Quote from: TinselKoala on April 17, 2017, 04:08:17 PM
Very nice result on the frequency scan. Your coil's parameters are very similar to mine, and that's great as our results can be more easily compared.

See MH's drawings for how the field "circulates" around the windings and thus around the whole disk, like a big torus or donut in space. With a big enough disk the lines would actually be parallel to the disk surface over much of the disk, only becoming orthogonal at the edge and at the hole.


But what about the results I posted earlier where I show that there is still plenty of induction, hence plenty of alternating magnetic field,  going on even when the current sensing resistor voltage indicates no voltage across the resistor?

Yes,   working on that too, need another pickup coil first.

Perhaps thats the secret of the TBP coil right there 

Itsu

Quote from: itsu on April 17, 2017, 04:07:15 PM
Hi Mags,

no it is like my (and MH's) drawing above, when skimming from top to bottom (TBP coil vertical like my earlier picture) from the upper edge to the middle hole we see a increase/decrease of strength, same with the next part after the hole (no changing of the Hall sensor) increase / decrease until the lower edge (opposite direction detected)

Hope that is clear   


Itsu

Are you testing each area with the hall in the proper orientation as shown below for each section of coil?  Im just showing half for illustration. I left the hall diagrams at the top incase you want to show otherwise you can plug them in.

Because if you are going around the outer edge with the hall in the same orientation as it is above the flat side, then you will show less flux strength at the outer edge because the hall is 90 deg of the flux.


Mags

The "red" and "blue" assignments are incorrect!

Hold the Hall sensor parallel to the plane of the disk and travel all around the disc's edge, keeping to the plane of the disk. You will see that the polarity does not flip, as it would if the colors were correct.

@Tinselkoala,

Here's another Amos and Andy explanation below:


"The "negative" sign on your ammeters is there to show you which way the current is flowing, not to indicate the existence of your imaginary current".

Negative current is positive current moving backwards.

You admit to switching current direction, but you object to calling the reversal a reversal of polarity.

QuoteAre you testing each area with the hall in the proper orientation as shown below for each section of coil?  Im just showing half for illustration. I left the hall diagrams at the top incase you want to show otherwise you can plug them in.

Because if you are going around the outer edge with the hall in the same orientation as it is above the flat side, then you will show less flux strength at the outer edge because the hall is 90 deg of the flux.


Mags

Ok,  i see what you mean,  no i just sweep from one side to the other in a straight line.
When doing it your way, i have the most strength in the center at the hole, not at the edges.

If you can combine the drawing from post #1014  (http://overunity.com/17186/the-bifilar-pancake-coil-at-its-resonant-frequency/msg504697/#msg504697) with the below
one, you might get the picture.


Itsu