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Electromagnet Project

  1. Aug 7, 2014 #1
    Hi Everyone, I hope this is ok to post in this section this is my first time on here. I recently was watching a show on maglev trains (I know this is not new technology but I found it really interesting). I love to tinker with little projects in my shop and was wanting to build a gadget to lift using an electromagnet. This is what I had in mind and was hoping for some help to tell me if my thinking is way off or not.

    From what Ive researched an electromagnet will repel a permanent magnet. I would have two platforms connected on rails to keep them centered. When the electromagnet is energized it would repel the permanent magnet attached to the top platform, thus lifting any weight on top (Picture Below).

    Thanks any help/suggestions/corrections would be appreciated.:smile:


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  2. jcsd
  3. Aug 7, 2014 #2

    Simon Bridge

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    You will also need some way to work out the force between the two magnets.

    ... though I don't know what sort of permanent magnets you have access to.
    Don't forget to include the weight of the plate and the permanent magnet with the load.

    Your electromagnet and PSU in the sketch seem optimistically small for your load - but you'll find that out.
    You'll also want something to hold the plate horizontal or it may twist and jam the guides in the holes.
    Consider using a potentiometer too - to vary the magnetic field strength.
  4. Aug 8, 2014 #3
    Greetings, Mr((?Dr) Bridge,
    I believe some 'maglev' systems use the principle of induced fields to generate the opposing magnetic
    field to lift the vehicle off the track. I (somewhat remotely) recall a system, using fixed magnets in the
    levitating train, which are approximated to either an aluminum track below, or closed circuit coils of wire.
    By this, i mean that the coils are not supplied with current from an outside source, but rather, develope an induced
    current as a magnet passes by (in the train) overhead. The induced current produces an opposing
    magnetic field which generates the lift for the train. An energy source is still needed to propel the train
    along the track - I am unsure of the details about this aspect. If only an aluminum track is present, the
    principle is the same. Experiment: make a disk of aluminum, say 3 - 4 inches diameter, with a 3/8ths steel
    bar protruding from the center. Mount this in a drill press, and spin at some safe, sane speed (perhaps 100 rpm).
    Hold a strong magnet close to the outer, bottom aspect of the Al disk as it spins. You may be surprised at
    the repelling force generated as you bring the magnet close (several mm) to the spinning disk. Stop the disk movement and repeat. Nothing there, now!
    Anyway my 'quick reply'. Hope this adds to your project! stanleysmd@gmail.com
  5. Aug 8, 2014 #4
    An addendum to my message that I just finished. These trains have roller supports for the train, to
    allow the train to go from 'no movement' to moving status, during which the 'cars' will lift, freeing the
    wheels from the track while train is at speed.
    stanleysmd; best of luck with your endeavor!
  6. Aug 8, 2014 #5
  7. Aug 8, 2014 #6

    Simon Bridge

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    "Simon" is fine :)

    This is correct - either magnets on the train lifting against an aluminium track (Germany) or magnets on the track pushing against the train (Japan).


    I used to have a maglev demo that was a transformer coil with a cut iron core - it would levitate an aluminium plate with a hole in the middle (for the iron core to pass through) and ran off mains. The AC meant that the plate bounced a lot.

    This is more sophisticated:

    The spinning disk approach:
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