Partnered Output Coils - Free Energy

[picowatt]

Tinman,

Since I'm logged on at the moment, I can't help but comment on that low inductance of 120uh! It would seem that from the physical size and number of turns that it should be higher. Hmmmmm!

I have no reason to question your measurement so it is somewhat puzzling! Surely the core material isn't diamagnetic?!?

partzman

Partzman,

I as well found that low value surprisnig.  It sure "looks" like a lot more than 120uH.

I had noticed in some of Tinman's sweep tests that his xfmr seemed to saturate at fairly low amplitude levels when the applied frequency was 500Hz or less (i.e., the observed non-linearity).

I do not know what Tinman's L meter uses for a test frequency, some use 100Hz.  If I were him, I'd scope across the L meter leads while testing to check what frequency the meter is using and see what the waveform looks like.

Although I am not sure how non-linearities might affect his meter's accuracy, I think it would be wise to verify that low inductance using an alternate method.  Connecting the toroid in a voltage divider with a known resistance and applied frequency (or resonating with a cap), for example, might at least confirm that 120uH is "in the ballpark".

PW

[TinselKoala]

Hi Brad,

I use a free software program to estimate the permeability and the A_L values of unknown ring cores, here is a link to download the Mini Ring
Core Calculator:
http://mini-ring-core-calculator.software.informer.com/  and the downloading file name is minirk12_install.exe what you need to install on
your computer if you wish to use it.

In its Tools Menu there is the A_L and Permeability calculator when these are unknown and using your measured inductance of 120 uH for the
200 turns and your core's mechanical sizes, I got a permeability value, u=2.5 and for A_L=3 nH/N².

This means that the iron-filings are not so close to each other to form a dense ferromagnetic core volume, more filings would need to be stuffed
in to get higher permeability. However, if you made the previous core with a similar mixture ratio of the filings and epoxy (and assuming
also 200 turns and similar mechanical sizes), then the presence of the outer core will surely increase the 120 uH inductance to a higher value.

Gyula

Hi Gyula and Brad

I have that calculator (great Help sections in there) , but I found a different, simpler one to be somewhat easier to use for this problem.

http://coil32.net/download-linux.html  (windows and android versions also available)

Using Coil32 and the "ferrite ring core" selection, Brad's dimensions, and subbing in various values of permeability until I got near 200 turns required, the calculator tells me that u=10 will reach the 120 uH inductance with about 200 turns.

I think that a permeability in the range of 3-10 is plausible for a home-made iron powder core, so I'm not too worried about Brad's 120 uH inductance measurement.

Still, it would be nice to confirm the measurement as Picowatt suggested, by resonating a tank circuit, and it also would be nice to see the frequency that his inductance meter is using for the measurement.

Keep up the good work, mates.
--TK

[myenergetic]

Below is a picture of the !just finished! larger inner secondary inductor.
Very low on inductance as it sit's-just .12mH

Will see what happens when i encase it with the outer core material.

Hi Tinman
From your data of primary toroid A=144mm^2, l=132mm and L=120uH, permeability ur of your core material unknown
L=uAN^2 /l and since the measured inductance is 120uH by calculating the permeability of your core will be around u=L*l/AN^2 = 2.75nH @ unknown frequency, while the inductance of free space is u0 4pi*10^-7 H/m quite strange. What type of material, compound, and or mixture you are using in your core?? Even-though I don't know what it is but you are heading in to something!!!
jj

[TinselKoala]

Are you quite sure you've done your sums right? At least the calculators Gyula and I have used agree to within an order of magnitude and give reasonable answers.
TinMan's core material is iron filings mixed with 2-part epoxy, isn't it? Sort of like a "fortified" JB-Weld kind of stuff. Probably not really too different from a powdered-iron material toroid but with even less permeability due to the size and separation of the iron filings.

[gyulasun]

Hi Tinman
From your data of primary toroid A=144mm^2, l=132mm and L=120uH, permeability ur of your core material unknown
L=uAN^2 /l and since the measured inductance is 120uH by calculating the permeability of your core will be around u=L*l/AN^2 = 2.75nH @ unknown frequency, while the inductance of free space is u0 4pi*10^-7 H/m quite strange. What type of material, compound, and or mixture you are using in your core?? Even-though I don't know what it is but you are heading in to something!!!
jj

Hi Myenergetic,

The formula you use for calculating u is for solenoid coils. For toroidal coils, the formula is different, see for instance this link
https://www.easycalculation.com/engineering/electrical/toroid-inductance-calculator.php  and a possible formula is at the bottom of the page.

Gyula

EDIT    One more thing: for permeability of a core, you cannot get nH dimension, permeability for ferromagnetic cores is just a relative number so it has no dimension.