RE: [TCML] First light (maybe second light) on mid-sized coil

["Lau, Gary" <Gary.Lau@xxxxxx>]

Hi David,

I think there is nothing abnormal with what you described.  It's just not a healthy thing to do.  I haven't tried it myself, but if the Variac is adjusted to just below the point of firing, it means that the transformer is constantly charging and discharging the cap to just below the firing voltage, but since the gap never fires, that energy is constantly being traded between voltage on the cap and current in the transformer secondary, likely to the point of core saturation and ferroresonance.  If the Variac were just a bit higher, the gap would fire and the capacitor energy from each charging cycle would have a place to exit rather than causing the high current and avoid this problem.

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of David Rieben
> Sent: Wednesday, April 16, 2008 7:50 PM
> To: Tesla list
> Subject: [TCML] First light (maybe second light) on mid-sized coil
>
> Hi all,
>
> I have figured out that the real current hog culprit in this coil project
> is the 80 nFd primary cap. I realized that as I turned the variac
> up to only 30 on the dial, the SG is just at the threshold of be-
> ginning to fire intermittently. If I turn the variac to this point and
> stop just before the SG starts to sputter and leave it powered up
> in this position for a couple of minutes, the 22 amp Staco variac
> will still manage to get pretty warm and if left long enough, it will
> even begin to smoke! I assume this is just the primary capacitor
> load on the transformer as the SG is not even firing yet! Am I go-
> ing to have to settle for  a smaller primary capacitor to stay happily
> within the bounds of a 120 volt, 20 amp service or just say the heck
> with it and upgrade this baby to 240 volt service? Any suggestions?
>
> David Rieben
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