ECN Forum Forums General Topics of the Trade General Discussion Area 208/480

Hotline,
You must have pressed enter before I did. You stoled my thunder.

Doc

New ballasts=New fixtures
Transformer=Old Fixtures
I'd do the ballasts, I think.

[This message has been edited by electure (edited 01-20-2005).]

Thanks to all for your thoughts, I'll let you know how I made out.

Dnk

HotLine1: wouldn't that be 416 volts out?

Why not wire the 120/240 side as 120 and run it from a 120 volt L-N connection?

 
Consider a drytype with hiside taps. Using the lowest (-5%) FCBN tap, a ratio of 480:240x0.9, 208V on the secondary will produce ~437V on the primary.
www.acmepowerdist.com/pdf/Page%209.pdf
www.acmepowerdist.com/pdf/Page%2055-63.pdf
Connection Diagram 3 — PRIMARY: 240 X 480 SECONDARY: 120/240 TAPS: 2, 2½% ANFC, 2, 2½% BNFC

[There are 208∆—480Y/277 transformers available, but they start at 15kVA. ]www.acmepowerdist.com/pdf/Page%2014.pdf]




[This message has been edited by Bjarney (edited 01-22-2005).]

 
To save some transformer capacity, it may be possible to obtain a 208—120/240V 1ø drytype, connected in a split autotransformer configuration.
www.acmepowerdist.com/pdf/Page%2055-63.pdf
PRIMARY: 208 SECONDARY: 120/240 TAPS: 2, 5% BNFC

480V discharge fixtures should operate acceptably down to about 440V, although cold weather or motor starts on the 208V system my complicate this. If nonimal 208V runs low, moving the transformer connection from H4 to H3 will increase output voltage. {Its normal for 150°C-rise drytypes to run very hot—they should always be mounted in an area with adequate ventilation and clearances as labeled.}






[This message has been edited by Bjarney (edited 01-22-2005).]

Thanks Bjarney, I had no idea you could do that to that type transformer.

I appreciate your input on this dilema I am having. The prices I got from suppliers for a 3kva is about the same price as a 15 or 30kva 3phase transformer.

However, I found a reconditioned GE 120-460 single phase 3 kva from Midwest for $100.

http://www.swgr.com/products/DRYXLO_Inv_GENERAL%20ELECTRIC.asp

They are not there till monday. I am wondering, (it is not listed on their website) whether this is an open core, dry, or encapsulated type. If it is an open core, like I suspect, can I mount this in a Hoffman box?

Seems like the most economical way for now.


Any input on this?