Input ratings?

[fergus]

Looking at buying some old used welders...there are many possible input ratings for this specific model of welder and I'd like to understand input ratings better...mostly to make sure I don't buy something I can't use.

So here goes. An input rating of 208/3/60 means 208 volts, 3 phase and 60 Hz right? I'd buy a phase converter to use normal 240 single phase power.

How about 220/440/2/60? 220/440 volt, 2 phase(???) 60 Hz??? I looked up 2 phase and its some archaic thing from the early 1900s for electric motors. Surely I'm wrong...right?

 

[WhoWhatNow]

I don't think you can run a welder on a phase converter, but I could be wrong.

 

[Steevo]

Welders use transformers, and won't work with a phase converter.

 

[madosta]

Depending on the welder and input transformers, you MIGHT be able to rewire them for use with single phase 240v service. Some come marked. Miller typically does this. There was a pretty common TIG that ran on 480v that people were able to get running on 240v, but I can't remember the specific model.

 

[fergus]

Its an old Lincoln welder from the 50s, 250-Mk, its motor driven, as in an electric motor spins the welder and the welder guts are rumored to be the same out of an SA 200 engine driven welder.

 

[wyliesdiesels]

Looking at buying some old used welders...there are many possible input ratings for this specific model of welder and I'd like to understand input ratings better...mostly to make sure I don't buy something I can't use.

So here goes. An input rating of 208/3/60 means 208 volts, 3 phase and 60 Hz right? I'd buy a phase converter to use normal 240 single phase power.

How about 220/440/2/60? 220/440 volt, 2 phase(???) 60 Hz??? I looked up 2 phase and its some archaic thing from the early 1900s for electric motors. Surely I'm wrong...right?

There is no such thing as 2-phase these days. What that may mean is 2 single phase legs/2 hots. And yeah, like others have said, a welder won't run on a phase converter. The welder u describe might run on a converter since u said it has a motor. That seems like an inefficient 'plug in' type welder since its a motor spinning an alternator vs. the transformer plug in types.

 

[ezzzzzzz]

I'd look at getting a good welder, new or used, not some old hobbled unit....period. You'll be happier in the long run. As for power requirements, it depends on the unit. Some are 120V, others 240V and others still are 480V. My Miller 175 is 220V using two hot legs and one neutral. This effectively 2 phase since your using two hot legs. My Miller plasma cutter is the same. My Miller Syncrowave 250 can be wired for 208V, 220V and 480V. Mine is jumpered to use 220V. In your case, I'd run 220V since it is probably available in your breaker panel. You don't mention where this stuff will be plugged in though. If you need to run power to a subpanel it will require 4 wires (two hots, one neutral and one ground). Depending on the distance I'd use #8 minimum and probably #6.

 

[wyliesdiesels]

If your welder is 240v only then it doesn't need a neutral. It should be fed with 2 hots and a ground. And 2 hot legs is not 2 phase since they come from 1 secondary coil. 120v/240v 1Ø is called split phase.

 

[Steevo]

If it is the old motor-driven Lincoln type, with a 3-phase drive motor, then it probably can be powered by a rotary phase converter.

 

[Norcal]

There is no such thing as 2-phase these days. What that may mean is 2 single phase legs/2 hots. And yeah, like others have said, a welder won't run on a phase converter. The welder u describe might run on a converter since u said it has a motor. That seems like an inefficient 'plug in' type welder since its a motor spinning an alternator vs. the transformer plug in types.

2Ø still does exist in some areas such as Philadelphia.......

 

[lakee911]

There is no such thing as 2-phase these days. What that may mean is 2 single phase legs/2 hots.

I ran into something like this on a job a few years ago ... took a while for me to get my head wrapped around it. Utility only had two phase conductors on the pole near the property. I had A, B, and G and C was missing. So, I could use A-B at x voltage, or A-G or B-G both at sqrt(3)*X voltage. Somehow they could give me three phase using transformers at a reduced rating but if I recall properly, I ended up going with a huge 240/120 single-phase service.

 

[wyliesdiesels]

I ran into something like this on a job a few years ago ... took a while for me to get my head wrapped around it. Utility only had two phase conductors on the pole near the property. I had A, B, and G and C was missing. So, I could use A-B at x voltage, or A-G or B-G both at sqrt(3)*X voltage. Somehow they could give me three phase using transformers at a reduced rating but if I recall properly, I ended up going with a huge 240/120 single-phase service.

Oh yeah. I do remember reading something about that system. It uses earth ground as the third conductor instead of running a third phase wire. It's used in very rural areas where considerable $ can be saved by using only 2 conductor wires! I think it's still considered 3Ø but I could be wrong!