Service/Transformer Help

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Natural1

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This is my first post, so if I have posted this in the wrong area... yada, yada. I apologize. That being said, I am having some difficulty deciding which direction to go. Heres the run down. I have a commercial building that I need 480v 3ph power to operate a lathe, a milling machine, and a boring mill . I also need 120v for my lighting.. No big deal right? Well, I also need 220v single phase to run 2 of my Lincoln Welders and maybe my plasma cutter. What would be the easiest way to reach all of these goals with the least expense or least headache (time is also money). Everyone I talk to has an opinion which conflicts the last. I can't get a straight answer from anyone. I have an electrican, but I want to know that what he says is correct. I know this is a tall order, but any help would be greatly appreciated. I feel that with the cost of labor and the quality we as consumers receive in the end, you really need to have some good knowledge of what you are doing/having done to reach a favorable outcome. I have knowledge of three phase power, as I deal with inverter motors and VFDs daily as a distributor. The transformation and available options have me kinda stumped.

The load list is as follows. These are not breaker sizes, just load ratings for equipment or a given area.




Office Area................ - N/A 120V 1ph 60hz 20A

Shop lights/recpticles.. - N/A 120V 1ph 60hz 40A

Lathe....................... - 10hp 460V 3ph 60hz 13A

Bridgeport Mill............ - 2hp 460V 3ph 60hz 1A

Boring Mill................. - 10hp 460V 3ph 60hz 15A

#1 Lincoln MIG 255C... - N/A 220V 1ph 60hz 55A

#2 Lincoln MIG 255C... - N/A 220V 1ph 60hz 55A

ESAB 1250 Plasmarc... - N/A 230V/1/3 or 460/3 66A/29A/20A

Dake ColdSaw........... - 3hp 220V 1ph 60hz 15A


The power I am expecting to have run to the building is 480/277. I was going to run a straight 480v, but the addition on the 277 (neutral) will give me more options.. Right? The only transformers I see are 480V-Delta to 208Y/120. How do I get 220V single phase? Each leg of the "Y" represents a 120V/1ph leg for three total. Maybe the answer to the 220v/1ph is ridiculously simple and I just don't realize it.



Thanks! :confused:
 
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Natural1 said:
How do I get 220V single phase?
Click to expand...
Unless you want to have to add another transformer or buck-boost units, the 220v 1-ph devices need to be able to run on 208v 1-ph.
 
You are not going to want to put machines on the same panel as lighting and other general office use stuff.

Have 480V brought into the building, set the main panel as 480V. Use two transformers off the 480V panel, one as a 120/240V for the office and a 208Y/120V for the shop.

This will provide the most felxibility and reasonable cost (now and later).
 
??? 480V Delta to 120/240V? I was unaware I could get one..? Yeah, I never wanted to mix the office and shop and I am setting the 480V panel. I hadn't been able to find a transformer that would give me a 480V-D to a 120/240/1ph. Anyone got a part#? Wouldnt the 240 be a 240Y? I am almost certain I am going to have to boost the 120 to 220/1 to make this work.
 
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480 to 240/120 delta (with center tap) is available, but you have to be careful as the 120v is very limited. If I read correctly. your 240 loads can be single phase so a 480/240-120 single phase transf should be sufficeint for your 240/120 loads. kingpb has the solution.
 
The total of the listed loads is 75KVA.

If the 460V loads can be re-configured to operate at 208V (for example, if they have dual voltage motors and the operating range in low voltage is suitable for 208V), then the _simplest_ approach is a 208/120V wye service; no transformers needed.

As kingpb notes, you may have power quality issues if your lights and tools share a single transformer.

What are your plans for future expansion. If you are going to get more 480V three phase tools, then 480V is the way to go. But if your list is what you will have for the foreseeable future, then spending more now for expansion capabilities might not really be worth it.

Finally, examine the cost of two separate services from the power company. This will involve more expensive metering, but less expense on the installation side, plus you have the benefit of two entirely separate transformers for your different load types.

-Jon
 
Ding, Ding!! We have a winner! I had thought about that, but was unsure whether or not it would be a feasable option. I like it, and I already have the 110/220v in place. I could add an additional service for the 480V/3. Anyone have any objections to this?? Any downsides?

:grin:
 
There is no way that we can answer that question for you. Having two separate services is entirely up to local rules and the power company. Usually having two separate services means two separate meters and monthly basic charges for _each_ meter. That cost has to be juggled against the installation and operating costs of your own transformers.

If you really want to research this so that you can properly understand the options that your electrician offers, then you will need to find out just what your power company is willing to provide; minimum billing and power requirements, etc.

You need to define your future expansion requirements.

You need to define what choices each piece of equipment provides; in particular, can your lathe and mills operate at 230V?

Remember that the bulk of your loads are 240V loads, with very little in the way of 480V loading. Do you need the expansion capability that 480V will provide? Are there cost differences from the power company for 208 or 240 or 480?

If you put your 220V welders on your current 120/240V single phase service, then you won't get any benefit of separating your tool loads from your lighting loads.

Do you really have 120/240V single phase, or do you have 208/120 three phase?

-Jon
 
If this shop is a small commercal size really from my past experince it more festable to run 208Y/120 system because the reason why because if you have exsting service there you can uiltized it.

but let get to the point for a min if you have 120/240 v 1? service and if you have 3? supply nearby then you can ask the POCO to provide the 3? system and keep in your mind please check with the POCO for the lastest Info on the 3? system.

as my POCO they will not provide delta to new customers anymore only the exsting one can use the delta system for new 3? it more normally get on Wye format set up.

speaking of service size you may want to check the POCO some will have a charge for over the certen size.

Most of small commercal shops i useally install minuim of 200 amp service [both 1? and 3? system]

Merci, Marc
 
I understand. Code wise, I don't even know if I can get by running 2 seperate services, and after some thought, it just sounds like a hassle. It sounded neat at the time but I am desperate. I have no future expansion planned for this facility. I will be building a new one on the acreage on the other side of this existing facility in about 2 years. I just need to get this running. I am renovating this facility (I own it) and it is a blank slate at this point. I am just needing to get this moving. At this point, I think am going to run a 75kva for the shop and a 15kva for the office. Input will be a straight 480 Delta off the main panel. I'm done with the 220V/1 and the 277v/3. The welders are going to have to run off 208v/1 until I buy 480v/3 units. I am running off a generator right now... it's ridiculous..
 
frenchelectrican said:
If this shop is a small commercal size really from my past experince it more festable to run 208Y/120 system because the reason why because if you have exsting service there you can uiltized it.

but let get to the point for a min if you have 120/240 v 1? service and if you have 3? supply nearby then you can ask the POCO to provide the 3? system and keep in your mind please check with the POCO for the lastest Info on the 3? system.

as my POCO they will not provide delta to new customers anymore only the exsting one can use the delta system for new 3? it more normally get on Wye format set up.

speaking of service size you may want to check the POCO some will have a charge for over the certen size.

Most of small commercal shops i useally install minuim of 200 amp service [both 1? and 3? system]

Merci, Marc
Click to expand...

I have the option of Wye or Delta. I have already spoken with the service provider. One of their guys visited me at the shop last week. As far as charges.. here they do a "usage credit," the more you plan to use the less the install is. If you are going to use 400A you better estimate to them that you plan to use 75% of that or they will charge you for a percentage of their initial field service. They calculated usage and the service fee is $0.00, and it included the new pole transformers. He said it would be no problem. This keeps people from requesting a service larger than they will ever use.
 
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