Magnetic fields within a toroid inductor.

[Dave45]

Been playing with my setup, Im not getting a very good coupling between the toroids and the pickup coil,  perseverance

I may hit it with some high voltage just to see if I can get liftoff 

[Magluvin]

And AC current.    60Hz is no problem for many Hall sensors.

Absolutely ac and dc. I just never knew it was a hall sensor. I figured wire wound pickup can read ac, but how dc?  I suppose it could be possible that a pickup coil used in a clamp could measure dc current if the pickup coil had an imposed ac signal(small as not to affect the circuit being measured) and the meter circuit monitor the differences between the pos and neg portions of the signal. DC produced field in the clamp core would polarize the meters ac signal as it tries to induce the clamp core. But the hall is much easier.

Mags

[Magluvin]

Opened another older controller box and it had 2 of the same current sensors. Both boards have a very strong conformal coating, so removing parts is a bit of a chore. Dont want to break the tiny leads of the hall sensors. Only removed 1 from each board, and only one of which I could read the pt no. 3503u. Data sheet below.

Says tested from 0-23khz, then typ is listed as 23khz.  So Ill check that to see if thats the limit.

If we want to read field in the hole of a core, and had bridges as shown below in the core, then I put the hall sensor in the gap, up and down reading, would there be any field measured by the hall? And what if the gap is shorter? What if the gap was longer? I believe we are going to find that flux propagates across the hole of the toroid core and is not 'just' locked in the core.

Now if this is where all or most of the mutual inductance between windings, in the hole, then what of the parts of the winding on the sides and outer diameter of the core? And would those parts of the winding be more included if the toroid were encased in a shell core? These are some questions I have with all this.

Mags

[Dave45]

I wasnt getting a good coupling between my toroid coils and the pickup coil, because the pickup was not part of the magnetic path 

Been thinking about the tpu
I think he figured out a way to stop bemf, turned it into femf

[Dave45]

So I hooked the Rodin type toroids to the zvs circuit, I am able to dimly light a 12 volt auto bulb from the pickup coil