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



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
> > > > > >
> > > > >
> > > > >
> > > >
> > >
> >
>
>
>