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Making the Most Powerful Home Electromagnet

  1. May 23, 2016 #1

    I have been wanting to make a big ol' electromagnet for a while now. I thought instead of just going out to buy random stuff perhaps I should explore the science first.

    My plan was to get some rebar, a car battery, and some insulated wire to wrap around the rebar to creat en electromagnet and, well, a permanent magnet. Then I decided to stop and think.

    I have a number of questions.
    1. I've done something like this before. Why does this process create an electromagnet and THEN a permanent magnet that's just less powerful than the electromagnet. Do just some of the domains stay aligned when the current stops?
    2. Is rebar my best cheap option? It's unrefined steel right? So there should be plenty of iron in it. What would be my best option for a rod for cheap (I live near lowes and walmart) -- A side questions, which has the most magnetic potential period, iron, nickle, or cobalt? Why?
    3. Is it the voltage or the current that provides the increase in magnetism? I would LOVE to understand this with math.
    4. From what I understand smaller wire is better. Why is it better? What wire would be too small (I'd rather not start a fire)?
    5. Could I somehow plug it into the wall? How would I make a safe circuit with nothing being powered? Would AC or DC make a better magnet? Why?

    P.S. If I figure all of this out I will absolutely post pics and prolly a vid.
  2. jcsd
  3. May 24, 2016 #2
  4. May 25, 2016 #3


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    Gold Member

    bold by me
    Okay. Here's a place to start with interactive poke points. Look it over, do some clicking and come back with any questions.

    The magnetic field.
  5. May 25, 2016 #4
    I know all of the basics. I mean the exact science of this particular process and the formulas behind it. I was hoping for some more direct help.
  6. May 25, 2016 #5

    jim hardy

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    Science Advisor
    Gold Member

    Well, put up the basic formula and ask some questions about whichever terms you're unsure about how to optimize.

    You haven't indicated that you understand induction and Faraday's law.
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