What is a transformer "J-Tap"?

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Pizza_Guy

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I am specifying transformers that include +/-2.5% taps. (2FCAN, 4FCBN) but vendors are asking if "J-Taps" are acceptable.
We have other transformers on site with taps to use at different MV levels (14400, 13800, 13200, 12870, 12470, 12000, 11700). Our primary distribution is all 12470V, and the +/-2.5% would be more useful.

What's the difference? And what are "J-Taps"? From my research, both systems are J-taps, only the taps are physically on different windings.
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petersonra

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maybe the difference is that you wire the incoming phase conductors to the same terminals and then connect the tap wire to the tap instead of connecting your incoming conductors to the tap directly.
 
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Pizza_Guy

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JoeStillman said:
Some kind of Eaton express-ship program? Sound's like they are offering some kind of in-stock, pre-engineered standard design.

I found this on the interwebs...
Click to expand...
Yeah, that's the first thing that popped up on Google. Pretty sure that's not it.
 
synchro

synchro

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Chicago, IL
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I think "J-taps" might refer to the shape of the jumper on a transformer schematic symbol like the one below. The jumpers to complete the delta connection are on one end of each winding.

Transformer_Taps-J.jpg


That's compared to having the jumpers across two taps in the middle of each winding like below.

Transformer_Taps-C2.jpg

That said, it's still a guess.
 
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Hv&Lv

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X) NO TAPS
A) 2 - 5% FCBN
C) 4 - 2/5% FCBN (Series Connected ) 2-5 % FCBN (Parallel Connected)
D) 6 - 2.5% 2 FCAN, 4 FCBN
E) 4 - 2.5% 2 FCAN, 2 FCBN
F) 2 - 5% 1 FCAN, 1 FCBN
H) 3 - 5% 1 FCAN, 2FCBN
J) 6 - 2.5% 4-FCBN, 2-FCAN, (Series Connected) 3 - 2-5% FCBN 1-5% FCAN (Parallel Connected)

I think your asking for “D” taps, and he is asking if you can get by with “J” taps.
That pretty much covers everything most of the time.
 
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Pizza_Guy

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Hv&Lv said:
X) NO TAPS
A) 2 - 5% FCBN
C) 4 - 2/5% FCBN (Series Connected ) 2-5 % FCBN (Parallel Connected)
D) 6 - 2.5% 2 FCAN, 4 FCBN
E) 4 - 2.5% 2 FCAN, 2 FCBN
F) 2 - 5% 1 FCAN, 1 FCBN
H) 3 - 5% 1 FCAN, 2FCBN
J) 6 - 2.5% 4-FCBN, 2-FCAN, (Series Connected) 3 - 2-5% FCBN 1-5% FCAN (Parallel Connected)

I think your asking for “D” taps, and he is asking if you can get by with “J” taps.
That pretty much covers everything most of the time.
Click to expand...
This makes a lot of sense. Do you have a source for this? i’d like to share it with the team, to avoid further confusion.
 
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