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Three phase delta transformers

  1. Aug 1, 2013 #1
    Dumb question - if the phases are tied together in a three phase delta transformer why don't the phases short out against each other in the same way the transmission lines would fault phase to phase if the touched each other in the overhead? I think I understand the wye winding situation in which the current vectors cancel each other out. Is that same in this case? Thanks
  2. jcsd
  3. Aug 2, 2013 #2


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    Staff: Mentor

    The transformer winding is not a short circuit. The winding transforms the load impedance, in the ratio N2, so electrically the winding presents as an impedance proportional to the consumer load.

    With no secondary load, the transformer primary winding is seen as a high impedance and very little current flows.
  4. Aug 2, 2013 #3
    Also - note at any given time the Vectorial SUM of the 2 phases is = to the Third. Not a dumb question - and you were on the right track with the Y reference. -- It is interesting to note that the nameplate on a power transformer will have a winding diagram - if this diagram is done properly, the diagram also represents the angular relationships of the windings.
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