Magnetic fields within a toroid inductor.

[xee2]

TinMan,
The coil around half of the core has less wire than the coil around the entire core, thus there is more capacitance between the windings in the coil around the entire core. This capacitance creates a parallel resonant circuit with the coil inductance. As the coil goes through self resonance the voltage across it increases. As the frequency goes beyond resonance the reactance goes from inductive to capacitive which is what produces the phase shift. You should be able to see the self resonance of each coil by increasing the frequency until the voltage peaks. In your video it looks like the blue coil peaks at a lower frequency than the other coil. This gives some more information about self resonance >> http://www.cliftonlaboratories.com/self-resonant_frequency_of_inductors.htm

[tinman]

Hi xee2
The three coils are of tha same length of wire.The coil wound around the half core has more turns that the two around the whole core-but the lengths are the same,as i cut all three lengths side by side befor i wound them.
It wasnt to show anything speacial,just sharing an experiment i did to see what would happen.

[xee2]

Hi xee2
The three coils are of tha same length of wire.The coil wound around the half core has more turns that the two around the whole core-but the lengths are the same,as i cut all three lengths side by side befor i wound them.
It wasnt to show anything speacial,just sharing an experiment i did to see what would happen.

Then it may be that the capacitance of both coils is the same. But the inductance of the coils is most likely different. However, if you look at the charts in the link I referenced, you can see how the phase changes as the frequency goes through the self resonance of the coil. I think this is the phase change you are seeing.

[Magluvin]

Just got finished with my lasersaber motor. Still working on my dual reed switch holder, but have made a single to mess with in the mean time. May get out a vid tomorrow. 

Should have my linear hall sensors this week hopefully to do some tests on a wound toroid.  I want to test one that is wound all the way around and one that has a primary on one portion and a secondary on the other.  I can imagine that if there are fields in the hole of the toroid, if wound all the way around, fields, or say flux will be coming from all the turns at the same time from all angles. So it may read neutral in the center, but more the closer to the inner windings. But, if I wind primary to the left and sec to the right, and still get a neutral enter, I should get a difference from left to right and up and down from center. At least these are my ideas on testing this and anticipated outcomes, possibly.

But one of the reasons Im even writing this is some thoughts I had on other test. Lets say we have 2 toroid cores and wind them the same. Then use a ferrite rod through the toroids centers like an axle with wheels. I wonder if input to one would induce the other? Just thinking. If we can run 1 wire through the toroid, equal to 1/4 turn, really, and get output from that wire, then why not see if we can draw out any flexing fields from one core to another via an axle core.  Also, how would a core in the hole of a toroid affect the toroid coil function, or value. All things to try.

Tinman. Nice idea on the home made split core with windings inside the core.    I have thought of that before but never tried. I have seen parametric transformers that seem similarly buried in the core in relation the other winding.

So the buried coil has less output compared to the outer secondary. Well, only half the length of its inner windings, being they turn into the core half way, are available for induction in the hole as compared to the other secondaries inner portions of its winding as they go all the way around.  Even though there are more turns on that other secondary, Im sure it is not double the outer turns, and the difference in output is not half either. So it may be that you are showing some possible proof of what I was saying about all the action is in the open area of a toroid.  Maybe not. But it sure does fit the ideas possibilities.

Now, what would really kick off some brain cells is to cut the kids toy 90deg from where you cut the first mold for your core so that you have an outer diameter part and an inner diameter part. lol, just thinking of this as I write and I need to get to bed, but... 

Now, when you cast your parts, if there is a way to create a gap, so the parts could fit with windings through the gap, then, wind a coil on the outer diameter part, then wind the inner diameter part then apply more JB weld or what ever mix your using to glue it together, Then wind a primary over that.

What will be interesting is which secondary, the inner or the outer will have what output. It would be funny if the inner had more, especially considerably more.

Nite

Mags

[Magluvin]

Hey Tin

Below is an illustration of how I think it should be wound as to isolate the windings from each other to eliminate winding to winding proximity and to let the core do its thing.  If we wind primary directly over the secondaries, the secondaries will surely get induced by the primary directly as the flux from the primary is attracted to the core, cutting the secondaries along the way. This might not show us exactly what we are looking for, which is how the primary flux engages the secondary using the core as the path from the primary to secondary. Also having 2 secondaries wound on top of one another may affect the outcome because they share the area in between the cores.  So isolating them from each other should give more definitive results as to what is going on with the core being the only connection(magnetically) between windings.  Then fill in the gaps in the 2 cores with your liquid core material. Hope that makes sense. 

Also, no need for many windings. I would do 10 turns for each and just 1 tight layer each. Just use a current limiting resistor, non inductive, in series with the primary to accommodate signal gen capabilities.  Results should be as good as many turns without all the work.  My soundstream amp uses 3 turns of 6 parallel wires for a primary and it works great. And thats at 60khz. But play with the freq all you want.
Mags