Re: dead C.P.caps
Subject: Re: dead C.P.caps
Date: Wed, 04 Jun 1997 10:25:25 -0400
From: "Edward J. Wingate" <ewing7-at-frontiernet-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Tesla List wrote:
> > You are using a safety gap across the capacitors, aren't you?
> > I always use a safety gap across both the transformer and the
> > capacitors. A safety gap across the cap will bark to let you know if the
> > tuning isn't quite right and is quite inexpensive when compared to the
> > cost of a new cap.
> > Forever in search of lasting components......
> > Ed Wingate
> Thanks for the response. No, I am not using a safety gap across the
> cap. I
> never have, maybe I should try it. I do have a safety gap on the high
> voltage feed lines but that is maybe 25 to 30 feet away from the cap.
> about just using a piece of #12 solid copper wire bolted on each end of
> cap and bent up over the ends so the wire ends are about 1.0" apart?
> gap spacing would you suggest for 14,000 volts, for 16,000 volts? The
> capacitor is buried down in the cabinet the coil is mounted on and is
> 30 feet away from where the controls are. It will be diffilcult to see
> the gap on the capacitor is firing.
> Ed Sonderman
I use RG 8 coax in lengths up to 10-14 ft. to feed the high voltage to
my systems and 99 44/100% of the time the safety gap on the cap will
fire when tuning the system, but not the safety gap on the transformer.
I usually power arc that one!!
The wire idea sounds fine to me. It doesn't have to be fancy, just
there. I use 1/2" diameter rod stock in aluminum or brass stands for my
safety gaps and put a full 1/4" radius on the end of the rod. Points or
burrs are not acceptable, so you will want to add small brass, or
whatever material you can find, balls to the ends of the wire. In leu of
balls, you can always fold the wire back on itself in a large radius. It
would still be a good idea to deburr the end of the wire. As for setting
the gap spacing, the voltage rating on the cap is the key, not the
transformer voltage. I use a gap spacing of 1 to 1.125" for my 45kv DC
pulse rated caps. For the caps on my twin coil, which are rated .15 MFD
-at- 22,900 VAC I use a gap setting of 1.250. I run two of these puppies in
series on the twin for a total tank capacitance of .075 MFD.
Believe me, you won't have to be able to see the safety gap on the cap.
You'll hear it!!
Keep us posted on your results.