Bifilar pancake tesla coils, pulsed at longitudinal mode

evostars

Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #50,  »
if the longitudinal transmission should fail, it might be due to the dielectric field sticking in between the bifilar windings. If so a near field transmission should be examined.

Konstantin Meyl's unifilar pancake coils seem to have some distance between the windings. this might prevent the dielectric field to build up inbetween the windings. the added ball capacitance is then becoming the part where the dielectric field can radiate.
but not outwards, but inwards to the center of the hollow ball where it is grounded in counterspace.

this dielectric ground makes it possible to oscillate the earth ground connection.
Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #51,  »
I have now a setup with the two coils.
both coils are a phi hole primary and a secondary around the primary (same plane pancake).

I have made used a metal plantcup as a capacitance.

both coil resonate at around 1000khz.

but so far no resonance at the second coil.

but... I do get this signal on the earth connection. I put the probe on the radiator when i made this picture.

setting was 2V per division.

why is there a signal on the earth ground i wonder? and... its fits inside the resonant frequency of the coil but its a few octaves higher.

I wondered if that signal coild be from a AM radio. but those are almost all gone around here. I did have contact with a am transmitter nearby but they only transmit at 675khz. the signal is more around 4mHz

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Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #52,  »
why are those photos always in landscape mode?
Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #53,  »
why doesnt the second coil set resonate?
might it be because the bifilar coil is not suited? because the dielectric field is stuck between the windings instead of around the external bal capacitance?

I will need to rewire the coils into unifilar mode. but that whould also raise the resonantfrequency.

I think it's more interesting to see what happens in the near field of these coils.

with these two I can stack them(with a gap inbetween equaling the diameter or radius of the center hole) and pulse both coils into resonance. see what happens.
transmission 100% one wire
« Reply #54,  »Last edited
BINGO :P

played around with the setup.
removed the outside capacitance.
 removed the earth connection from the transmitter coil. put a probe in the middle and connected the outside of the resonant coil to the outside of the reciever coil with a long wire.

at the reciever resonating coil I grounded the inside hole to ground (removed the external capacitance and replaced it with ground).

the outside coil was grounded in the center and probed on the outer end.

both coils showed a resonant voltage rise of 100v sine wave.(!)

no external capacitance was needed.
I do have some doubts:
the transmitter resonant coil is grounded via the reciever coil. this means the transmission is via the wire and cant be replaced by the earth connection. A solution would possibly be a capacitor to ground where the probe is at the transmitter coil. still this leaves the wire in place (still not bad simce its a single wire).
 :cool:

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Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #55,  »
this was at around 1080 khz
the coils seemed to be a slightly detuned.

when I placed my hand (change of capacitance) on the reciever coil both signals changed (one resonant system).

is there another signal at pi/2 higher frequency? and is the pulse signal weaker at this point?
Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #56,  »
The pulse generator is with the earth connectected to the outside rim. the positive is on the inside. the earth is switched by the igbt to ground.
this makes a 2200uF 12V capacitor discharge to ground via the coil.  I want to determine a spin direction... but I cant.
The transmitter coil resonates with the pulse of the primary.
The probe has a small capacitor inside that is connected to one end of the coil.
 the other end is connected via a wire the the reciever coils outside rim. the inside rim of the reciever coil is connected to ground.

Is one coil spinning inwards, and the other coil spinning outwards? Due to the earth and capacitance connections?  Yes it seems so.

The receiver outside coil is probed on the inside rim and grounded on the outside rim.

The sine wave is still confusing me. What is really happening? is it a standing wave? is the pressure wave simultaniously over the whole lenght of wire? Is there still a transverse or longitudinal motion along the wire from A to B?

Is earth ground a fixed stable body? I have seen there is a 5mHz 8V signal on it.

This earth ground signal doesn't make sense to me. What if the coil would resonate at that earth ground signal? would the earth start to resonate? There is a amateur radio band 60m  that operates at that frequency. but a radio signal should not be stable. it should modulate.
Re: Bifilar pancake tesla coils, pulsed at longitudinal mode
« Reply #57,  »
Al this seems a bit of a waste.
I already had the single wire transmission. nothing new here. the signal is even much weaker.
a resonanting bifilar coil by itself transmits the resonanting frequency through one wire.
It even transmits through the air. As I can see the resonanting signal also on metal items in the room.
So...
Nothing new.

I will now start to focus on the Bemf and Bmmf.
Back Electro Motive Force from the collapsing magnetic field (inductor)
Back Magneto Motive Force from the collapsing dielectric field (capacitor)