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Equation for Permeability of an electromagnetic core

  1. Jul 18, 2009 #1
    well i hope im posting this in the right section, im new here.

    im making some electromagnets for a personal project im doing but i want to get all the calculations done before i get all the materials and actually build the thing.

    i need to know what/if there is an equation to find the permeability of the core material of an electromagnet. the type im making are solenoids and i was thinking of using ferrite (alpha iron) as the core material. so its going to be a pipe/tube of ferrite with insulated copper wire wrapped around it and a patch of air through the middle.

    i searched around on the internet but couldn't find anything usfull, oh and it needs to be an equation thats doesn't use the magnet flux density because im trying to find the permeaility so i can then find the flux density which i can go on to find the force it will pull an object relative to its distance from the magnet. ill work out the last bit after i get the permeability.
  2. jcsd
  3. Jul 18, 2009 #2


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    Assuming you're buying this core, that data should be available from the manufacturer. I the manufacturer is unknown or you're making the core yourself (!) the easiest way is to just measure the inductance of a known, small number of turns and calculate it from that.
  4. Jul 18, 2009 #3
    i was thinking that i might have to get the info from the manufacturer but it was worth asking, thanks for the help.
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