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Author Topic: The bifilar pancake coil at its resonant frequency  (Read 567751 times)

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1290 on: May 02, 2017, 03:09:51 PM »
I have a bifi coil made of 26ga.  The dimensions  are 1in w 2 1/8in dia and 5/8 air (some plastic) core. Dont have the turns no.  It is 1.16mh and 16.07nf.  Switching on dc then cutoff the scope says 14.88khz for the wave developed.  Calc says like 35khz  Anyway,  Im wondering if this coil needs to be run in the mhz range like what you guys are finding to get the results you get.  Could it be more the length of the wires that is dictating that upper freq range above the normal resonant freq that needs to be hit?

Mags

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1291 on: May 02, 2017, 03:13:33 PM »

No....no.....no....

Hmmm.  Well Im trying to figure it out.  Seemed like a relationship of what was said and what is happening was developing. 

But Ill nix it for now...

Back to the drawing board...

Mags

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1292 on: May 02, 2017, 03:13:44 PM »
Mags, that Hantek is a nice looking unit... but does it really say "Forse" on the Force Trigger button?  That's even worse than the Rigol's "pluses" for pulses error, because at least you don't have to always see the "pluses" in the Rigol!

 :o

A decent stand-alone DDS AWG or FG will produce the standard 15 v p-p into 50 ohms and should be able to provide a Watt or two of power I should think. Some older analog units like my Interstate F43 are considerably more powerful than that... the F43 will do 40 v p-p into 50 ohms. But it is limited to about 4 MHz max frequency and at the top output and top frequency the sine wave starts to distort. That may just be down to old age though... I should probably re-cap that thing at some point.

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1293 on: May 02, 2017, 03:17:34 PM »
Hmmm.  Well Im trying to figure it out.  Seemed like a relationship of what was said and what is happening was developing. 

But Ill nix it for now...

Back to the drawing board...

Mags

Actually it depends on the circuit and the exact type of coil. The "ordinary" TBF pancake or solenoid coil is quite stable when voltage is varied when only connected to a minimal circuit, say, to establish resonant frequency by itself. But we have seen more complicated circuits where these coils and other coils do change their characteristics depending on the voltage supplied to the circuit and also to surroundings which can interact through capacitance, and this IS highly voltage dependent. SO... no no no, and also yes yes yes.

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1294 on: May 02, 2017, 03:25:55 PM »
I have a bifi coil made of 26ga.  The dimensions  are 1in w 2 1/8in dia and 5/8 air (some plastic) core. Dont have the turns no.  It is 1.16mh and 16.07nf.  Switching on dc then cutoff the scope says 14.88khz for the wave developed.  Calc says like 35khz  Anyway,  Im wondering if this coil needs to be run in the mhz range like what you guys are finding to get the results you get.  Could it be more the length of the wires that is dictating that upper freq range above the normal resonant freq that needs to be hit?

Mags

To get the actual distributed capacitance you have to work backwards from the resonant frequency and measured inductance. Just separating the two half-coils by disconnecting the centertap link and measuring capacitance between the two halfs doesn't give you the correct distributed capacitance value. SO get the ringing frequency from your scopetest, which is 14.88 kHz (nice and low due to your high inductance of 1.16 mH) and go to the Resonant Frequency Calculator here:
http://www.1728.org/resfreq.htm
and enter the freq and inductance and solve for capacitance. This will be your correct interturn distributed capacitance. If you have the inductance and capacitance values correct that is.


Yes, at the high frequencies being used to see the "effect", inductances of probe connections and other wiring become significant.

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1295 on: May 02, 2017, 03:34:45 PM »
To get the actual distributed capacitance you have to work backwards from the resonant frequency and measured inductance. Just separating the two half-coils by disconnecting the centertap link and measuring capacitance between the two halfs doesn't give you the correct distributed capacitance value. SO get the ringing frequency from your scopetest, which is 14.88 kHz (nice and low due to your high inductance of 1.16 mH) and go to the Resonant Frequency Calculator here:
http://www.1728.org/resfreq.htm
and enter the freq and inductance and solve for capacitance. This will be your correct interturn distributed capacitance. If you have the inductance and capacitance values correct that is.


Yes, at the high frequencies being used to see the "effect", inductances of probe connections and other wiring become significant.

Says 71nf.  Was just showing as an example wondering if this coil possibly needs to be operated in the mhz range also.  Just thinking.

Mags

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1296 on: May 02, 2017, 03:37:28 PM »

I find your devotion to single sine function curious.  You read Tesla's statement and owing to your "conditioning", "automatically" assume" that he is talking about what you think he is talking about.  Why do you people insist on isolating the one from of the many, rather than embracing the many, and applying to them, that which is applied to the one!

Just trying to work with these guys a bit to see the other things that are being looked at. Hopefully we will figure out what you are trying to get us to figure out also.

Mags

evostars

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1297 on: May 02, 2017, 05:28:26 PM »
Russ Gries his video response #2 to tinman

https://youtu.be/a86D2MPLmpE

get your calculators out!

hfo

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1298 on: May 02, 2017, 05:33:04 PM »
Thought I'd try isolating both input and output with toroids, hand wound approx 1 to 1.

Setup:
FG hooked directly to primary of first toroid.
Secondary of first toroid hooked to device (to resistor, as though replacing FG in Tinman setup).
Replace output resistor with primary of second toroid, moving output resistor to secondary of that toroid.
Both resistors 150 Ohm metal film (couldn't find any 100 Ohms).
Sine wave (analog BK 4001 FG) input.
Testing at resonance at 304 kHz.

Input voltage drop as measured across input resistor: 0.820 V P-P (820 mV).
Output voltage across resistor at secondary of second toroid: 3.1 V P-P.
FG output voltage: 18.4V P-P.

If I remove the output load resistor:
Voltage drop across input resistor: 6.52V P-P
Voltage at output of secondary of second toroid: 42.0V P-P
FG output voltage: 17.6V P-P.

Note that the voltage across (and current through) input resistor DROPS when the load is applied.  I'm having a hard time understanding this.

Anyone have a theory yet on what's going on?

For those who want to replicate this novel experiment, the hardest part for me was winding that coil.  I took a 10" x 10" piece of aluminum plate (could be steel or glass) and taped down down some paired hookup wire in the center.  Then I started tacking down the pair of wires using a hot glue gun every 30 degrees or so, making a circle, and going out from there.  I would put a blob on the metal and quickly push the pair of wires into it, and keep going.  Took a couple of hours to make it.  At the end I put a lot more hot glue on the outer windings then hit the whole thing with a hot air gun (hair dryer may work, don't know).  Then slid a drywall knife under it to lift it off the aluminum, and put some tape on it to hold it together.

Some folks have talked about grain of wheat bulbs, which I think run at 12V.  I believe that the old incandescent small Christmas tree bulbs may work at a lower voltage (seems like 6V), if you can find some.

MileHigh

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1299 on: May 03, 2017, 12:30:57 AM »
Partzman's testing and attempts at replication are interesting and a worthwhile exercise.  However, this is at best indirectly related to the bifilar pancake coil.  Just look at title of his schematic, "Bifilar Pancake Transformer."  It's not a coil, it's a transformer.  I still encourage this discussion on this thread.

The transformer discussion has pretty much hijacked the real purpose of this thread.  I was leaving it up to the contributors to continue the discussion about the Tesla series bifilar pancake coil.  What unique purpose or purposes does it serve?  What is special about it and what can you do with it?  What practical applications are there for it that specifically require a Tesla series bifilar pancake coil?

So is it real or is it just one of millions of patents that were never used in the real world and the only reason it is discussed is because Tesla's name is on it?

The field is wide open and I hope we hear more than crickets chirping.

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1300 on: May 03, 2017, 02:07:36 AM »
Here it would seem the paths can go in many directions ,Evostar is exploring a path more inline with his topic here, TinMan has posted an effect also  and Partzman is exploring his ongoing [years long] MEI work with Bifilar coils ...

there will be another thread here to focus more on A Partzman MEI build that all can replicate to get an "effect" to play with.

hopefully by tomorrow ,

it will also be in the moderated section here.

respectfully
Chet K

hfo

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1301 on: May 03, 2017, 02:52:37 AM »
I had the opportunity to get away from the bench and think about this some.  Tinmans original observations pertained only to current flow in input resistor vs. resistor in center of coil.  He made no claims as to overunity.

In fact FG voltage * input resistor current is approximately equal to output voltage * output current in my experiments.

So, overunity no, odd behavior due do to distributed capacitance yes.

nelsonrochaa

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1302 on: May 03, 2017, 12:56:45 PM »
Partzman's testing and attempts at replication are interesting and a worthwhile exercise.  However, this is at best indirectly related to the bifilar pancake coil.  Just look at title of his schematic, "Bifilar Pancake Transformer."  It's not a coil, it's a transformer.  I still encourage this discussion on this thread.

The transformer discussion has pretty much hijacked the real purpose of this thread.  I was leaving it up to the contributors to continue the discussion about the Tesla series bifilar pancake coil.  What unique purpose or purposes does it serve?  What is special about it and what can you do with it?  What practical applications are there for it that specifically require a Tesla series bifilar pancake coil?

So is it real or is it just one of millions of patents that were never used in the real world and the only reason it is discussed is because Tesla's name is on it?

The field is wide open and I hope we hear more than crickets chirping.



Seems that you really need go to bench work a bit and make some tests  , and discover by yourself about the questions that you ask , like others do .  Sitting around waiting as someone expects rain is never a good solution.

For sure you will have many things to talk after do some tests about the subject of pancake coil , otherwise like you say you only able hear crickets chirping, because other people are more concerned in working to clarify some of the points of the thread, that call's research  :)
Now if you assume is nothing more to explore on this thread try not be so repetitive about your questions otherwise ,you run the risk of looking a annoying person ask all time the same things .

Why you don't try play a bit with such coils ? even you spend some of your precious time is better than you become annoyed without know in first hand, some of the points that you refute  about any possible advantage of this coils .
I really don't understand such position .  :(

About you say the transformer discussion has pretty much hijacked the real purpose of this thread, i really don't agree with you , because we already change some posts between us about themes like  efficiency of power transfer with this type of coils with a video shot included, but you simple argue and refute saying that a normal transformer  have much advantage in this process of transfer power in relation to a transformer made by bifilar pancake coil , but now you say that a bifilar coil is not a transformer and is only indirectly related   .... this is to i laugh ? what seems to you that ? https://www.youtube.com/watch?v=aEZSCNHDYJs
Is only a coil ?

Do you think people are stupid that not understand what is a transformer and a coil  ? Or you think you are really more cleaver than others  ?
Make something  useful instead of simple create noise, because until now you not add nothing practical and positive to this thread with such behavior.
Do you think you are help anyone at moment ?  To me seems not

Have a nice day

Nelson Rocha




 



web000x

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1303 on: May 03, 2017, 01:13:01 PM »
Russ Gries his video response #2 to tinman

https://youtu.be/a86D2MPLmpE

get your calculators out!


I'm not sure the way he is measuring power in that is even useful.  He is using L1 & R1 for one power measurement and L2 & R2 for another.  The current into L1 is not the same as the current leaving L1.  The current into L2 is not the same as the current leaving L2.. Therefore his attempt to isolate the power in each coil section by way of volt-amp-phase angle seems to not be very informative.


Dave

nelsonrochaa

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1304 on: May 03, 2017, 01:21:36 PM »
Another interesting effect observed between a bifilar pancake coil when transfer power to a normal bifilar coil properly tuned,  is that seems the input is not affected when load is connected, where apparently the input decrease when a load is connected.
Just another simple test that could be made with this coils .

https://goo.gl/photos/BtUjDgGUQW39GU8f7

Nelson Rocha