bank transformer connection

[saudi_lineman]

Good morning to all

I have a question and I hope everyone involved in the answer

When connecting the transformer bank is connected to only one of the transformers in the ground as shown in the picture
Why

And if there are any references Please advise us of

I thank mybrother Pootnaigle
for his answer, but I want more details

[topgroove]

If you tried to put a ground on that transformer on the right on X2, your high side fuse would blow imediatly!

Alot of linemen have dificulty with delta primary and secondaries. I've worked with them my whole carreer so it kinda comes easy for me. The thing to remember with a delta.... is that a delta can take one ground. It dosen't matter where the ground is as long as only one ground exists. That ground on X2, thats on the transformer to the left, mearly helps to give the bank secondary a refrence to ground and help the fuses clear in case of a fault on the secondary side.

[Highplains Drifter]

Good morning to all

I have a question and I hope everyone involved in the answer

When connecting the transformer bank is connected to only one of the transformers in the ground as shown in the picture
Why

And if there are any references Please advise us of

I thank mybrother Pootnaigle
for his answer, but I want more details

Saudi-Lineman….welcome! There is a man that frequents this forum, who spent over twenty years working on your system. We’ll see if he can answer your question!!!

[topgroove]

thanks HD...... .... Damn you! I just blew half a beer out my nose laughing.

[T-Man]

Like TG said in an earlier post, that ground is there for refrance. I haven't seen one like this where the x2 is the ground, but I have built them with one of the x1 or x3 legs grounded. Usually b phase. On any system there can be one ground added intentionally or by accident, it's the secomd ground that will blow fuses, burn down wire and cause havoc. That first ground is to protect the system from unwanted current flow by being a direct short when the second ground appears.

[topgroove]

I hear ya T-man. that is an intresting place to ground. We normaly ground the outside ,outside leg. We always use three transformers in a bank.

[saudi_lineman]

If you tried to put a ground on that transformer on the right on X2, your high side fuse would blow imediatly!

Alot of linemen have dificulty with delta primary and secondaries. I've worked with them my whole carreer so it kinda comes easy for me. The thing to remember with a delta.... is that a delta can take one ground. It dosen't matter where the ground is as long as only one ground exists. That ground on X2, thats on the transformer to the left, mearly helps to give the bank secondary a refrence to ground and help the fuses clear in case of a fault on the secondary side.

Saudi-Lineman….welcome! There is a man that frequents this forum, who spent over twenty years working on your system. We’ll see if he can answer your question!!!

pls try to found him and ask about this

Like TG said in an earlier post, that ground is there for refrance. I haven't seen one like this where the x2 is the ground, but I have built them with one of the x1 or x3 legs grounded. Usually b phase. On any system there can be one ground added intentionally or by accident, it's the secomd ground that will blow fuses, burn down wire and cause havoc. That first ground is to protect the system from unwanted current flow by being a direct short when the second ground appears.

i know the fueses will burn but if we connect all transforme to the ground x2 why fuses burn this is what i mean
if you say short circut tell me how?

thanks guyz

[topgroove]

You saudi guys crack me up... Always trying to blow stuff up. The reason the fuse will blow is by grounding that second transfotmer your putting a second ground on a oppisite leg. Your confusing a wye with a delta. With a delta there is no common.

[barehander]

[/quote=saudi_lineman;108412]
[/quote]

I'm surprised that Groove & T-Man have never seen this hookup. I've built thousands of these OD banks, 120v, 240v, 208v. They are used for many applications. A residence with a 2 or 3 wire service with a 4 wire 3 phase well service. Commercial building with an office and 3 phase motor load. Small horsepower water wells. We wire the secondary delta a little different, but the outcome is the same.

If you tried to put a ground on that transformer on the right on X2, your high side fuse would blow imediatly!
Alot of linemen have dificulty with delta primary and secondaries. I've worked with them my whole carreer so it kinda comes easy for me. The thing to remember with a delta.... is that a delta can take one ground. It dosen't matter where the ground is as long as only one ground exists. That ground on X2, thats on the transformer to the left, mearly helps to give the bank secondary a refrence to ground and help the fuses clear in case of a fault on the secondary side.

Groove, I'm not sure what you've said is true, I may be wrong. The ground on X2 to the left, gives a voltage reference to the bank. If you vector it out (haven't done that in over 30yrs) you can measure 120, 240, & 208. What that diagram doesn't show is C phase to X2, which is 208v.
Here's a pic I took this morn. of a 240v 3 wire bank........



No neutral, all it's seeing is phase to phase.

Here's how we wire these banks...



The delta is different from the diagram, having the outside bushing of the right side TX being the stinger, or power leg, 208v to neutral.

Here's a pic about a 1/2mi from my house, commercial on on side of the street, residential on the other. There are 3 OD banks almost in a row. The closest one shows service to 2 commercial cust., and to the right, 2 houses. On this 3/4mi street, I counted over 35 OD banks. It's versital, and cheaper than a closed bank.
Just my thoughts.

[Pootnaigle]

Ummmmmmm we also built our 2 pot banks like this for 120-240-3 phase . Like Barehander said there is a hi leg. But all phase to phase secondary voltage is 240.
If you look closely at his drawing the centertap( ground) could be removed since there is no neutral in his circuit, to carry a 120 volt return anyway. I beleive ONE ground can be applied anywhere regardless if its on A, B, or C phase or on the centertap itself. the second one is always gonna blow sumpin up.
He isnt understanding that he is essentially making ONE transformer out of 2, or 3. and ONLY One ground can be applied on any Transformer.