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Basic (I think) question on electromagnet combos

  1. Aug 17, 2015 #1

    I'm brand new to this forum. I'm an artist and musician and have just recently started delving into inventing, my scientific knowledge is very limited. I've made a simple electromagnet but I want to get the strongest pull between the magnet and another small surface. I want strong pull but I want to keep the space confined. So I don't want to use a huge piece of metal wrapped a million times or a huge car battery (or similar) to power it. And I want the power supply to be confined to the same small space, so no plug in power supply.

    I was wondering if I would get a much stronger bond if I used the electromagnet (using because I want to turn off the pull) and a permanent magnet, as opposed to using the electromagnet and a piece of steel or iron. I know there will be some pull between the permanent magnet and the bolt used to make the electromagnet when there is no power supply on the electromagnet, but I'm thinking of separating them by a thin sheet of plastic which will minimize the pull when the electromagnet isn't powered.

    Also, I believe I read somewhere that an electromagnet can de-magnetize a permanent magnet. In this case I'm referring to a Neodymium magnet. Is this correct?

    Thanks in advance for your help!!
  2. jcsd
  3. Aug 17, 2015 #2


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    Staff: Mentor

    Welcome to the PF.

    Yes, an electromagnet or another permanent magnet can be used to demagnetize a permanent magnet. Kind of unproductive, eh?

    You get the strogest magnetic force by minimizing the distance that the magnetic flux passes through air versus passing through ferrous metal. That's why horseshoe magnets and other closed-path magnets are configured the way they are. Can you show us more about what you want to do?
  4. Aug 18, 2015 #3
    Thanks for the reply.... What I want to do is make an electromagnet that will attract a metal plate and basically lock with it. Maybe not so strong that a machine couldn't pull it apart, but so strong that the average human couldn't. I tried a piece of sheet metal with my electromagnet and it picks it up, but you can easily pull it off. I was thinking maybe if I put a magnet on the other side of the sheet metal that might help - ?? Also, I was planning on wiring a potentiometer to the electromagnet to control the force of pull.
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