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Need to build a Large Lift Electromagnet

  1. Jul 4, 2015 #1
    Hi Everyone,
    not sure why it is so difficult to find any info on how to build a simple electromagnet with diagrams or plans... but it is!
    I need to lift sheet plate... thousand poinds or more... something like a 2 car battery design electromagnet for lifting....
    Please, Please, don't tell me I can buy one.... I know I can buy one. If I had the money I would and would not be wasting my time here!
    I have tons of material to build one... I strictly wish to build one and need some simple specs with drawings,,, simple drawings on a cocktail napkin would even work!
    either Im really stupid and everyone on the planet earth knows how to build these without simple drawings or Im not entering the right search criteria to get some simple plans??? or its a conspiracy? UFO thing? restricted info? Not sure why I cant get some simple plans?????
     
  2. jcsd
  3. Jul 5, 2015 #2

    mfb

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    It does not work, that is the point. A proper electromagnet design will need much more work, especially if you want to lift something heavy. Doing it wrong can be really dangerous.
     
  4. Jul 5, 2015 #3

    jim hardy

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    kinda a niche market.. not every hobbyist needs one.

    http://www.academia.edu/9265533/Des..._Electromagnet_for_magnetic_levitation_system


    look at this sales brochure - there are common sense features doubtless learned the hard way

    http://www.truninger.com/fileadmin/Brochures/Prosp_Magnethebetech_GB_web.pdf


    There's a liability issue - should your magnet drop a thousand pound plate on somebody , they can sue whoever gave you the plans for it.. i'd guess that's why the dearth of DIY plans.

    Beyond pointing you toward the basic physics, i dont think PF can help very much.
    Lots of MMF, big poles, extreme reliability in electromagnet power circuit.

    Stay out from under it.


    www.youtube.com/watch?v=SGoOu8cPmeM
     
  5. Jul 5, 2015 #4
    A 500 kg magnet requires several kg of copper wire, which you can buy for less than 100$ or get from old transformers, motors, etc.
    Also you need a few kg of iron. The power consumption of the finished magnet is probably gonna be somewhere between 40 and 100W, so a single car battery would be more than enough,
    What kind of materials do you have available?
     
  6. Jul 5, 2015 #5
    I have about 500 pounds of 10 gauge, 12, gauge, 14 gauge, each of insulated copper wire. Literally tons of iron... plus a machine shop, I can build anything just need a halfway decent drawing of a coil... I can even copy an existing design if I can find a drawing and or schematic of lifting magnets. This shouldn't be a difficult project. Or complicated.... Back in the old days we built a coil hooked up a car battery and lifted 5x10 sheets of steel and plate... that's all I want to do... This is for me, no one else. I have a calculator for the specs. Just need a simple design, or close enough.... or send me to something that's close...
     
  7. Jul 5, 2015 #6
    My apologies up front if I am being stubborn, or difficult, or whichever I should or would be labeled. I am strictly interested in getting an existing design that will lift anywhere from 200 - 2500lbs of 5x10 steel sheet. Don't need a PC controller, Battery back ups, Safety features, There are regular plain Rare Earth Lifting magnets that already exist that do not require anything but a release lever.... If I had a Simple Rare Earth Magnet that I could create a simple Manual Release Lift Magnet out of I would have already done it. I have no concerns about being crushed, killed, smashed, or mutilated. That's why its called DIY. I state like this in order to save the forums time responding with information that is not useable for my goal. As an example of what I am after. http://www.magnetics.com/product.asp?ProductID=11
     
  8. Jul 5, 2015 #7

    jim hardy

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    good wiki article here
    https://en.wikipedia.org/wiki/Electromagnet
    Lifting_electromagnet_cross_section.png


    it gives a link to the 1914 book where that drawing came from.
    But the examples there are in cgs units., the ancient ones i learned on .

    From WIKI
    liftmagnet1.JPG

    so leaving some headroom that dictates at least 10 square inches of magnet pole area for every 1000 lbs.
    liftmagnet2 .JPG


    Force is in Newtons and a pound is 4.45 Newtons
    N and I are the number of turns and your amps
    A is area of the electromagnet core in square meters, and a square inch is only 0.000645 square meters
    μ is the relative magnetize-ability of your iron. Garden variety steel should be a few hundred. 4130 is 190 at 60hz, will be somewhat higher at DC.
    source:https://www.utexas.edu/research/cem/ESRDC_pub/PR 435 Wilder.pdf
    μ0 is a natural constant, 4pi X 10-7
    L is length in meters of your magnetic path, including the gap that'll be bridged by your work.

    That's the physics you'll need to rough out a prototype design..

    You'll need a few more amps than that formula says because the air gap is never quite zero.

    I never built one of these - just that's where i'd start.

    Machinist hobby sites will likely have practical tips.
     
  9. Jul 7, 2015 #8

    Baluncore

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    I maintain scrap magnet controllers. You are going to need to be careful with your controller if you are to avoid arcing and destruction of the internal wire insulation. Ask for more specific information about turning off your magnet once you know it's specs. It will be essential to provide a flyback diode.

    Attached is some data from my old archives.
     

    Attached Files:

  10. Jul 7, 2015 #9

    Baluncore

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    And then there are more;
     

    Attached Files:

  11. Jul 7, 2015 #10

    billy_joule

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    DIY electromagnetic boots using microwave transformers and car batteries:



    The (rather mad!) user has is a 'making of' video too.
     
  12. Jul 7, 2015 #11

    NascentOxygen

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    I think any particular electromagnet will be able to lift a lot more when you can provide finely polished contact surfaces. So, rather than lower the magnet directly onto your sheets of rough steel, you clamp a block of carefully-chosen soft-magnetic material (with polished surface uppermost) to the load, and lower the electromagnet's core (its lower end likewise smooth and polished) onto that matching polished surface.

    Obviously, there's a tradeoff in convenience when you are lifting steel material, but it's the way to achieve maximum lift with any given power.
     
  13. Jul 7, 2015 #12

    NascentOxygen

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    If this is true, then perhaps discussion should focus on disconnecting a permanent magnet from a steel load. To achieve this, you just need an electromagnet to briefly overcome the field of the permanent magnets. The question then becomes can this be achieved without degrading the strength of the rare earth magnets?

    I'm not sure how robust rare earth magnets are, and whether the heavy clang as a strong magnet is dropped onto sheet steel will significantly degrade its strength.

    Perhaps others can give an opinion on the practicalities in what I'm considering.
     
  14. Jul 7, 2015 #13

    Baluncore

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