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Polarity switching electromagnet

  1. Sep 10, 2012 #1
    I wanna make an electromagnet to rapidly switch polarity back and forth. I hear the core should be made of laminated iron to avoid heat losses; is this correct? Where could I get one such core from, and is there anything else I should consider?
  2. jcsd
  3. Sep 11, 2012 #2
    Well since power transformers are laminated and do switch polarity efficiently, I would suggest you look around for surplus, burned out or otherwise unwanted power transformers and take your parts from that. (you can use the copper wire if you can get it out in usable lengths.) AC electric motors have laminated cores also.

    You are familiar with the problems involved in driving an inductive device with a switched signal with a fast rise time?

    Last edited: Sep 11, 2012
  4. Sep 12, 2012 #3
    Eddy currents and heat losses? Is there anything else?
  5. Sep 12, 2012 #4


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    Staff: Mentor

    In a circuit with inductance, current exhibits a reluctance to undergo any rapid changes. The more rapidly you try to make it change, the more stubborn it becomes.

    The inductor equation, v=L.di/dt shows that if you want a high value of di/dt, you have to apply a high v.
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