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Re: [TCML] Odd VTTC Streamer Behavior

> Since you have a plate lead choke/resistor, the arcs will
> appear subtle.  Without the choke, the arcs would be
> spectacular and possibly instantly destructive.

I don't think I'm getting tube arcs.  I use no choke, and no resistor on the
plate lead, I like to live dangerously!  So if like you say the arcs are
instantly destructive without the choke then I haven't been getting them.

On Tue, Oct 21, 2008 at 20:44, <futuret@xxxxxxx> wrote:

> Seems it's not a tube problem.  If the cap is failing, it can
> change the tuning, which can effect the forking.
> But the forking effect could
> be something else.  I had a lot of trouble with spark
> splitting on my small 4-250A coil which gave 20" sparks,
> and on my (2) 833A coil which gave 24" sparks.  I found
> it to be sensitive to the type of power supply even.
> For example if I used a 4450 volt plate transformer,
> then the splitting occured.  But if I used an MOT with
> level shift, and the correct number of level shift caps,
> then the splitting didn't occur.

I use a 2nF 13000V oil-filled filter cap.  It's huge and I hate it, it sure
was cheap though at $10.  Is it possible I could get better results with
higher capacitance?

>  But it split occasionally
> anyway.  It can be difficult to get longer and longer
> sparks and continue to avoid the splitting.  It may
> help to lower the breakout point on top of the toroid
> or something like that.  The toroid affects the electrostatic
> conditions in that area and may help to funnel the spark
> straight up.

The tip of my breakout point is about 3" above the toroid.  I'll have to try
moving the toroid up or the breakout point down to see if that.

>  I think the splitting has a lot to do with
> how the spark originates at the breakout point as
> it begins to grow at each burst.  If it splits early
> as it's forming, then it will stay split.  The trick is
> to get the spark to form without splitting.  This
> makes it sensitive to tuning and various adjustments also.
> Did you try varying the main tank tuning some?

Yes, even added taps to my primary.  I have L maxed right now, though I've
added more L and the spark length does not increase, and it certainly does
not help with the arc splitting.  I tried adding more C today and after I
tuned it out there was really no difference in the spark length, if anything
it was slightly shorter.

> It may even be beneficial to use an MOT which
> saturates, because the waveform distortion which
> results can help to stop the splitting perhaps.
> In any case, varying the number of level shift
> caps may help.
> John
> -----Original Message-----
> From: Phillip Slawinski <pslawinski@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Tue, 21 Oct 2008 7:15 pm
> Subject: Re: [TCML] Odd VTTC Streamer Behavior
> I just tried the 833A I have laying around.  It was the same situation as
> with the Penta 833C.  I also examined the inside of the C and everything
> looked perfect.
> Would the cap really cause the streamers to fork like that, and not gain
> any
> length?
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