Self running coil?

[chadj]

Well GB,

here is my  about the Finemet cores. Maybe no one got some because they are next to impossible to buy.

Metglas says their distributor is Elna Magnetics. I called Elna Magnetics and they have no stock, never had. You have to fax them a detailed purchase request and then they will look into it. So I called Metglas and the one person operating this business is away till tomorrow

This does not sound like an available item to me. Nothing else can be found!

User Peterae sent me a Toroid a month ago: http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=3057010 
I was saving it for when I find the ideal winding I want. However, last night I decided to wind it using 1 meter of 30AWG 25mm wire on that core which gave 24 turns. The resulting inductance is 9mH which I found kind of high so I wound the same 1 meter of 30AWG 25mm wire on the ferrite toroid core that I have been using in all my tests and it gives 30 turns. Its inductance is 1.22mH.

I'm confused as to why there is such a big difference. Is it the little bit of extra mass? Peterae Toroid TX36/23/15-3E5: OD 36.30mm, ID 22.55mm, height 15.5mm, width 6.8mm compared to my Regular Toroid I have: OD 34.45mm, ID 20.0mm, height 11.95mm, width 6.85mm

If someone can help explain the difference that would be helpful and appreciated.

Luc

Luc,

I think someone else already explained that the higher permeability is why you are getting more inductance. The material permeability has nothing to do with weight. It relates to how much the magnetic domains rotate when you apply an H-field (magnetizing force) with the coil. Some lighter materials have greater permeability. When the coil applies a magnetic field the core responds by creating a parallel B-field (magnetic field) much stronger then the H-field because it is paramagnetic.

The ratio of B to H gives the permeability. When the core begins to saturate its permeability will decrease until it is the same as air. Materials with hysteresis get magnetized when they approach saturation. When this happens you get (conventionally) energy loss because it takes energy to magnetize and demagnetize the core. You would typically only want to drive your coil to saturation for current regulation or amplification (mag-amp).

Ferrites have very little hysteresis but cores made of materials like metglas or orthonol are designed to have lots of it. These are called strip would cores because they are made from a long metal strip. It is often hard for amateurs to get these because suppliers don't want to deal with them but you can find a few cheap ones at this surplus site:

http://www.surplussales.com/Inductors/FerToro/FerToro-3.html

I can't really say if you would want to experiment with a strip would core because the ferrite is supposed to be more efficient. Maybe someone can buy a bunch of strip wound cores from a supplier and sell them on e-bay? (great biz-op!)

I hope this helps,
Chad.

[darik]

Hi Luc,

You may want to check the lecture 22 of Professor Lewin.
http://www.youtube.com/watch?v=ddU6HBFlvEk&feature=PlayList&p=A19E8985A925326B&playnext_from=PL&index=7

I found it very informative and helpful.

[mscoffman]

Because this may be relevant to experimenters here:

According to Paul Lawrance via his blogsite; http://globalfreeenergy.info/

“A tip is that all of my cores show a highly unusual property that is *NOT*
typical. The inductance of a normal core will decrease when placed near
a magnet. The Metglas MAGAMP cores show the opposite, where the
inductance actually increases when placed near a magnet. Of course,
if you place a strong magnet too close, then the inductance shoots
down even in the Metglas MAGAMP cores.

Some quick measurement taken a few minutes ago using the DM4070 LCR
meter on my Metglas MAGAMP cores shows an increase of 1.4 to 1.5 times
typically.”

My Disclaimer:

Like him, I am concerned about the possibly that the measurement
procedure used by a particular instrument might present a "less than
global” picture about what is going on in the inductor. He goes on to
claim that this behavior in toroids as shown by his equations equates
to the basis of free energy.

:S:MarkSCoffman

[Magluvin]

Been reading a pdf(below) that show these oppositely wound coils. I shows some different ways of connecting them.

The pdf is a bit cryptic. But the ideas come through after reading a few times.

Luc, I see the circuit you used(its been a while) back then.
No diode. Is there one in the fet for charging the cap?

Just finished winding a toroid your way, but not 5 layers of turns. Trying things.

Mags

[Magluvin]

Sorry, the file is word(forgot) and is too large to upload. Ill see if I can convert to pdf or zip it tomorrow.

Mags