Thanks Lou, that is a fascinating toy. It supports my thoughts that the energy of the initial field is reduced when more iron is brought into contact with a permanent magnet. Until I realized that the COE would force the external field to eventually go away, I was actually considering that the extra iron would extend the field due to the increase in size of the net device.
Now I will apply this knowledge in an effort to understand some of the magnetic motors that keep showing up. My current beliefs are that they are not well understood and not over unity. Dave -----Original Message----- From: pagnucco <[email protected]> To: vortex-l <[email protected]> Sent: Mon, Jan 21, 2013 10:34 pm Subject: Re: [Vo]: COE and Magnetic Field Question David, The following paper presents (literally) a toy example of extracting energy from a static magnetic field: "A Magnetic Linear Accelerator" http://www.physics.princeton.edu/~mcdonald/examples/lin_accel.pdf It provides a simple formula illustrating conversion of magnetic field energy to kinetic energy. While it does not completely answer your excellent question, it's a starting point. -- Lou Pagnucco David Roberson wrote: > Recently I have been exploring magnetic concepts. I have been seeing so > many references to magnetic motors that I believe are not possible, but > they keep coming so I decided to perform some thought experiments. Let me > present one that is somewhat associated with the motor concepts. > > > All I ask is that you give it some serious consideration and post what you > think the results should be. > > > Take an iron rod and wrap a coil around it. The rod is initially not > magnetized. > > > Apply a voltage to the wire for a short period of time that allows enough > current to flow to result in a permanent magnetization of the iron rod. > > > Now, if you are very good at measuring energy, you would be capable of > directly measuring the input energy supplied by the voltage source. > Record this energy for later reference. > > > At this point in time, the rod maintains a magnetic field that contains a > certain amount of field energy and heat has been given off due to losses > within the wire and due to mechanical effects within the rod, etc. > > > I would assume that we would now have a direct measurement of the energy > stored within the field so it is time to make it do some work. > > > Take a large collection of iron pellets that are not magnetized and work > with them one at a time. Attach a scale to the first one that records the > attraction force between the magnet and the iron pellet. Allow the pellet > to slowly approach the magnet while you record the force applied. > Integrate the force times distance to arrive at the work performed by the > action of the field upon the pellet. > > > Now, continue to add pellets one at a time while your record the work > performed upon each one. Continue this operation until either one of two > things happen. The first is that there is no more force available to do > work on additional pellets. The second is that you run out of pellets > after a large pile of them is attached to the magnet. > > > The question becomes: Does the external field become zero just as all of > the energy applied to generate it by the voltage source less losses is > exactly equal to the work done on the pellets? Or, does the net energy > supplied by the pellet motion end up as some fraction of the initial field > stored energy while leaving some if not most of the field energy intact > but contained within the pile of iron? Or, would you suspect that the > field would never cease to supply energy to additional pellets since it > expands due to the extra iron? Any other possibilities? > > > My bet is placed upon the second condition. I would expect the > COE(conservation of energy) to limit any work that can be taken from the > rod to a value that is less than the initial field energy, but that much > of the field would be left contained within the iron pile. > > > What do you others think will happen? Can we obtain infinite energy with > such a system? > > > Dave >
