@donhradio posted:You can nitpick,... ...the U post is not always the U POST!
The "U" post is always the "U" post.
However, the convention up until the MW transformer was introduced, with very few exceptions, is the "U" goes to the center rail Lockon clip 1, the "A" post(and frequently some optional post for lower voltage operation) is common on single train transformers.
"U" is common on multi-train transformers(Type R is an exception). This is very important when phasing power supplies.
@donhradio posted:A even better example of this is the early CW-80 transformers. U on them is not like U on a ZW or Z etc
The original CW's have the red posts common(A & B), later units (2006-up)have the black posts common(U & U).
If the original CW(OR any CW, for that matter) was connected with "U" to the center rail, the whistle & bell functions would be transposed. The work-around for using the early CW on common ground layouts, using "A" & "B" as common, works well as long as you accept that the whistle & bell functions will be swapped.
