For the Swampgas.

[wtdoor67]

I noticed once at a municipal system, a 3 pot platform bank. It is a 12470/7200 system and this bank serves a safeway store. The pots are 167 KVA and are connected in a Wye/Wye configuration. The hot leads come from the X4 and the ground/system neutrals come from the X1 bushing. There are no connections from the X3 and the X2. My question is what do you surmise as far as secondary voltage etc?

[lewy]

240/416 ? If I was there for a trouble call I would likely no what the secondary voltage was & I would check the plate & also open the lid to see if anything was done.

[topgroove]

hard to say without seeing the nameplate... it could be a 120/208 or maybe a 277/480

[Meat]

Unless I'm missing something there might not be a connection between x3 and x2 (which would series the coils) there should be an external connection from x2 x1 and x4 x3 (which would parallel the coils) and would make this a 120/208 secondary.277/480 would be a 2 bushing secondary.If I'm wrong what the heck I gave it my best shot!Meat.

[wtdoor67]

My guess would be the posts are split, and the voltage is 120/208.

But surely that's not right, or you wouldn't have asked me.:p

blind sow finally found an acorn. Swamp you win the fur lined piss pot. The thing you guys didn't mention was the fact that there were no connections made on the X3 and X2. That tells me that some knot head must have lifted the lid off unnecessarily and paralled the coils on the inside.What a bone head.

Meat is right. All 277/480 OH pots only have 2 bushings on the secondary side. You guys are smarter than a bunch of electric foxes.

[lewy]

Where I come from a large 120/240 tx with 4 bushings on the secondary if the windings are left in series & you do not ground th X2 & X3 you would get 240 from each tx & in a wye/wye bank you would have a 240/416 V bank .

[wtdoor67]

lewy, I have never worked in Canada eh, but I believe you use the same kind of pots etc. manufactored under NEMA rules. Any thing from a 167 on up, single phase etc. will have 4 secondary bushings. X4,X3,X2 and X1 from left to right on an additive pot will correspond to A,C,B and D. If you desire to leave the windings in series you make a bus from X3 To X2 and if to parallel, then a bus is made from X4 to X3 and from X2 to X1. Then of course working leads can come off each respective spade as there are extra holes for whatever hookup is desired.

[lewy]

lewy, I have never worked in Canada eh, but I believe you use the same kind of pots etc. manufactored under NEMA rules. Any thing from a 167 on up, single phase etc. will have 4 secondary bushings. X4,X3,X2 and X1 from left to right on an additive pot will correspond to A,C,B and D. If you desire to leave the windings in series you make a bus from X3 To X2 and if to parallel, then a bus is made from X4 to X3 and from X2 to X1. Then of course working leads can come off each respective spade as there are extra holes for whatever hookup is desired.
I agree with the above so when the txs are in series without grounding X2 & X3 you would get 240 from them, I made the assumption from your earlier post
"The hot leads come from the X4 and the ground/system neutrals come from the X1 bushing. There are no connections from the X3 and the X2. My question is what do you surmise as far as secondary voltage etc?"

that X3 & X2 were joined externally , but not grounded which would give you 240 accross X1 & X4 which in a wye bank would be 240/416, but as you had said some one had made internal connections ( not the norm) which I would have realized when looking at them because without the internal or external connections it would be an open connection betwen X1 & X4, but yes since they are in parallel you would have 120/208