Re: Tuning, toploads and tank caps

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jonathon,

On 25 Jul 01, at 16:08, Tesla list wrote:

> Original poster: "jpeakall by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jpeakall-at-mcn-dot-org>
> 
> Malcom,
> 
> 
> 
> > Firstly, your cap claulation is in error. Putting two in series
> > halves the capacitance and for the same gap setting, cuts the primary
> > energy in half. Leaving losses out of it that means your output
> > voltage will have dropped by SQRT(2).
> 
> The caps I refered to arent two of the 7nf ones. It is a maxwell .035uf and
> a resonace research inc .025 in series. Both are a little off thier rated
> specs.

I stand corrected on which caps you're using. It's not a good idea to 
series two different capacitances - they will share voltage 
unequally. By my calc, you get about 14.6nF with that combination.  
> 
> > Your biggest problem is the operating frequency of your coil which
> > demands a low primary inductance be used. You aren't left with too
> > many tapping options by the time only three turns is in the circuit.
> > Ironically, you should be tapping more turns in for your series cap
> > combination and that will reduce you primary losses and might well
> > offset the drop in output voltage caused by the energy reduction.
> 
> And this is determined by the # of wraps on my secondary, so other that
> lower tank capacitance, my only other option is to wrap another 2dry (which
> I am going to do anyway, just getting it all straight) with more wraps.

Good luck with your action plan. I expect that by now the problems 
are becoming clear.

Malcolm