Apologies to all...........

Discussion in 'General Electronics Chat' started by PackratKing, Sep 2, 2008.

  1. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
    .........who managed to read my misguided musings on 3-Phase power before I gave up and deleted them...........
    I have gotten out the ol' textbooks, and am doing a self-imposed refresher course on the relevant technology.

    One question that I skimmed the books for........but either haven't or won't find.

    What is the Phasing of the household Pole-to-AC distribution panel. Since there are two leads in to two busses that will yield 240, are they phased 180 degrees apart, or just two taps off the pole transformer at identical phase ??
  2. bertus


    Apr 5, 2008

    Some information on powerdistriburion can be found over the links on this page of the EDUCYPEDIA.

    I think that the signals on the cables are out of phase,
    otherwise they would follow the same signal and there is no difference between the cables.
  3. SgtWookie


    Jul 17, 2007
    For a typical residential service, you get L1, L2 and N(eutral) from the power company.

    Basically, L1 and L2 are opposite ends of the transformer's secondary winding, and Neutral is the center tap. L1 and L2 are indeed 180° out of phase from each other. That's why you can get 120VAC and 240VAC from a service panel depending upon whether you're measuring between L1 or L2 and N, or between L1 and L2.

    Neutral has to be tied to ground at the service panel.
    PackratKing likes this.
  4. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
    Thanks, Sarge, for a clear, concise return on my point of confusion.

    Part of what did not make sense, considers an electric [ induction ] motor, Capacitor start and run, 240 volt, 3450 rpm. By design, for the speed, the motor of course has only 2 stator field "run" coils, which are @ 0 and 180 deg. across from one another in the frame, and 2 "start" coils @ 90 & 270 deg.
    It only stands to reason, that if L1 & L2 were fed with power @ phase of 120 deg separation, [ assuming that residential service were actually 2 legs of a 3-ph. grid ] that the motor would buck and heat like a demon posessed, if it ran at all.

    I hope I put that in clear terms, as I am still trying to get the whole thing straight, since I am going back to work in the HVAC & motor shop I bailed out of in Y2K.

    "" 7 years and a wake-up " :D then I get to retire and amuse myself with whatever I find that presents a challenge and turns an honest buck. Building a network !!
    Last edited: Sep 2, 2008