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Homework Help: Magnetic circuit question

  1. Sep 26, 2012 #1
    the question is;

    if there only a current in coil a, and it is AC, calculate the rms current required in coil a to maintain an alternating flux in core section a with a peak value of 1.2T calculate the rm voltages at the two coil terminals if coil resistances are neglected

    (attached in the previous question which is continued on by this)

    So I derived the magnetic equivalent of this circuit which is basically mmf connected to reluctance (R) equivalent. What do I do from here?

    at the moment I am here;

    F = R * Flux

    With that

    F= NI, N = 200, R = Req which i have found already and flux = B*A

    200 I = Req * B*A

    do i substitute in 1.2T for b and solve for I? then multiple by √2 or am i going in the complete wrong direction?

    help will be greatly appreciated.

    Attached Files:

  2. jcsd
  3. Sep 26, 2012 #2

    rude man

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    Did they give you the permeability?
  4. Sep 26, 2012 #3
    relative permeability is 10,000,
    multiply that by uo
  5. Sep 27, 2012 #4

    rude man

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    Well, you got NI = flux*reluctance right, so what's preventing you from solving for I? And yes, you need to divide by √2 to get rms current. The formula NI = R*flux is for instantaneous values of I and flux.

    To get the two winding voltages you go to Mr. Faraday.

    (Realize that there are two reluctance paths, right?)
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