Re: RE: Heat & Rotary Gaps (success?)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: DRIEBEN@xxxxxxxxxxxxxxx 

Gary, all,

Yes, having a secondary coil in place (or a suitable
dummy load) is important when firing a coil. Also, a
poorly (too loosely) coupled secondary coil can cause
these same issues to a lesser degree. I had noticed
that when initially tuning in my Green Monster Tesla
coil system: www.dawntreader.net/hvgroup/david/gm
With the secondary coil set at about 4" above the
plain of the flat spiral primary coil, the rotary gap
component electrodes would get VERY hot in a pretty
short order. Also, the primary capacitor would get pretty
warm to the touch fairly quickly and the output was li-
mited to a dismal 6 to 8 ft sprarks with a 15 kVA pig
and a .1 ufd primary cap. Once the secondary coil was
lowered to about 1" instead of 4" above the primary
plane, then the output grew to a more respectable
11 to 12 ft and the primary circuit components were
having a much more reasonable thermal gain. If I lowered
the secondary coil anymore, I fear that over coupling would
occur along with the dreaded racing sparks.


David Rieben

----- Original Message -----
From: Tesla list <tesla@xxxxxxxxxx>
Date: Saturday, October 22, 2005 9:23 pm
Subject: RE: Heat & Rotary Gaps (success?)

> Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
>
> Running a coil without a secondary is extremely stressful on one's
> caps,and would explain why your gap got so hot.  If you want to
> run things
> without a secondary, construct a dummy load out of a string of 6
> or more
> (?) 150W/120V halogen bulbs and use that in place of your primary.
> With
> my 15/60, I used 4 lamps.  You'll need more, but I can't predict how
> many.  That will safely dissipate the power and it will also allow
you
> to determine the best gap phase setting by noting when the lamps are
> brightest.
>
> Chokes?  Between the gap and NST for protection?  Loose them -
they'll
> either do no good or make matters worse, particularly it they're
> air-core.  See my web page on protection networks at
> http://www.laushaus.com/tesla/protection.htm for full details.
> How do
> you know the chokes are dampening kickback?
>
> Regards, Gary Lau
> MA, USA
>
> > Original poster: tesla popp <teslas_lab@xxxxxxxxx>
> >
> > Good question.  I didn't have a secondary in it at the
> > time.
> >
> > I now have assembeled one of the twins and I am a bit
> > irritated.  It is only making 4' sparks at the ~15/120
> > I am getting from the tranny.  My chokes are really
> > dampering A LOT of kickback.  Now that the secondary
> > is in it, my trannys safety gap is firing at 98% full
> > power, which makes me leery.
> >
> > Thanks for getting to the point.
> >
> > Coiler forever: Jeremiah Popp
> >
> > --- Tesla list <tesla@xxxxxxxxxx> wrote:
> >
> >  > Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
> >  >
> >  > When running an NST through a Variac, the optimal
> >  > phase setting of the
> >  > SRSG will vary depending on the Variac setting.
> >  > Additionally, NST's are
> >  > not the well-behaved linear devices that intuition
> >  > and simulation models
> >  > would have us think.  Ferroresonance occurs at
> >  > higher mains voltages,
> >  > causing an LTR cap to become mains-resonant, and
> >  > draw lots of power.
> >  > Very bizarre stuff and impossible to predict or
> >  > model.  But it does
> >  > effectively supercharge an NST power supply.
> >  >
> >  > Have you metered your NST primary current?  That
> >  > will give a better
> >  > indication of how much power is actually being
> >  > processed by your gap.
> >  > My 15/60 NST pulls close to 20 Amps on the
> >  > input-side of my 120VAC
> >  > Variac, and this is WITH PFC caps.  And as such, my
> >  > propeller gap
> >  > spinning rod is just moderately warm.
> >  >
> >  > I have to ask what may be a dumb question - do you
> >  > have a secondary in
> >  > place and is it properly tuned?  If no or no, then
> >  > the power cannot be
> >  > transferred to streamers, and will be expended as
> >  > heat in the gap
> >  > instead, which may be what you see.
> >  >
> >  > Regards, Gary Lau
> >  > MA, USA
> >  >
> >  >
> >  >
> >  >  > Original poster: tesla popp
> >  > <teslas_lab@xxxxxxxxx>
> >  >  >
> >  >  > Ok, I have a 15/120 NST.  My cap is 0.05uF
> >  >  > Tungstin rod got hot enough to change color.
> >  >  >
> >  >  > I ran it for 30sec and it seams like it won't get
> >  >  > overly hot if I have everything in phase.  Yet,
> >  > if I
> >  >  > run it at 70% power, it gets hot twice as fast!?
> >  >  >
> >  >  > Coiler Forever: Jeremiah Popp
> >  >  >
> >  >  >
> >  >  >
> >  >  > --- Tesla list <tesla@xxxxxxxxxx> wrote:
> >  >  >
> >  >  >  > Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
> >  >  >  >
> >  >  >  > You didn't say what kind of power supply
> >  > you're
> >  >  >  > using?  With my 15/60
> >  >  >  > NST, the rotating rod gets just moderately
> >  > warm.
> >  >  >  > But I'm sure if one
> >  >  >  > were using a pole pig, that may be pushing
> >  > one's
> >  >  >  > luck.  You are using a
> >  >  >  > shield in case things go bad, right?  I
> >  > couldn't
> >  >  >  > comment on a subjective
> >  >  >  > "too hot to touch" without an actual
> >  > measurement,
> >  >  >  > but it is cause for
> >  >  >  > concern.
> >  >  >  >
> >  >  >  > Regards, Gary Lau
> >  >  >  > MA, USA
> >  >  >  >
> >  >  >  >  > Original poster: tesla popp
> >  >  >  > <teslas_lab@xxxxxxxxx>
> >  >  >  >  >
> >  >  >  >  > Just set up one of my twin coils with a
> >  > propeller
> >  >  >  >  > gap...
> >  >  >  >  > I found that after 10 seconds at 50% power,
> >  > the
> >  >  >  >  > rotating tungsten rod was far to hot to
> >  > touch!
> >  >  >  >  >
> >  >  >  >  > Should I be worried about the "heat" VS the
> >  >  >  > SRSG's
> >  >  >  >  > plastic the  case /melting the high density
> >  > PVC
> >  >  >  > that
> >  >  >  >  > holds the rotating tungsten rod?
> >  >  >  >  >
> >  >  >  >  > Jeez is this thing LOUD!!!
> >  >  >  >  >
> >  >  >  >  > Coiler Forever: Jeremiah Popp
> >  >  >  >  >
> >  >  >  >
> >  >  >  >
> >  >  >
> >  >
> >
>
>
>