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Author Topic: The bifilar pancake coil at its resonant frequency  (Read 567345 times)

nelsonrochaa

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1440 on: May 06, 2017, 02:17:50 PM »
Unfortunately your video shows very little in the way of correct power analysis method's--it has to be far better than that.


Brad

Hi Tinman, about your comment, I agree, that power analysis method's is not the best,but give a slight idea :) to people that not have a scope , and for sure you will agree that forum is not only you or me or a single minority , but a community of lot people that not have the same tools like some have .

About you say that i need make better than that in relation to “power analysis method's” , I left that job to people more skilled than me  like you :) with you bench tests . Good luck to feed back the system ;)


Cheers


Nelson Rocha

AlienGrey

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1441 on: May 06, 2017, 02:32:06 PM »
Don't think coax cable will work.  Tried a bunch of that.  But PCBs...   Yeah, that's the ticket.

You guys jump in with some specs and I'll design'm, post'm and you can play with'm.
try not to talk too much about 'slugs' at eating times! But have you noticed the cost of compact low voltage bell wire ? is it gold plated?
Anyway has anyone tried using obsolite coils of ribbon cable dead cheap and compact? just a thought that might be of use.

AG

tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1442 on: May 06, 2017, 03:27:24 PM »
Wound another coil today,just to see what would happen.
I used 3mm multistrand wire,plastic insulated.

As expected,the capacitance value was low,as well as the inductance value.
So this means a higher operating frequency-but i did get it to work.

The lit bulb is where R1 go's in Partzman's circuit,and the unlit one has one leg between R1 and R2,and the other leg is at the P/in point.


Brad

tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1443 on: May 06, 2017, 03:30:10 PM »
Hi Tinman, about your comment, I agree, that power analysis method's is not the best,but give a slight idea :) to people that not have a scope , and for sure you will agree that forum is not only you or me or a single minority , but a community of lot people that not have the same tools like some have .

About you say that i need make better than that in relation to “power analysis method's” , I left that job to people more skilled than me  like you :) with you bench tests . Good luck to feed back the system ;)


Cheers


Nelson Rocha

My skill set is not with electronic's-although i am getting better lol.
My scope is also an el-cheapo,and one channel is misbehaving-but we carry on with what we have.


Brad

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1444 on: May 06, 2017, 03:58:53 PM »
I did notice DogOne made a comment about ribbon cable being no good [and he was sad]

This is not the case at all.

AlienGrey
I will ask for a clarification on that today [I believe it is preferred in some cases of MEI work

thx
Chet

Dog-One

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1445 on: May 06, 2017, 06:59:19 PM »
Quote from: Jimboot
I'm on board Matt (pun intended) My understanding was high impedance, more turns will get desired effect at a lower frequency, so more accessible.

From my comprehension of what's going on here, spacing between conductors and
perimeter is critical.  What I don't know is if completely flat like a PCB is better than
having the surfaces facing each other--like the way a electrolytic capacitor is rolled.

Evostars was wishing there was a 3D electric field simulator available that could show
how the fields manifest, but without such a piece of software, I suppose we wing-it
for the moment and find out trial-n-error.

Anyway Jim, I'll continue on with a PCB design and post it.  That will give some of
us a reference platform to work from where we can compare notes and focus on the
drive circuitry.


I did notice DogOne made a comment about ribbon cable being no good [and he was sad]

This is not the case at all.

That's good because I now have a bunch of it.

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1446 on: May 06, 2017, 07:19:38 PM »
hmm
somebody posted an image which grew the page
anyhoo
here are some interesting control experiments  which Poynt had requested [were actually on  Tinsel's "things to do/Check list " ]


http://www.overunityresearch.com/index.php?topic=3445.msg61765;topicseen#msg61765

respectfully

Chet K

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1447 on: May 06, 2017, 11:53:57 PM »
And  poynt's control circuit result is being discussed further

http://www.overunityresearch.com/index.php?topic=3445.msg61775;topicseen#msg61775

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1448 on: May 07, 2017, 02:52:14 AM »
Had a lith batt pack on charge on my bench and later into the charge I heard a PSSSSSSSsssss.  Went and looked and sure enough 1 of the 18650 cells ruptured and spewed liquid on the bench a bit but that was it. I said, dang I gota get this outside now. I disconnected the charger and grabbed it by the pigtail and got half way to the open garage door..........

Mags

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1449 on: May 07, 2017, 03:07:34 AM »
Yep. Got me.  Learn new crap every day. ::)   But Im glad it didnt happen on my bench on front of my scope, PS, stereo, bench surface, charger, etc. It was like having like a firework of some kind.  Like 4 road flares 2 in the opposite direction, times 5 on the output, then just flamed for a bit..  lol just noticed I dont have any hair on that arm on most of it below the elbow. Im a freak now.lol

Im doing work for a guy that his business uses these packs of 4 set up for 7.4v series parallel with the safety circuit board on top. This pack was one that we were testing to see if it would take a charge as the charge circuit in the device wasnt charging it.  Ends up it was one of the first ones of the bunch.  Sooo now I am getting a metal cabinet for this stuff for testing and charging. 

An event like that can really make ya an instant critic on lith batts..  Yup

Tesla cars have 444 18650 panasonics in each pack.  I imagine when they go its a bit more, emmm, explosive. :o

Mags

citfta

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1450 on: May 07, 2017, 03:51:19 AM »
Hi Mags,

One indication of a bad lithium is a slightly swelled case.  I had one that took a charge fine.  When my RC plane was climbing out it got to about 100 feet up and bang the lithium battery blew apart and caught fire.  Luckily the explosion blew it out of the plane and it fell on the runway and burned there and the plane of course just tumbled down because of the loss of balance without the battery and no power.

Most places that sell the RC size lithiums also sell a charging bag to put them in while charging them.  I never charge one without it being in the bag after seeing the kind of fire they make when they go bad.  I think the bag is made of Nomex.

Sorry to see the nasty burn you got.  Very glad it was not worse.  I have heard on the RC forums about  people losing their homes because of fires started by lithium batteries.  I cringe every time I see a post where someone is trying to charge a lithium with their Joule Thief or other pulse type charger.  They are literally playing with fire.

Take care,
Carroll

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1451 on: May 07, 2017, 05:26:56 AM »
Hey Carrol

I will check on the bags, thanks

These were 18650 cylinders. Ive seen the flat packs swell, but these not yet. After the PSSSSssss  there was a bubble on that cell about the dia of a dime and out about 1/4 in. After that it was looking ok, but after seeing vids on these doing just that I quickly decided to move it. If i had waited 5 seconds to find something to grab it with it would have done a lot more damage on the bench than I care to think about. Flames were shooting like 2ft in a couple directions on the floor after I dropped it and went on for like 10sec then just pop pop smoke pop smoke.  Funny I had a long sleeve white shirt with the sleeves pulled up just below the elbow. On the top of my arm below that is now a golf course. All hairs 1mm.  but the shirt was untouched.  So as it ended up it was worth the burn to avoid the damage it could have cost.  But that is not going to happen that way again or anything close to it in the future.

The cells were just bare cylinders where most all have that shrink plastic cover where usually the color of the wrap indicates the type of drain the thing is made for. Like i said we believe it was an older pack..The protection board is suppose to limit the charge and discharge and do a balance on series cells. So at times we have a battery that the batteries are at the low limit and when you try to read the voltage at the pigtail there is nada till it is charged up past the threshold and then you can read voltage and use till it breaches again. So this one was just that, nada and put on charge to test. 



These batteries and other high energy density power sources as we see them now and as they get smaller and more powerful in the future should be an encouragement to find what we are looking for here. Energy on demand without the huge storage components that when they are damaged or have some fault could light up a city block under the right conditions. Not saying that an FE device couldnt have its lets start a fire today episode, but I think with the right safety features, at least there could be a redundant shutdown, or even just good old fuses to shutter down, where the batteries, there isnt much you can do to stop what these batteries will do once the damage is done. Run forest run!!

I wonder if you charged a 300f 3.2v cap and hit it square with a sledge hammer what might go down. :o Like cap gun caps. 1 dot and bang. 1 roll with a hammer and your ears are ringin like never before and you feel the blast hit you and the hammer at times really bounces back up from the preasure.

Anyway enough of that and Thanks

mags

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1452 on: May 07, 2017, 03:39:46 PM »
Boom
Mags, Thanks for sharing your close call with The lithium ,a good reminder to all.

the work continues with the builders ...amazing group effort from the builders here.

what a privilege to read and wonderful to see.

http://www.overunityresearch.com/index.php?topic=3445.450

I MUST ADD

this investigation is just getting started !!

stay tuned !!

respectfully
Chet K

AlienGrey

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1453 on: May 07, 2017, 04:56:12 PM »
.
« Last Edit: May 07, 2017, 11:53:11 PM by AlienGrey »

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1454 on: May 07, 2017, 05:13:22 PM »
Xee2 tested the inductance of the two different kinds of windings on ferrite cores and measured a 5% increase in the series bifilar in both low and high perm cores:
« Last Edit: May 07, 2017, 08:42:09 PM by synchro1 »