Adding a Three Phase Service

[e57]

I want to thank you very much for the schematic, that's very helpful.

But I hate to say that the rest of your post is rather a joke to me. For instance, I haven't and don't need to ask "what a delta is".

Master electrician is parenthisized because I find it humorous.

And you would scrap $100,000 of equipment because you're incapable of providing 40 silly amps of three phase. thanks for the advice.

And three phase is right out side.

Sorry I took it as a snarky criticism of your boss..... Thanks for the PM....

Any $100K for the equipment could also easily be $100K for the poco to set re-sized transformers depending on the load already on it. Mention of swapping a motor an option? Most equipment only would need 3 phase for motors in them - and the control circuit only from one/two legs (depending on voltage). From the comfort of my chair here - that always seems the least costly, and often for people who just go out and ignorantly (unknowingly) buy equipment they don't have the service for - one of the few options left for them. i.e. Rather than a rotary converter - a motor/generator in a sense - go buy an equal Hp motor with the same mount as the OME. Viola.... No more need for 3 phase. And often in the thousands rather than 10's of thousands.

 

[e57]

What is this, 120/240 delta you speak of? I've read your responce but this peice of it sort of slipped by me. I've always considered deltas to be semetrical, otherwise it would be shaped like a sling slot, not a delta (triangle). Sometimes I hate knowing what words mean, it doesn't seem to help.

FYI the sling shot a WYE looks like a Y....

 

[physis]

FYI the sling shot a WYE looks like a Y....

Please don't make me continue to go through this kind of stuff e57, a Y is not delta no matter how you slice it, that's kind a "wye" they have different names.

But then again, I am a tad bit out of my element with three phase.

 

[physis]

Mention of swapping a motor an option?

It's not that simple, there's a lot of other DC motors and control electronics on this thing, the main drive motors can simply be reterminaled to change operating voltage but that wont change what it's electronics operate on.

 

[physis]

Sorry I took it as a snarky criticism of your boss..... Thanks for the PM....

Any $100K for the equipment could also easily be $100K for the poco to set re-sized transformers depending on the load already on it.

Yeah, that's a typical figure for a three phase service.

 

[e57]

Yeah, that's a typical figure for a three phase service.

For an underground vault up-sized or in a new location, it could be... (Depending on size/distance) A pad about 1/3 that, pole pig 1/4+. The poco just doesn't show up and give it to you for free. And just because there may be 3 phase available - doesn't always mean it is in the size, voltage or flavor you want it in. Could be a straight 480 or corner grounded and over-loaded to boot??? (Hard to tell from the comfy chair) Once you call the poco one of the first persons there is an estimator.

It's not that simple, there's a lot of other DC motors and control electronics on this thing, the main drive motors can simply be reterminaled to change operating voltage but that wont change what it's electronics operate on.

3 phase electronics? What is this thing? Got a schematic?

Anyway - this is the best advice I think I can give to any commercial or industrial customer - "Research the availability of the power requirements of your equipment before ordering." For instance: Many ignorant people buy equipment based on cost and function. This is not unlike some people buying that big hot tub they got a great deal on, then finding out once they deliver it that it needs a crane to get it into the back yard, on the other side of the house from the service, and getting a service up-grade that cost more than the tub. This is no different except for scale and a few other technicalities IMO.

This also reminds me of a guy who owned a glass shop - bought this $2M glass cutting machine - called to ask for us to hook it up - had to tell him "Sorry - you need to move your shop to someplace you can get 100 amps at 480 delta"

 

[Smart $]

3 phase electronics?

Yep. Some (many?) industrial variable speed drives with DC motors use a switch-mode supply powered by 3? AC. As I recall the supply uses SCR's or triac's to go straight from AC to DC with only a minimal amount of buffering. I haven't worked on any in over 20 years. I assume the popularity and availability of VFD's has curtailed their implementation.

 

[physis]

For an underground vault up-sized or in a new location, it could be... (Depending on size/distance) A pad about 1/3 that, pole pig 1/4+. The poco just doesn't show up and give it to you for free. And just because there may be 3 phase available - doesn't always mean it is in the size, voltage or flavor you want it in. Could be a straight 480 or corner grounded and over-loaded to boot??? (Hard to tell from the comfy chair) Once you call the poco one of the first persons there is an estimator.

3 phase electronics? What is this thing? Got a schematic?

Anyway - this is the best advice I think I can give to any commercial or industrial customer - "Research the availability of the power requirements of your equipment before ordering." For instance: Many ignorant people buy equipment based on cost and function. This is not unlike some people buying that big hot tub they got a great deal on, then finding out once they deliver it that it needs a crane to get it into the back yard, on the other side of the house from the service, and getting a service up-grade that cost more than the tub. This is no different except for scale and a few other technicalities IMO.

This also reminds me of a guy who owned a glass shop - bought this $2M glass cutting machine - called to ask for us to hook it up - had to tell him "Sorry - you need to move your shop to someplace you can get 100 amps at 480 delta"

e57, you are so killing me. This guy simply needs 240v. 3 phase at 40 amps. nobody's trying to reconfigure the universe. This is pretty much easy. I'm not getting grey hair from this.

And as far as the schematic, I do have a request with the manufacturer for that.

 

[physis]

3 phase electronics? What is this thing? Got a schematic?

It's a tile saw/fabficator. What? You've never seen electronics driven from three phase? Go ahead and hook this thing up to 480 and watch the smoke. I can't even beleive I'm having to endure this nonsense. I thought the people I'm working for were bad.

 

[hardworkingstiff]

This is getting to be comical.

 

[physis]

This is getting to be comical.

I feel like that myself, and I'm as at fault as anybody else.

 

[jim dungar]

Your point being? So a delta high leg as he mentioned is still suitable for 240 3-wire, as well as four wire.

My point is that: While all "high legs" are deltas; not all deltas are "high legs".
The posted diagram did not say it was for a specific type of delta connection.

In my part of the country, it is not uncommon to see both a 120/240 1Ph 3W service and a 240V 3Ph 3W service feeding the same building.

 

[George Stolz]

I feel like that myself, and I'm as at fault as anybody else.

I would say more so. You (as the OP) have more details about the nature of the problem (both technical and interpersonal) than we do. If we are talking about re-engineering a building to accommodate a device that can be readily exchanged for a more appropriate device, then your advice is going to be "sounds like they should have bought the right device in the first place."

We don't have all the information at hand to solve your problem for you; and it sounds like you don't have all the information necessary to make the best decision either (key being actual price differences between options).

Quit snarling at people trying to help you with incomplete information, please.

 

[e57]

My point is that: While all "high legs" are deltas; not all deltas are "high legs".
The posted diagram did not say it was for a specific type of delta connection.

It was the one mentioned previously, and for the purpose mentioned....

It's a tile saw/fabficator. What? You've never seen electronics driven from three phase? Go ahead and hook this thing up to 480 and watch the smoke. I can't even beleive I'm having to endure this nonsense. I thought the people I'm working for were bad.

Thank you.... And yes I have, mostly air field com and radar equipment. (Many years ago) And... I would love to - but prefer my toast to smell better. That reminisent memory was about a glass guy with a single phase over-loaded 200a service mile from any 3 phase who just bought his "dream machine". He ran it on a generator until he found a place to move to....

As George mentioned, as well as myself - from the comfort of my comfy chair - we do not know what you are looking at if you do not know how to, or refuse to describe it. And maybe, the problem with your employer is you.

 

[physis]

- from the comfort of my comfy chair - we do not know what you are looking at if you do not know how to, or refuse to describe it. And maybe, the problem with your employer is you.

Alright, maybe I've been a bit difficult with you, and I have, but it's only because you've been the same to me.

And I have not failed to describe the equipment, what, you want a picture of it? :grin:

40 stupid amps, three phase 208 or 240. this just isn't all that complicated. I'm just looking for a practical means to feed it.

But I have managed to get even George mad at me and I do apoligize to the entire forum for doing so.

Maybe I need a stress pill, I am stressed, but forget excuses.

 

[jim dungar]

There are only two ways to get three phase power.

1) From the utility
2) make it your self.

You need to contact the utility and see what they have to offer. We can give you all sorts of information on delta systems, but it is useless if the utility will only provide you with a wye.

If you want to make it yourself, there are many phase convertors available. Lately my preference has been solid state units from Phase Perfect. I have used them with two different 'CNC' machines with the blessing of the machine manufacturer.

 

[glene77is]

to Phyis,
and thank you George.

We have installed Rotating 3phase generators to supply 208 3phase
alongside of normal residental single phase.
I have seen this done in the past, where the single phase drives the motor,
and a 3phase generator is attached to the load shaft.

Our master said that he could install a Semiconductor 3phase converter,
to do the same thing.

On this project, he reworked a Single Phase to 3phase transformer setup,
which required a capactor to phase shift things around.
I believe I was correctly told by our master that the phases
were not exactly 120 degrees off,
but the effect on this particular system was OK,
and it did run smoothly.

Keep Reading.

 

[e57]

Alright, maybe I've been a bit difficult with you, and I have, but it's only because you've been the same to me.

And I have not failed to describe the equipment, what, you want a picture of it? :grin:

40 stupid amps, three phase 208 or 240. this just isn't all that complicated. I'm just looking for a practical means to feed it.

But I have managed to get even George mad at me and I do apoligize to the entire forum for doing so.

Maybe I need a stress pill, I am stressed, but forget excuses.

IMO where this started is your description of your "Master Electrician" as an idiot - yet a few posts down the line ask "what is this delta you speak of" I merely pointed out that discrepancy, especially since you are on a forum comprised of Masters, C-10's, lead JW's and Foremen, as well as juinior JW's, and Apprentices... The information your seeking is going to come from the leadership side of the industry - why alienate the side you need? That was the point I was trying to make. It's like saying lawyers suck on a legal forum - then say 'I need legal advice'.

We're all here to learn are we not? I have 18 years in the trade and I'm still learning - sometime re-learning.

Back to my suggestion of swapping the motors - you may find that with some carefull examination of the schematic for the machine - that the only need of 3 phase is one or two motors, such as it is with many (not all) machines.

Since the decision is between your employer, and his client - maybe you let them figure it out? Let us know what they come up with.

 

[amptech]

There are many things that factor in to deciding what the best way to serve a 3? load is. My best answer to you is to tell you what I would do if it were my situation here, where I live.
Here, if there was 3? available from the PoCo, it would cost $55.00 per month surcharge over and above the kwh usage on the 3? meter. You would also be looking at the cost from me to install a 3? service entrance. All of that info would need to be figured in to this 40A machine's overhead cost.
Option #2 would be to have the PoCo bring a 120/240V 3? service to the building and remove the 1? service. You could re-feed the existing 1? panel from the new 3? panel using the (2) 120V phases. You would still have the $55.00 per month surcharge but you would be metering all of your kwh through one meter thus having a higher kwh total each month on one meter. Here there are price per kwh breaks at each 500kwh of use. Here, at 3000kwh the $55.00 per month surcharge is dropped. I would have to see if usage would be high enough to make this option feasible.
Option #3- Rotary phase converter. This is usually the best option when the 3? load is so small a part of the over-all electrical load for a building.
Another thing that would need to be considered is who owns the building? This is important because if the building is rented any upgrades to the service involving the PoCo is equity for the building owner and stay with the building. A rotary phase converter would be separate from the building and would go with the renter or be liquidated for cash.

 

[John Valdes]

I've already found out what VFD is but thanks non the less. I've managed to sort a steer these guys into that but now they're overly bent on going with that. The trouble is that the VFD costs about $2000 and the existing single phase panel is only 100 amps. I think it would cost less over all and allow for expansion if we installed an additional three phase panel. These people, or more specificly this "master electrician" still will not contact the power company to get any details on the three phase that's available. At some point I'm going to do that myself but unfortunately it's not gonna matter, the best I can do is sort of sublimanaly guide this guy. Hardly an electrical issue but it is in a very real sense, part the job.

And I do appreciate your guys's input.

VFD's are designed to operate motors. They are not designed to operate equipment/machines. You can use a VFD just for the motor in the machine, but you must supply the controls independently.