RE: Heat & Rotary Gaps

["Tesla list" <tesla@xxxxxxxxxx>]

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
>  >  >
>  >
>  >
>