Tinman, those wirewound "cement" power resistors will be introducing phase shifts and also false amplitudes due to their inductance. They really aren't suitable for use as current-sense resistors in measurements where phase and precise amplitude is important. The long ground-clip leads on the probes will also affect phase and amplitude. For more accuracy, it is recommended that you use real, non-inductive resistors and connect them as "kelvin probes" as closely as possible to the body of the resistor. I think Poynt99 has some videos on this subject, as do I.
These effects may not be so great at your low frequencies but it would be nice to see some comparative testing, to see how much shift is caused by the resistor inductances alone.


http://www.youtube.com/watch?v=-a1plHZwmWg

Below is a picture of my setup,and associated components.

My P/in is from a transformer running from main's,so the frequency is 50hz.
The voltage and current are slightly out of phase on the primary(voltage leading of course),but both are in phase on the secondary. The secondaries voltage and current phase are in phase with the voltage across the primary coil,but lead the current phase on the primary coil 

The scope shot in the background shows the current trace on both the primary(blue trace),and the current on the secondary(yellow trace). As you can see,even though the wave form is distorted due to the transformer being unable to supply enough power,that the current on the secondary is leading the current on the primary-some how.

@Tinman - I agree with partzman - It appears your Core is in Saturation.

If you want to see some very interesting results from this area of expertise, then if I may suggest a very simple experiment that I can not recommend highly enough! The Flux Gate Magnetometer!!!

URL: Flux Gate Magnetometer or Solid state Generator?

I think this was my most interesting Experiment from the early days! Yes it does Generate Electricity, from Moving Fields! Its NOT OU but its a very worthwhile experiment all the same...

   Chris Sykes
       hyiq.org

P.S: Anyone paying attention will see that there is an error in this video clip: https://www.youtube.com/watch?v=fjEcmMT-GSs

P.P.S: Some of my terminology is not correct, unfortunately. Saturation should be Reluctance, or Magnetic Gating of each Leg of the Core.

Been putting the ideas for the toroid tests together before I decide how i want to wind it. Going for low power and low freq, up to 20Khz.   The hall sensors I kinda worry about as the leads will be subjected to induction, but probably not an issue being all 3 leads are parallel and all would be induced in the same direction, hopefully cancelling out any interference there.

The thing is, Im not seeing any real good foundation that it is the E field that poses the induction between the pri and sec. Too many things dont make much sense. If the E field circles around the core, then an outside coil that has its winding against the core should be induced just as if the coils windings were in the core, with both cases the rest of the large outer coil being far away from the core. The inner coil producing currents in one direction and the outer producing currents in the other direction..  Where when we consider the idea magnetic fields of the primary cross over the hole of the core to complete the magnetic loop in the core is much more of a possibility. 

In my experiences over the years, I find that magnetic fields are always in a loop. Whether they are distorted, stretched or flexing, there always seems to be a path back to the other pole. I have a strong feeling that if you had a hollow sphere of magnet material that were magnetized S in and all N out that the N field might not be present outside of the sphere, as the all S in would force the fields of the material to cancel out by giving those fields nothing more to do than loop back within the material itself, being there would be no alternative path for the loop to exist. If the spher were made of pieces, the path would be between those pieces, as could be seen with magnetic film.  If the solid sphere were imperfect, then there would be N patches and S and neutral patches.  So making one would be mostly an impossibility.


Considering the horse shoe core vs a rod core, is it not easy to understand why the fields of the coil wound around the U of the horse shoe core would tend to have the fields loop back to the other pole mostly through the space between the 2 legs of the U core?.  So it should not be hard to understand how the fields of the primary can traverse across the hole of the toroid and 'cut' the secondary windings, thus producing currents in the secondary.

Now consider if we put an outer coil with a portion of its windings against the outer part of the U where the core windings are. Will it be induced there? And if we put those windings of the outer coil through the inner side of the core winding, as if it were in the toroid, it will have induction.


And if a hall sensor picks up say a 10khz mag field change in the hole of the core, would that be a false reading??

Mags

Tinman, those wirewound "cement" power resistors will be introducing phase shifts and also false amplitudes due to their inductance. They really aren't suitable for use as current-sense resistors in measurements where phase and precise amplitude is important. The long ground-clip leads on the probes will also affect phase and amplitude. For more accuracy, it is recommended that you use real, non-inductive resistors and connect them as "kelvin probes" as closely as possible to the body of the resistor. I think Poynt99 has some videos on this subject, as do I.
These effects may not be so great at your low frequencies but it would be nice to see some comparative testing, to see how much shift is caused by the resistor inductances alone.


http://www.youtube.com/watch?v=-a1plHZwmWg

I have used my SG to drive the transformer,and even at 10 MHz i get no distortion across the resistors or transformer. I can produce a very clean sine wave up to this frequency on both the primary and secondary coils. Of course we are at much lower power levels than that scope shot you see in the pic of my setup.

'If' it is the E field that induces other conductors from the primary, and the E field is circling around the core, then what would be the difference between the 2 depictions below??  Would the inner conductor be induced(as we know it is) and the outer not be induced?

Mags

That is correct Mags. Once a wire goes through the center of the toroid, it has to loop all the way around eventually. So this constitutes a single turn secondary.

If you simply place a wire or coil against the outside perimeter of the toroid, there is no secondary that is formed. The wire or coil has to be exposed to the full loop of the E field. And it doesn't have to be a perfect circle, as you saw in that video Tinman posted a link to. As long as the wire completes at least one loop around the core.

Ultimately, yes. The B field is produced by the primary current, and the B field (through the core) induces the E field. I've been trying to solidify this for a couple pages.
Why not? Doesn't the primary voltage lead the primary current?

Because it is the current in the primary that creates the E field-not the voltage across the primary. So if it is the E field that is causing the EMF in the secondary, then the secondaries EMF shouldnt appear before the primaries current, as it is the primaries current that causes the E field in the first place-not the voltage.

OK-you lost me...

You're right of course. I think I understand the need for the diode on the primary now.
Don't hate me for saying this but now I'm not sure I understand why the secondary benefits from a diode. Is it the same basic reason as the primary?

If not I tried to come up with a reason shown in the image. Basically I see the secondary being cut by two different magnetic poles at the same time, which means two apposing currents are flowing, which is bad, so we need to cancel one out. I see the secondary coil being cut by the flux from its own core, and I see the secondary coil being cut by the primary core which are different polarities. If we stop current from flowing in one direction then we have effectively cancelled the effects of one pole. So the secondary coil turns into a N from being cut by its own core and stays an N.

 My dog gets a hard life!