Re: Question on Variac lighting

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi JT,

I wouldn't necessarily be concerned about that.  A lot depends on 
where your tank capacitance is relative to the resonant value.  With 
the smaller cap, you may have been closer to resonance and the 
resonant rise could have been large enough to fire the gap with a 30% 
variac setting.  Let us know what transformer you are using and the 
type of spark gap (static or rotary) and we can help with the Cp 
value.  If static, you should try to get about 1.5 to 1.6 * 
Cres.  This will help keep resonant rise down and give you a BPS around 120.

Gerry R

> Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
>
> I had a 7.4(about) nF  MMC in my tesla coil. The spark gap would 
> light at about 25% on my variac.
>
>
>
> After some issues, I now have a 10 nF MMC. But now, my spark gap 
> lights at 55%! I have lost much, much control of power of my coil.
>
>
>
> *Before 55% on the variac, i can clearly hear hissing and high 
> voltage corona coming from the coil, but in pitch dark, i see NO 
> sources for the sound
> *Coil starts up at 55% power.
> Can somebody help me. I want to regain the ability to controll the 
> coil. Any suggestions or solutions?
>
> Please respond ASAP. I am using my coil for my "Senior Success 
> Seminar" for my high school(need to pass to graduate)