1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Ideal Step-up transformer

  1. Apr 18, 2015 #1
    1. The problem statement, all variables and given/known data
    An 5kVA ideal step-up transformer having a turns ratio of 200:1700 and is connected to a primary voltage of 1000V. Determine the primary current at full load.

    2. Relevant equations
    Vs/Vp = Ns=Np = Ip/Is

    3. The attempt at a solution
    I think it is 1700/200=Vs/1000=8500V
    But, I do not know how to calculate the current,
    I think it is 5kVA/8500 is Secondary current
    then when I have Secondary current is 10/17 (0.58823)
    ((10/17) x 8500) / 1000 = 5A

    I think the primary current at full load is 5A????

    Thank you
  2. jcsd
  3. Apr 19, 2015 #2


    User Avatar
    Homework Helper
    Gold Member

    All sounds good to me.
    Since it is ideal, 5 kVA can be used on primary or secondary:
    primary 1000V x 5A or secondary 8500V x 0.588A both = 5 kVA
  4. Apr 19, 2015 #3

    rude man

    User Avatar
    Homework Helper
    Gold Member

    Since the transformer has capability of 5000 VA and 1000V is connected to the primary, the input current is at "full load" is 5000/1000 = 5A, a quick way to your answer.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted