Re: 3 Coil System Was: A photographic tutorial ofPancakeCoilwinding...with movies...(fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Mon, 25 Jun 2007 04:46:09 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 3 Coil System      Was: A photographic tutorial
    ofPancakeCoilwinding...with movies...(fwd)

Hi Dave,

>>I think we have made some progress to understand views of 
>>inductive coupling. Good discussion.
>>    
>>
>
>Yes, I agree.  You have corrected a couple errors in my thinking.
>
>The inductive coupling on my coil must have existed, even though it was
>minimal.  Still, that would explain why there was a discharge on the
>topload.  As Bert was pointing out, a discharge of any kind demonstrates a
>non-zero current.
>
>According to the longitudinal wave idea I am developing, it would be
>necessary to eliminate inductive coupling to eliminate current.  It is also
>necessary to maximize potential by maximizing resonance.  
>  
>
What do mean "maximize resonance"? For me (engineer), resonance is a 
frequency where maximum current is possible. This occurs when inductive 
and capacitive reactances are equal and opposite, resulting in zero 
reactance (ideally) and why resonant rise occurs.

>You made it clear to me that a coil can act as a capacitor in a three coil
>system.
>
Yes, every object will. A coil, a cylinder, and even a cup of coffee. 
Hey, there's an idea. Forget the telescoping cylinder and just fill up a 
liquid in a plastic cylinder.

>It is the capacitance I want to utilize in developing and
>maintaining standing waves on the third coil.  So it makes perfect sense to
>eliminate the wire windings of the third coil and simply use a copper tube.
>  
>
You'll have to prove that one to yourself first, then us.

>Will the inductive coupling be the same for a copper tube, as opposed to a
>wire wound tube?
>
No. The inductance of the tube is much smaller. For example, a tube 2"D 
x 20"L is about 0.3uH (really small). The coupling is a product of the 
mutual inductance. Thus, consider the inductance of the tube. The tube 
is just a really short fat wire. Think of it that way. You could calc 
the tubes inductance in Javatc using the lead length inputs. It's 
designed for lead inductance, but just throw in your tube dimensions 
(may need to install a primary coil to get it to calc anything).

>know that in a waveguide the copper tube will have
>inductance and capacitance as though it were a wire wound coil.  But Bert is
>saying a copper tube in a third coil position is not a waveguide because it
>is too low of a frequency.
>  
>
He is saying that if the cylinder is to be used "as a wavequide" with 
the frequency of the driver, the cylinder is 3 magnitudes off. Maybe the 
term "wavequide" should not have been used.

>I am not interested in waveguide properties.  If there is no waveguide, then
>there is no inductance, is this correct?
>
The tube has inductance regardless, it's just not enough to be a factor.

>All I want is the capacitance
>property of the tube so that I can create standing waves of electrons on it
>and have no inductive coupling to the secondary.
>
And that you have. The tube "will" act upon the secondary as a topload 
object with a capacitive effective on the distributed capacitance.

>I have the parts on order to build a telescoping tube for the third coil.
>The telescope property is necessary from what I saw with JavaTC.  Changing
>the capacitance changes the primary/secondary frequency, and changing the
>primary/secondary frequency changes the capacitance needed for resonance
>(The herding of cats thing).
>
Yes, exactly.

>Using my own speed of electron wave constant,
>  
>
Well, there you go off into electron wave stuff... <grin>

>I calculated the range of the tube length I will need.  The tube would be
>too long for a 1:1 octave ratio, so I'm using the 1:3 octave ratio
>previously used in my combination coil.  In fact, I'm using the old 25.25"
>flat spiral for this experiment since it has a better coupling ratio than my
>new system. If I can afford it, I'm also going to change the primary cap to
>.0055uF.
>
Experiment. But, also measure at least the most basic properties 
(inductance, coupling, and frequency).

>If you would post your method for measuring inductive coupling, either to
>this list or to a web page, I would greatly appreciate it.  I want to do
>some measurements of my own to get familiar with the coupling strengths in
>various situations.
>
http://www.pupman.com/listarchives/1997/november/msg00898.html

The above link is an email from Terry Fritz many moons ago. It's the 
best method for measuring coupling that I have found. I've done it a lot 
of different ways, but this is easy and accurate. Note that the current 
through a coil must be as constant as you can make it. I've used giant 
resistive loads, elements, and other gizmo's, but they heat up and the 
current will change drastically. What I have found the most suitable 
ballast for this test is a simple everyday hair dryer. A hair dryer has 
the ability to provide 5 to 10 amps of current through the coil and 
includes a high output fan to cause the heating elements in the hair 
dryer to reach a balance in temperature and therefore a stable current. 
Once this balance is reached (and it doesn't take long), the current 
remains constant. Big hairdryers produce more current which is desired. 
But even a small hairdryer will do fine.

The second successful tool is to ensure you have 2 meters (one to read 
amps, the other volts) side by side so that you can take concentric 
readings. This ensures current and volt readings are on target. If you 
try to do this with 1 meter, your error increases substantially.

It's simple, but do be careful with AC leads lying around.

Take care,
Bart