Proof, Two-Wattmeter Power Measurement (3 Phase)

Discussion in 'Homework Help' started by jegues, Oct 8, 2011.

  1. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
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    43
    See figure attached.

    We are supposed to show that for a balanced three-phase power system that the sum of the readings of the two devices is indeed equal to the three-phase power.

    How do I go about showing this?

    Can someone give me a hint as to where to start?

    I can see that Vab, and Vcb will be the line voltages, but I'm still not sure where to start.
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Draw the phasor diagram and the approach becomes more obvious. In any case there are numerous on-line examples of the proof. Google "two watt meter method three phase power".

    I have a "proof" of my own - if you are interested I'll post a copy.
     
    Last edited: Oct 9, 2011
  3. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
    735
    43
    Absolutely.

    Please post, I'd love to see your method as well, does it differ from others?

    Thanks again!
     
  4. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    It's most likely very similar to others. I haven't taken the trouble to check (lazy I guess). Also didn't check whether the AAC online volumes have anything already written on the topic.
     
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