star connected spource to balanced star load?

Discussion in 'Homework Help' started by davo, Sep 21, 2010.

  1. davo

    Thread Starter New Member

    Sep 21, 2010
    1
    0
    Hello all.

    New on the site and hope to be able to contribute . I have a question I am stuck with.

    It gives 4 cases and I cant find the answer anywhere and have long forgotten the equations.

    Here it is.

    3 phase 3 wire system 50HZ Line voltage of 400V, Source is Star connected and load is balanced star connected.

    Cant figure out how th work out the Current in the connecting lines between source and load, Source phase currents and load phase currents with 10 ohms in each arm.

    I get 230.9V in each phase? thats as far as I can go.

    Can someone please kick the old memory back into gear?

    Cheers
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    The individual source phase current, phase line current & load phase current will be the same in your scenario.

    If the phase-to-neutral voltage is 230.9V then the current in the 10Ω star connected arm of the corresponding phase will be 23.09A. The corresponding phase line current will be 23.09A and the source phase current will be 23.09A.

    The three respective phase variables will be equal in magnitude but phase displaced from one another by 120° [electrical].

    There are other connection scenarios including delta connections which you will probably want to consider. I'm surprised you've not found anything searching the web. Or on this forum for that matter ...

    http://www.allaboutcircuits.com/vol_2/chpt_10/5.html
     
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