The Secret To The Self Oscillating Transformer

[sm0ky2]

if he is resonating at 60Hz, I have to assume the entire circuit is not at resonance.
they may all be operating at 60Hz, but a coil with a 60Hz self-resonant frequency...
would be a copper wire something like 5 million meters long......

If it is in resonance, its hitting on a node, not the full wavelength

in a truly resonant circuit, all components, coil(s), inductor(s), capacitor(s),
are designed to be self-resonant at the operating frequency.

This is a good read, not all of the information here is applicable to us,
as this was written for radio-builders,
but if you want to understand how resonance affects your circuit,
This will give you everything you need to know. Also there is reference to a useful piece of software.
http://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qex/2001/09_10/page33/index.html

[Just..Sayin..]

I think it is worth repeating, to keep would be experimenters encouraged, Floyd Sweet's first self oscillating transformer resonated at 60 cycle, Steven Mark's transformer resonated at low frequency which must have been in the neighborhood as he ran a drill... and resonance surely has to be the prime component of the Kapandaze device that draws electrons out of the earth.

[ayeaye]

What i think. Resonance in the core should not depend on the dimensions or shape of the core, only the magnetic material of the core. And it should not depend on the resonance of the coil or any external components. It should be some frequency, and multitudes of that frequency. The signal should most likely be sine. It can be though that some higher harmonics of the signal cause resonance. All i can think, it should be some very exact frequency, somehow related to some properties of the atoms. At that, this frequency may slightly vary even in the cores of the same type, due to slight differences of the magnetic material. It cannot be 60 Hz, as then it did appear in most transformers in everyday use. I think it should be much higher. At 60 Hz, it may be caused by some harmonics. This is likely not the same as the resonance of a coil or a capacitor, and has nothing to do with it. The only way i think to find that frequency, is to smoothly increase the frequency, but then the approximate range should be known. All i can think.

[Just..Sayin..]

I just ran into an interview with Jack Durban re the Steven Marks device that I never knew existed. I just excerpted the follwoing from the interview and post here for the benefit of those who have not heard it. Jack worked with Steven Marks early on in the project and visited with him approximately ten times at the mansion Steven was working out of. At this period in time Steven was not yet successful in powering inductive loads such as motors and is the time when Durban parted company with him. But did power inductive loads shortly after.

One of the first things Jack makes clear is that the torroidal design had absolutely nothing to do with the function of the device. He also says it was not Steven's design and that it reminded him of an early Tesla patent. Durban was a Tesla fan.
"I was part of the family and he was even careful with me, because I think, that he could tell that if I had just had enough time with the unit and could take it apart or help him build one, that I would discover just how simple the technology really was.

Most everything in the device was purchased at Radio Shack. A Reed switch, a magnet and a couple of other components. There was a large polypropolene Cap and a choke that were sitting on top of the large 15 inch diameter unit. It is not a very complicated device, it is just very  complicated to get working properly. The winding of the unit was very laborious... output levels could be changed based on ratios and things like that... a very elemental, fundamental device, not very sophisticated... just unstable and difficult to tame... he was not a very intelligent guy... I see the deification all over the internet, but this is not the kinda guy that invented this device, he came across it somehow and tried to make it work as a tinkerer... Steven was very paranoid as this device was not that difficult to figure out.... he did not want anyone looking over his shoulder or he would become instantly obsolete... this guy was not a technical person, just a tinkerer... that also goes to the simplicity of this device... Question... how did he cloak it so that people couldn't tell what he was doing? I am glad you asked... one of the tricks that he employed that I thought was rather amusing, was using a magnet to drop into a little receptacle that would cause the device to come to life, and all that was was a reed switch that was inside the receptacle.... he went to a lot of lengths to wrap the coils with electrical tape... the unit I was most familiar with was the large unit... it was not that complicated... you would think that there was mosfets and all kind of triggering relays, but there is none, there is no solid state technology.... I do not think that Steven knew which end of a diode to use where...

The full interview...  https://www.youtube.com/watch?v=tPuhI03ZMR8

[sm0ky2]

What i think. Resonance in the core should not depend on the dimensions or shape of the core, only the magnetic material of the core.

Not correct.  The material properties DO play an important role, a coefficient of the specific material is part of the equation.
but the physical Dimensions are precisely what determine the resonant frequency of the core.
If you are using a manufactured core, the self-resonant frequency is provided by the manufacturer.

And it should not depend on the resonance of the coil or any external components.

Not correct. The self resonant frequency of the coil SHOULD be the same frequency (ideal), or a multiple or divisor thereof.

It should be some frequency, and multitudes of that frequency. The signal should most likely be sine.

Yes, exactly.   And, not always Sine, though in a "round" wound coil, it is often the case, but only when every component is operating at a resonant node, with respect to the system as a whole.

It can be though that some higher harmonics of the signal cause resonance. All i can think, it should be some very exact frequency, somehow related to some properties of the atoms. At that, this frequency may slightly vary even in the cores of the same type, due to slight differences of the magnetic material. It cannot be 60 Hz, as then it did appear in most transformers in everyday use. I think it should be much higher. At 60 Hz, it may be caused by some harmonics. This is likely not the same as the resonance of a coil or a capacitor, and has nothing to do with it. The only way i think to find that frequency, is to smoothly increase the frequency, but then the approximate range should be known. All i can think.

or one could use the manufacturers specs for the inductive core (or available data for air cores),
then calculate the dimensions, thickness, length,etc, # of turns, diameter, and everything
for a coil that is self-resonant at that frequency.

If you cannot physically create a coil to match the self-resonant frequency of the inductor,.....
  Then a coil tuned to a lower octave of this frequency will be self-resonant with the core, at that node.

Steven Marks talked about this extensively.

and you are right, the torroid shape has nothing to do with the effect.
a "TPU" could be build using a cylindrical inductor or any other type.
though you may have to call it a "CPU"