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Author Topic: The bifilar pancake coil at its resonant frequency  (Read 567762 times)

tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1200 on: April 26, 2017, 11:01:43 AM »
 author=Magluvin link=topic=17186.msg505484#msg505484 date=1493144011]
 

Quote
Well thats interesting. Your single wire coil seems to outperform inducting the square coil.  For sake of argument, those screw terminals in the middle of the coils look to be different sizes and could be acting as cores in what is suppose to be an air core test. Just thinking. The one in the single is larger.

The chocky blocks are marine grade-all stainless steel.
I used them for the very reasons you mentioned.

Quote
Did you record the freq for each result? Or were both coils results happening at the same freq?

52.8KHz for both coil's
This is the frequency maximum amplitude was reached across the 680 ohm resistor on the pickup coil,for both pancake coils.

Quote
This would be a first for me that a supposed identical single wire coil actually outperforms a bifi of the same. If the resistance and inductance are the same, where do you suspect the loss to be credited to?

I suspect the loss is because of the very thing most here seem to think is a wonderful thing--that being the larger value of voltage between turns in the BPC.
Think about it. Both coils have the same surface to surface area,so we could expect that the overall capacitance of the coils to be the same value.
Difference is,with the single wound coil we are trying to charge each set of plates(parallel windings) to a small value of say 1.2 volt's,and with the BPC,we are trying to charge each set of plates to say 50 volts.
So,instead of most of the input energy going into the primary coil being used to induce the secondary coil,some of that available energy is going into charging the self capacitance of the coil,and with the BPC,that charge is a lot higher than that of the single wound coil.

TK done a video a couple of days ago,that also showed that the single wound pancake coil had a slightly stronger magnetic field.


Brad

tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1201 on: April 26, 2017, 11:08:40 AM »
Typically we see field collapse spikes and they are pretty much prevalent.  So I changed up the voltage scale from 20v to 5v and lengthened the time scale to possibly see what is going on around the oscillations I had shown above. I also added the blue trace at 5v scale, but shifted the trace above the yel trace of the coil so both can be seen easier.

Gnd of both scope probes and neg of power supply(set for 4.2v) and one leg of the coil are all connected together. The blue trace is monitoring the power side of the micro switch, and the switch on sends current through the coil.

The first shot is switch off

The second shot is when switch is turned off from being on. I cannot switch the switch fast enough to capture on and off of the switch in one shot. So the coil is taking on full current before the switch is turned off...

We see that when the switch goes off, the yell trace goes low for a bit before the oscillation occurs.  ???  What is that? Is that our spike dissipating current across the switch gap before the oscillation portion of the trace appears? Switch is open and only the scope across the coils leads.

More later...

Mags

That is the coils self capacitance being discharged.
And it is also the same as what i get for the first negative pulse.




Brad

tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1202 on: April 26, 2017, 12:07:11 PM »
 author=Magluvin link=topic=17186.msg505364#msg505364 date=1493033673]

Quote
Hey brad

 Thats not the brad I thought I knew. The Brad that comes up with out of the box ideas on things that captures everyones attn. Where did ya go?  Miss ya.

Took me a while to find this post lol,but i knew it was there some where.

Ok Mag;s
I didnt let you down--i kept on hunting-->and i found it.

Be prepared to be blown away--even MH will have to rethink how inductors/coils work--well in the case of the BPC anyway.
Were about to gain a new understanding about the BPC,that i have not seen in any other coil.

But first
I give all the Tesla BPC guru's a chance to put forth any differences they have found with the BPC,to that of any other coil.

The way this is going to happen.
First step-i will shoot a video.
I will then show TK the video,and ask him to confirm my findings.

Once that is done,i will post the video here,and show you what i have found.
I also believe i have an answer as to why this is happening--but we'll leave that till later.

Until then.


Brad






hoptoad

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1203 on: April 26, 2017, 12:54:40 PM »
snip...
Be prepared to be blown away--even MH will have to rethink how inductors/coils work--well in the case of the BPC anyway.
Were about to gain a new understanding about the BPC,that i have not seen in any other coil.
snip..
This toad is curious. Hope you found a worm, better still, a can of worms. I love worms.  :) 
Cheers

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1204 on: April 26, 2017, 03:50:26 PM »
Easy to explain Mag's
As explained in post 1266--Quote: I have a diode on one of the input leads to each coil,so as we get a DC pulse going into the coils only.

The diode is clamping the bottom half of the wave  ;)


Brad

Ok.  Well then the collapse neg swing should not be 13.6 for each as you claimed they were the same for each coil. Just clarifying that, as one coil was higher in up swing than the other, it did not make sense that the first bottom swings were identical and limited. So the diodes removed should change those readings, even the up swings for each of 20v and 25v as the initial down swings were burning up the in the diodes before the up swings.

So the inductive kickback is not the same for each coil as you stated and should be corrected as the diode was limiting it to be the same for each. ;)

Mags

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1205 on: April 26, 2017, 05:24:24 PM »
That is the coils self capacitance being discharged.
And it is also the same as what i get for the first negative pulse.




Brad

I suppose.  I wonder what limited the down stroke to -15v and release at about -8v into an oscillation that goes beyond the scopes top an bottom borders, of which only displays the 54v pp of whats on the screen.  Maybe the power supply through the gap of the switch? Cuz thats all there is, sbifi coil, power supply, switch and scope. Wouldnt be the scope as it lets the oscillation breach that 15v as we see in the oscillation portion..

I used a micro switch as they have a nice tendency to switch very quickly.  When I was thinking on that before the tests, was thinking of using a spring loaded lever that would quickly hammer a set of switch contacts(modded for such) open and away from each other as fast as possible. So I could try that and see if there is any difference, or try and make a rotary switch. 

Seems the reason for the quenched spark gaps were for this very reason, to apply input and provide a complete disconnect from the input as to not disturb the outcome.

Mags

« Last Edit: April 26, 2017, 07:47:24 PM by Magluvin »

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1206 on: April 26, 2017, 05:42:24 PM »
And oddly enough, the blue trace is of the input where you can see it was being held down by the load before the switch opens, and once open, noisily keeps being held down and gradually gets back up to no load level once the oscillation sets in. Needs to be looked at more as to what exactly is going on, and would the oscillation portion be losing out because of that initial dump loss.  Also i will compare using batteries to see if the power supply is clamping the initial neg swing. The blue trace doesnt really indicate that, but maybe through the resistance of the spark gap of the switch, this is what we see.

Mags

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1207 on: April 26, 2017, 06:09:25 PM »
Looking at the shot closer, just an observation, I see a pos spike in the power supply blue trace just before the oscillation is allowed to set in. And there is a neg spike in the yel coil trace also.  Not at shop till later, but I want to look at that closer with the scope. Possibly when the switch spark gap cuts out this is what we see. Will do more shots of that.  The scope is set up for auto single shot and the switch method shows repeatable shots.  These were at 4.2v in and the first ones were .02v in. I want to see if there is a difference in this initial down stroke before oscillation there also. Maybe it helps to run really low voltage in to 'help' avoid spark across the switch. Have to look at that.

Mags

sm0ky2

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1208 on: April 26, 2017, 06:56:31 PM »
im sure this has been covered somewhere, but I have not the time atm to read 86 pages..

just in-case::

Tesla wrote about the direction of which these coils are to be used. intended to be used from the outside-> towards the center.
atomically negative, electrically positive. (not the - to + flow many tend to follow around a circuit?).
If used in the other direction, induction translates outwards which decays the energy out into the atmosphere, instead of
into the next inner trace of the coil.
When used properly, the collapsing field of each outer trace assists in inducing current in the next inner trace, at ~ the
same time the electricity is traveling through that portion of the coil.
these things happen at close to the speed of light, and are not visible on our scopes.
the scopes that can see this cost tens to hundreds of thousands of dollars!!! wish I could get one of my own....
I have heard of them being grabbed up at Army surplus stores (old naval o-scopes 50+Ghz)
but I haven't not been so lucky to find one.

one also has to be careful when choosing copper wire of different diameter. something not always disclosed is the alloy.
it is best to ensure you are using 100% (or 99.999+) copper, not an alloy as these change depending on diameter and
strength / intended use.
you can usually see the difference in color, which denotes a different alloy of each of your two wires. This means the two
coils will not have the same electrical properties. Caution should be used when making assumptions based solely on visual
examination of your coil, as discoloration can be due to oxidation, not a difference in alloy. So if there is a difference in color,
there are other methods of testing to determine what type of wire you have, one is the thermal coefficient of expansion.
this can be calculated, then tested experimentally with each wire by heating them under controlled conditions.
other methods are more complex, but its' easier to just get 100% copper.

at frequencies less than or greater than a resonant node, induction of the BC's will be, in general, greater than that of an
identical SC, drawing more current from the source. As a resonant node is approached, induction will decrease, allowing for
a higher voltage and lower current. Up to a point, where ~R(o) = 0. [voltage dependent impedance of air, ~1-2MV]
This is similar to the function of a 'spark gap', but for the entire volume of the electric field.
Which, at great voltages can encompass the entirety of the building or space occupied by the coil.
At this point, current reaches a maximum 180-degrees out of phase with the voltage max.
resulting in a maximum B-field (greater than that of the identical SC) 90-degrees to the electric.

When you start the coil up, it uses more power than the SC and produces a smaller field, but at operating freq. it uses less.
to produce a greater field. If operated long enough, it becomes more efficient than the SC.
If operated in pulses or switched on/off in rapid succession, the SC will generally perform better.
BC's are intended to be used at a consistent freq. very close to (but not exactly at) a resonant freq. or node.
This corresponds to a max. V amplitude, as observed on your scope.
More accurately, you should find TWO max. amplitudes, one slightly less than and one slightly greater than a node freq.
The higher the freq., the shorter distance between the max. amplitudes and the actual resonant freq. node.
The actual measured amplitude of the two maximums may vary in your particular set-up, for a couple of reasons.
If one is slighter greater than the other, you should expect to find an unwanted impedance on the other half of the circuit.
this can be balanced out by adding an impedance to the side with the greater amplitude. (or finding the problem and removing it)
to clarify this statement, the lower freq. side of the node indicates a lower impedance on the preceding half of the coil.
[time-based perspective].
If the amplitude of the maximum is greater on the high freq. side of the node, this indicates that the half of the coil which
is induced at a later [time] has a lower impedance. [Flux/Collapse].
It is important that both halves of the circuit maintain an equivalent impedance, as all other scenarios result in a lowering of
efficiency.
For the coil to behave in its' natural state, electricity must be able to flow consistently both IN and OUT of the coil.
Imbalances in impedance effect not only the location of the nodes on the frequency spectrum, but also the amplitudes of
the maximums preceding and following them.

and umm,,,, circular vs square? what??

no!

Fibonacci spiral. (duh!)



 

 

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1209 on: April 26, 2017, 09:05:49 PM »
author=Magluvin link=topic=17186.msg505364#msg505364 date=1493033673]

Took me a while to find this post lol,but i knew it was there some where.

Ok Mag;s
I didnt let you down--i kept on hunting-->and i found it.

Be prepared to be blown away--even MH will have to rethink how inductors/coils work--well in the case of the BPC anyway.
Were about to gain a new understanding about the BPC,that i have not seen in any other coil.

But first
I give all the Tesla BPC guru's a chance to put forth any differences they have found with the BPC,to that of any other coil.

The way this is going to happen.
First step-i will shoot a video.
I will then show TK the video,and ask him to confirm my findings.

Once that is done,i will post the video here,and show you what i have found.
I also believe i have an answer as to why this is happening--but we'll leave that till later.

Until then.


Brad

Such a tease. :-*    Well as said by Brad Pitt,,  Whats in the boooox?

Mags

tinman

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1210 on: April 26, 2017, 10:16:04 PM »
Such a tease. :-*    Well as said by Brad Pitt,,  Whats in the boooox?

Mags

The effect has been confirmed by TK.

I will post the test setup,and video showing the effect tonight after work.

Brad

evostars

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1211 on: April 27, 2017, 12:51:42 AM »
 :o Cliffhanger!
 ;D

Dog-One

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1212 on: April 27, 2017, 02:14:34 AM »
:o Cliffhanger!
 ;D

So is this confirmation of what you said evostars--at a particular frequency the magnetic field becomes stationary?

ramset

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1213 on: April 27, 2017, 03:22:51 AM »
I would imagine it will be 6 or 7 hours yet until the Tinman has access again.
to upload the vid.


TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1214 on: April 27, 2017, 03:27:13 AM »
The answer to Dog-One's question is "No".