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Simple electric motor

  1. Nov 15, 2014 #1
    1. The problem statement, all variables and given/known data
    Hello ! I'm making a simple electric motor. Using copper wires and 1.5V battery.
    2 magnets, 2 thumbtacks, 1 block of wood, 2 paper clips, and approximately 2m of insulated copper wire.
    -The diameter of the loop must be 1"
    CAN'T use other materials, only the above listed.

    2. Relevant equations
    I just want to ask what do I need to do to have 1500 RPM or more.. Thanks!
    3. The attempt at a solution
    -Maybe the setup/orientation will be a factor.
    -See the uploaded file.
     

    Attached Files:

  2. jcsd
  3. Nov 15, 2014 #2

    Evo

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    Hi sharm8, thank you for the diagram
     
  4. Nov 15, 2014 #3

    NascentOxygen

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    For maximum speed I think you should aim to minaturize it, and make the rotating part as symmetrical and evenly balanced as you can. Use strong magnets, and a large sized battery. The big cells (D cells or bigger) are still only 1.5 volts but they can supply more current. If your copper wire is thin, perhaps run two strands together as one so it acts as though it is thicker copper.

    You'll have no idea how fast it will spin, you just have to construct it using good techniques, then run it and see how it turns out.

    Post a photo when you have it working.

    Good luck!
     
  5. Nov 15, 2014 #4

    SteamKing

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    A speed of 1500 RPM is pretty ambitious. You should set your sights on getting the motor to turn.
    At a speed of 1500 RPM, a motor fabricated by hand is going to have a lot of imbalance in the rotor. Even if you were to achieve this speed, the motor would probably destroy itself due to vibration in short order.
     
  6. Nov 15, 2014 #5
    Thanks for your advice, it will be a big help! :D
    I think I will be using subwoofer magnet.
    Thanks again, I will update you as soon as I finished it :D

    Haha yeah you're right. But every 100 RPM, I will have 1 point. haha.. I guess there's no harm in trying..
     
  7. Nov 16, 2014 #6

    gneill

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    Wear safety glasses when you're testing it it!
     
  8. Nov 17, 2014 #7

    CWatters

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    The strength of the magnets changes the efficiency of the motor (and that might be a factor here) but in general stronger magnets make the no load speed slower. The motor will accelerate from rest until the back emf equals the applied voltage. If you increase the strength of the magnets the back emf increases so it matches the applied voltage at a lower rpm. Best experiment with different magnets.
     
  9. Nov 17, 2014 #8
    Noted :)
     
  10. Nov 17, 2014 #9
    Nice idea. thanks :) I will have different magnets.
     
  11. Nov 17, 2014 #10
    the problem with 1500RPM is: with the limited materials you are allowed to use even if you use a near perfectly turned center piece to coil on you only have paper clips and thumbtacks to hold it in place while it spins neither of which will make a solid or even balanced axle.
     
  12. Nov 17, 2014 #11

    Mark44

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    Use 16d (16 penny) thumbtacks :D
     
  13. Nov 17, 2014 #12
    rebar sized paper clips?
     
  14. Nov 17, 2014 #13

    Mark44

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    There you go...
     
  15. Nov 19, 2014 #14

    CWatters

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  16. Nov 19, 2014 #15
    I'd have to say 10k/rpm claimed is still a stretch but the idea of using the magnet to attach the screw to the battery was a nice touch removes half the instability of the shaft.
     
  17. Jan 11, 2015 #16
  18. Jan 11, 2015 #17

    NascentOxygen

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    Well done!

    Thanks for posting. http://imageshack.com/a/img29/6853/xn4n.gif [Broken]
     
    Last edited by a moderator: May 7, 2017
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