Kapanadze Cousin - DALLY FREE ENERGY

[Void]

The following two scope shots show the resulting peak when the PWM is set to 5 kHz.
Coil pulse voltage is 2 V.
Duty Cycle is approx. 10 microseconds.
Average current draw into the coil is only about 6 mA.
Peak at around 1.28 MHz or so.

Verpies, the second scope shot is with a stack of three creramic cube magnets attached
to the end of the yoke core. The frequency of the peak does not change very much, but the
peak frequency is changing a bit from test to test anyway, so the small change in frequency
seen between scope shots might not be related to the magnets being attached. You can see
that the amplitude of the peak increased a bit with the ceramic magnets attached however.
I would need to repeat this test a few more times to see if the small drop in frequency with
the magnets attached is related to the magnet being attached or just normal frequency drift of the peak.

Edit: Verpies, I repeated the ceramic magnet test several more times and the frequency of the peak
does not change noticeably at all. However, the amplitude of the peak increases by about one full vertical division
(~50mV) with the ceramic magnets attached. Not sure what that might mean at this point, but that is what happens.
Also, keep in mind that the average current draw through the coil for this particular test was only about 6 mA.

I also tested again by grabbing the winding on the yoke tightly in my hand, and the frequency of the
peak again did not change noticeably.

[itsu]

Hi Void,

i will try to replicate that, i have severall yoke halfs here.
So you use a yoke half (just the half?), with a coil (how many turns?) wrapped around it and use your PWM to drive that coil.
What about the pickup probe, its attached to a piece of alu foil wrapped (also like the coil?) around the yoke half (same half?   Is it over the coil or underneath it?)

Thanks, Itsu

[itsu]

I did some tests with 2x 12V/21W bulbs in series on the 24V PS as a load and i think that D1 an T1000 are correct, i get the same cycling, so
its the difference between the 24V battery voltage and the 24V PS voltage which battle it out.
See first part of the below video.

I think we can put this one to rest as it is as Void says not too much of a concern.


The 14Mhz signal was traced to the both MOSFETs, so probably, as was mentioned by verpies, its the MOSFETs ringing or a LC parasitic.
I notice that both MOSFETs show a different frequency peak (14.08MHz versus 13.75MHz), so i guess it could be the ringing from the primaries LC frequency
which could sligthly differ from each other.

Waving with a stack of 4 ceramic magnets has no influence on these peaks (or not noticeable) but i do see and hear a sudden change when approaching the yoke
It starts to squeel and we see severall peaks coming up all over the spectrum, which is probably what i call the chaotic mode and causes the oscilloscope to
show the many fuzzy signals it does.


Video here:  https://www.youtube.com/watch?v=Zs2r5VI8FH4&feature=youtu.be   

Itsu

[verpies]

Verpies, I repeated the ceramic magnet test several more times and the frequency of the peak
does not change noticeably at all. However, the amplitude of the peak increases by about one full vertical division
(~50mV) with the ceramic magnets attached.

That is not bad news because the expected frequency shift for iron would be approximately 1%, and I expect a similar shift for ferrites, too. 

A FFT of the signal at this resolution would not be able to show this shift.
So a steady peak is actually good news.  A slight increase in amplitude is not bad either.

However, before we jump to conclusions, lets try whether a different winding will affect this peak.
Also please try a 47pF cap from gates to sources and/or from drains to sources of our PWM driver to see if that changes the frequency of that peak by altering the LC parasitics.


P.S.
Closed magnetic paths are always better than open ones.  That goes for the yoke's core and for permanent magnets.

[AlienGrey]

I did some tests with 2x 12V/21W bulbs in series on the 24V PS as a load and i think that D1 an T1000 are correct, i get the same cycling, so
its the difference between the 24V battery voltage and the 24V PS voltage which battle it out.
See first part of the below video.

I think we can put this one to rest as it is as Void says not too much of a concern.


The 14Mhz signal was traced to the both MOSFETs, so probably, as was mentioned by verpies, its the MOSFETs ringing or a LC parasitic.
I notice that both MOSFETs show a different frequency peak (14.08MHz versus 13.75MHz), so i guess it could be the ringing from the primaries LC frequency
which could sligthly differ from each other.

Waving with a stack of 4 ceramic magnets has no influence on these peaks (or not noticeable) but i do see and hear a sudden change when approaching the yoke
It starts to squeel and we see severall peaks coming up all over the spectrum, which is probably what i call the chaotic mode and causes the oscilloscope to
show the many fuzzy signals it does.


Video here:  https://www.youtube.com/watch?v=Zs2r5VI8FH4&feature=youtu.be   

Itsu

Sounds like this ones from the dark side have grabbed this video !!!!!!!!!!!!!!!!!!