open delta bank

[davis.lineman]

would not work. it would not blow the fuse instantly like everyone thinks unless the coils were in bad shape. but your transformers already being banked together out of phase from each other on the high side. so on your secondary coil side your going phase to phase until it burns those coils up. seen this done contractors didn't know how to build an open bank and messed up quite a few times. so if your fuse holds long enough your voltage will be anything until something blows. but like the others have already stated if the transformers were different polarities from each other would work just fine as an open. as for it being an open bank with single bushings that's fine. because you have an internal ground on what would be your h2 bushing to your tank. because in order for it to work you have to have your hi side grounded out. unlike a 3 pot wye/delta where you would float your hi-side to prevent your bank turning itself into an open on its on and cause a burnout trying to back feed. also if you grounded your hi-side on a 3 pot wye delta if you have an imbalanced feeder when one phase on the secondary coil side your other transformer would try to compensate and back feed the other transformer to maintain voltage trying to regulate your system, this will also cause excess current to be thrown back on the system and you can see odd phenomenons like sympathetic tripping. making single bushings on 3 pot wye/deltas a no no. but investor owned utilites seem to use single bushings more than most it seems.

[rcdallas_]

would not work. it would not blow the fuse instantly like everyone thinks unless the coils were in bad shape. but your transformers already being banked together out of phase from each other on the high side. so on your secondary coil side your going phase to phase until it burns those coils up. seen this done contractors didn't know how to build an open bank and messed up quite a few times. so if your fuse holds long enough your voltage will be anything until something blows. but like the others have already stated if the transformers were different polarities from each other would work just fine as an open. as for it being an open bank with single bushings that's fine. because you have an internal ground on what would be your h2 bushing to your tank. because in order for it to work you have to have your hi side grounded out. unlike a 3 pot wye/delta where you would float your hi-side to prevent your bank turning itself into an open on its on and cause a burnout trying to back feed. also if you grounded your hi-side on a 3 pot wye delta if you have an imbalanced feeder when one phase on the secondary coil side your other transformer would try to compensate and back feed the other transformer to maintain voltage trying to regulate your system, this will also cause excess current to be thrown back on the system and you can see odd phenomenons like sympathetic tripping. making single bushings on 3 pot wye/deltas a no no. but investor owned utilites seem to use single bushings more than most it seems.

Woah...that is very hard to read.Have seen the secondary side that had x1 to x1 and had screwy voltage, remember it being over 300 some volts.Some old school junk out there where CSP's were used.