# Re: [TCML] Back again....and Tesla Magnifier Tuning

And that is, i still think, the one and only benefit of a Magnifier System - in separating the driver equipment from the tertiary coil, which produces the sparks. I can't see any reasons, why a 3-coil system should produce longer sparks, than an equivalent 2 coil setup - and thats the goal we all go for - doesn't it? ;-)
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Am 09.08.2018 um 14:34 schrieb Greg Peters:
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```Thanks for all your advice Antonio.

In that case I think I will stick with conventional 2 coil systems.

Although the idea of leaving the cumbersome driver set up in the garage
permanently and just being able to erect the extra coil outside quickly
when needed is tempting... Much easier than moving a big two coil system!

On Thu., 9 Aug. 2018, 1:17 am Antonio Queiroz, <acmdequeiroz@xxxxxxxxx>
wrote:

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```  Em 07/08/2018 06:20, Gregory Peters escreveu:

Thanks Antonio,
Having to match the parts so carefully certainly would be a challenge
and does put me off the project a bit. In the unoptimised version,
does the tighter primary:secondary coupling offer any performance
increase over a regular two coil system? My simulations don't suggest
it does, but it seems it should given that magnifiers are routinely
run with K > 0.5.
I have a few other questions I may contact you off-list about.
Many thanks!
Greg.

The tighter coupling is just a consequence of the small part of the
secondary-tertiary system that is coupled to the primary.  From  one of the
formulas in http://www.coe.ufrj.br/~acmq/tesla/magnifier.html, if the
secondary coil of the conventional Tesla coil
is split in two coils with inductances L2 and L3, and k123 and k12 are the
coupling coefficients for the conventional coil and for the magnifier
driver respectively, the system has the same behavior if k123 =
k12(L2/(L2+L3))^(1/2). For example, if the original secondary coil
inductance
is split in a 8:1 ratio, k12=3*k123. Of course this assumes negligible
capacitance across L2.

Antonio Carlos M. de Queiroz
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