Wiring old three phase machines

8wire · Aug 15, 2020

I recently bought a house with three phase in the garage. It is 4 prong 230v. I have a welder from the 1940s that I am restoring that I would like to connect but it is just 3 wires. I am assuming that the forth missing wire is the ground. How do I wire this machine to connect to the three phase outlet?

I also have an old horizontal mill that I plan to restore. It is also three phase but the plug does not match my outlet. Can I just change out the plug for one that matches? Whats the smartest way to do it?

I appreciate any help. If this is something i should just leave to an electrician will any old electrician do?

Cheers.

true temper · Aug 15, 2020

I am guessing you don’t have 3 phase, my guess is you have a 50 amp plug with two hots one neutral and one ground terminal.

thermite · Aug 15, 2020

8wire said:
I recently bought a house with three phase in the garage. It is 4 prong 230v. I have a welder from the 1940s that I am restoring that I would like to connect but it is just 3 wires. I am assuming that the forth missing wire is the ground. How do I wire this machine to connect to the three phase outlet?

I also have an old horizontal mill that I plan to restore. It is also three phase but the plug does not match my outlet. Can I just change out the plug for one that matches? Whats the smartest way to do it?

I appreciate any help. If this is something i should just leave to an electrician will any old electrician do?

Cheers.

You do not have 3-Phase. You have a current-code-compliant split-phase branch outlet. L1, L2, Neutral, Protective Earth AKA "ground".

Just go and look at the circuit breaker for it in the service entrance or sub-panel load center.

Find a 2-Pole common-trip circuit breaker.

A 3-Phase branch has a breaker with three poles. The whole load center is made differently for the extra bus conductor.

BTW: "We" cannot see your WELDER from here as easily. It might not BE 3-Phase, either. IF NOT, a cordest change might do yah.

With Electricians, yes. "Old". Generally the older, the better.

8wire · Aug 15, 2020

The welder is definitely 3 phase. The plate is still readable. So is the mill. Appreciate the help and your time.

thermite · Aug 15, 2020

8wire said:
The welder is definitely 3 phase. The plate is still readable. So is the mill. Appreciate the help and your time.

Might do a recce, search term "Haas Kamp" and/or your welder make and model "Right here, on PM".

Another couple of PM members, Peter Haas and Dave Kamp, worked out a clever means of converting MANY 3-Phase welders with a bit of modification magic to work really well off split-phase. Age of your one, it might not be a candidate, but the search is cheap enough.

If your welder is one of the many already so converted, there will already be experience with doing it and reports of how well it welds, "right here, on PM".

The mill, you are probably going to be best served by building or buying an RPC for.

Can you run a welder off an RPC? Been done. I wouldn't.

I'd go find another welder that was happy on split-phase , ex-factory. Or was at least among those know to be Haas-Kamp modifiable, already.

Modern ones have a lot of neat capabilities not yet known, 1940's

8wire · Aug 15, 2020

Im not an electrician so I could be wrong. However, I'm positive I have three phase power in the shop. The box outside the building looks nothing like a normal panel. The breakers inside the building are bridged together so three breakers move together. There were three phase machines in the building before I bought it and three phase outlets inside. The welder and mill both have plates that are still readable and clearly state three phase. Weirdly the welder had an old 220 plug on it, that I took off.

Assuming I do have three phase is there a way to safely ground the old welder that just has three huge wires coming out of it?
Can the mill just have a new plug put on it to match the outlet?
Would I be better off replacing the outlets with something more modern?

Thanks for your time. I appreciate the response. I can post pictures if that helps.

johnoder · Aug 15, 2020

8wire said:
The welder is definitely 3 phase. The plate is still readable. So is the mill. Appreciate the help and your time.

Good - now look in your residence breaker panel - any three pole breakers? They are big guys (three times the size of a single pole) like these Square D jobs - even though some are only 20 amp

(oopps - two minutes late!)

jamscal · Aug 15, 2020

I think you should get an electrician in there to at least advise, but barring that test each leg to ground to see what you got, voltage wise, because it matters.

I have 208v 3 Phase in my shop. Any leg to ground is 120v.

On some 3 phase, the third leg is higher than the others, which might make for a bad day.

I run my single phase welders off two of the hots and get what I need.

upthebikes · Aug 15, 2020

Go outside to where the box feeding the garage is. Look up (or down) in the general vicinity and see how many cables are feeding it from the utility supply. That will tell you what you need to know.

thermite · Aug 15, 2020

8wire said:
Im not an electrician so I could be wrong. However, I'm positive I have three phase power in the shop. The box outside the building looks nothing like a normal panel. The breakers inside the building are bridged together so three breakers move together. There were three phase machines in the building before I bought it and three phase outlets inside. The welder and mill both have plates that are still readable and clearly state three phase. Weirdly the welder had an old 220 plug on it, that I took off.

Assuming I do have three phase is there a way to safely ground the old welder that just has three huge wires coming out of it?
Can the mill just have a new plug put on it to match the outlet?
Would I be better off replacing the outlets with something more modern?

Thanks for your time. I appreciate the response. I can post pictures if that helps.

Well, Hell, mate. You didn't buy a "house", then. You bought an industrial facility!

Some among us would bring kneepads to be so lucky!

Yah - it is the breakers as tell the tale.

3 poles if they show, or 3-slots wide as the internally-coupled single-external handle ones John just showed in the photo with some of each.

You'd still be wise to have an Electrician look it over. He'll see in minutes what we, here, cannot see at all.

IF that branch outlet is on Wye service, it is meant to have FIVE conductors, current practice. Mine do.

Not that it needs changed, but only a local sparks will be aware of the local situation. And the cost of such options as you might need. Or not need.

Code is what it is, but the nuances and the Code enforcement are usually a County thing + Powerco policy, most of America.

California just has reason to be far more attentive .. than places with lower fire risk.

8wire · Aug 15, 2020

Thermite, you are right. I practically cartwheeled down the driveway. Neither my realtor nor the sellers realtor knew what three phase was. The old owner passed away on 2004 and was a raceway builder/ owned a fabrication shop in San diego. So I guess he had it put in. I think you are right. I need am electrician. I'll chuck up some photos in a second if I can figure it out.
Cheers.

jim rozen · Aug 15, 2020

thermite said:
You do not have 3-Phase. You have a current-code-compliant split-phase branch outlet. L1, L2, Neutral, Protective Earth AKA "ground".
....

Ah, clairvoyant too! Can see things far away as well.

I've seen a number of legacy 3-phase installations over the years. Without peak demand meters.

thermite · Aug 15, 2020

8wire said:
Thermite, you are right. I practically cartwheeled down the driveway. Neither my realtor nor the sellers realtor knew what three phase was. The old owner passed away on 2004 and was a raceway builder/ owned a fabrication shop in San diego. So I guess he had it put in. I think you are right. I need am electrician. I'll chuck up some photos in a second if I can figure it out.
Cheers.

Lucky dog!

But yazz. "Old". Time was, Powerco would do the Delta thing, last few feet of run.

Over time, Powerco's went over to a preference for Wye - as mentioned. All legs same potential with reference to Earth. Safer, as there are no "gotcha" surprises.

My one is NOT utility-mains 3-Phase. "True" Wye off the Diesel gen set, else either of a Phase-Perfect (floating Delta output) or an RPC (floating Delta output)... but..

...via a transfer switch to a Delta-Wye transformer. Then to the 3-Phase Square-D "QO" load center.

So I gets a "re-derived local neutral". And all legs same-same to Earth "Wye". just @ 240 VAC rather than 208, so my 120 VAC is now a good deal higher. But I don't need it at any of the machines.

Age of your one, it could be either Delta or Wye?

You can tell which with a meter easily enough, per above advice.

But you'll STILL be wise to have a consultation from that experienced local "sparks" (commercial guy where 3-P is near-as-dammit "always" his meat. Not "residential") to advise on realistic options and costs if you should or .. just want to.. alter anything.

Among other nits, he'll know what is or is not locally "grandfathered" and what has to meet more recent code if you want to get into adding or changing this or that.

As to the "cartwheels"? Downside to utility-mains 3-P is the billing.

I'm waaaay TF better-off, cost of power wise with the converters, here.

8wire · Aug 15, 2020

Yeah it was put sometime between 1977 and 1988 i THINK. I know it was put in legally then. I understood basically zero of the above comment besides get an electrician that knows commercial buildings so I shall do that. I have a thing for old tools so I really want to get these running. As for the cost. Fair comment. I'm yet to see how expensive it is as i'm spending time renovating the house not with my tools right now. Solar installation should help offset the cost and i'm just a hobby tool guy 'im not running a real shop so I don't think (hope) its not prohibitive.

thermite · Aug 15, 2020

8wire said:
Yeah it was put sometime between 1977 and 1988 i THINK. I know it was put in legally then. I understood basically zero of the above comment besides get an electrician that knows commercial buildings so I shall do that. I have a thing for old tools so I really want to get these running. As for the cost. Fair comment. I'm yet to see how expensive it is as i'm spending time renovating the house not with my tools right now. Solar installation should help offset the cost and i'm just a hobby tool guy 'im not running a real shop so I don't think (hope) its not prohibitive.

It be the daggone "demand" calculation, also "minimum billing" that bites "episodal" users like ourselves in the arse. Revenue shop ripping chip all day, every day - it still matters, and enough that even some of those forego 3-P for serious LARGE RPC.

We have a demand charge here even on residential single-phase for several years now, fancy new meters according. So I 'stagger start" the multi-stage RPC at looooong intervals. And/or run DC motored machine-tools that inherently soft-start.

Pioneered with thermal solar back in the early '70's when PE made no economic sense.

PE has light-years better economics and longevity now, but still enough of a PITA, my age all I want is enough of it to keep the batteries sweet on the gen set..

... and run a modest inverter to charge power tools, phone, LED lanterns and such plus keep the freezers cold at night when not even being opened.... so that IF I need the Diesel it is only for a few hours a day, not much of the day, let alone ALL day.

Best economics in MOST things are to grab the "low hanging fruit" where the bulk of the savings are .. and then NOT go chasing diminishing returns any further.

Ohio Mike · Aug 15, 2020

8wire said:
Im not an electrician so I could be wrong. However, I'm positive I have three phase power in the shop. The box outside the building looks nothing like a normal panel. The breakers inside the building are bridged together so three breakers move together. There were three phase machines in the building before I bought it and three phase outlets inside. The welder and mill both have plates that are still readable and clearly state three phase. Weirdly the welder had an old 220 plug on it, that I took off.

Assuming I do have three phase is there a way to safely ground the old welder that just has three huge wires coming out of it?
Can the mill just have a new plug put on it to match the outlet?
Would I be better off replacing the outlets with something more modern?

Thanks for your time. I appreciate the response. I can post pictures if that helps.

We do love pictures. I assume you have two services? One for the house that is single phase and one for the shop that is 3 phase?

One of the important things we would want to determine is if the 3 phase service is Delta or Wye and be sure its low voltage as it could be a 480 volt service. A low voltage Wye will be 208 VAC between phases and you can use all three phases for anything. A Delta service will be 240 VAC between phases but will have a "wild leg" or stinger leg. That wild leg will actually read 200+ volt to ground so you CAN NOT use it for any 120 volt circuits. In fact you want to track that leg in your installation so you're not powering any controls transformers etc inside any machines with that leg. In my service we always have the wild as the "B" phase on the outlets. Reversing a 3 phase motor is a simple task of swapping any two phases. So in my case I would always swap "A" and "C" phases.

Mike

thermite · Aug 15, 2020

Ohio Mike said:
A Delta service will be 240 VAC between phases but will have a "wild leg" or stinger leg. That wild leg will actually read 200+ volt to ground so you CAN NOT use it for any 120 volt circuits. In fact you want to track that leg in your installation so you're not powering any controls transformers etc inside any machines with that leg.

Actually.. "the wise" don't use 120 VAC primary control transformers at all in this type of environment. We use a 2XX primary so it can go across the hot legs, no longer has to care about either of ground nor Neutral.

We are not meant to work power TO Protective Earth anyway. Meant to work to a Neutral.

And Delta either has no such animal nor even resemblance to one at all. Or half-ass fakes a counterpart to it at relatively low amperage with a CT in one leg "for lighting use."

Too much draw above "trivial", and that tap messes up the balance and the heat rise budget.

Better to just NOT even need it.

Delta is at its best when it serves a pure Delta load "nailed up" no messing with it, nothing else involved.

Strostkovy · Aug 15, 2020

Hardly on topic but neither is this thread so whatever.

I moved into a three phase warehouse and it's amazing (I don't get the whole warehouse, but that's okay). The downside is I had a 12 space panel in my area which I upgraded to a 30 space panel, yet I've already added 45 breaker poles and still need more. Point being, those 3 phase breakers take a ton of space and breaker panel sizes don't really seem to cater to a bunch of low power three phase equipment being run on one panel.

No matter to me though. I've got 1200 amps of 208 on the other side of the wall I can pull off whenever my budget allows for more panels.

Rob F. · Aug 15, 2020

8wire said:
Yeah it was put sometime between 1977 and 1988 i THINK. I know it was put in legally then. ... Solar installation should help offset the cost and i'm just a hobby tool guy 'im not running a real shop so I don't think (hope) its not prohibitive.

If you are thinking about solar the solar consultant "should" be able to help tell you what you have. Get a few solar contractors out to visit. If you do have two services, one for shop and one for house the solar on one can be sized to offset both meters by backfeeding one meter.
Then if solar guys dont offer enough help then get a "real" electrician out, they may even send one from their staff.

Where in Ca are you?

thermite · Aug 16, 2020

Strostkovy said:
Hardly on topic but neither is this thread so whatever.

I moved into a three phase warehouse and it's amazing (I don't get the whole warehouse, but that's okay). The downside is I had a 12 space panel in my area which I upgraded to a 30 space panel, yet I've already added 45 breaker poles and still need more. Point being, those 3 phase breakers take a ton of space and breaker panel sizes don't really seem to cater to a bunch of low power three phase equipment being run on one panel.

No matter to me though. I've got 1200 amps of 208 on the other side of the wall I can pull off whenever my budget allows for more panels.

LOL! Square-D "QO" family since their Big Bang. Dad was, IIRC, a "Senior Construction Inspector", not yet a "Resident Engineer" so when the US Army Corps of Engineers adopted those "QO", so did WE.

After over 60 years, both farms, several residences re-done if not already "QO", I had PLENTY of breakers. But all of them 1-P!

And then.. I got a "deal" on a pair of NOS Eaton C-H 3-P load centers...

Welll.. must get in your blood, Square-D, "QO"?

Had second thoughts, bought a large Square-D 3-P "QO" panel.. gutted the Cutler-Hammers for ignorant desk, shop drawer, and people-door key cabinets!

Square-D or burn coal....

Well Hong Kong flat, 3-P, we have Schneider Telemechanique. Then again it be Schneider as OWN Square-D, lo these many years, already, so....

Seems to be more to the most peculiar race than just fighting with their feet and f**king with their face, after all?

Wiring old three phase machines

Plastic

Stainless

Diamond

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Stainless

Cast Iron

Diamond

Plastic

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Titanium

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Titanium

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