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Classic Electric Power Generation

  1. Sep 8, 2008 #1
    A magnet surrounded by copper wire spins generating a A/C current down a wire for as long as it spins. Are electrons generating the current and amperage? If so, where are the electrons emenating from and why don't they ever run out? Also why doesn't the copper and or magnet end up becoming increasingly positively charged as time goes on year after year?
     
  2. jcsd
  3. Sep 8, 2008 #2
    "circuit"
     
  4. Sep 8, 2008 #3

    atyy

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    If you move a conducting plate through a magnetic field, then the magnetic force will cause the charge carriers in the plate to move in opposite directions. So there will be some charge separation. The charge separation itself causes an attractive force between the separated charges which are now attracted back to each other. So the charge separation builds up only to the point where attraction cancels the magnetic force. I'm not sure the exact scenario you have in mind, but this mechanism prevents the plate from becoming more and more charged the longer it moves in the field.
     
  5. Sep 8, 2008 #4

    jtbell

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    The electrons were in the wire in the first place. The changing magnetic field creates an induced electric field which is also continually changing, and which pushes the electrons back and forth along the wire. They don't "run out" because they never leave the circuit.
     
  6. Sep 8, 2008 #5
    Charges produce electric fields. Electric fields move charges. Moving charges (e.g. electrons) produce magnetic fields. Changing electric fields also produce magnetic fields. Magnetic fields also affect motion of charges. Changing magnetic fields produces electric fields... and much more. Lots of nice things for you to study :-)

    jf
     
  7. Sep 9, 2008 #6
    Thanks PF. What if the charge then goes into a circuit that does work then moves to a ground. Since the electron can no longer move backwards in the circuit, is there somewhere where an electron goes missing (wire, generator, air)? I was thinking perhaps it might not be best to imagine electrons moving but a electric wave.
     
  8. Sep 9, 2008 #7

    russ_watters

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    You can't have electrons continuously flowing in an open circuit. What you can do, however, is have them oscillate back and forth in a single wire connected to ground. That's how you can have a single-wire radio receiver, for example.
     
  9. Sep 9, 2008 #8
    Oh I see. That makes things much clearer.
     
  10. Sep 10, 2008 #9
    Am I correct in stating that basically some books are simplifying when they say electrons flow out of a hydroelectric generator down wires, into circuits to a ground? In reality, they are oscillating electrons back and forth a certain amount of molecules like a series of waves. If this is the case can I double the computing power of a computer by making a return gate as the electron moves back to its oscillating beginning state?
     
  11. Sep 10, 2008 #10

    russ_watters

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    Where did you read that? That's not how generators work. Look at the plug you have on your computer: it has at least two wires on it!

    Electric power from the power company actually comes over three wires, with waves that are 120 degrees out of phase with each other. But there is no connection to ground.
     
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