Re: Best cap size for a sync gap

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: FutureT-at-aol-dot-com 

In a message dated 5/1/04 12:19:14 AM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:

>BTW, I'm not sure I saw the voltage reversal mode you spoke of at any time
>with all of the differing Cp's.  I did note that when the phase was way out
>of whack, I would see the gap firing at 60 BPS, with the voltage
>necessarily reversing polarities, but I assume you were talking about
>something occurring at 120BPS?  The mains current at 60BPS was
>breaker-tripping!


Gary,

Yes my currents also went very high due to a very bad power
factor in the VR mode.  I'm not sure if my firing was at 120 bps.
In any case with some NST - cap value combos, the coil actually
gave longer sparks in the VR mode.  Since this was unacceptable,
I had to increase the cap value to go deeper into LTR mode to
correct the situation.  The VR mode seems to be capable of long
sparks only when the cap value is not deep enough into LTR-ness.
I seem to remember that the rotary gap was a factor too because
I was using a small rotary which produced more jitter.  I ruined a nice
9/30 NST running in VR mode when I forgot to let the NST cool
between runs.  I was planning to use that NST in a proposed
TT-32 coil, but I then abandoned the project.

Yes, the rotary phase is radically different when operating in
the VR mode.

In another issue, here's a 120bps vs 240 bps test I came
across in my notes from work I did on 5/25/99.

      bps    watts     spark length

     120      570        42 inches
     240      800        42 inches

This was using my old research coil powered by a potential
transformer.

John