or 1-Phase Power
Rated Output

3-Phase: 300 A at 32 V, 60% Duty Cycle
Single-Phase: 225 A at 29 V, 60% Duty Cycle

Same duty cycle, lower output current.

Here's the 200's literature. Same thing - output on single phase 70A lower.

http://millerwelds.com/pdf/spec_sheets/AD4-8.pdf

Thanks for looking up the information and validating what i originally said.

This is at best misleading and in reality, completely untrue. For instance, the maximum output of my Dynasty 350DX is 350 amps whether it be single or three-phase power. That said, the duty cycle is reduced when running single phase input power but not the max output amperage. Furthermore, the newest version of the 200DX (which I have) has identical output amperages/duty cycles between 230V single phase and 3 phase input power

[Fishy Jim]

Ok, so if the duty cycle drops substantially (my invision 354mp has a 100A hit on the top output on single phase which is not compensated for with a reduced duty cycle beyond being dropped to 20% - which is virtually useless in tig), you still wouldn't notice the machine kick out when it hit thermal protection without looking at the dial?

Can you honestly say that you wouldn't notice a machine with a 20% duty cycle at full power? Weld for 2 minutes and wait for 8 to get back to work.

Kevin, I'm happy you get all the brand new stuff. Post up some literature supporting it if it's available to the general public, because if it isn't the point isn't valid. That it exists means nothing if you can't buy one yet.

[KB Fabrications]

Kevin, I'm happy you get all the brand new stuff. Post up some literature supporting it if it's available to the general public, because if it isn't the point isn't valid. That it exists means nothing if you can't buy one yet.

Here, read the manual for yourself. Newest version.

http://www.millerwelds.com/om/o2240v_mil.pdf

[KB Fabrications]

Can you honestly say that you wouldn't notice a machine with a 20% duty cycle at full power? Weld for 2 minutes and wait for 8 to get back to work.

Yes, I can. I have owned different versions of all three Dynasty models and have never once hit the duty cycle on any of them. Yes I have run them all at full power and I weld all day every day, for a living. Maybe it helps that miller tests all their machines in 104 degree environments and then gives them a duty cycle rating. Maybe it helps that I live in a very moderate climate where heat is only an issue for a few days out of the year. Who knows. I have run all these machines hard and continue to be impressed by what they are capable of.