open delta bank

[Orgnizdlbr]

Saw one built once with the H1 on one pot and the H2 on the other connected to the primaries. It was 4 KV and 120/240 secondary. New service, no connected load. It was connected X1 to X1 (because the top was flopped of course). It was closed in and the foreman checked the voltage at the meter base. He said. That one leg pegged the voltmeter. It was opened of course and the high side was changed.

Seen the same thing after contractors did a job for us, problem was they threw it in and drove away......needless to say, the owner of the bakery it fed wasnt real happy cuz he had some equipment burned up and coudlnt make his cakes and pies.......

[rcdallas]

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[hotwiretamer]

Well you posted the picture of the two pot bank with CSP's and has luck should have it I come back from a trouble call with just that.

Simple problem; power leg is broke at the secondary bushing. Easy simple fix right. Nope. Feeds a convenient store and the owner conveniently doesn't speak english too well to get him to kill his load. Well after tackling that battle now it comes down to lifting the hot tap off line line on some armless construction. By golly the hot tap on the power pot is seized up.

Anyway finally called for someone to come watch me in the primary and ended up getting it done. Got the hot tap off; killed the lighting, etc. CSP's suck. They suck even more when their built like crap on armless construction in a two pot bank.

Yeah, you got to love lifting those stingers off csp's, relying on that switch to be in working order! I normally check voltage at the secondary bushings to confer that it is working. Especially when it is a bank!
That stinger you lift and then release to grab the next can be suspect to backfeed.

[Tester]

single bushing pots - lighting pot hooked up normal, power pot X3 bushing hooked to X3 on lighting pot and X1 voltage will be what? regular wild leg voltage (208v-215v)? fault? a freind of mine and I disagree on the output on this build just throwing it out there to other linemen.

If you have 240 volt transformers, and connect the x3 bushing together, you will have bad voltage, but nothing will blow up. Both the transformers will have 240 x1-x3. The x1-x1 will be 415 volts. The wild leg, (power leg) to neutral voltage will be 317 volts.

[reppy007]

If you have 240 volt transformers, and connect the x3 bushing together, you will have bad voltage, but nothing will blow up. Both the transformers will have 240 x1-x3. The x1-x1 will be 415 volts. The wild leg, (power leg) to neutral voltage will be 317 volts.

Just wondering if ........did you actually wire one out this way and check voltage?

[bobbo]

We have all different terminologies from different areas and different systems. One bushing cans I think of those Y system cans. Can ground is bonded to the coils and neutral? and one primary bushing thats it? Just trying to get apicture in my head.

[Tester]

Just wondering if ........did you actually wire one out this way and check voltage?

Yes I have, in a transformer class that is a controlled setting.
Using 7200/120/240 volt transformers.
Here is how we hooked it up.

[Tester]

If they are both additive or subtractive you can not connect both X3s together you will blow a fuse.

They will not blow a fuse. You will just have bad voltage.

[lewy]

They will not blow a fuse. You will just have bad voltage.

Ya your right 240/416 the same as 120/208 an old voltage they had here long before I started.

[lewy]

We have all different terminologies from different areas and different systems. One bushing cans I think of those Y system cans. Can ground is bonded to the coils and neutral? and one primary bushing thats it? Just trying to get apicture in my head.

Ya most of our new transformers are single bushing, with the bushing on the top. 1 side of the primary winding is connected to the bushing & the other end is connected to the inside of the tank, at the same spot on the outside is a tab to connect your lead to the system neutral. On the secondary side there is a tank strap that is connected to X2 along with a separate case ground. Our 347/600s are the same except they only have 2 bushings.