Re: High K lower pole tuning DRSSTC (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 29 Oct 2006 14:26:56 -0800
From: Jimmy Hynes <jphynes@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: High K lower pole tuning DRSSTC (fwd)

Hi,


> I think that DRSSTCS shall be designed with the drive frequency between
> the two resonances. This is what results in the minimum input current and
> maximum efficiency. The driver must be kept on until the first notch in
> the primary current, and then switched off. Excitation at the resonances
> increases the output voltage, certainly, but also increases even more
> the input current and reduces the efficiency.
> The voltage gain is inversely proportional to the coupling coefficient.
> Values around 0.1, or even somewhat lower, appear to be the best.
> The resistance of the secondary wire has little effect.
> http://www.coe.ufrj.br/~acmq/tesla/drsstc1.pdf
> http://www.coe.ufrj.br/~acmq/tesla/drsstc.html
> I will soon update these files with a practical full power example.
>
> Antonio Carlos M. de Queiroz
>

That was my original idea with the DRSSTC, and I agree that it's
better in theory. In practice, however, I found that it didn't 'notch'
very well because the leaders throw everything out of whack. This
became harder and harder as K was lowered, so I eventually gave up and
used the lower pole.

"If I increase the primary L instead of increasing the capacitance then I
would be able to give better exitation of the secondary and create a slower
wave system so it has just a bit faster energy transfer and keep the peak
power the same while kepping the lower secondary lower pole frequency making
it more efficient because the losses are less.

Josh"

I'm not sure what you mean by "better excitation" or "slower wave
system". If you are driving at the lower pole, you won't get notches,
so the 'magic Ks' are not so special anymore.

If you are running the lower pole, and not notches, then coupling and
energy transfer aren't directly tied anymore. You can drive it for as
long as you'd like. The total energy transferred in that time can be
set by choosing the right LC surge impedance; larger L and smaller C
means higher Z, and less power.