Magnetic Induction Measurement, need help ...

[Guest Gazeeeb]

Hi all,

 

I would like to know if I am crazy, or not. I hope to determine if it is possible to transfer kenetic energy by dropping magnetic core material (speed of gravity) through an energized coil. Any way to develop equations to measure voltage induced?

 

I am thinking large. Imagine a series of coils of 100 foot, or 1000 foot, or 5000 foot - How much voltgae could be induced? The idea is that more volatge would be induced with higher altitude and the acelerated speed of gravity.

 

I would like to see if I could use this as a interesting scientific disseration topic.

 

I know many factors need to be considered. number of windings in a coil. size and material of magnetic core. I would like to use reasonable approximations if possible.

 

Any help or encouragement would be welcome.

 

Thanks in advance.

[Ollie]

This kinda reminds me of a current balance experiment I performed a couple of months ago. Two magnetic fields (generated by coils) at right-angles to each other. One is fixed to one end of an arm of length l with a mass at the other end, you get:

 

I^2=mgl(2a1)/{(mu0)(n1)(n2)(A2)}

 

where I is the current flowing through both coils (they're connected), a1 is the radius of the larger coil (it was oriented with its direction vector pointing off to one side in our experiment, or maybe "forward", I forget), n1 and n2 are the numbers of turns on the coils and A2 is the area of the smaller coil. By adding mass, the smaller coil is forced to rotate in one direction, but the opposing magnetic fields generated by the current resist this motion. By tweaking the current until the arm was horizontal again we could check the current predicted by the above formula with that oberved. Typically the current we observed was in the rage of 1 to 4 Amps.

 

While this set-up itself is not quite what you're looking for, it's something to consider.

[Klaynos]

Oh! I remember that experiment wrote my end of module report on that one heeh

 

There are formulae which can tell you the induced current created in coil of wire, this requires you to know the B field of the magnet which you are putting through it.

 

Unfortunatly someone has "organised" my EM notes so I might not be able to give you the full picture...

 

You'll be wanting to use Faraday-lenz Law

 

http://en.wikipedia.org/wiki/Faraday%27s_law_of_induction

 

http://en.wikipedia.org/math/6f958596c8e25f96f7d429f8937fcc65.png

 

is the specific formulae which you will find useful where V is the induced EMF on the coil, N is the number of coils and dphi/dt is the rate of change of flux.