# Is this a delta-wye?



## jclarmo (Oct 18, 2012)

well?


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## jclarmo (Oct 18, 2012)

Ok, so from what I've read its a T-T. Does anyone know if I could replace it with a delta-wye?


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## Rollie73 (Sep 19, 2010)

If you are feeding a load that needs a 120/208 3 phase 4 wire system then why couldn't you??


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## Big John (May 23, 2010)

You're right, it's a Scott connection. What does this supply?


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## jclarmo (Oct 18, 2012)

120/208 panel


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## Big John (May 23, 2010)

Alright, I guess what I'm trying to understand is why is it there? Do you actually have a 2 phase connection on some part of this system? 

If so, I don't know of any way to achieve a phase conversion without a Scott T transformer, so the short answer would be: No, you can't just put in a delta-wye.


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## Roger (Jul 7, 2007)

Big John said:


> Do you actually have a 2 phase connection on some part of this system?


This is the deal breaker, the loads would seemingly have to changed if the transformer configuration is changed.


Roger


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## jclarmo (Oct 18, 2012)

The xformer has 3 phase 600 feeding it, so why would I not be able to use a delta wye? Its 3phase in. 3phase out.


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## Rollie73 (Sep 19, 2010)

As long as all of your loads are either 120 volt.....single phase 208 (phase A to phase B or A to C etc..) or 3 phase 208......you can use a Delta/Wye. 
What exactly are we talking about here when you say a "two phase connection" ???


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## Big John (May 23, 2010)

Rollie73 said:


> ...What exactly are we talking about here when you say a "two phase connection" ?


 I meant literal two-phase power where you have two circuits 90° out of phase with each other. That's the only application where I know Scott transformers were ever used, but admittedly, I'm not familiar with them, because I've never worked on one.

If the OP does have regular ol' three phase on both sides, I see no reason why he couldn't drop in a delta-wye. I know when two-phase was eliminated, the Scott connections could be upgraded to a reduced-power three-phase service without being replaced, and maybe that's what he's got. I don't know another explanation.


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## Rollie73 (Sep 19, 2010)

Big John said:


> I meant literal two-phase power where you have two circuits 90° out of phase with each other. That's the only application where I know Scott transformers were ever used, but admittedly, I'm not familiar with them, because I've never worked on one.


Ahhhh yes......it makes sense in this tired old brain of mine now.:laughing: 
It's been a long week and for the life of me, I couldn't wrap my head around what you were saying.:no:


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## micromind (Aug 11, 2007)

I can't see the connection diagram, but as far as I know, 120/208 can be gotten only from phases that are 120º apart. A two phase system is 90º, and cannot produce 120/208/

If there actually is 600 volts 3ø on the primary, and the secondary is actually 120/208, then there is no reason why a basic standard ∆ - Y wouldn't work. The end result is the same either way.


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