Talk:Y-Δ transform

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I wonder if this ought to be written as Wye-Delta rather than Wye-delta, because for obvious reasons the letter Δ needs to be a capital? Michael Hardy 21:32, 18 Sep 2004 (UTC)

This article is mixing in "Y-delta" starting of motors - that technique should be moved to the induction motor article. --Wtshymanski 03:51, 14 Jan 2005 (UTC)

The formula is WRONG, the pictures name the resistance Rac, Rab, Rbc, Ra, Rb, Rc and the formula is written in terms of R1, R2,R3,Ra,Rb,Rc. See http://en.wikipedia.org/wiki/Analysis_of_resistive_circuits in the delta to wye part for show is should be. Someone please edit it. I only know the basics of wikiditing.

Here are a few suggestions:

  1. The article could give an example of a bridge circuit that can't be broken down into parallel and series parts unless the Y-delta transformation is used. Otherwise it's not clear from the article why the transformation is useful.
  2. The transformation can be derived from the condition that the resistances of the two circuits are equal when voltages are applied to any two terminals, and the third is left floating. However, it's not trivially obvious that this also makes them completely equivalent in all other cases, e.g., where no terminal is floating. I'm not a big fan of mathematical proofs in WP articles, but the logic could be made more clear without giving the actual proofs.
  3. Can the Y-delta transformation be used to break *any* network of resistors into series and parallel parts?

--Bcrowell 16:47, 26 September 2005 (UTC)


[edit] 30 degree phase shift

Can someone explain why there is a 30 degree phase shift between delta-wye and wye-delta transformer configurations. I've check numerous sites, but all the sites say is that there is a phase shift of either +30 or -30 degrees.

If a transformer has DELTA in primary and both STAR & DELTA in secondary so what will be the phase difference in secondary between STAR and DELTA.

[edit] Balance

I’ve tried to clean up the article a bit. Since I did not understand the intent of the statement

Balanced System: R_{\Delta} = 3 \times R_y

I’ve moved it here. Can somebody put it back in context or explain it? —xyzzyn 01:12, 14 January 2007 (UTC)