Delta to wye to delta

[jathanstover94@]

Hello all , I’m just stumped and curious
We have a 120/208 v 3 phase high leg delta service on a job and we have installed a sub panel for a car charger (more in the future) but the one we are having trouble with is the the 480v charger
We have 212v to 215v on our x1,2,3 side of our transformer but our high voltage side is 560v to 565v - I have tried switching taps around and nothing brings down the voltage ,

We have 3 phases and a ground coming into our transformer as delta (480v) does not need a neutral to carry it to the car charger-

How or what am I missing here?
Does this need a neutral on x0?
Please help

 

[ptonsparky]

Is it specifically a step up transformer or are you back feeding a typical delta Wye step down?

You may not need a neutral on the secondary but you will a grounded conductor.

 

[jim dungar]

We have a 120/208 v 3 phase high leg delta service on a job.....

No you do not.
You either have a standard 208Y/120V wye connection, where all three lines are 120V to ground.
Or, you have a not uncommon 240/120V delta connection where 2 lines are 120V to ground while the third leg is 208V. These 4 wire delta are often called wild or high leg.

 

[roger]

I don't understand the title of the thread verses the problem. As Jim said you do not have a 120/208 high leg delta, there is no such thing but back to the 560 V primary, who is supplying this?

 

[hillbilly1]

If your back feeding a 120/208 transformer with a 240 volt delta service, you will get around 560 if the 480 taps are set to 480. You can change the primary (secondary now) to lower the voltage output. Depends on how many taps you are given.

 

[hillbilly1]

Hello all , I’m just stumped and curious
We have a 120/208 v 3 phase high leg delta service on a job and we have installed a sub panel for a car charger (more in the future) but the one we are having trouble with is the the 480v charger
We have 212v to 215v on our x1,2,3 side of our transformer but our high voltage side is 560v to 565v - I have tried switching taps around and nothing brings down the voltage ,

We have 3 phases and a ground coming into our transformer as delta (480v) does not need a neutral to carry it to the car charger-

How or what am I missing here?
Does this need a neutral on x0?
Please help

Definitely do not use or bond XO!