Re: Primary to primary sparking?

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

Original poster: Chris Roberts <quezacotl_14000000000000-at-yahoo-dot-com> 

Well, it's a 9/120 NST with a TCBOR gap which has some red plastic at the 
top. When the gap is sparking, the light shines through, and it gives it 
that neat glowing look. The primary is .25 inch tubing with .25 inch gap, 
and it rests on rubber cut from an old tire tube to prevent any problems. I 
guess I just may have had the tap too close. But I am still confused as to 
why it would want to do that in the first place... Oh well. I guess the 
coil must've been bored with just running as it should, and decided to have 
some fun with me. =D

Tesla list <tesla-at-pupman-dot-com> wrote:
Original poster: "John Richardson"

Hi Chris,

I've got a few thoughts, which may or may not help. I am going to guess
that you are tapping at a relatively small number of turns, and that your
turn to turn spacing is on the small side, say under a 1/4 inch. I've found
this to be a big mistake. Try to keep turn spacing 3/8 or better. It seems
at higher power levels, when tapped at low turn numbers, that the easiest
path for energy dissipation can sometimes be the next turn as opposed to the
secondary. This will especially be pronounced if you are out of tune, which
the lack of streamers leads me to believe. Are you sure that your tapping
mechanism isn't coming within a hair's width of the adjacent turn? This
will also cause your problem. BTW, what is your power source, and what type
of gap are you using? All I can make ! out from the picture is a glowing UFO
type of deal, and I'm thinking it's a TCBOR style gap.

John Richardson



-Chris