Lenzless resonant transformer

[verpies]

In this case L3 sees "clockwise" flux through the bottom part of the toroid and "counter-clockwise" flux through the top part of the toroid.  The net flux that L3 sees is zero.

Yes, unless the flux leaves the core.
e.g. this leakage flux will induce voltage in L3 when the L2 counter-current becomes high (as when L2 is shorted).

So in essence L3 is a "nonsense" coil that is illogically placed and does not really contribute to the operation of the magnetic circuit. 
Similarly, when you connect the signal generator to L3 then the toroid sort of acts like a cylindrical core for L3. 
In this case L1 and L2 will barely pick up a signal either, they are stuck in magnetic limbo. 

L3 might not contribute but it does affect the energy transfer between L1 and L2.
If you'd apply a saturating DC to L3 (through a choke in series) then you'd see how the transformer action is affected between L1 and L2 over one polarity of the input AC cycle (the polarity which exacerbates core saturation).

[itsu]

L3 might not contribute but it does affect the energy transfer between L1 and L2.
If you'd apply a saturating DC to L3 (through a choke in series) then you'd see how the transformer action is affected between L1 and L2 over one polarity of the input AC cycle (the polarity which exacerbates core saturation).

But as we have no transformer action going between L1 and L2 (the 2 200 turn coils), this can not been checked.
Or do you mean when also injecting a signal in L1?

Regards Itsu

[verpies]

In the last experiment you drove the L3, so indeed direct transformer action between L1 and L2 is not applicable.
However, if L3 is driven hard enough so the current through L3 is sufficiently high to cause saturation of the core, then its differential permeability will be modulated and any LC tanks formed by L1 or L2 will be excited parametrically by the varying inductances of L1 and L2.

Nontheless, if the L1 is driven with AC then a transformer action will exist and when a saturating DC is applied to L3 (through a choke in series) then it will affect the AC power transfer from L1 to L2 through the modulation of differential permeability and the magnetic coupling coefficient.

[itsu]

In the last experiment you drove the L3, so indeed direct transformer action between L1 and L2 is not applicable.
However, if L3 is driven hard enough so the current through L3 is sufficiently high to cause saturation of the core, then its differential permeability will be modulated and any LC tanks formed by L1 or L2 will be excited parametrically by the varying inductances of L1 and L2.

Ok,  i put in more power into this L3 coil using my MOSFET power amp., and it now shows the resonances of the secondary coils again around 85KHz.

Not sure if it has saturated the core, but allthough the PA and transformer used are not designed for 85KHz, it made the resonance of the secondary coils reappear again.

Video here:  https://www.youtube.com/watch?v=41eEfFJMd0Y&feature=youtu.be


Regards itsu

[Magluvin]

Am I missing something. Jacks last pic posted, seems to have bifi windings for 1 and 2, but I only see single wire on Itsu coil posted just before that. 

Mags