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How do I calculate an electric generator's power?

  1. Apr 21, 2009 #1
    I'm thinking of making an electric generator. I want to use a 100kg U shaped magnet. Inside of this U magnet is 100kg coils of wire. The 100kg coils of wire turn 360 degrees every ten seconds. How much electrical power will this electric generator generate? Also what would happen if I placed the 100kg coils of wire inside of a 100kg circular shaped magnet?
  2. jcsd
  3. Apr 21, 2009 #2
    The size of your magnet and coil imply that this generator is a very signifignificant project, and so needs some serious design work. You should review Faraday's induction equation, because 360 degrees every 10 seconds (6 RPM) is probably a factor of 200 or more below what you need to develop a good output voltage. Are you planning to use a commutator (or slip rings) and brushes to get the DC (or AC) voltage & current off the armature? Maybe an alternator configuration is better?
  4. Apr 23, 2009 #3
    I'm planning to use slip rings and brushes. So what equation should I use to get electric generator's voltage calculated? Faraday's induction equation? Please tell me. By the way I don't know Faraday's induction equation.
  5. Apr 24, 2009 #4
    Faraday's Law of induction, written for an alternator with a DC (permanent magnet) two-pole stator, is

    V = - N A (2 pi RPM/60) B

    where N = number of turns on the armature (example N= 50)
    A = area of coil on the armature (example A = 0.1 meter times 0.05 meter = 0.005 m2.
    RPM = armature rotation speed (example 3600 RPM)
    B = DC magnetic field (e.g., 0.5 tesla)
    V= volts out (example V = 50 x .005 x 2 pi x 3600/60 x 0.5 = 47.1 volts @ 60 Hz)
  6. May 1, 2009 #5
    Is there any way to theorize how much "N" I could get from 100 kg of wire turns and how much "B" (in Teslas) I could get from a 100 kg horseshoe magnet?
  7. May 1, 2009 #6
    Here's a new type of generator I'm working on:

    The outer magnets, (LO)NS and SN(RO), repel the inner magnets, (LI)SN and NS(RI), back to where they came from. Then inner magnets (LI)SN and NS(RI) repel each other again while each of those two magnets turn gears and the repelling process and gear turning process keep repeating. Actually the motors turn magnets (LO)NS and SN(RO) 180 degrees for 5 seconds every 16 hours to (restrengthen?) magnetic fields of the four top magnets. Each of the outer and inner magnets are on a rolling rectangular block and between each rolling rectangular block and adjacent magnet is a layer of adhesieve that connects rolling rectangular block to magnet. The six magnet engine uses six magnets to create electricity by having two outer magnets repel two inner magnets that repel each other back and forth. The two repelled back and forth magnets each turn a gear and each of those gears turns a gear and each of those latter gears turns a magnet to generate electricity. I wouldn't call this perpetual motion; the adhesieve would wear out over time.

    _______Lgear_ Rgear
    _______Lgear_ Rgear
    _______LNS__ NSR
    _______coil__ coil
  8. May 5, 2009 #7
    The coils would of course be connected to transformer coils. Is it possible for such a generator to provide enough power to move a car?
  9. May 5, 2009 #8


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    Staff: Mentor

    C'mon - you asked questions in the beginning that imply you know you don't have anywhere near the understanding of these concepts necessary to even evaluate a generator and now you think you've developed a perpetual motion machine!??

    Stop fooling around - you're wasting your time and ours.
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