# 500KVA Transformer dry type delta/wye



## l0sts0ul (May 7, 2011)

Yes, so long as you don't hook up the XO To ground or from the feeder. 


So now line side is the x connections or 208, load side is the h connections and it puts out 480. Like I said leave the xo alone. 3 wires and a equipment bond in and out.


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## Nycwireman3 (Feb 1, 2013)

Ok so let me get this right don't bring the ground to xo like normally from the line side but I can bring the neutral to the xo from the load side correct?


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## l0sts0ul (May 7, 2011)

No, 

Do NOT connect ANYTHING to the XO. You will end up with a floating ground and your phasoral currents will be wonky, not to mention the voltages.


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## l0sts0ul (May 7, 2011)

it becomes a wye delta transformer without the neutral


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## Nycwireman3 (Feb 1, 2013)

So what do I do about picking up a neutral for the load side


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## l0sts0ul (May 7, 2011)

Sorry, I'm not trying to be rude but are you an electrician? Your explanation of the problem and you questions don't add up.


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## RePhase277 (Feb 5, 2008)

There is no neutral on the 480 side. It is a delta. The best you can do is ground one phase, but it is still just straight 480 V. NOT 480/277.


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## l0sts0ul (May 7, 2011)

That is correct. Why do you need 277 on the output side?


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## brian john (Mar 11, 2007)

l0sts0ul said:


> No,
> 
> Do NOT connect ANYTHING to the XO. You will end up with a floating ground and your phasoral currents will be wonky, not to mention the voltages.


You will not have a floating ground and your voltages will not be wonky (I checked the IEEE Dictionary and wonky does not show up).

But you are correct in not connecting the neutral, additionally check the XO for any factor to ground (frame) connections.


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## brian john (Mar 11, 2007)

Nycwireman3 said:


> Is it possible to wire a 480V - 208V 500KVA delta/wye dry type transformer 208V-480V and vise versa by just changing the cables coming in and going out on the X & H terminals


 
Fisrt you are not changing the cables you are changing what is your line/supply and load. 

You feed X1, X2,X3 with 208 VAC 3 phase 3 wire, lifting any factory XO grounds as noted. Your secondary voltage will be 480 3 phase 3 wire, no neutral. You will need to ground one corner of the 480 Delta or install ground alarms.

If you need a neutral at 480/277 VAC buy a 280 delta to 480/277 transformer.


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## Nycwireman3 (Feb 1, 2013)

Yes I0 I am an electrician just not very edumacated with transformers lol the problem is there are 2 transformers and the GC had them put in the wrong locations. They are both mounted and when we started wiring them we noticed they were wrong so instead of pulling them back out off there pads I wanted to know if I can wire them in reverse but after reading all the answers I see I cannot do that so it will now become an extra$$$$ cha Ching. Gentleman thank you for all your input have a wonderful weekend


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## frenchelectrican (Mar 15, 2007)

Oui., It can be done in reversed connection mode however as few mention keep the XO bonding isolated or lift them up and corner grouned one of the phase on 480 volt side.

However with this set up you will *NOT *get 277 volts in this fashon at all unless you get proper 208-480Y277 transfomer.

The other thing I will bring it up as other may forgot to remind ya the inrush current will be higher when you spin or heated ( engerized ) it for first time and some case the breaker you sized you may have to go to max OCPD sizing on primay side. This is common with reversed transfomers.

Merci,
Marc


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## micromind (Aug 11, 2007)

brian john said:


> Fisrt you are not changing the cables you are changing what is your line/supply and load.
> 
> You feed X1, X2,X3 with 208 VAC 3 phase 3 wire, lifting any factory XO grounds as noted. Your secondary voltage will be 480 3 phase 3 wire, no neutral. You will need to ground one corner of the 480 Delta or install ground alarms.
> 
> If you need a neutral at 480/277 VAC buy a 280 delta to 480/277 transformer.


The only way I know of to get 277/480 from a 3ø 3 wire 480 system is to use 3 single phase transformers connected in a zig-zag fashion. This will create a neutral from an ungrounded 480 system. Then you would ground the newly created neutral.


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## brian john (Mar 11, 2007)

micromind said:


> The only way I know of to get 277/480 from a 3ø 3 wire 480 system is to use 3 single phase transformers connected in a zig-zag fashion. This will create a neutral from an ungrounded 480 system. Then you would ground the newly created neutral.


Well, you could buy a transformer, and while a zig zag transformer will work, I think a transformer is the more utilized method?

Zig Zag may be a bit cheaper.


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## micromind (Aug 11, 2007)

brian john said:


> Well, you could buy a transformer, and while a zig zag transformer will work, I think a transformer is the more utilized method?
> 
> Zig Zag may be a bit cheaper.


Agree, the proper transformer is the best way to go. 

Besides, I doubt that very many people know how to connect zig-zag transformers.


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