Re: 10 Questions to help me construct my first TC

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Harvey,

At 12:02 PM 12/15/2002 -0800, you wrote:

>--- Tesla list <tesla-at-pupman-dot-com> wrote:
> > Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> >
> > Oops,
> >
> > "John's formula you mention is really great!  "Power
> > is proportional to
> > spark length" really is the key regardless of many
> > other things.  You are
> > looking at 15 to 20 inch arcs as the formula says."
> >
> > Actually, "spark length is proportional to the
> > square root of input power".....
> >
> > Cheers,
> >
> >       Terry
> >
>That would mean that it isnt really proportional, more
>like inversely exponential?  Do they call that a
>logarithmic relationship? My math is rusty here! What
>you are implying of course is that for twice the arc
>distance, 4 times the original power input would be
>required, correct?  HDN

Yes, four time the input power = 2 times the streamer length.


>Another question I have that really bugs me is this. A
>LTR cap on the tesla primary is often cited. Is this
>larger than resonant?

Yes, often about 2.5X in a sync gap system.

>Then there is the problem that
>if we rate the max delivery of the current limited
>transformer, find that largest capacity it can supply
>with that current by finding the capacitive reactance
>X(C) value to match to the rated voltage, then we have
>a peculiar problem. Since the transformer secondary is
>current limited by the impedance, (predominantly
>inductive reactance, when we then match that value of
>capacitive reactance with it as a load, this is
>essentially "series resonating" the secondary, which
>means we should then expect a higher than rated
>voltage output, and consequently more current delivery
>than what the current limited spec.s specify.  This
>would be a bad practice, No?

Hey, we do it real careful :o))  We load the NST with capacitance so much 
that the voltage falls back to it's normal value.  However, the current 
is  "higher".  NSTs don't mind delivering extra current since they are made 
to work in like Las Vegas in the sun 24 hours a day.  We might draw 90mA 
for a 60mA NST.  Not a big deal at all, but that is where the extra energy 
comes from.  We can also do this without raising the voltage avoiding all 
those problems.

>The voltage would be
>going higher than the secondary was designed for, thus
>sensibly speaking we would be stressing the secondary
>beyond its ratings. Is this what happens or not?

That is what would happen with a resonant system doing the same thing.  But 
we load it down with capacitance to reduce the voltage and use the extra 
current.


>My
>second question about this is simple enough, and
>obviously I must be having a misunderstanding here.
>Since it is the C value that we use that determines
>the frequency that will be produced by its combination
>with L of the primary, how can we just arbitrarily
>increase that C value, (as this larger than resonant
>LTR acronyn implies), without in of itself having that
>practice CHANGE the resonant frequency of the primary
>tank itself.

You DO have to return the primary (take primary turns off) to match the 
secondary always.  Since most LTR systems are designed like that it is just 
tuned the first time with the new cap.  However, if one goes from resonant 
to LTR, you do have to retune the primary coil substantially.


>So this issue totally confuses me. Are
>folks instead reffering to a cap in parallel with the
>NST primary as a power factor correction?

Nope, nothing fancy.  Where are just using bigger primary caps.

>That would
>typically be a large capacity. Logically thats the
>only way I can figure what it is that is being talked
>about. Any light at the end of the tunnel here? Do I
>need a crash course on acronyms?

I think the above will clear it all up. Richie's site also has great 
information on all this:

http://www.richieburnett.co.uk/tesla.shtml

http://www.richieburnett.co.uk/resonant.html#resonan

http://www.richieburnett.co.uk/indkick.html#kick

Cheers,

         Terry



>Confused in Ohio.
>HDN