three pahse into single phase for 300a/bp tig

[bicyclepatrol]

Hey there, im new to the site and have a small dilemma. I just got an old miller 300a b/p tig. It runs off single phase 208/240/480. This is fine because I have 240v in my shop but, it draws 148a at this voltage, and my whole breaker is 100a. This is where the three phase comes into play. I have a 208v 400a 3phase breaker with nothing running on it. Is there any way i can safely run my single phase monster tig off of the three phase line? Thanks for any help. Oh yeah, why are electricians so expensive?

[gmwalley]

I would be very surprised if your welder were actually single phase. 3 phase is used to lower the current draw on any single phase for high power machines. Electricians are expensive because it is NOT TRIVIAL to get through the training / education / test gauntlet to get your license. I have BS and MS in electrical engineering and have an electrical contractors license - that test was as hard as any I ever took in engineering school. Good luck!

[buildhauer]

If you've got a 208 3 phase panel in your shop by all means use it. I won't bore you with all the details but you can run a single phase welder off a 3 phase panel. With a three phase panel you can get single phase from it. Electricians can be expensive but I can't imagine it being that expensive for one to put in the right breaker and wiring for your machine. Sometimes the breakers can be expensive depending on what type of panel you have. As far as the question as to weather or not the machine is a single phase 208/240/480 or not, you don't need the BS and MS to read the plate on the machine specifing its voltage, amps and phase. I have an old Hobart TR-300 (great condition picked it up off a college that never used it) it is a 300 amp welder, single phase 208/240/480 and an old Miller Dialarc Tig, which is single phase 208/240/480 also. I'm running both on 480 single phase, properly wired off a 480 volt 3 phase panel. So check around and ask for a few price quotes it never hurts to ask and you just have to ask yourself wether or not it is worth it to run your welder on its higher settings and not worry about tripping a breaker or burning out the machine. Once your power is in, check your owners manual to make sure the little brass plates for the voltage changeover are on the right terminals, before you turn it on.

Happy welding!

[LowlyOilBurner]

From what i know, you can just take 2 of the 3 hots and you have 208v or what ever(230, 240, 220 ect,ect). At this ski shop i currantly work at, we have 2 big-*** ski/board tuning machines. One of them is 3phase, the other is 208v-230v. We just ran another breaker for 3phase and connected the hots on the 230v machine to 2 hots coming off the 3phase, and connected the ground. Works fine. But, please, i am not an electrician!!!!!!!!!

[Sandy]

buildhauer has the correct advice based on what little I know about the subject.

First step might be to have an electrician look at and take a quick measurement or two to verify the voltages available at your panel. That'll verify the 208/240 issues. Shouldn't be a big deal but you never know. The next is have the same one look at your machine for any straps and/or jumper changes internally that might be necessary for operating at the supplied voltages. Then he can look at the box and set you up with a breaker and help with the wire run and any hardwiring materials and advice you may need.

He gets a few bucks and you get class advice.

:)

[Pentawelder]

There are two three phase connections. Delta and Wye, they are not interchangeable. The emergency generator where I used to work was overhauled and set up wrong. The fluorescent lights were 208 volts when they switched to emergency power it blew every ballast in the place, threw an electrical box across the power room and tripped breakers on all the recrifiers.

[caosesvida]

There are two three phase connections. Delta and Wye, they are not interchangeable. The emergency generator where I used to work was overhauled and set up wrong. The fluorescent lights were 208 volts when they switched to emergency power it blew every ballast in the place, threw an electrical box across the power room and tripped breakers on all the recrifiers.

they had a Y and hooked it up delta. This makes one leg 208 to ground, which of course will blow up a lot of 120 volts things!

[caosesvida]

Hey there, im new to the site and have a small dilemma. I just got an old miller 300a b/p tig. It runs off single phase 208/240/480. This is fine because I have 240v in my shop but, it draws 148a at this voltage, and my whole breaker is 100a. This is where the three phase comes into play. I have a 208v 400a 3phase breaker with nothing running on it. Is there any way i can safely run my single phase monster tig off of the three phase line? Thanks for any help. Oh yeah, why are electricians so expensive?

That sounds like a pretty unusual set up. YOU are saying that you have two voltage systems in your shop,. 208 and 240.Do you have a three phase service from the electric company, then a transformer from the three phase panel, to a 100 amp panel. Or do you have two services to your shop? In either case If you have a 400 amp three phase panel, you can and should hook up the welder to three phasem panel. You just use a 2 pole breaker instead of a three pole breaker. I don't think electricians are any more expensive than welders are they?