Re: Extra coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 
> Original poster: "Nebojsa Kovacevic by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <morfeus-at-EUnet.yu>
> 
> Hello All!
> 
> Thank you all for the comments about the extra coil. I was considering that
> coil strictly from the
> theoretical point of view, don`t have any experiences with coils like that,
> only with 'regular' ones. But
> I would like to know from all of you who had the practical experiences with
> extra coils, what are the
> diferences, comparing the three system with two system coil? Is there any
> dieference, and is it really
> irrelevant?

A reason for building a magnifier structure instead of a two-coil
system exists if you want very fast energy transfer, with low loss
due to smaller time taken in energy oscillations in the system:

-With a conventional two-coil system, total energy transfer can occur
in just one cycle if k=0.6. Nothing faster is possible.
-This easily leads to insulation problems between the primary and
secondary, and the still mysterious phenomenon of "racing sparks".
- A solution is to split the secondary in two, moving the top part
to some distance away, as the "third coil". This requires even tighter
coupling between the primary and the secondary coils, as the overall
system operates with an effective lower coupling coefficient, but
now the voltages at the secondary coil are not so high, and insulation
problems are reduced. 

Up to this point, higher output can be obtained due to higher break
rates possible. Losses are smaller during the energy transfer, but
there is a problem:

- When the output voltage reaches the maximum, there is still energy
in the distributed capacitance of the junction between the secondary 
and the third coil, and in other parts of the system too, due to the
presence of this significant capacitance, that distorts the normal
operation of the system. This energy is not available to increase the 
output voltage or to produce more energetic sparks, and when the 
terminal is discharged, it is still oscillating in the system until 
complete dissipation, an is wasted as heat.
- If an extra capacitance is added in parallel with the secondary,
it is possible to reach a condition where all the energy is transferred
to the output capacitance. The design procedure for this is
described in my site http://www.coe.ufrj.br/~acmq/tesla/magnifier.html

By the way, I updated the page recently, with some extra material and
better equations.

What can be gained over a conventional two-coils system? Faster
energy transfer, and maybe somewhat higher voltage output, if the third
coil is mounted far from other parts of the system and the ground,
due to reduced self-capacitance of the third coil in this condition.

Unanswered questions are:
- Would the "racing sparks" phenomenon appear in a magnifier? I haven't
  seen references to this problem, but all the magnifiers described
  in the "literature" (the web) appear to not exploit the possibility 
  of one-cycle energy transfer.
- When will -I- build a high-power demonstration system to show that
  this really works? ;-) 
  It works at low power. I even have a 4 coils system that works.

Antonio Carlos M. de Queiroz