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EI Core electromagnet questions

  1. Jul 14, 2016 #1
    Hello. I am trying to design an EI-core electromagnet (think two c-shaped cores with their gaps abutting). The coils would go on the top and bottom legs of the E (legs B and C in my sketch). There is a sketchbelow and you can find one here: http://www.everychina.com/m-ei-core?cpc_kw=ei core lamination&cpc_flag=c66082

    I had a few questions

    1. does anyone foresee any problem with making it in two c-shaped halves (1/2 A+C+1/2 D and its mirror on B) then joining the two?

    2. Would it be better to make it as an E and an I and join them? If so, why?

    3. I have the chance to make this out of iron or steel, and maybe ferrite. It's being run DC so my thought was iron (relatively cheap, good permeability, and customizable). Does anyone foresee problems with iron?

    Thanks to all.

    + ++ +
    B + Gap + C
    + ++ +
  2. jcsd
  3. Jul 16, 2016 #2


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    Science Advisor

    An electromagnet needs a gap that will close, or somewhere for the magnetic field to get out to attract a nearby object. You know what you want but we are not mind readers and cannot guess the details needed to usefully advise you. Draw a sketch of your core, show where your windings will be placed and where the magnetic field will flow to attract whatever.

    Ferrite is not good for electromagnets because it will shatter if hit by some attracted object.
    Laminations are only needed for AC transformers or high speed magnets.

    How quickly do you need to turn the magnet on, and how long to turn the field off ?
    Why are you using laminations when you could use solid iron blocks bolted together ?
    What size dimension is your design ?
    What power supply will you use to power the magnet. Voltage ? maximum current ?
    How will you control the magnet current ?
    What is the application of this electromagnet ?
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