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Author Topic: The bifilar pancake coil at its resonant frequency  (Read 567350 times)

Grumage

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Re: The bifilar pancake coil at its resonant frequency
« Reply #645 on: April 11, 2017, 09:00:05 PM »
Grum, thanks for posting that nice large famous photo of St. Nick sitting next to his big flat coil.

The scale of the photo makes it easy to trace the turns outward from the center.

So is it bifilar, or not?    8)

Dear TinselKoala.

You're most welcome.

Now, is that a hint that it needs re sizing ?   ;)

Cheers Graham.

MileHigh

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Re: The bifilar pancake coil at its resonant frequency
« Reply #646 on: April 11, 2017, 09:05:42 PM »
If only someone could come up with a practical real-world application for a series bifilar pancake coil.  It appears that they can't.  In my opinion this is all just a bunch of fuss over a Tesla patent that was never even used in anything.  I will remind you that the wording of the patent clearly states that the coil is supposed to be used for power factor correction because of the capacitance associated with the coil.  Power factor correction is real, but nobody is using series bifilar pancake coils to do it, they use capacitors.

It's just like a Bedini motor, the only practical application for it would be to power it with a wall wart, and use the motor to charge a battery.  There is no point in powering it with a battery.  And using a 555 timer with a transistor and a coil will give you a simple inductive-pulse battery charger that will outperform any Bedini motor.

I am just posing the uncomfortable issues to make you think.  If you just want to play with some coils on your bench then fine, play with a series bifilar pancake coil or a Bedini motor, just don't expect anything amazing to happen.

And of course there is a real-world analysis that could be done that I seriously doubt anybody is going to touch.  That being compare a series bifilar pancake coil with a plain ordinary cylindrical solenoid coil.  No fancy bifilar anything, just an ordinary solenoid coil.  The ordinary solenoid coil will outperform the series bifilar pancake coil in just about any application that you can think of.

The only place I am aware of where they use pancake coils, and I mean regular pancake coils and not bifilar pancake coils, is in kitchen ranges with induction cooktops.  There is no "magic" here at all, they use a flat pancake coil because its geometry is the shape of a flat pancake, and that's what they need.

<<< Induction cooking heats a cooking vessel by magnetic induction, instead of by thermal conduction from a flame, or an electrical heating element. Because inductive heating directly heats the vessel, very rapid increases in temperature can be achieved.

In an induction cooker, a coil of copper wire is placed under the cooking pot and an alternating electric current is passed through it. The resulting oscillating magnetic field induces a magnetic flux which repeatedly magnetises the pot, treating it like the lossy magnetic core of a transformer. This produces large eddy currents in the pot, which because of the resistance of the pot, heats it.

For nearly all models of induction cooktops, a cooking vessel must be made of, or contain, a ferromagnetic metal such as cast iron or some stainless steels. However, copper, glass, non magnetic stainless steels, and aluminum vessels can be used if placed on a ferromagnetic disk which functions as a conventional hotplate.  >>>

Grumage

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Re: The bifilar pancake coil at its resonant frequency
« Reply #647 on: April 11, 2017, 09:26:55 PM »
Dear MileHigh.

Whilst I agree with your sentiments, there must have been " some " reason for Tesla to have built a coil of that size. Does anyone know ?

In answer to TinselKoala, I have drawn two Yellow lines, the coil seems to end in the centre with a pair.

Cheers Graham.

evostars

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Re: The bifilar pancake coil at its resonant frequency
« Reply #648 on: April 11, 2017, 09:47:17 PM »
Dear evostars.

Is that one of R M Cybernetics PWM's you're using ?
yes,  it is indeed. works great.

I think the reason tesla made his coils so big,  is because he used high voltage.  the distance between the windings prevents sparks. 

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #649 on: April 11, 2017, 09:48:35 PM »
Grum, thank you for muddying the waters again. Perhaps you would take another look,
this time with your glasses on.

Start anywhere, follow the wire around the coil and see where you end up.


Grumage

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Re: The bifilar pancake coil at its resonant frequency
« Reply #650 on: April 11, 2017, 09:57:24 PM »
Grum, thank you for muddying the waters again. Perhaps you would take another look,
this time with your glasses on.

Start anywhere, follow the wire around the coil and see where you end up.

Perhaps I should have taken these off ?   8)

You're quite correct, the photo does get a little blurry just before my yellow line.

Cheers from a rather embarrassed Grum.

MileHigh

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Re: The bifilar pancake coil at its resonant frequency
« Reply #651 on: April 11, 2017, 10:05:31 PM »
Dear MileHigh.

Whilst I agree with your sentiments, there must have been " some " reason for Tesla to have built a coil of that size. Does anyone know ?

Cheers Graham.

I am no expert on Tesla's life but from what I can remember from watching a few documentaries, at certain points in his life he lost his benefactors or his employers and he fell on hard times.  He needed to generate renewed interest in what he was doing to make himself more marketable.  So I think that's the main reason for things like the various staged photographs.  There is the famous time exposure picture with all of the big electric arcs for example.  So that big pancake coil may have been used for experimenting initially and then afterwards as a prop for some publicity photographs.

Is there any writing by Tesla about that big pancake coil?  To go full circle, it's just a coil.

I think the greatest thing he did was the Niagara Falls power dam project and all the associated technology and equipment to bring AC mains power from the dam all the way to the consumer.  It's not really rocket science but somebody had to do it first and that man was Tesla.  It's comparable to the invention of the steam engine.

MileHigh

shylo

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Re: The bifilar pancake coil at its resonant frequency
« Reply #652 on: April 11, 2017, 10:16:40 PM »
Well I don't think there is anybody trying to mis-inform , I do have a question.
Take a single coil, pass a single magnet over the coil, a flow is created in one direction,upon approach of the magnet, but as soon as the approaching magnet begins to induce that flow, an opposite flow begins, right?
But this reverse flow is not as strong as the flow that is being induced,so it can't be used to create an inducing  flow of the same strength, right?
But what I'm trying to do is take 2 of the reverse fields add them together so they are stronger than the initial.
You need to use more than just one machine to be able to do this,but it is still a catch 22 because you use 2 to make one.
I should say the coils are loaded at all times.
artv

evostars

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Re: The bifilar pancake coil at its resonant frequency
« Reply #653 on: April 11, 2017, 10:36:36 PM »
I made a new topic describing some of my experiments.
http://overunity.com/17222/some-bifilar-coil-experiments/msg503913/#msg503913

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #654 on: April 11, 2017, 10:38:07 PM »
MH: Right you are, as often. Another thing that is not often appreciated by the modern experimenter is that in Tesla's day, back at the beginning of radio, frequencies of 1MHz or more were practically unknown. You can see Tesla's words in many places where he speaks rather in awe of "one million, or millions, of pulsations per second!" Yet today these frequencies of 1-10 MHz are supplied by even the cheapest hobbyist function generators without much difficulty. Hand in hand with frequency is the rise and fall time of "pulsations". Tesla would have been in hog heaven if he could have attained rise/fall times in the single-digit nanosecond range, and he spent lots of his creative juice on spark gap designs specifically to minimize rise/fall times. Yet today we play around with single-digit rise/fall times even on the amateur's bench.

Grum: No problemo, mi amigo! It's hard to decontstruct stuff from ancient photos that were likely published first in half-tone dots in some newspaper of the time.
I'm waiting for someone to argue that there are two wires bundled together in that thick tarred-cotton-wrap insulation.  Could be, but I don't think so, since there is no evidence of the "crossover" connection that has to be there for a TBF winding.  Does anyone  know the date of that photo? Perhaps the coil was made before the invention in #512340 was filed. Why a big coil in the vertical plane? Maybe it was upended as a photo-op. Just speculating.

Shylo: Not current, but EMF, that is, voltage.
-E=d(B)/dt .... Faraday's Law of induction and Lenz's Law (the minus sign)... meditate upon that until you can grok the fullness of it.    ;)

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #655 on: April 11, 2017, 10:43:27 PM »
Well I don't think there is anybody trying to mis-inform , I do have a question.
Take a single coil, pass a single magnet over the coil, a flow is created in one direction,upon approach of the magnet, but as soon as the approaching magnet begins to induce that flow, an opposite flow begins, right?
But this reverse flow is not as strong as the flow that is being induced,so it can't be used to create an inducing  flow of the same strength, right?
(snip)
artv

Well, the "reverse flow" is weaker because of inevitable losses. Consider the case of the superconductor, where there are no resistive losses. The opposing flow induces an opposing field that is equal to the field of the approaching magnet, and so results in suspension, where the magnet floats over the superconductor, and in fact is "pinned" there even if the setup is inverted so it tries to fall away, but can't. 
But even without superconductors, and with losses, the opposing field induced by the eddy currents can cause major "slowdowns". I'm sure you know the simple demonstration of dropping a magnet through a copper pipe, or sliding a magnet along a copper or even aluminum plate.

MileHigh

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Re: The bifilar pancake coil at its resonant frequency
« Reply #656 on: April 11, 2017, 10:44:36 PM »
A great one from from across the Great Divide:

<<< The Tesla serial bifilar pancake coil was suppressed because it served as an EMP directed energy weapon, with top secret classification by the U.S. War Department. >>>

I will give you a real example of something that I am pretty sure was top secret during World War II, the frequency spectrum analyzer.  If you had a frequency spectrum analyzer it would help you discern the sounds emanating from ships or planes, as an example.  The sooner you could identify the enemy's hardware by its frequency spectrum signature, the more time you would have to take appropriate countermeasures.

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #657 on: April 11, 2017, 10:49:28 PM »
(snip)

I think the greatest thing he did was the Niagara Falls power dam project and all the associated technology and equipment to bring AC mains power from the dam all the way to the consumer.  It's not really rocket science but somebody had to do it first and that man was Tesla.  It's comparable to the invention of the steam engine.

MileHigh

Don't forget about the Polyphase AC motor invention.

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #658 on: April 11, 2017, 11:09:17 PM »
Allen
if you are done speaking in tongues and sentence hatchet quotations
maybe you should just give this man his thread back?

this
http://www.energeticforum.com/renewable-energy/20714-magnetic-field-bifilar-pancake-coil-2.html

is a much more interesting path than your half measures....
a solid state spinning event happening over pancake coils ..

maybe you should start your own Scrapyard magnet secrets thread ?
you could probably milk it for a few years...

evostars started on a much more interesting thesis with  pancake coils [solid state]
ala TPU perhaps

let him have his thread back
while he has told you he finds your work interesting
its not his path...
please respect his request here...many are intrigued by evostars work

@ramset,

Maybe you should send some complaint mail to Aaron.

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #659 on: April 11, 2017, 11:29:13 PM »
here is evostars new thread for his builds
http://overunity.com/17222/some-bifilar-coil-experiments/msg503934/#new
and his energetic thread
http://www.energeticforum.com/renewable-energy/20714-magnetic-field-bifilar-pancake-coil-2.html

Allen
I hope this off topic reply gets removed with your off topic comment
But I see that tossing a line over to quotes from the other forum [MH] always causes these types of issues [tinder for a flame up.

I am glad evostars started another thread for his work ,perhaps he can get some feedback from people who are building and experimenting there ?

and Allen
I finally understand how it could take seven years to get a straight experiment from you on a claim 
I don't think its possible ....ever....?

for clarity I have never exchanged an email or a message with Aaron nor have I asked for you to be moderated here or even discussed you.[why would I ? we have never interacted ..
maybe one unanswered Question to you 5 -6 years ago ??

let experiments rule the day ,and hearsay stay in the wind ...not to be taken as fact
until proven otherwise.

Brutal honestly ,and no wooden Nickels.

I guess you figured out when Grum signs off for the night [moderator] and TinMan and magluvin have fulltime jobs ....

no I suppose you don't care..or respect much here anyway.

you just like fighting !!
seven years you say {with Tinsel and others] ??
never an experiment to define your claims in real time ?

I bet you could drag that out for ever...

Allen
some here who love this place and really try to do experiments actually like the  TOS agreement .
here >>>http://overunity.com/register/#.WO1N8Ll1roY
I am told it will be the guide for posting at this forum ?
and moderation will be by choice [your choice if you break the rules].

do you have a cause you feel passionate about an experiment you simply must share ?

please do