240V delta

[hillbilly1]

I thought a zigzag transformer was the only way to derive a neutral?

Would those (WYE)'s derive their own neutral, without a feeder neutral?

Absolutely

 

[Jraef]

If its center tapped that would be what I call 4 wire.
Why not use the center tap and just do a single phase 120/240 panel for the 120V loads?

Those often have very limited capacity for the 120V circuits.

 

[tortuga]

I thought a zigzag transformer was the only way to derive a neutral?

Would those (WYE)'s derive their own neutral, without a feeder neutral?

Its just like a 480D : 208Y/120 but instead you have 480D : 220Y/127.
That way, if all the 208 loads are compatible with 220, he could remove all the other 240D :208/120 transformers , which it sounds like there at least one other.
The kwh/year savings would be something to look into, and a place like that sounds like they have a pretty big electric bill.
The ANSI C84 'minimum range B' of a 240V system is 209V, but in ANSI C84 extended 220Y/127 is 190, so they'd have to look carefully at voltage drop.
The maximum range B on the 127 side is 135, and for our normal 208/120 its 127.

 

[jeff motta]

Its just like a 480D : 208Y/120 but instead you have 480D : 220Y/127.
That way, if all the 208 loads are compatible with 220, he could remove all the other 240D :208/120 transformers , which it sounds like there at least one other.
The kwh/year savings would be something to look into, and a place like that sounds like they have a pretty big electric bill.
The ANSI C84 'minimum range B' of a 240V system is 209V, but in ANSI C84 extended 220Y/127 is 190, so they'd have to look carefully at voltage drop.
The maximum range B on the 127 side is 135, and for our normal 208/120 its 127.

I appreciate your suggestion, I'm sure they would love to save some money on their electric, but this would be a much bigger undertaking and some professional engineering. My original question was more about sizing, I haven't had to size a transformer in a while and wanted some assistance. I am utilizing a spare 200a breaker (has trip settings), from what I understand my primary ocpd is sized @ 125% (75000/415.2 = 180*125% = 225A) and my secondary does not need ocpd because the 10-25ft rule, my new 208/120v panel will have a main breaker rated at 200a. I would be installing a 240v delta to 208V/120V 75kva transformer.

 

[roger]

I thought a zigzag transformer was the only way to derive a neutral?

Would those (WYE)'s derive their own neutral, without a feeder neutral?

Here is a center tapped wye transformer

 

[ramsy]

Here is a center tapped wye transformer

Thank you, sir. Very nice diagram.