Hi everyone,

It's been a while since I posted a new video!

Lately I've been thinking of applying what I personally learned while working with Thane Heins at the Ottawa University a few years back. I'm now considering of re-testing Thane's high Inductance coils with new core material and biasing magnets.

A little over a year ago a researcher named Eric YouTube user ericsclips: http://www.youtube.com/watch?v=PuzSkKlnCzc
He also shared his findings at this Forum: http://www.physicsforums.com/showthread.php?t=399801

What he found was that a coil wound on a Finemet toroid (nanocrystaline) core would increase in Inductance as much as 3 time when approached to a magnet (up to a certain point)

I do have 2 of theses Finemet toroids so I wound a coil on one to test it.

The idea here is to use Finemet as core material on Thane's delayed Lenz coil technique. This may give a huge advantage as we could achieve higher than expected Inductance using minimal wire lengths.
High Inductance is the key factor to Thane's coil effect and the benefit of using less wire is not just less cost but it reduces the coils resistance which in turn gives more current output.

Here is the video of my test so far: http://www.youtube.com/watch?v=_cCYKChCFqk

I also included (below) the two scope shots from the video demo test.

Please post your comments.

Thanks for looking

Luc

is the square part of the pulse the load time?

thanks for sharing.

Hi Luc
               With regards to the increase of core inductance,This is quite normal.as these
  cores are "Square Loop" .Bringing the core close to a bias magnet will push it into
 a high permeability zone of the core.For your interest this effect will also occur  in other non tape wound cores ,but are Square Loop..i know this having worked with square loop cores in the construction computer memory stores in the 1950`s.
You will find the toroid's make really good pulse motor drivers.
also check this out.

http://www.metglas.com/downloads/finemet_magamp.pdf
 Just another point 3R1 cores are a lot cheaper than the tape wound.Here is some info.http://www.ferroxcube.com/appl/info/square.pdf
Also if you are in the UK you can get them from |Farnell
Best Regards Dave

Hello ,

please note the difference between square lopp cores and metglas:

the finemet core, see description : supressing surge in current and voltage

http://www.metglas.com/products/page5_2_2_3_3.htm

square lopp cores are designed for magnetic amplifier applications.

Do not get confused. Modern Electronic components are specifically designed for distinctive applications.

Damping and controlling by saturation is something of a big difference.

So using it for new exotic applications such as the muller-gen you have to know which is doing what.

Kator01

Hi Luc,

lecture on kinetic inductance Lk. Pay notice to his remark about thin-films. This finemet inductors are made from thin-film-layers.

http://www.youtube.com/watch?v=MAHkYROmriY&feature=related

Besides this- there is no increase in the inductance as the negative spike amplitude is decreased. Also the area the first curve containes is also decrease meaning : the magnetic energy is reduced. The meter is fooled as the oscillation is damped as it is clearly seen in you vid. The higher fourier-components 2nd, 3 rd and 5 th are strongly damped. Look at the decreasing slope and the damping of the negative overshoot at the cut-off.
These finmet-core are especially designed for damping high frequencies running along conductors and doing their job well.

This physicist should know this.

These cores are interesting in that you can use them for delaying the collapse-time of the magnetic field whe used in series with the coils in a mull-generator - thus one will be able to control the point in time the anti-lenz appears.

Regards

Kator01

Thanks Kator01 for looking at this topic and posting your comments.

I will look into this some more.

One thing is for sure that when a PM is close these cores delay the flyback. Just this effect could be worth something.

Do you know or can explain why it uses much less current when a PM field is applied?

Thanks for sharing

Luc

Hello ,

please note the difference between square lopp cores and metglas:

the finemet core, see description : supressing surge in current and voltage

http://www.metglas.com/products/page5_2_2_3_3.htm

square lopp cores are designed for magnetic amplifier applications.

Do not get confused. Modern Electronic components are specifically designed for distinctive applications.

Damping and controlling by saturation is something of a big difference.

So using it for new exotic applications such as the muller-gen you have to know which is doing what.

Kator01

Hi Kator
           Just looked at the link to Metglas ,I don`t quite get what you mean,about the difference,in the type of core.Metglas is the name of the Company.
It looks like to me Square Loop and surge suppression use the same core ,click on the the data link on that page.

Regards Dave

Hi Dave,

you are absolutely right, I just checked the BH-Curve of these finemet-core.
Now I might add some information concerning the current -reduction.

I have studied the old transductor-techniques ( 1930)  now for about one year including extensive practical testing for power-level up to 1,5 KW. I mention this so that your know that I am speaking from practical experience about the following process:
If you look at the attached pic which I extracted from the Fe SquareLoop-Core-brochure, I have added 2 red arrows which mark the level of a static pre-magnetisation - done either by approaching a magnet ( like Luc did)  or by a dc-current through an additional control-winding. Now the remaining magnetic loop oscillates between almost full inductance starting at the level marked by the arrows and low inductance in the right upper saturation-area. In such a way you have no reverse-magnetisation which takes place if you make the way around the full loop ( see the bottom--figure). Therefore you have no de-and remagnetisation-losses. You just use a smaller BH-Area of the curve. You just use a well known magnetic-amplifier-technique. I had the chance to visit a company here in germany which produces transductors ( part of a magamp ) and I was told the the losses using a normal transformer-lamination for 50 Hz for these devices is no more than 5 % of the maximum-power to be controlled. A 20 KW-transductor in the size of a small briefcase consumes 1000 W for controlling the power-out.
Using permagnet magnets just needs the kinetic energy for approaching the coil.

Regards

Kator01

Hi Luc
            I measured the increase in inductance in Square loop  cores about four
years ago when playing around with Steorns Orbo.Any way I did a quick test again
It was what I expected with the same core I used then.
26.5mH no magnetic bias 33.8mH with Magnetic Bias.With Square loop the increase
of inductance will remain until it is reset by a reverse bias.As you can see the increase is not as great as your tape wound core,but that is to be expected being made from a more exotic material.The answer to your question why is there a reduction in current when your core is biased,is because the inductance has increased therefore so has the impedance .When you bias your core as shown in your Vid, does the inductance remain high when you remove the bias magnet?

Regard Dave

Hi Dave, thanks for posting your additional comments and new test results.

I'll try again to see if I can get a small Inductance change in the FERROXCUBE.

Concerning the current drop when the core is biased. You believe there is an inductance gain! ... how interesting. Kator01 says there is no Inductance gain. I don't know what an Inductance gain would look like on the scope. So I started this topic to see if anyone has the answers. So far we have a split.

Not sure why you ask "does the inductance remain high when you remove the bias magnet?"

I think the answer is no but I show the differences in the video (with and without magnet)

Thanks for sharing

Luc