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Author Topic: The bifilar pancake coil at its resonant frequency  (Read 400148 times)

Offline tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1260 on: April 30, 2017, 01:57:38 PM »
Repeating the above calculations and taking the scope's reported RMS values and phase shift as "exact", along with a more precise measurement of the DC coil resistance as 10.4 ohms, I get

Total Input Power = 0.011846 W or 11.85 mW.
Total dissipated power in R1+R2+Rcoil = 0.01178 W or 11.78 mW.

Rounding to three significant digits we have 11.8 mW in = 11.8 mW out.

So your coils are dissipating all the energy they receive?
Quite odd for an inductor-dont you think?.

Is this at it's resonant frequency?,or have you tried a range of frequencies?.


Brad

Offline TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1261 on: April 30, 2017, 02:46:10 PM »
So your coils are dissipating all the energy they receive?
Quite odd for an inductor-dont you think?.

Is this at it's resonant frequency?,or have you tried a range of frequencies?.


Brad

No, it's not at resonant frequency, I have tried a range of frequencies and these shots are done where I can get a display that looks somewhat like yours in terms of phase shift.

The coils are acting like a combined resistance + inductance. They are dissipating essentially no power in the inductance and are dissipating power in the resistance. Perhaps they are radiating a little power in RF but that is really negligible. As you can see the calculations come out very balanced as to "input" vs. total dissipation in the resistive elements, both for your coil (assuming very small resistance of your coil) and for mine (using its measured 10.40 ohms DC resistance). No, it's not odd for an inductor, it is behaving just as expected, I think, where it is dissipating power only in its DC resistance.

Offline TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1262 on: April 30, 2017, 03:08:17 PM »
I finally got a set of measurements including the Average Power that are consistent. I think the Rigol's measurements are very sensitive to how many cycles of waveforms are on-screen and how much screen height they take up.

So now the Average Power in this scopeshot, calculated manually from Vrms x Irms x (cos phaseshift) reported values,  is equal to the scope's automatically calculated Average Power on the Math trace.




Offline partzman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1263 on: April 30, 2017, 03:29:22 PM »
I finally got a set of measurements including the Average Power that are consistent. I think the Rigol's measurements are very sensitive to how many cycles of waveforms are on-screen and how much screen height they take up.

So now the Average Power in this scopeshot, calculated manually from Vrms x Irms x (cos phaseshift) reported values,  is equal to the scope's automatically calculated Average Power on the Math trace.

TK,

Yes you are correct regarding the number of cycles taken in the overall measurement as they must be complete cycles for the greatest accuracy.  At present all the math is being calculated from screen edge to screen edge.  Does your scope or TM's have the ability to take measurements between vertical cursors?

PM

Offline TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1264 on: April 30, 2017, 03:53:40 PM »
TK,

Yes you are correct regarding the number of cycles taken in the overall measurement as they must be complete cycles for the greatest accuracy.  At present all the math is being calculated from screen edge to screen edge.  Does your scope or TM's have the ability to take measurements between vertical cursors?

PM

Yes, the Rigol has vertical and horizontal cursors, but they only report raw voltage, delta-voltage and time and delta-time values. So phase shift would still have to be manually calculated from the delta-t between zero crossings of the waveforms, I guess. There is also an automatic cursor mode that "tracks" what the "quick measurements" show, in other words, the cursors will snap to the portions of the waveform(s) that correspond to what the Measurements are showing. But the cursor readouts themselves only have voltage and time values.

TM's scope also has cursors but I don't know what they can show. I'll have to check the Atten manual.

Offline sm0ky2

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1265 on: April 30, 2017, 07:24:23 PM »
Those tiny incandescent lamps are called "grain of wheat" bulbs and I am happy--- and rather astonished--- to see that they are still available in this day of the ubiquitous LED.

http://www.ebay.com/sch/?_nkw=grain%20of%20wheat%20lamps


I think the onset of the LED marketplace is what has brought all these
'grains of wheat' out of there warehouses, in an attempt to unload obsoleteness.

Offline sm0ky2

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1266 on: April 30, 2017, 07:58:16 PM »
I love when you guys completely ignore me....
It gives me a chance to repeat myself from multiple perspectives...


Patent 512,340::::


Clearly states that electricity flows from coil A, TO coil B.


Why then is it insisted upon that people run it in reverse?
It this intentional?  Or merely a consistent oversight?


Is there something you are looking for by creating unnecessary
losses in the system?


Perhaps we should discuss the process of induction.


Emil Lenze described this mathematically as:
V= - [d(flux)/d(t)]


What does this mean?
In short, that the Magnetic flux is induced OPPOSITE
of the direction of current.


How does that apply to our BFPC??


If we had a 'true a/c' it wouldn't matter,
But since our modern timing circuits and SG's
operate by creating a virtual-signal, we have no
negative impulse. What we have is only a positive impulse
and a virtual negative side of the waveform. (see circuit ground)


+ starting from the first coil (outside) of the BPC induces a magnetic flux that
starts at the other end of the second coil (inside).
Following the flows of current and flux, we find the flux inducing a current in the
direction of the current that induced the flux!!


This is what Tesla talks about


If you use the coil backwards, the induced flux dissipates into the surrounding area
instead of outwards to the next adjacent coil trace.


It is not just a matter of magnetic polarity, as is with the SPC.
The loss in flux creates an observable decrease in magnetic field strength.
And in turn, a loss of induction of the response current. (Lenze).




In other words (as Lorentz put it):


F = qE + qv x B


The force (F) of a charge (q) traveling at velocity (v),
through magnetic field B.


In leymans terms, when using the BPC as Tesla prescribes,
the charged particle (electron) increases in velocity.
If operated in reverse, it slows down!


You want to get around this problem?
Create a true a/c condition, by biasing two tandem SG's,
180-degrees out of phase and of opposite polarity,
to a centered arbitrary "0-point",
and you will observe symmetrical operations of the coil in both
directions.


This work-around was not possible (or feasible) in Tesla's time,
which is why he tells us HOW to use it.


Remember freshman class of basic electrical engineering






Offline sm0ky2

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1267 on: April 30, 2017, 08:05:48 PM »
We ignore this in signal processing because we are concerned with
the data, not the electricity.
Our signal generators produce the desired "waveform" on our scopes,
therefore we often forget how we got there.


Negative voltage (with respect to circuit ground) is not the same as
applying a + voltage to the other side of the coil.

Offline TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1268 on: April 30, 2017, 09:18:49 PM »
I love when you guys completely ignore me....
It gives me a chance to repeat myself from multiple perspectives...


Patent 512,340::::


Clearly states that electricity flows from coil A, TO coil B.


Please quote the exact passage in Tesla's patent 512340 where he "clearly states" this.

Quote


Why then is it insisted upon that people run it in reverse?
It this intentional?  Or merely a consistent oversight?


Please state exactly WHICH half-coil of a TBF pancake or solenoid is "A" and which is "B".
What exactly do you mean by "run it in reverse"? Can you demonstrate "forward" and "reverse"
operation of a TBF coil and show the difference in some kind of instrument readings?

Quote


Is there something you are looking for by creating unnecessary
losses in the system?


Perhaps we should discuss the process of induction.


Emil Lenze described this mathematically as:
V= - [d(flux)/d(t)]

That is Faraday's Law of Induction. Lenz's law is the minus sign, indicating that the EMF induced has opposite sign
to the rate of change of the inducing magnetic field.

Quote


What does this mean?
In short, that the Magnetic flux is induced OPPOSITE
of the direction of current.


No, it doesn't.

Are you perhaps confused by the meaning of the differential d(phi)/dt? This is the Time Rate of Change of the magnetic flux.
What happens to the arithmetic sign of this value when phi is increasing or decreasing over time?

Quote


How does that apply to our BFPC??


If we had a 'true a/c' it wouldn't matter,
But since our modern timing circuits and SG's
operate by creating a virtual-signal, we have no
negative impulse. What we have is only a positive impulse
and a virtual negative side of the waveform. (see circuit ground)


That is not true.  I don't know what kind of Signal Generator you might have, but any "normal" SG or FG can be isolated so that, for example, a sine wave output is referenced to GROUND at the zero volt crossings. This is what the Oscilloscope is telling you when the entire full cycle is half above the zero volt reference and half below the zero volt reference.

What is the difference between a "virtual negative" and a negative impulse? Which one will fail to light up a LED or fail to flow through an ordinary diode?

Quote


+ starting from the first coil (outside) of the BPC induces a magnetic flux that
starts at the other end of the second coil (inside).
Following the flows of current and flux, we find the flux inducing a current in the
direction of the current that induced the flux!!


Do you actually understand how a TBF coil is wound? The entire coil goes in the _same direction_.  If you want to "start" at the outside, the first half winding goes from there all the way to the "inside", then the short straight series link goes _back to the outside_ and once again winds from there all the way to the inside again, parallel to and in the same direction as the first half-coil.

Quote

This is what Tesla talks about


Again, please quote the exact passage in Tesla's patent that supports your statement.

Quote


If you use the coil backwards, the induced flux dissipates into the surrounding area
instead of outwards to the next adjacent coil trace.


Please explain how to "use the coil backwards", when it is being stimulated by AC.

Quote


It is not just a matter of magnetic polarity, as is with the SPC.
The loss in flux creates an observable decrease in magnetic field strength.
And in turn, a loss of induction of the response current. (Lenze).


Please demonstrate what you are talking about, by comparing a "backwards" use of the coil
with a "forwards" use and show the difference in induction or "response current" or magnetic field strength.

Quote




In other words (as Lorentz put it):


F = qE + qv x B


The force (F) of a charge (q) traveling at velocity (v),
through magnetic field B.


In leymans terms, when using the BPC as Tesla prescribes,
the charged particle (electron) increases in velocity.
If operated in reverse, it slows down!


Once again, please demonstrate this slowing down of electrons when a TBC coil is
"operated in reverse".

You also seem to be scrambling the multiplication operation symbol 'x' with the vector cross product 'X' and you are neglecting the electric field contribution
entirely.

Quote

You want to get around this problem?
Create a true a/c condition, by biasing two tandem SG's,
180-degrees out of phase and of opposite polarity,
to a centered arbitrary "0-point",
and you will observe symmetrical operations of the coil in both
directions.


I am eagerly looking forward to seeing your demonstration of this "workaround".

Since we are clearly observing symmetrical operations of the coil in both directions
in every experiment involving AC that we have performed, you seem to be talking about something
that nobody has actual experience with. SO once again, please demonstrate
some kind of "non-symmetrical" behaviour of a TBF coil using a function generator or any other
form of AC or DC stimulation.

Quote


This work-around was not possible (or feasible) in Tesla's time,
which is why he tells us HOW to use it.


Again, please quote the exact passage in Tesla's patent 512340, or any other of his
patents or other publications, that supports your statement.

Quote


Remember freshman class of basic electrical engineering

I remember, but apparently you don't.

Offline TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1269 on: April 30, 2017, 09:22:25 PM »
We ignore this in signal processing because we are concerned with
the data, not the electricity.
Our signal generators produce the desired "waveform" on our scopes,
therefore we often forget how we got there.


Negative voltage (with respect to circuit ground) is not the same as
applying a + voltage to the other side of the coil.

And exactly what is the difference? Please DEMONSTRATE what you are talking about.


Offline Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1270 on: May 01, 2017, 07:01:48 AM »
Hey brad

What was the res freq of the bifi you have? These 1.2mhz and 1.3, which you had shown at first, are they way above the res freq? Dont remember what yours was.

It seems as though your light test in the 2nd vid to russ, it is possible that if you get rid of the Lt1, Lt2 may get brighter by reducing that added voltage division in the circuit. This is something I hadnt heard of yet for testing and seems to be good.  Like the middle connection between coils is where the load should be? ??? Well thats different for sure. ;) Like the bifi can be used as a sort of supercharger..   Hmm, if we removed r1, would there be balance in the coil and no current in r2? The only thing to set it off balance would be the windings if one is a bit different than the other, like if the ends of the outer windings break off in the same place, one of those, the outer winding, would be a longer wire in the end...


Mags

Offline tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1271 on: May 01, 2017, 11:04:00 AM »
Hey brad

What was the res freq of the bifi you have? These 1.2mhz and 1.3, which you had shown at first, are they way above the res freq? Dont remember what yours was.

It seems as though your light test in the 2nd vid to russ, it is possible that if you get rid of the Lt1, Lt2 may get brighter by reducing that added voltage division in the circuit. This is something I hadnt heard of yet for testing and seems to be good.  Like the middle connection between coils is where the load should be? ??? Well thats different for sure. ;) Like the bifi can be used as a sort of supercharger..   Hmm, if we removed r1, would there be balance in the coil and no current in r2? The only thing to set it off balance would be the windings if one is a bit different than the other, like if the ends of the outer windings break off in the same place, one of those, the outer winding, would be a longer wire in the end...


Mags

Those frequencies seem to be where less P/in for most P/out is.

Never really looked at the specific resonant frequency ,but the ringing in the below picture is it-if you can work that out  :D

It seems that L1 and L2 must work together,in order to get the high current between them.

Not long got home from work,so it's grab a coffee time,and back to the bench.

Going to try that HF isolation transformer at the center tap of the BPC,and see what i can get out of it.


Brad

Offline tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1272 on: May 01, 2017, 02:28:06 PM »
Mag's and Stefan

I will no longer be acting as a moderator of this thread.


Brad

Offline nelsonrochaa

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1273 on: May 01, 2017, 07:53:09 PM »
It seems like things are getting exciting! :) And for those who until now never recognize anything special  in the pancake bifilar coils ...... please me, they are so entertained at moment ! ;) ;D


Nelson Rocha


Offline ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1274 on: May 01, 2017, 08:07:17 PM »
Many years in the works ,

actually partzman's open source MEI Bifilar work has been going on for a long time,  it is an ongoing investigation.

more here
http://www.overunityresearch.com/index.php?topic=3445.msg61454;topicseen#msg61454
been at his open source bench there for many years.

respectfully
Chet K

edit: spelling correction
« Last Edit: May 02, 2017, 03:42:49 AM by ramset »