Acoustic magnetic generator.

[itsu]

Generally that's a good arrangement because as the piezo expands and shrinks the two rods constitute symmetrical counterpoises to that motion ...on both sides of the piezo.  What's are the lengths of these rods anyway?

In order to get a clear visualization of the acoustic standing waves forming in the ferrite rod, that are not affected by capacitive and magnetic sensing artifacts, please take a Dremel tool with a diamond wheel and cut a small groove in the rod as shown here.
Fill the groove with fine dry sand and observe as the sand collects at nodes of longitudinal standing waves, as you vary the piezo drive frequency.
BTW: use some kind of a linear slide to guide the Dremel tool (or the rod) in order to grind a straight groove of constant depth.

Please do not skip this node visualization tool.

The present rods are 200mm by 10mm, the new ones will be 200mm by 20mm.
I did use some sort of container taped around one of the rods filled with table salt (see picture), but no movement was observed at all.
Could be the salt is to sticky or somehow no resonance was taking place during this initial test.

Yes, PA+IMT should be good for that purpose.

I used my PA in the following clip (changed the setup a little too), but this limits the frequency range till about 60KHz which could be a problem.
I was able to input >300V pp into the piezo without seeing anything special.

https://www.youtube.com/watch?v=BGrgsJCRVe0&feature=youtu.be

That's clever but the magnets will cause acoustic reflections due to the discontinuity in the speed of sound in them.
Also note that NdFeB, SmCo and AlNiCo magnets are electrically conductive and thus no good at HF because eddy currents form in them - they act as shorted turns at HF.

Ok,  need to remove them somehow then. 
For the new rods i have some clamps which might fit which will push them against both sides of the piezo. 

A narrow coil is fine for detecting permeability and flux changes in the rod, however before you start trusting that coil as an AC field sensor you should determine its LC resonance frequency because this coil will have a lot of interwinding capacitance which will form an LC tank with its self-inductance.
Once you determine this LC resonance frequency, you should remember not to trust this sensor coil at this frequency.

Also, note that the piezo can be a source of intense AC electric fields, that can capacitively couple to various sensors and scope probes.  Use idle scope probes to feel around the piezo to determine how much of a capacitive coupling problem you have.  If it is obnoxious then shield the piezo and its clips/wires with grounded copper foil (without touching the piezo or the ferrite rods with the foil).

Right, good point i will try to find its LC resonance frequency.
With the PA (>300V pp) there was a noticeable ac field which i could feel with my finger when touching the piezo.
This touching caused a greater response in the pickup coil, also when touching the pickup coil (to move it), there is a big influenze on the amplitude of the signal (increase), which somehow does not seem right.

The author of this patent does not mention NAR.  He mentions only the Villari effect.  Maybe this device inadvertently causes NAR if it is subjected to an accidental magnetic field at a 90º angle.

General advices:
1) Remember to pay special attention to any frequency doublings (I think your video showed it at one point)
2) Even a paper-thin air gap in a magnetic path can easily increase its reluctance by 10x.
3) Remember that the differential permeability of permanent magnets is close to air/vacuum and because of that permanent magnets not make good AC magnetic flux guides.  Even high permeability magnetic flux guides do not function well if they are gaped, thin or if the width to height aspect ratio of the flux path exceeds 1.5:1.

Thanks, i did change the layout of the permanent magnets so they form a continuous path now, see latest video.
When i use the formule V/(2*L)=F from the patent and using 5000 m/s (v) for the ferrite used (20cm), i calculate a Frequency F of 12.5KHz.
But no response seen on that frequency yet.

On my first clip user "attikanagy" responded with some similar experiments with even more simple components (postcard speaker) everybody can collect.
He seens to be able to light a led, see: https://www.youtube.com/watch?v=qauZ4WBwAOM


If i stepped on any toes for misusing this thread, please speak up, i will gladly open another one for this.


Regards Itsu

[verpies]

I did use some sort of container taped around one of the rods filled with table salt (see picture), but no movement was observed at all.  Could be the salt is to sticky or somehow no resonance was taking place during this initial test.

Yes, salt never worked for me either.  Eventually I had success with aquarium sand that I got in a zoo/pet store as well as sieved abrasive powders from a hardware store.

I found that for sensing longitudinal waves, the sound's amplitude and longitudinal friction should be maximized.
The exaggerated cross section of a grain of sand in a groove, illustrates this.

[verpies]

Thanks, i did change the layout of the permanent magnets so they form a continuous path now, see latest video.

A semicircle would be better. because of a shorter flux path and less leakage flux due to larger distance from the ferrite rod.

The diagram below illustrates the leakage flux of an inferior rectangular path.  Your rectangular flux path is much wider than higher, thus much more susceptible to such leakage.

[verpies]

When i use the formule V/(2*L)=F from the patent and using 5000 m/s (v) for the ferrite used (20cm), i calculate a Frequency F of 12.5KHz. But no response seen on that frequency yet.

The formula is correct but the speed of sound might not be because for long thin rods you should use the slower extensional speed of sound.

On my first clip user "attikanagy" responded with some similar experiments with even more simple components (postcard speaker) everybody can collect.  He seens to be able to light a led, see: https://www.youtube.com/watch?v=qauZ4WBwAOM

Yes, this effect is real.  Note that he tunes his standing wave frequency less coarsely than you
Also he does not have a counterpoise in the other side of his piezo which is bad - it limits his amplitude.

[synchro1]

Wrong! You're looking at two axially magnetized spinning disk magnets

Please keep the discussion coherent and at a decent debating level.
He wrote "radial" - not "axial".
...in a Faraday Homopolar configuration.

There you go again.
He wrote "synchronous", not "Homopolar"
The magnetic fields are stationary.

Why are they stationary if their sources are non-uniform and moving?
Anyway, Milehigh specifically wrote about changing magnetinc fields, not about moving or non-stationary fields.
Conflation of "changing" with "moving" confuses direction with magnitude and brings the discussion to a new lower level.
This statement seems to imply that the magnetic field is non-constant after all.  According to the statement above, the field "grows" as a result of some spinning motion.
Is there a relationship of the flux or flux density to time or angular position?  Is this relationship periodic or monotonic?

@Itzu,


Please continue to keep posting here on this thread. I plan to open a new thread to continue the Bayles discussion.


@Verpies,


I'll catch up with you on the new thread. You're way off base in your ridicule bub. Just because Milehigh said radial does not change the polarization from axial as it is. What are trying to pull? You sound like some kind of nut case. You obviously don't have any idea what you're talking about. I lost all respect for you over that last series of comments.