[TCML] solenoid primary coupling, in house coil

[Barton B. Anderson]

Hi Jim,

I'm not in agreement with version 9.1 at all. That's really an old 
version and couping is not good if your talking about the primary 
"below" the secondary by 2.5". Things didn't get good in Javatc until 
version 10 ;-) . Upgrade!

I'm interpreting the primary as a 16 turn helical with an 8" diameter 
also has about an 8" height. The top of the primary would need to be at 
3.3" above the bottom of the secondary winding for a k of 0.155.

I personally would recommend a coupling of 0.13 on this coil. Primary 
placement then is the top of the primary 2.5" above the secondary bottom 
turn.

I highly (HIGHLY) recommend updating Javatc to the latest version 
available at:
http://www.classictesla.com/java/javatc.html

It's not uncommon to run helical primary's low or even below the 
secondary. But in your case, you need to be a little above the 
secondary. To use all those turns you'll want to get the tank cap as 
close as possible for resonance (but keep an eye on the caps resonant 
value with the transformer as you should be above that value by about x1.5.

Doubt you'll be able to tune with the primary. Although there is more 
Cext with the helical versus a flat primary, the change in k is large 
with small changes in position. For minor tuning, you could use the top 
terminal height above the secondary or simply use some off axis inductance.

Jim Mora wrote:
> Hello All,
>
> I have a 4" 24" acrylic secondary wound 23.25" for about 1150 turns (25 or
> 26awg). Furthermore, I have wound an 8" primary with 16 turns of .25" Cu
> tubing spaced .25" (poly rope) on a 14" high acrylic form. The coil can be
> moved up and down on the form as the outside is epoxied.
>
> If I am interrupting my old version (9.1) of JavaTC the secondary needs to
> be above the top winding about 2.5" to get a k =.155. Does that sound right?
>
> What about an ideal ground plane distance? 
>
> I haven't played with a disruptive coil with a close solenoid primary
> before. If you are in agreement with my interpretation of the JavaTC run,
> what do you think about gluing a plexi disk about 3" from the top of the
> primary, affixing the secondary bottom to it, and adjusting the primary up
> and down to fine turn the coupling?
>
> The PSU is a static gap, forced air, 40-50ma 12kv repotted France neon.
>
> Am I interrupting the Java run correctly? Having the secondary above the top
> of the primary solenoid winding seems a bit weird. I would appreciate some
> feedback before I affix a base disk inside the primary tube a few inches
> near the top. Any corrections or suggestions welcomed. 
>
> Thanks,
> Jim Mora  
>
>
>
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