Peter, whatever happened with Eric P. Dollard?

[jake]

There's some issues with the equations for the extra coil, not sure if it's just a misprint or haste. I've worked through the secondary coil dimensions and although at first blush they work out, they are also the basis for the extra coil. The Eq Eric has for the spacing factor seems odd. I'm working on the fundamentals of the math behind the dimensions still, hope to have something by morning.

That's what brought me out of the closet.

Why the spacing?????? Eric Please why??

[Kokomoj0]

That's what brought me out of the closet.

Why the spacing?????? Eric Please why??

I was thinkin it has something to do with the capacitance between windings. when you move 2 surfaces farther apart the working capacitance reduces. I just assumed he is attempting to make a coil as purely inductive as possible? The problem of course is that it will also reduce the inductance, so maybe 62% is the best compromise distance?

[lessismore]

I do not know why.

<two cents>
But I do notice that 62%, 0.62, is an approximation of 2 / (1 + sqrt(5)), or 0.618 (rounded to 3 digits), which is the inverse of the Golden Ratio, (1 + sqrt(5))/2
</two cents>

[madhatter]

I do not know why.

<two cents>
But I do notice that 62%, 0.62, is an approximation of 2 / (1 + sqrt(5)), or 0.618 (rounded to 3 digits), which is the inverse of the Golden Ratio, (1 + sqrt(5))/2
</two cents>

I noticed that too, it may be a coincidence though.

[pnajafi]

Pancake shape

pnajafi,

"Does anyone know why pancake coils generate more voltage than an standard coil between each turn?"

I think it is caused from distributed capacity or mutual-capacity K. We have e, or voltage seen from mutual capacity, E, the reactance voltage, and finally, ((i+I)r) or the voltage drop due to current flow against a resistance. e & E can add depending upon their phase orientation, whereas ((i+I)r) is always a voltage drop. So bringing it altogether; ((j(i+I))r)-j(e+E)=Volts (induced voltage would be negative), the phases of the currents i & I and voltages e & E need to be taken into account for this equation to be useful. Note that this is very different from a parallel or series LC circuit, and could be seen as a type of parallel LK circuit, even though we think of it as just another inductor. My 2cents, hope it helps.



Garrett M

Thanks. This gives me more clues and connection on what to look for. Do you know whether Tesla experimented more and used just intuition to come up with it or he actually was aware of these mathematical theories,etc and worked from there?

[madhatter]

apperantly editing isn't working...
Update to the 62%

It seems very related to the skin effect and maybe Erics calculation for the proximity effect. As the skin effect is related to 1/e and 63% of the current in the depth, possibly this was the relation.

[Kokomoj0]

I noticed that too, it may be a coincidence though.

yeh same here, 1.6, .6, numbers I use in acoustic design, Fibonacci popped into my head too.

Fibonacci number - Wikipedia, the free encyclopedia

[dR-Green]

Notes on the Crystal Set

When measuring the velocity difference between underground and our ground, the two seperate receivers can be brought into phase unison by the use of a test oscillator. Both receivers must have a primary tank circuit, here you can place your measurement equipment.

The detected AM output, audio frequency, signal is immune to receiver phase shift. This is a property of A.M. detection. Use the audio to measure propagation delay.

Using more than one method of testing to reduce the margin of error as much as I can. Radio station is broadcasting at 882kHz. 555 signal generator is not 100% stable, multiple readings taken. Fluke scope doesn't display actual reading in Scope mode but seems to round it up or down (varies between 862-892kHz but won't display 882kHz as it will do in Meter mode). Audio signal of the normal receiver was very poor with a lot of noise so software scope shots are also included. Under ground receiver required up to -18.31dB and over ground receiver required +6.02dB gain to get the levels somewhat equal to my ear. PicoScope when not running is displaying current value reading of the whole sample, not the average.

Test oscillator signal







Waveform A (Blue) (Left audio channel) = Tesla receiver
Waveform B (Red) (Right audio channel) = Normal receiver

Receivers in phase unison











Received radio signal

[dR-Green]

Audio signal

[7imix]

I think the reason for the 62% spacing is because you have to think of each pair of windings as a capacitor. As the windings get further apart, the distributed capacitance between every turn starts to add up. The farther the plates of a capacitor are apart, the smaller the capacitor. Therefore, the farther the turns in a coil are apart, the smaller the distributed capacitance of the coil. You can see tesla calculating this and talking about it in "Colorado Springs Notes."

And yes, the relation to fibonacci sequence is highly likely.

Most "tesla" coils that people build have narrow diameters, close-spaced turns and many, many, many turns, making for a much greater capacitance relative to inductance. It seems tesla was trying to do the opposite, make the inductance as large and the capacitance as small as practical, while still matching the inductance to capacitance for quarter-wave resonance.

[garrettm4]

Tesla Transformer Windings

7imix,

I would have to disagree somewhat with what you just wrote. In the secondary I believe you increase the diameter of the windings and decrease the number of windingss to proportionate the magnetic field to dielectric for a subsequent balanced ELECTRIC FIELD as per Mr. Dollard's "Transmissions" have pointed out (less turns less magnetic energy, larger surface-area between turns more dielectric energy). I may be wrong but I believe that the two voltages e & E are designed to nullify one another in the secondary BUT the currents i & I DON'T. Thus creating a MONO-POLAR or longitudinal current for ONE WIRE transmission through the earth (with an appropriate receiver of course). The extra coil, which isn't always used, on the other hand is made to do the exact opposite, or have the least self capacity and mutual inductance while having the most self inductance and possibly mutual-capacity as well. Here the currents i & I nullify leaving only a mono-polar voltage. The terminal capacity, and its delay line, may be used to control the voltage gradient emitted by the extra coil, which is clearly seen to be a problem in the Colorado Springs transmitters. The exact relation of the secondary and extra coil is a bit cloudy for me right now. Exactly how these all work together, I'm unsure at the moment.

Garrett M

[madhatter]

a note on conductor spacing, since the height is a fixed dimension per the diameter in both secondary and extra coils the spacing eq. should look something like this:

H-(d-N)/N-1

where:
H = hieght of coil
d = Diameter of wire
N = number of turns

This will give the tangent spacing between wire per turn.

I was also thinking, and this is beyond what Eric has stipulated. That the 40% size of the extra coil to the secondary might be adjusted to 37% based on the 1/e ratio. Meaning that if the secondary coil is treated as a cross section of a conductor and the skin effect is 63%, then 37% might be enough to keep the extra from being mutually induced. it also plays into the proximity effect as well.

I've been trying to figure where Eric came up with the Pi^2/4 constant for conductor length. why 1/4 of the squared ratio as a multiplier?

[madhatter]

This is real PITA! the edit function is a not working!

The above equation should read: H-(d x N)/N-1

[madhatter]

running the eq you'll notice that the numbers will still be negative unless you use the active copper dia as the wire dia, however this poses the issue of wire gauge, as this gets into very fine gauge.

[jake]

Active Copper Volume

Is it correct to say that:

When using a solid conductor the active copper is equal to:

[(pi) * (d/2)^2] - [(pi) * ((d/2)-g)^2)] * lenght

d=diameter
g=skin depth=10/sqrt(F)
F=frequency

And then use an equal volume of copper primary?