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Homework Help: Input and output voltages of a transformer?

  1. Apr 26, 2004 #1
    okay, I Don't quite grasp this concept but!. Vo/Vi = No/Ni.

    And I have this problem. A Generator at a power plant produces AC at 24,000 V.A transformer steps this up to 345,000 V for transmission over power lines. IF there are 2000 turns of wire in the input coil of the transformer, how many turns must there be in the output coil? :biggrin:
  2. jcsd
  3. Apr 26, 2004 #2
    Heres how u do the problem....

    First let me tell u the basics of a transformer. A transformer is a mutual inductance based device that transfers power from one part to the other. It does so by virtue of stepping up the voltage or the current.
    i.e VI = constant. So if the input voltage, current and the number of turns are V1, I1 and N1 and those on the o/p are V2, I2 and N2, then,

    N1*V1*I1 = N2*V2*I2 .

    So, the voltage or current level can be stepped up or stepped down accordingly. Do u understand the concept now????

    And about the solution to ur problem, I think u have answered ur qn. The answer is: Vin/Vout = Nin/Nout.

  4. Apr 26, 2004 #3


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    Science Advisor

    Yes, "Vo/Vi = No/Ni" . Also you are told that Vi= 24000, Vo= 345000 and Ni= 2000. Put those into the equation and you have:

    345000/24000= No/2000. Can you solve for No?
  5. Apr 27, 2004 #4
    ah! thanks guys.. see i thought i had the answer down! But, the tutors at my school we're telling me something else! Thanks for ellaborating! :biggrin:
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