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: Inductance of inductor

  1. May 2, 2007 #1
    1. The problem statement, all variables and given/known data

    a non inductive resistor passes a current of 20A rms, when connected to a 100v rms supply (50HZ). When connect in series with a pure inductor across a 230v supply the combination draws a current of 15A calculate impedance of the circuit, inductance of the inductor

    3. The attempt at a solution

    R = 100v/20A = 5 ohms

    Z = V/I

    Z = 230/15 = 15.3

    z = square root R^2 + X^2 Find X^2

    Z^2 - R^2 = X^2

    SRoot 15.3^2 - 5^2 = 14.45 ohms

    From what I found how do I find the inductance of the inductor. I only know one way using flux density but there is no data given on this in the question.
  2. jcsd
  3. May 2, 2007 #2
    I know that the formula for reactance is Xl = 2(pi) f L
    How do I find L thats the just of what I want.
  4. May 2, 2007 #3


    User Avatar

    You know that [tex]X_L = 14.45\Omega[/tex] anf f = 50Hz.
  5. May 3, 2007 #4
    Do yous get 21.7 for L
  6. May 3, 2007 #5


    User Avatar

    I found 0.0458H
  7. May 4, 2007 #6
    How did you get that
  8. May 4, 2007 #7


    User Avatar

  9. May 4, 2007 #8
    I see I made a substitution mistake in my forumla I devided by XL thanks for the help
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook