Re: Safety gap taking over

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Jeremy,

If you are using a variac, you could set the safety gap to just fire at
140VAC.  On my coil, I set the main gap so it draws most of the sparks and
the safety gap fires only occasionally,  Also my safety gap is located next
to and parallel to the main gap and benefits from the air flow from 2 100
CFM muffen fans that blows down onto the parallel string of CU pipes in the
main gap.  The fans are mounted on an acrylic cage  with three sides closed
so the air gets redirected and flows axially down the pipes and out the
fourth side.  This exit side air flow cools the safety gap that is also well
heat sinked.

The frequency of the safety gap firing does not seem to increase with time
nor does the streamer performance seem to decrease with time.

Gerry R.

 > Original poster: "Jeremy Gassmann" <gmann-at-fuse-dot-net>
 >
 >
 > Here is my problem:
 > While running the coil, as I turn up the input power the spark gap
 > begins to fire and as I turn up the voltage more, the safety gap does
 > the job of the spark gap.  Keep in mind that I set the spark gap to just
 > fire and the safety gap to just NOT fire.  When I set the spark gap to
 > just fire, the safety gap was hooked up as well.  Does that change the
 > breakdown properties of the spark gap?  I would think that it wouldn't,
 > but I am not sure.  I even bridged a few of the gaps in the spark gap to
 > reduce the firing voltage but the safety gap sometimes will take over.
 > I also have my Terry filter safety gap mounted upside down on the
 > underside of the primary shelf.  I don't know if this would affect
 > anything or not, but with no load at all, the safety gap acts like a
 > Jacobs ladder.  Also interesting to note is that when the safety gap
 > takes over the output still seems really decent...about 4' streamers
 > once the surrounding air is sufficiently hot.  I also use a leaf blower
 > to quench the spark gap that seemed to make the safety gap take over
 > even faster.  Is there too much air flow here?  Sorry for the long post,
 > but this has me a little confused.  Is the safety gap subject to a sort
 > of avalanche effect where it fires ones, gets hot then keeps getting
 > hotter and firing more often until it takes over?  Thanks to all in
 > advance for your help!  I know it has been stated a lot, but without
 > this list, there would be significantly fewer successful amateur coilers
 > out there!
 >
 > Jeremy Gassmann
 > Cincinnati, Oh
 > http://jeremyee.tripod-dot-com
 >
 >