Re: Basic TS curcuit conflict

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

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-uswest-dot-net>" <bert.hickman-at-aquila-dot-net>

Jonathan,

Theoretically, the behavior should be the same using either circuit. 

However, in practice you may be seeing a couple of effects. First, the
secondary winding will add some additional capacitance across the tank cap,
adding to the total capacitance in the tank circuit. You may be seeing a
shift in tuning between the two configurations, which if not compensated
for could result in racing sparks.  

Second, with the NST across the tank cap, you may be getting additional
losses in the primary circuit due to corona/arcing internally within the
NST. The additional losses will reduce the "effective" bang size, reducing
the probability of getting racing sparks.

I'd recommend using only the configuration with the spark gap across the
NST. Elevate the secondary to decrease the coupling and stop the racing
sparks. Then tune for best spark length. Finally, increase the coupling
until you're almost getting racing sparks. This should result in a safer
(for the NST) configuration that also delivers great performance. 

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
Email:    bert.hickman-at-aquila-dot-net
Web Site: http://www.teslamania-dot-com

Tesla list wrote:
> 
> Original poster: "jpeakall by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<jpeakall-at-mcn-dot-org>
> 
> Hi All,
> 
> I Have a small coil I have been operating off various power sources. The
> specs are:
> 
> 5 1/2" helical primarry, 12 turns of 12 AWG auto wire
> 3/12 " secondary, 436 turns of 22 AWG anameled wire.
> 
> The circuit I have3 been using is from John Couture's book, and in it one
> side of the transformer goes to one side of the tank cap, and the other
> trans lead to the other side of the tank cap. One side of the cap goes to
> the SG, and the other to one end of the primary.  The aligator clip side of
> the primary goes to the other end of the SG. On other circuits out there,
> like on Gary Lau's site, the trans leads both go to the spark gap, with the
> tank caps going between one end of the SG and the primary.
> 
> What is the difference between these two set ups? I tried the way it is on
> Garry's site, and it seems to work better, but I get tons of racing sparks.
> I had previously been using a .038 tank cap,, and I went down to .021 .014,
> still getting racing sparks. Very little backfire from the safety gap
> however. After a few seconds, I blew a tank cap.
> 
> Is it just that the other circuit is way less efficient, and so I never had
> the racing spark problems? Is hooking it up as on Gary's site harder on the
> caps?
> 
> Jonathan Peakall