Re: Smaller than resonance?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Harvey Norris <harvich@xxxxxxxxx>


--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Justin <rocketfuel@xxxxxxxxxxxxx>
>
> Hi All,
>
>
> I'm trying to figure out the right size tank
> capacitor bank to use with
> my new potential transformers.
>
> After much thinking and poking around on the net,
> I've come to the
> conclusion that pole pigs, potential transformers,
> and any other
> transformer (not just NSTs) can hit a resonant
> condition with the tank
> cap.
I am a little confused here, are you reffering to the
capacity used in the tesla primary resonating with the
ferromagnetic trnsformers secondary input, or are you
referring to a power factor correction to be made to
the transformers primary?  I would suppose those two
factors might be interelated since it is the
secondaries load that causes the impedance of the
primary to drop.


Please correct me if this assumption is wrong.
>  From what I
> understand today, it seems that the resonant cap
> value is a function of
> the inductance of the HV secondary and the line
> frequency.  Not sure if
> the primary side inductance has an effect.  It would
> be nice if I could
> simply measure the inductance of my transformer with
> a meter and work it
> all out on paper, but I have a hunch that a reading
> on a non-energized
> core will be different than when current is flowing
> through the
> transformer.
I am very interested in these saturation curve values
at the low end effect, as I am making an experimental
transformer where the primaries amp turns value will
be very low on the first model,(only 9 winds) and the
ferromagnetic core will instead be structured from
insulated steel windings, so I am wondering whether I
need a certain amount of minimum primary amp turns to
excite the magnetism of the core. Isn't it true that
on the saturation curve there are non-linear effects
both on the top end AND bottom ends?  This is
dramatically shown in the  bottom and top  ends of the
saturation curve of the rotating field of an
alternator interacting to produce flux change on the
transformer type stator windings.  I can say that an
ordinary NST current limited transformer will work
with a 4 volt input, as I used a variac to drive the
NST at that level in the production of current limited
silver colloidal water some time ago. I seem to recall
that at 1 or 2 volts, the expected voltage ratio on
the secondary output did not seem linear.  I will have
to look at these effects again.
>
>
>
> On to my "real" question.  In looking over several
> other people's coils
> online, it seems that many are running much smaller
> than resonant tank
> caps with these larger transformers with no
> problems.
How can you even ascertain what a resonant cap value
would be if you are not using a current limited
secondary?  Can a pole pig for example have a current
limited output measurement made by shorting out the
secondary outputs, simply by ballasting its primary?
Perhaps I am being silly here because thinking about
it, I suppose it could be done since the primary can
only consume so much amperage by proper ballasting,
and as long as the amperages are in the permissible
range, this secondary short measurement should be
possible.

 I say smaller
> than resonant as a guess based on results I've seen
> from JavaTC when
> entering the parameters listed on these coil sites.
>
> Is it possible to run STR rather than LTR to protect
> the transformer and
> capacitor bank?  Of course everything will still
> need to be matched and
> tuned.
>
>
> Thanks for any input,
>
> Justin in Austin
>
>
>