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Electric motor that was attached to a small turbine

  1. Nov 14, 2006 #1
    Hello all

    I am posting on this site to ask for help with my Theory section of a experimental investigation, below is what I have done so far, my teacher has asked for the theory to be able to be understood by a average high school maths student that does not study physics. The experiment used a small electric motor that was attached to a small turbine, which was moved by running water, hence producing current.

    So if possible can you be most critical, and help me with suggestions of what else to discuss, also can anyone please explain what Magnetic flux is in simple terms?

    Theory

    An electric motor converts electrical energy into kinetic energy. The reverse task can be accomplished by a reversing the operation of the motor. Electrical energy is the amount of work (i.e. force applied through a distance) that can be done by electricity, and kinetic energy is work needed to accelerate a body from rest to its current velocity (speed). In simple terms, this means that kinetic energy is needed to make something move, (i.e. Car wheel) while electric energy is needed to power things (i.e. Light bulb).

    The way that the electric motor can transform the two energies is because of a scientific process named Electromagnetism. Electric motors make use of magnets, which are objects that have a magnetic field; a magnetic field is a region in which magnetic forces can be observed. These magnetic forces exert forces on moving charges; moving charges are everywhere. Electric motors harness this property of magnets, to induce a voltage in a conductor by changing the magnetic field near the conductor. (A conductor is a material which electricity easily flows through.) So, by running electricity through a motor a process known as electromagnetic induction takes place, and the ....


    Any help would be greatly appreciated
    Matt
     
  2. jcsd
  3. Nov 14, 2006 #2

    andrevdh

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  4. Nov 14, 2006 #3
    thank you i will by the looks of it it looks good, but i think i am trying to ask is, WHY is it that moving wire through a magnetic field generates electrical current?
     
  5. Nov 14, 2006 #4
    The magnet moves the electrons inside of the wire, creating current.
     
  6. Nov 15, 2006 #5

    andrevdh

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    A magnetic field is a byproduct of the electric field of an electric charge. It appears when there is motion relative to the electric field generated by the electric charge. This means that one observer can say that there is no magnetic field around a certain charge, while another will say that there is a magnetic field associated with the charge - it is all relative. Guess where the descriptive theory comes from - special relativity - developed by Einstein. A magnetic field is a byproduct of the distortion of the electric field of a charge due to motion relative to it.
     
  7. Nov 15, 2006 #6
    wow

    lol ill need to read that a few times!! Thanks this sounds awesome!
     
  8. Nov 15, 2006 #7
    May I use what you have said? How should I reference it?
     
  9. Nov 15, 2006 #8

    andrevdh

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    No, I am certainly not the originator of this theory! You could just mention that Albert Einstein formulated it in his development of special relativity which he published in 1905.

    Here is some questions to ponder in the meantime:

    1. If a magnetic field arises due to relative motion between the observer and the electric charge how come a stationary piece of metal (a magnet) can display a magnetic field.

    and an evven more puzzling one

    2. Why can only certain materials be magnetized (since all materials contain electric charge) ?
     
    Last edited: Nov 15, 2006
  10. Nov 15, 2006 #9

    andrevdh

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    Some additions to previous post.
     
  11. Nov 16, 2006 #10

    andrevdh

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    Sorry. I forgot that one can only quote sources that one have actually seen or heard. So, yes you may quote me.
     
  12. Nov 16, 2006 #11
    Oh ok thanks, ill will soon post what I have done which is due in tomorrow! Yikes!! And if any one would like to try and help me improve it... hint hint! It would be greatly approached! Also can you find power if you only know the current? I don’t think you can, but if I could it would be good!
     
  13. Nov 16, 2006 #12
    Theory

    An electric motor converts electrical energy into kinetic energy. Electrical energy is the amount of work (i.e force applied through a distance) that can be done by electricity, and kinetic energy is work needed to accelerate a body from rest to its current velocity (speed). In simple terms, this means that kinetic energy is needed to make something move, (e.g. Car wheel) while electric energy is needed to power things (e.g. Light bulb). The reverse task, i.e. changing kinetic energy into electrical energy, can be accomplished by a reversing the operation of the motor.

    The way that the electric motor can transform the two energies is because of a scienfic process named electromagnetism. Electric motors make use of magnets, which are objects that have a magnetic field; a magnetic field is a by-product of the electric field of an electric charge (electric field exerts a force on other charged objects). It appears when there is motion relative to the electric field generated by the electric charge. This means that one observer can say that there is no magnetic field around a certain charge, while another will say that there is a magnetic field associated with the charge - it is all relative. The descriptive theory comes from - special relativity - developed by Einstein. A magnetic field is a by-product of the distortion of the electric field of a charge due to motion relative to it. Hence a magnetic field arises due to relative motion between the observer and the electric charge.

    These magnetic forces exert forces on moving charges; moving charges are everywhere. Electric motors harness this property of magnets, to induce a voltage in a conductor by changing the magnetic field near the conductor. (A conductor is a material which electricity easily flows through.) So, by running electricity through a motor a process known as electromagnetic induction takes place, the axel spins, and the electrical energy is turned into kinetic energy.

    Reversing this procedure, by means of moving wire through a magnetic field generates electrical current. So by reversing the electrical motor you are rotating a coil of wires through a magnetic field. The magnet moves the electrons inside of the wire, creating current. The faster the wire passes through the magnetic field, the greater the current.
     
  14. Nov 16, 2006 #13

    andrevdh

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    Last edited: Nov 16, 2006
  15. Nov 16, 2006 #14
    oh alright thanks again!
     
  16. Nov 16, 2006 #15

    andrevdh

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    Start your project out with a framework - key words or drawings. The organize the key elements into some logical order. Then fill in the meat of the frame work. Since it is a math student you should include some formulas too!

    The power delivered can be calculated if you know the resistance of the load connected to the generator.

    http://www.saburchill.com/physics/chapters/0056.html

    http://www.saburchill.com/physics/chap02.html

    http://phet.colorado.edu/web-pages/simulations-base.html

    Since you are suppose to explain it to someone with limited physics knowledge I would suggest that you build up a glossary of terms : voltage, current, magnetic field, magnetic flux at the end of you project so as not to break the line of thought by explaining what something means. In the text you then indicate that a particular term is explained in the glossary by changing the font of the term to say bold e.g. voltage
     
    Last edited: Nov 16, 2006
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