Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ideal Transformer

  1. May 15, 2006 #1
    something i read from the text book and i don't understand.

    "in an ideal transformer, no magnetizing current is required to produce the flux"

    so, where does the flux come from?
  2. jcsd
  3. May 15, 2006 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    If the secondary is open there is no power drawn from the power source. But there is current in the primary. The current in the primary is the cause and result of the buildup and collapsing of the magnetic field in the primary (it is self perpetuating).

    If the primary coil is a perfect inductor (in an ideal transformer R = 0) the current lags the voltage by 90 degrees. Since Power is [itex]VIcos\phi = VIcos90 = 0[/itex] the currrent does no work.

    Last edited: May 15, 2006
  4. May 18, 2006 #3
    TQVM. i think i understand it already.
    Last edited: May 18, 2006
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook