Coil Tests / Experiments

[Jim Mac]

This is just a little experiment, to see if I can duplicate this magnet setup in a coil..

When we place a small ring magnet inside a larger ring magnet, we get 2 opposite and distinct poles on each side..  And I am sure we all seen the videos of this configuration causing magnetic locking..

   

In this magnet setup,  the inside is North and the outside is South..  So we have 2 poles on either side, making 4 poles.

Can this be done with a coil?

I will find out. I will use a flat bobbin that is like a pancake coil.  It will not be only 1 layer though, but much wider than height.  I will start winding a few hundred turns 1 way, then reverse and wind the outside the other way.  

The aim is to simply see if it will mimic the magnet setup.  If it does, I have some tests I plan on trying

Excuse the crappy drawing

[Jim Mac]

Here it is.  100 turns 1 way on the inside and 100 turns the opposite way on the outside.

   

It does indeed exhibit interesting properties.  It does act like the magnet inside a magnet arrangement where the center is 1 pole and the outer circumference is another pole when powered with DC.

I also hooked it to my scope and did some induction tests.  it does induce a sinewave when passing a magnet over it.  But the Outside winding direction dictates the induced current direction.  Which is interesting.  

I don't want to speculate yet,  but using a magnet smaller than the inside direction coil and reciprocating in the center produces a wave that is identical to as if the whole coil was wound in the direction of the outside windings.  Hinting that the center portion (which is wound opposite from the outside) responds from induction with a magnetic field that is opposite that of a standard coil. Where the outside responds normal. 

And powering this with AC to induce a separate coil is also doing something interesting.  I will expand more later