# 480v to 240/120v transformer questions



## WarnerConstInc. (Jan 30, 2008)

Getting ready to move into a new building and have been trying to sort out the electric supply to my area. 

Building has 480v wye service (277v for lighting) 

I will have a 400 amp 480v panel set and will also want a transformer to get low voltage as well (couple other sections have 480v sub panels with transformers to get 208v).

I do not want 208. 

I would feed 200 amps of 480 to a 150kva transformer to get approximately 400 amps of low voltage, 240v. 

I would like to use that for my single phase, lighting, outlets, etc. 

What specific transformer am I looking for?

480v input to 240/120v output? 

I believe this exists. I really don't want to have to set a 208v then boost to 240v. 

It's my responsibility to track down what I need and they will buy it for me.


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## Railman (Jan 19, 2008)

I have two 114 kva 480/240 transformers available. I bought them for an additon to my old shop, & moved next door instead. I'll see if I can find picts of the name plates. 

I also have a 460/208/120 75kva? transformer available.

Joe


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## 480sparky (Feb 1, 2009)

Why are you wanting to toss out an existing 480/277v service just to install 120v lighting?


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## Mike-B (Feb 11, 2015)

We install single phase 50KVA, 480-120/240 XFMRS a few times a year. Our local suppliers has them in stock. 

I'm would think larger sizes are available


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## WarnerConstInc. (Jan 30, 2008)

480sparky said:


> Why are you wanting to toss out an existing 480/277v service just to install 120v lighting?



There is nothing in my space. I will have 400 amp 480v panel set in there and I need 240v as well. 

If a moulder shows up wired for low voltage, the cost to switch it to high voltage is more then the cost of a transformer. 

I would pull my 120v outlets and lighting out of the the low voltage, just because I will set lights up to plug in and 277v recepts are more money. My lights can run off either.


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## WarnerConstInc. (Jan 30, 2008)

Mike-B said:


> We install single phase 50KVA, 480-120/240 XFMRS a few times a year. Our local suppliers has them in stock.
> 
> I'm would think larger sizes are available


It's all 3 phase, as far as the service to the building and what I run my machinery on.


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## WarnerConstInc. (Jan 30, 2008)

I just need to know what transformer I should be looking for.


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## 480sparky (Feb 1, 2009)

I'm officially confused now.



WarnerConstInc. said:


> ..........Building has 480v wye service..........





WarnerConstInc. said:


> There is nothing in my space. I will have 400 amp 480v panel set in there and I need 240v as well.................


So is there a service to the building or not?


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## Mike-B (Feb 11, 2015)

WarnerConstInc. said:


> It's all 3 phase, as far as the service to the building and what I run my machinery on.


Understood 

If you want single phase 120/240 out of 3 phase 480 you install a single phase xfmr.

Feed the xfmr primary from a 2 pole breaker or disco. Only 2 hots and ground to the primary.


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## WarnerConstInc. (Jan 30, 2008)

480sparky said:


> I'm officially confused now.
> 
> 
> 
> ...



I don't understand how you are confused, unless you just didn't take the time to read anything.

480v Wye service to the building. The section I am moving into does not have a sub panel in it. They are setting a 400 amp 480v sub panel in my section plus I also want 240v 3ph as well and the ability to run all my single phase from that as well. 

They will meter my usage so they know what my share costs.


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## WarnerConstInc. (Jan 30, 2008)

Mike-B said:


> Understood
> 
> If you want single phase 120/240 out of 3 phase 480 you install a single phase xfmr.
> 
> Feed the xfmr primary from a 2 pole breaker or disco. Only 2 hots and ground to the primary.


I understand that, I am looking to have my low voltage be something other then 208/120v. Then I would have to boost 208v 3ph to 240v 3ph.

I don't want 3 transformers and 5 panels.


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## 480sparky (Feb 1, 2009)

WarnerConstInc. said:


> I don't understand how you are confused, unless you j.


The fact that I *QUOTED* your posts shows I read them. *How much more obvious can I make that?

Did YOU read YOUR posts I quoted?
*


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## WarnerConstInc. (Jan 30, 2008)

480sparky said:


> The fact that I *QUOTED* your posts shows I read them. *How much more obvious can I make that?
> 
> Did YOU read YOUR posts I quoted?
> *


I typed the same damn thing each time. 

480v service in building. Setting new 400 amp 480v panel in my section, what do I need to get 240v3phase with 120v single phase.

Said there was nothing in my space, how hard is that to understand?


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## Anti-wingnut (Mar 12, 2009)

Why are you so pissed off?


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## WarnerConstInc. (Jan 30, 2008)

Anti-wingnut said:


> Why are you so pissed off?


Poor reading comprehension skills?


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## 480sparky (Feb 1, 2009)

WarnerConstInc. said:


> I typed the same damn thing each time.
> 
> 480v service in building. Setting new 400 amp 480v panel in my section, what do I need to get 240v3phase with 120v single phase.
> 
> Said there was nothing in my space, how hard is that to understand?


YOUR posts are conflicting. What is so hard to understand about that?

One post says the building already has a service in it, and another says you're having one installed.

I will repeat them for your benefit:



WarnerConstInc. said:


> ..........*Building has 480v wye service*..........


This means there IS a service



WarnerConstInc. said:


> There is nothing in my space. *I will have 400 amp 480v panel set in there* and I need 240v as well.................


This means YOU are going to PUT ONE IN.

Does this help you with your poor reading comprehension skills?



WarnerConstInc. said:


> Poor reading comprehension skills?


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## Texas Wax (Jan 16, 2012)

Anti-wingnut said:


> Why are you so pissed off?


:whistling Getting to be that 'pissy' time of year up north? :blink:


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## tgeb (Feb 9, 2006)

WarnerConstInc. said:


> 480v service in building. Setting new 400 amp 480v panel in my section, what do I need to get 240v3phase with 120v single phase.


Here ya go.



> Eaton, V48M22T75EE, *480∆ - 240∆/120,* Dry Type Transformers, Transformers, Power Distribution, Cutler-Hammer, Westinghouse





> 75 KVA, 3-Phase, 480 Primary Volts - 240 Secondary Volts with 120 Volt Lighting Tap, NEMA 1, Energy Efficient, Energy Star labeled Transformer, Ventilated, 150 Degree C, Aluminum Windings, 60 Hz operation, Frame Size: FR914D. For Outdoors use Weather Shield WS39. ***Reverse Feed Capable***


https://www.platt.com/platt-electri...20/Eaton/V48M22T75EE/product.aspx?zpid=615106

Just what you need.


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## Anti-wingnut (Mar 12, 2009)

What does your electrical contractor say? Probably best to ask him, here you get what you pay for, and that seems to anger you.

Or else ask at DIYChatroom


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## WarnerConstInc. (Jan 30, 2008)

I guess the simplest way will be a 75kva transformer from the 480 to 240.

Then set a smaller transformer to go from 277 to 120.

Only other option is 208, but that will still require a boost for the things I need 240v for.


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## WarnerConstInc. (Jan 30, 2008)

Forgot my chart


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## Railman (Jan 19, 2008)

You could do 2 112's. 

I also have about 200 ft of 3" new & used conduit, w/ 90's, & 45's, & 22's.


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## WarnerConstInc. (Jan 30, 2008)

Railman said:


> You could do 2 112's.
> 
> I also have about 200 ft of 3" new & used conduit, w/ 90's, & 45's, & 22's.


To feed two separate panels? 

Right now it looks like will have 3 panels, 480, 240 and a 208. I am going to use one transformer they have sitting around to feed a 208 panel that I can just use for single phase stuff. Not ideal, but it's already there. 

The 4" conduit is already run and there.


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## WarnerConstInc. (Jan 30, 2008)

I am probably going to go with a 250a 480v feed instead. Between what is in the building, what I have, and what I would need it would be much more economical. I can always pull the bigger feeders in a couple years if I need more.

I will probably take one of those off your hands Joe, as long as they can be used with 480V Y. The one you linked to could be.


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## txgencon (Jan 4, 2011)

If you're wanting a 150 kva setup, this is what you would need or something like it.



Eaton V48M22T4916 150KVA, 3P, 480V, 240V, Energy Efficient Transformer 
http://https://www.platt.com/platt-electric-supply/Dry-Type-Transformers-480-240-120/Eaton/V48M22T4916/product.aspx?zpid=194672

Even though your supply is 480Y/277, the transformer can (and most likely will) be connected delta-delta internally.

The output will be 240 delta/120 volts. Each phase to phase voltage (A-B, B-C and C-A) will be 240 volts (probably actually closer to 250 volts measure under no load). The phase to ground voltages will be 120, 120 and 208. A four wire delta service inherently has a high leg (also called "freak" or "wild" leg in some locales) .

A 208Y/120 volt service will have all phase to phase voltages equal to 208 volts and ALL phase to ground voltages equal to 120 volts.

You could also use three single phase 277 volt-120/240 volt dry types. In such an application, because of the insulation levels of the dry type transformers, you would want to connect them wye-delta. You'd also want the "lighting" transformer to be larger than the two power (kicker) transformers as the transformer with the mid-point tap carries 2/3 of the 120/240 volt, single phase load and 1/3 or the 240 volt three phase load.


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## Railman (Jan 19, 2008)

specs at galco site
https://www.galco.com/buy/Acme-Electric/T-2A-53345-3S
pict of my name plate vs Galco site Acme specs of same model:







pict of transformer sitting in my shop:








When do you want to steal this thing?:whistling

If you pick it up, I'll give you the choice of the two I have at same price.
The other will be listed at about a grand.
Let me know,
Joe


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## WarnerConstInc. (Jan 30, 2008)

Just need to get with the owners and tell them what I need.


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## WarnerConstInc. (Jan 30, 2008)

Went on a little machinery moving hauling and delivery trip last night and today. 

Went to Osgood, IN last night to a buddy's place, dropped trailer this morning and headed to Joe's shop on the east side of Cincy. Picked up my transformer and got a good intro into some cool lathe work. 

Nice shop Joe, nice equipment, processes and products. I will be sure to visit again. Thank you sir.

Put another 550 miles on the old truck.


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## Railman (Jan 19, 2008)

Thanks Darcy.
It was good to meet you too.:thumbsup:

I'm sure you'll be happy with that transformer.

I ended up doing a run to Columbus & got back home at 8:30. Nice day for drive! Eveything you saw assembled, plus a little more, was delivered today.:thumbup:
Joe


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## WarnerConstInc. (Jan 30, 2008)

Railman said:


> Thanks Darcy.
> It was good to meet you too.:thumbsup:
> 
> I'm sure you'll be happy with that transformer.
> ...


I got back to Osgood and washed my truck and helped move a bunch of machinery around, ate some lunch and headed home. It was a great day for a drive with the window down.

I still need one more breaker to feed this from my 480v panel. It's always something.


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## Inner10 (Mar 12, 2009)

WarnerConstInc. said:


> I got back to Osgood and washed my truck and helped move a bunch of machinery around, ate some lunch and headed home. It was a great day for a drive with the window down.
> 
> I still need one more breaker to feed this from my 480v panel. It's always something.


Those breakers can be really pricy.


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## WarnerConstInc. (Jan 30, 2008)

Inner10 said:


> Those breakers can be really pricy.


I had to get a new 250a main breaker for my 480v panel, plus the main lug kit for the breaker. I found the kit for 65 bucks shipped, found the 250a breaker used for 70 bucks shipped (about 600 bucks new). 

The 125a one I need looks like it will cost more then that on the used market.

I can't really afford to buy new 480v stuff, its all very expensive.

The way it is, electricity part will be one of my most expensive investments and I am extremely thrifty with this stuff.


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## Luongo64 (Apr 21, 2013)

Didnt have time to read through all the final posts to see what you ended up with.

Did you find a 4wire delta secondary transformer? that should give you all you need for your 240/120 from the 3 phase supply. just remember some codes require the A phase to be separated and not used with single phase loads as you would get 208v from A-N. special panel required for this set up. Good luck with it all.


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