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Re: 2nd light of the "Green Monster" - sec vs. pri height



Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Jonathon,

The primary data is minimal (need to know inner and outer diam.). BTW, your cap is 0.0167uF and your sec turns are closer to 860.

Based on your coil data, if the flat pri is level with the bottom sec turn:

Pri to Sec clearance = 2", then coupling "k" = 0.125
Pri to Sec clearance = 1.75", then k = 0.128
Pri to Sec clearance = 1.5", then k = 0.132
Pri to Sec clearance = 1.25", then k = 0.135
Pri to Sec clearance = 1", then k = 0.139
Pri to Sec clearance = .75", then k = 0.144

It's funny, for such a long time coupling was always a "measured" sport. Nowadays, it's probably the #1 most accurate output of our programs.

Based on this data, it's likely you will achieve best energy transfer when the sec bottom turn is below the primary. But, as you can see, it helps to know the inner diameter. If I had that, I would have given the various k values at various heights.

BTW, regarding your 11 turn primary. If it is tapped at 11 turns, then you would need about a 37pF topload (9"x33"). I'm not sure of the topload size you have but I doubt it's that big (maybe). If the topload is something less, then if tapped at 11 turns, the coil is definitely out of tune.

Take care,
Bart


Tesla list wrote:

Original poster: kidd6488@xxxxxxx
Ok, this is one aspet of my coil I haven't really messed with in the past. Quick specs: 12/60 NST 1x9 geek cap MMC (forget the specs off hand) multiple static spark gap. ~11 turns flat spiral primary of .25" Cu tubing. about 30x6 secondary #20AWG (~900 turns?)


Right now my coil can only be raised above the primary. Would it be worth my time to try and adjust this up? It is doable but would take considerable work to do so. Also, would it be worth it to try to lower it? This would take a LOT of work, requiring some cutting of my nice little table and changing / jury rigging some of my neat wiring work.

Just up for suggestions... Also, do you have to be subscribed to the list to post to it? I sent one in from my work email, but then realized it might not go thru.....

thanks,

Jonathon

-----Original Message-----
From: Tesla list <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Sent: Mon, 08 Aug 2005 08:01:27 -0600
Subject: Re: re: 2nd light of the "Green Monster" - sec vs. pri height

Original poster: <mailto:DRIEBEN%40midsouth.rr.com>DRIEBEN@xxxxxxxxxxxxxxx
Jonathon,

This affects the primary/secondary inductive coupling.
With smaller coils, optimum coupling (the point at where
maximum output sparks are achieved WITHOUT racing sparks
running up and down the surface of the secondary coil)is
generally achieved with the bttom of the secondary coil
level with or slightly below the plane of the primary
coil, assuming that the primary coil is of the flat Ar-
chemedian spiral design and assuming that the secondary
coil is in the typical aspect ratio range (4:1 to 5:1).
However, with the design of large, high powered coils of-
ten dictates lower optimum coupling than with smaller coils.
Large secondary coils often run at the lower end of or be-&n
bsp;
low the typical aspect ratio and the output spark of a
large well designed and tuned system can reach up to 3
times the length of the secondary coil. Dr. Resonance has
suggested that the bottom of the secondary can be as high
as 7" to 9" above the primary plane for very large coils.
Having your secondary's verticle placement permanently
adjustable is a great feature to have in your coil. On the
down side, that feature is quite difficult to build into
a coil system and I my mechanical aptitude wasn't up to
par to allow me to build that into my coil ;^(

David Rieben

David Rieben

----- Original Message -----
From: Tesla list <<mailto:tesla%40pupman.com>tesla@xxxxxxxxxx>
Date: Sunday, August 7, 2005 8:37 pm
Subject: Re: 2nd light of the "Green Monster" - sec vs. pri height
 > Original poster: <mailto:Kidd6488%40aol.com>Kidd6488@xxxxxxx
>
> Perhaps I've been away from coiling from too long, but aren't most
> coils either level, or the secondary is BELOW the primary? Mine
> is
> built to be adjustable but only from 0 to several inches above the
> primary.... What exactly does this change when changing the height?
>
> Thanks!
>
> Jonathon
>
> In a message dated 8/7/2005 12:05:52 A.M. Eastern Standard Time,
> <mailto:tesla%40pupman.com>tesla@xxxxxxxxxx writes:
> The bottom winding of
> the secondary coil sits at 5/8" above the plane
> of the primary coil.
>
>
>
>
>