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Homework Help: Very quick question PLEASE - Star Connection

  1. Sep 6, 2010 #1
    Very quick question PLEASE - Star Connection!!

    1. The problem statement, all variables and given/known data

    i'm just working on some questions on power engineering and theres a question on star connections. the wording is a bit funny - wondering if can get some clarification please.

    "a three phase load is composed of three impedances of 10+5j. it is connected to a supply composed of three voltage sources of 220V. The three sources and three impedances are connected in star"

    i am then asked to state the magnitude of the line voltage. im confused about the wording - does it mean that the phase voltage is 220V (if there were three separate sources, this would be the case) or that the line voltage is 220V?

    thanks for your help



    2. Relevant equations



    3. The attempt at a solution

    i thought that the phase voltage would be 220 and so line voltage 220root3. is this correct?
     
  2. jcsd
  3. Sep 6, 2010 #2
    Re: Very quick question PLEASE - Star Connection!!

    since it specifically says that the voltage sources on the supply end are 220V and since it is star connected, the 220v refers to phase voltage. LL voltage would be 220root(3) as you thought.
     
  4. Sep 6, 2010 #3
    Re: Very quick question PLEASE - Star Connection!!

    if the sources are switched to delta, would the line voltage be 220?

    since phase voltage = line voltage for delta connectio
     
  5. Sep 6, 2010 #4
    Re: Very quick question PLEASE - Star Connection!!

    yes.
     
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