transformer,

Discussion in 'Homework Help' started by ninjaman, Oct 21, 2013.

  1. ninjaman

    Thread Starter Member

    May 18, 2013
    306
    1
    hello I have this problem:


    1. a 3300/250v, 50Hz,1pH transformer has a core of effective cross sectional area of
      13000m^2 and a low voltage winding of 80 turns.
    Determine:
    the number of turns on the high voltage windings
    a, 250v / 3300v = 0.075 80 / 0.075 = 1066.6 turns


    the maximum flux density of the core

    b, 13000mm^2 / 1000,000 = 0.013m^2

    3300/4.44*50*1066.6*0.013 = 1.072T

    I was told this was wrong, though I cant find what is wrong. I have a guess that maybe the 0.013m^2 may be wrong but im not to sure. or the method for finding the high voltage windings

    any help would be appreciated
    thanks
    simon
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Your primary turns calculation is the source of the error.
     
  3. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    +1 You have a rounding error.
    Try solving by cross-multiplying.
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    ratio of voltages are 3300V/250V = 13.2:1

    low voltage turns =80, so high voltage turns = 80x 13.2= 1056 turns
     
  5. ninjaman

    Thread Starter Member

    May 18, 2013
    306
    1
    hey thanks a lot everyone for your help
    I looked at a few formulas and found that answer

    I used np = vp*ns/vs 3300*80/250 = 1056

    I then got 1.0828T for maximum flux density by using

    3300/4.44*50*1056*0.013


    actually im not sure about that last part and cant figure it out properly.

    13000mm^2, is that 0.013m^2, I don't know if that's right?
     
  6. ninjaman

    Thread Starter Member

    May 18, 2013
    306
    1
    hello

    could I get some help, with this, im not sure if im right

    13000mm^2 is that 0.013m^2

    I don't know if that's correct?

    cheers

    simon
     
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