Re: I need advice on sync spark gap

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

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

In a message dated 11/8/04 10:18:02 AM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:


>Original poster: "Robert Hanford" <pomnept-at-comcast-dot-net>
>
>Hi everybody, I have a problem that I'm sure is a no- brainer for most
>experienced coilers.
>My coil has been working fine with a vacuum gap, so I thought I would
>experiment with a SRSG. Worked well at low power, but could not find the
>"sweet spot" at full power, even with quite a bit of monkeying around. I
>pulled the safety gap out a "little" too much, then it worked real well for
>a few seconds, then my MOVs went kaput.I am using a Freau phase controller,
>.011 MMC cap, 15k/60ma NST, and of course a SRSG. And a 4.5 inch secondary.
>Well, the damage was done, so it was time to quit. I haven't checked my NST
>yet.
>I hope somebody might give me a few ideas about possible errors- what was
>frustrating is that it was working so well at lower power. Do I need a
>larger cap?
>As always, any help is most appreciated.
>Robert Hanford
>


Robert,

A larger capacitor would most likely be helpful in keeping
the peak voltages down.  For a 15/60 NST, a cap value of about
0.025uf to 0.035uf or so should be good.  Your present cap is basically
a resonant value which will give a rather high voltage on the
capacitor.  I think Gary Lau now uses a 0.04uf cap on his
15/60 coil, and he has found this to give the best results on
his coil.  At Wingate's Teslathon, he got about 72" + sparks.

Also, the phase setting generally needs to be changed as
the power level in increased vs. the setting for a lower power.
I usually just determine the best setting for full power and
keep the phase set at that position.

Cheers,
John