Single phase/ 3 phase combo plug.

[WARRIORWELDING]

Wanting some real sparkys to chime in here.
I have welder capable of running single and three phase power. Invertor.
I want to make a plug ready for each by wiring it ready for three phase and still plug to my single phase in the shop. I've already ran both configured as suggested. I rewire the plug.

Directions say to drop the third leg isolate and remove. For single phase the two lines are across from one another and are the typical white and black arrangement. Red is dropped.

My plug always places the red across from the black and drop the white to the lower prong on three phase. It's another leg but miller specifies dropping the red wire for single....the difference is alternating the red and white should I wire it to the single phase color I normally use and adding the red leg for some portable work I do....

Simple form....would the third leg (red wire) being in the lower prong matter? I can't see how it not a electric motor.

Pic of plug. For reference. Pic of miller wiring for reference.

Tired of taking the plug apart.

 

[braxton357]

The plug you're using isn't a 3 phase plug, the white wire is supposed to be a neutral and won't be used by the welder in either mode. As a matter of fact if you were to plug it into a correctly wired single phase 240 w neutral outlet you'd probably damage the welder or trip a breaker.

The correct way would be to buy the right amp twist lock or straight blade plug and wire it 3 phase from the welder, buy a matching 3ph receptacle and some 2 conductor soow cord and make an adapter where the two hots on your single phase plug on the other end are the wht and black and would connect through to the same terminals on your 3ph female receptacle as you have wired on your welder.

All that being said, if you are wanting to keep it 3 phase to use in plants and other places, going to need several different plugs or adapters anyway and make sure you don't hook to 460 or 208

 

[WARRIORWELDING]

The plug you're using isn't a 3 phase plug, the white wire is supposed to be a neutral and won't be used by the welder in either mode. As a matter of fact if you were to plug it into a correctly wired single phase 240 w neutral outlet you'd probably damage the welder or trip a breaker.

The correct way would be to buy the right amp twist lock or straight blade plug and wire it 3 phase from the welder, buy a matching 3ph receptacle and some 2 conductor soow cord and make an adapter where the two hots on your single phase plug on the other end are the wht and black and would connect through to the same terminals on your 3ph female receptacle as you have wired on your welder.

All that being said, if you are wanting to keep it 3 phase to use in plants and other places, going to need several different plugs or adapters anyway and make sure you don't hook to 460 or 208

Well that confusing since I'm running it daily in my shop on single phase. Did you look at the miller diagram? None of it shows the neutral. I grasp the neutral on single phase that it ties back to the ground in the end......but as a 230 volt it has two legs tied to two terminals on "hot" sides of breakers.

Isn't three phase another leg of "hot".?
Edit with a better dedicated neutral. The question is why does miller specifically drop the red leg yet uses the white in single phase which has to be hot or you would have 110 volt.

 

[braxton357]

Colors don't really matter in this case and just make it confusing, that's just what the cord they use has. I'm saying the plug you're using or at least the picture of the manual of the plug you're using is a standard single phase 240 with neutral 3 conductor plug used for a dryer or stove. It uses the bottom spade for a neutral which is why that one should always be "white"--in a standard household settkng. I'm your case pretend your cord is black red blue, with the white being blue and wire it that way.
So basically what you're saying is correct, if they were actually going by a standard wire code...which they are not. They are just using a 3 conductor whip that has bk wt red instead of 3 ph colors.

 

[WARRIORWELDING]

Colors don't really matter in this case and just make it confusing, that's just what the cord they use has. I'm saying the plug you're using or at least the picture of the manual of the plug you're using is a standard single phase 240 with neutral 3 conductor plug used for a dryer or stove. It uses the bottom spade for a neutral which is why that one should always be "white"--in a standard household settkng. I'm your case pretend your cord is black red blue, with the white being blue and wire it that way.
So basically what you're saying is correct, if they were actually going by a standard wire code...which they are not. They are just using a 3 conductor whip that has bk wt red instead of 3 ph colors.

This is the data plate on my welder and I'm interested in learning. I think I've opened a personal can of worms...
Now I'm genuinely curious. As it says single and three phase. I'm reading between the lines that Miller never intended it to run on house hold single phase but three phase current just missing a leg.

 

[braxton357]

This is the data plate on my welder and I'm interested in learning. I think I've opened a personal can of worms...
Now I'm genuinely curious. As it says single and three phase. I'm reading between the lines that Miller never intended it to run on house hold single phase but three phase current just missing a leg.
View attachment 407407

The difference being 3 phase comes from the transmission lines and is 120* peak to peak and split phase is 180 or 0* phase to phase and comes from a center tapped transformer on one single transmission line. That welder doesn't care though which is why it is multi phase and multi voltage, if it was a transformer machine it would be a different story, your welder is using rectifiers and mosfets to rectify and amplify the input voltage and hz into whatever it wants

 

[WARRIORWELDING]

The difference being 3 phase comes from the transmission lines and is 120* peak to peak and split phase is 180 or 0* phase to phase and comes from a center tapped transformer on one single transmission line. That welder doesn't care though which is why it is multi phase and multi voltage, if it was a transformer machine it would be a different story, your welder is using rectifiers and mosfets to rectify and amplify the input voltage and hz into whatever it wants

I heard plug it in and run with it! I do better making sparks over herding them and safely contained circuits.