Step Up Transformer

[Npstewart]

Does Square D / Schneider make a Step Up SINGLE PHASE Transformer with a primary voltage of 120/240v and a Secondary Voltage of 277/480v-1?

I've been looking through the digest and using the product selector and havent been able to find one.

 

[infinity]

Do you need both 277 and 480 on the secondary?

 

[Npstewart]

No. This is a large warehouse with a 240/1 service but due to the size of the warehouse, I want to use 277v for the high bay lighting.

 

[ActionDave]

You can't get 277V without three phase.

 

[LarryFine]

Does Square D / Schneider make a Step Up SINGLE PHASE Transformer with a primary voltage of 120/240v and a Secondary Voltage of 277/480v-1?

First, you can step 240v up to 277v with a buck-boost. But, why can't you just use the 240v?

Second, the difference in current between the two probably isn't worth adding the transformer.

You can't get 277V without three phase.

Sure you can. I found a 120v-to-277v lighting transformer.

 

[Jraef]

No. This is a large warehouse with a 240/1 service but due to the size of the warehouse, I want to use 277v for the high bay lighting.

Pointless exercise, waste of money for the transformer, Just use 240V for the lighting if it’s all new.

Unless you ALREADY have 277V ballasts / power supplies in your light fixtures, in which case, as mentioned, just get a boost transformer to go 240-277V, it will be less expensive.

 

[ActionDave]

Sure you can. I found a 120v-to-277v lighting transformer.

Well I'll be. Learned something new.

 

[LarryFine]

Learned something new.

That can happen here if you're not careful.

 

[JFletcher]

You can't get 277V without three phase.

I think you were meaning you cannot get 277/480 volts on the secondary without a 3-phase input, in which case you are correct.

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Without knowing what type of lights the original poster has, their current draw/kW rating, how many are on a circuit, etcetera, there is no way to advise whether or not he could wire them with 240 volts. The additional amperage at the lower voltage could very well exceed what the branch circuit wiring or circuit breakers can handle.

What size transformer did you need?

 

[infinity]

No. This is a large warehouse with a 240/1 service but due to the size of the warehouse, I want to use 277v for the high bay lighting.

That's why I asked, since you only need to go from 240-277 and not 480 you should be able to find a suitable 1Ø transformer. If you were searching for 1Ø, 240-277/480 transformer I don't think that you will find one without going to 3Ø.

 

[Andy Delle]

That's why I asked, since you only need to go from 240-277 and not 480 you should be able to find a suitable 1Ø transformer. If you were searching for 1Ø, 240-277/480 transformer I don't think that you will find one without going to 3Ø.

Not off the shelf but you could have a 120 primary to a 480v secondary with a 277v tap custom wound

 

[winnie]

I presume that 240V is line-line, whereas 277V would be line-grounded conductor.

If there are lots of separately switched circuits, then the transformer might make sense. If large banks are being turned on with the breakers or contactors then this is probably not a big benefit.

-Jon

 

[Besoeker]

Not off the shelf but you could have a 120 primary to a 480v secondary with a 277v tap custom wound

Agreed. I don't see the problem.

 

[kwired]

Not off the shelf but you could have a 120 primary to a 480v secondary with a 277v tap custom wound

Which leaves you with 203 volts on the other side of the tap - should only allow using 58% of the transformer kVA rating also unless you are able to connect some lights as 208 volt loads.

 

[LarryFine]

Not off the shelf but you could have a 120 primary to a 480v secondary with a 277v tap custom wound

Why bother with the 480v winding if it's custom-made? I'd opt for 240v to 277v, whether standard, auto-transformer, or buck-boost.

 

[Andy Delle]

Which leaves you with 203 volts on the other side of the tap - should only allow using 58% of the transformer kVA rating also unless you are able to connect some lights as 208 volt loads.

Yeah, I missed the 240v primary requirement. But then you could have a 240v to 480v with a 277v tap single phase xformer wound.

MGM Transformer in Los ANgeles does custom winds. But then there is the subject of listing. Not sure is a custom design is listed even if the manufacture has UL certification.

 

[kwired]

Yeah, I missed the 240v primary requirement. But then you could have a 240v to 480v with a 277v tap single phase xformer wound.

MGM Transformer in Los ANgeles does custom winds. But then there is the subject of listing. Not sure is a custom design is listed even if the manufacture has UL certification.

Do transformers need to be listed as a general rule? Some specific applications do.

Doesn't matter what the primary voltage is, if you have a 480 secondary with a 277 tap - you only get 58% of the VA rating of the transformer from that 277 tap - might as well have gone with a 277 secondary to begin with unless you have a use for the remaining 203 volts on the other side of the tap.

 

[Andy Delle]

Do transformers need to be listed as a general rule? Some specific applications do.

Doesn't matter what the primary voltage is, if you have a 480 secondary with a 277 tap - you only get 58% of the VA rating of the transformer from that 277 tap - might as well have gone with a 277 secondary to begin with unless you have a use for the remaining 203 volts on the other side of the tap.

Ok I see what you are saying.