# eaton 15 kva transformer how to wire 480volt to120v



## lowman

can anybody tell me how to wire this type of transformer the connections are confusing.


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## Highvoltage77

Hey 
Ur using as a step down..... Correct 
It's a single phase xfrmr 
Your 480v hot connects to H1
Your 480v white connects to H4
I'm not 100% on this part but from what I recall from school u need a jumper between H2 and H3
So they r in series 
On the lv side 120v
Your 120v hot connects to X1 
Your120v white connects to X4
Then jumper between x1-x3 
And another jumper x4-x2 
So they r parallel 
I don't have ur picture on my screen to look at so confirm those r correct designation 
Can't say for certain so get another opinion I my self have not done a lot of xfrmr connections


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## lowman

*15 kva transformer*

yeah that's what I thought to, but looking at the connections and diagram high side of transformer 480volts connect H2-H3 Line H1-H4 240 volts connects H1H3-H2H4 line H1-H4 low side of transformer 240volts connect X2-X3 line X1-X4 120volt connect X1X3-X2X4 line X1-X4 240/120volt connect X2-X3 line X1-X3-X4 I thought on the line side 120 volt connected X1 is neutral be cause the leads have a color code white on it and X4 has a black color code and X2has a orange code and X3 has a pink code on it that's what is confusing me:blink:. on the 480 side of this I think H2-H3connects but was not sure.


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## Bad Electrician

Highvoltage77 said:


> Hey
> Ur using as a step down..... Correct
> It's a single phase xfrmr
> Your 480v hot connects to H1
> *Your 480v white connects to H4*
> I'm not 100% on this part but from what I recall from school u need a jumper between H2 and H3
> So they r in series
> On the lv side 120v
> Your 120v hot connects to X1
> Your120v white connects to X4
> Then jumper between x1-x3
> And another jumper x4-x2
> So they r parallel
> I don't have ur picture on my screen to look at so confirm those r correct designation
> Can't say for certain so get another opinion I my self have not done a lot of xfrmr connections


The item in bold must be a Canadian thing, your use of white, this is not a given.

In the USE the ungrounded conductor/phase conductors/energized conductors One would connect to H1, the other conductor will connect to H4,


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## Tsmil

First post and asking a question like this. Hmmm.... 

First, a little punctuation in your posts helps a lot. It took me several attempts to get through that last post. 

Secondly, let us know a bit about yourself so that we can respond to you appropriately. 

Lastly, welcome aboard.

Tom


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## glen1971

Looks pretty straight forward to me.. You have either 240 or 480 coming in and it will give you 120, 240 or 120/240 out.... Depends on what you have coming in and what you are looking for coming out..


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## lowman

do H2 and H3 connect on the 480v0lt high side


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## wildleg

dude, people are scared to tell you what to do because it sounds like you are in over your head, and nobody here wants to see you blow yourself up. It's a simple connection and it's written right there in the picture on your first post on the panel cover. Please don't take this the wrong way. Your profile says you are a jman - is this true ?

look at the cover again:









now make the connections. if x1 is white, look for a jumper to the case, and test all x1 thru x4 to case. test all the high voltage to case. leave the high terminals isolated, and derive x1 or x4 as ground to case if there is not jumper as shipped. make sure all the connections are torqued. make sure to meg all the connections again for short to case. If you aren't sure at this point, get someone to help you before you even think of energizing.


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## lowman

most of the transformers I have worked on have been 50kva 37.5 25 and bigger first small transformer and another electrician said he did not think H2and H3 connect I thought he was wrong because it is in series. just checking thought I may have missed something


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## Big John

You're correct, he's mistaken. You need to have continuity through any winding. If you don't connect H2-H3 you won't have a complete 480V circuit.


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## Southeast Power

lowman said:


> most of the transformers I have worked on have been 50kva 37.5 25 and bigger first small transformer and another electrician said he did not think H2and H3 connect I thought he was wrong because it is in series. just checking thought I may have missed something


Your friend, he was not an electrician.


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## lowman

not a friend, looks to be not a good electrician he messed my head up a little I thought it was wrong, he's older than me so I thought about it just started this job here don't no these guys that well. worked on the larger transformers . Never worked on the small encapsulated x-formers so the diagram and what I saw inside as for has the color codes of the wire's had me a little confused . But they are not that different than those other x-former's.


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## lowman

jrannis said:


> Your friend, he was not an electrician.


quote=lowman;1320968]not a friend, looks to be not a good electrician he messed my head up a little I thought it was wrong, he's older than me so I thought about it just started this job here don't no these guys that well. worked on the larger transformers . Never worked on the small encapsulated x-formers so the diagram and what I saw inside as for has the color codes of the wire's had me a little confused . But they are not that different than those other x-former's.


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## Southeast Power

lowman said:


> not a friend, looks to be not a good electrician he messed my head up a little I thought it was wrong, he's older than me so I thought about it just started this job here don't no these guys that well. worked on the larger transformers . Never worked on the small encapsulated x-formers so the diagram and what I saw inside as for has the color codes of the wire's had me a little confused . But they are not that different than those other x-former's.


That little chart splains it all.
Good thing you challenged him on it.
Good job!:thumbsup:


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## power

I own an electrical company from Canada. This is a simple connection. 

In your original post, I am understanding you want the 480 to 120 connection:

 Jumper between H2 and H3
Jumper between X1 and X3
Jumper between X2 and X4

Your high voltage conductors (480vac) would connect to H1 and H4. 
Your low voltage conductors (120vac) would connect to X1 and X4. 

If your supply voltage is 480vac, ground the X4 terminal.
If your supply voltage is 120vac, ground the H4 terminal.

*NOTE/FYI*: It does not matter whether your stepping voltage up or down; the connections are the same. Unfortunately, the manufacturer EATON uses the terms "Primary", and "Secondary" to identify it's H and X windings respectively. It therefore could be misunderstood that "Primary" is always the SUPPLY voltage. These dry-type transformers can indeed be used to step voltage up or down. However, as I mentioned above, *you must ground the "OUTPUT" side of your transformer*. While your only connecting a single-phase unit, this is especially true of three-phase transformers. As was commented in earlier posts, a _white conductor_ is rarely found in 480vac circuits, if ever. In Alberta Canada, we use orange, brown and yellow for phase A, B and C respectively on 480vac 3-phase systems (wye or delta), and the color white for it's neutral on 277vac circuits.


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## dronai

Ground that biaatch on the secondary side


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## rayjwvu1

Ok I have a question 3 phase 460 to 3 phase 208 4 wire , do I ground the neutral into the panel I am feeding because there is no neutral buss, also on primary side I know H1 , H2 , and H3 is where I am feeding , do I tie 6-9 together and 5-8 together and 4-7 for my 460?


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## SteveBayshore

I'm afraid to answer you. Are you an electrician?


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## micromind

rayjwvu1 said:


> Ok I have a question do I tie 6-9 together and 5-8 together and 4-7 for my 460?
> View attachment 158694
> View attachment 158694
> View attachment 158694


Connecting 4 to 7, 5 to 8 and 6 to 9 will burn up the transformer.


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## gpop

Its a transformer not a 9 lead motor. 

H1, H2, H3 on the primary for 460v. Transformer should have a grounding strap on the secondary X0 so you end up with 4+ a ground leaving the transformer. (also read up on bonding a transformer as there are rules to follow)


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## paulengr

As per the instructions you pick the closest voltage which if you actually have 460 is 4, 5, 6. Wire nut the other Hs if they are loose wires. If the output voltage is high or low just move the connections on the high voltage side. Adjusting primary side taps is pretty common. On some larger dry transformers you might also see shorting taps on the middle of the coils and on oil filled there is often a tap selector switch.


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## MikeFL

I'm going to go ahead and close the thread.
The qualifications of the member in a recent post were questioned by another member. As a result, I asked that new member to update their profile, and that has yet to happen.
Until that profile gets updated we're going to close this thread.
Thanks for your understanding and be safe.


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