Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electromagnetism and Clean Energy

  1. Jun 23, 2014 #1
    Hey, currently I am a high school graduate going into college in the fall, but that isn't why I am here. There has been this question eating at the back of my head. Is there some way to induce an electromagnetic field, that could then induce a current in a wire or other some such medium, to power back into the field with enough left over to power of appliances? I understand that the question borders on perpetual motion machines, as well that may be what I am asking for. It is just that with my limited knowledge of physics I have some hope that there is a way to do this. If not, be so kind as to let me know and explain to me why. If there is, post a link to where I or others may find more information on this. Thank you for your time.
     
  2. jcsd
  3. Jun 23, 2014 #2

    Matterwave

    User Avatar
    Science Advisor
    Gold Member

    You can certainly induce E-M fields using currents. And E-M fields can certainly induce currents. But you have to get the energy from somewhere.

    Energy is conserved, that is one of the major tenets of physics. As such, in order to perform work, you have to supply the energy to do so. In other words, in order to drive a current through my wires, I will have to perform work. I can't make the currents move arbitrarily. You can perhaps look at the basic principles behind an electric generator: http://en.wikipedia.org/wiki/Electric_generator
     
  4. Jun 24, 2014 #3
    If I understand your question correctly, the answer is yes, but remember that energy is conserved. You could certainly create a situation where you power an appliance and also partially replenish the original EM source fields. However, you could never fully replenish those fields because that would violate conservation of energy.

    In most cases, I can't see why you would want to do this. The process of "replenishing" the field isn't going to be 100% efficient, so you're pretty much just creating an energy-wasting loop. It's almost like collecting some of the water from your shower and feeding it back into your hot water tank to replenish the hot water tank--all that water will just lose heat energy while it travels back to the tank, and you'll have to waste energy heating it up again. You would be better off just turning down the tap on your shower.
     
  5. Jun 24, 2014 #4
    This is a question commonly asked by people contemplating a form of "leeching" by people who live near very high voltage towers. I've never seen this actually done and suppose the height of the towers, the distance away from the lines and the inverse square law preclude it's effectiveness. I would like to see the Math though.
     
  6. Jun 24, 2014 #5
    IIRC, Mythbusters tried this and found out that it was impractical. Theoretically, it's possible, but you'll need a lot of loops of wire, and you'll need them to be pretty close to the lines, which means you'll be building a big tower right beside the power lines to mount your inductive "collector" on. At that point, you might as well just tap into the power lines directly.

    In the context of this thread, it's worth noting that whether you tap in directly or use a crazy inductive coil system, it looks pretty much the same on the power company's end. They just see that one of their lines is losing power when it shouldn't be. There's nothing magical about electromagnetic induction, it's just more complicated.
     
  7. Jun 24, 2014 #6

    berkeman

    User Avatar

    Staff: Mentor

    Welcome to the PF.

    What you are asking about amounts to a Perpetual Motion Machine (PMM) or "Free Energy". Both are banned topics here on the PF. (See the PF Rules under Site Info at the top of the page)

    Please follow the links in the Rules to learn why PMMs and Free Energy do not work:

     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Electromagnetism and Clean Energy
  1. Electromagnet energy ? (Replies: 5)

Loading...