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Electromagnets

Discussion in 'General Electronics Chat' started by horsebox, Jun 16, 2007.

  1. horsebox

    Thread Starter Active Member

    Jun 9, 2007
    32
    0
    I wound some stranded copper wire around an allen key about 15 windings and applied about 7 volts to it but it did absolutely nothing.

    It may have been a steel allen key. Could that have been the problem? Or was the voltage too low?
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,073
    8
    I can almost guarantee it was a steel allen key. I've never run across any other kind. Steel is an alloy of iron and carbon, by the way. All room temperature steels are magnetic - except the austenitic stainless steels.

    Try using a lot more windings.

    (I trust the wire was insulated, yes?)
     
  3. horsebox

    Thread Starter Active Member

    Jun 9, 2007
    32
    0
    Yeah I guessed it was steel. Is there a big difference in flux between using an iron core or a steel one?

    I stipped the insulation off the wire. Was that a mistake?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,808
    295
    Yes, taking the insulation off the wire was a mistake. The turns just acted like a short, so no magnetic field got created.

    Another thing that will help, besides using insulated wire - use a softer steel for the core. Something like a big nail will be more permeable than a hardened steel Allen key.
     
  5. recca02

    Senior Member

    Apr 2, 2007
    1,211
    1
    also try a lot more windings,
    i remember long time ago when i made one i used a lot of windings and the book
    suggested abt 200 turns.
    use a thin enamelled wire (the one u wud find in small transformers)
     
  6. bloguetronica

    AAC Fanatic!

    Apr 27, 2007
    1,359
    26
    With 7 windings you may experience magnetic atraction, but due to the excessive current. You will make a short for sure. Use wire until you have an appreciable DC resistance (20-50Ohm would do).
     
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