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Re: coupling
to: Bart, Bob
Another concern with "racing sparks" is the method used to clean the sec
coil. I've seen people use anything from Windex to "409" cleaner and give
absolutely no concern as to what additives these cleaners might have. When
you are dealing with hundreds of kiloVolts you have to consider all these
properties to prevent surface tracking. We use only alcohol for all our
sec coil cleaning -- no commercial cleaners or waxes whatsoever. We
started to discover these "cleaner effects" while cleaning Van de Graaff
insulating towers as the small microAmperes of leakage current down the
tubes would invisibly drain all the charge off the terminal faster than the
belt could replenish the charge. Many experimenters never clean their
coils -- or very seldom do. With many kV's looking for a ground a lot of
dust (carbon based material) looks like an excellent path. Keep your coils
covered with a cloth material and remove prior to operation. Clean sec
coils with alcohol sprayed on a lint free cloth. Also, don't operate for
at least 5 minutes until all the alcohol has evaporated or you may get
another "interesting effect" you don't want.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: coupling
> Date: Monday, September 14, 1998 7:04 PM
>
> Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net>
>
> Bob,
> When I first setup my coil, I had the secondary in line
> with the primary (flat style). I had a problem with
> racing sparks down the secondary. I elevated the
> secondary a little over an inch and the racing sparks
> down the secondary stopped. Raizing the secondary
> loosened or reduced the coupling (opposite of your
> thoughts posted). I was able to achieve the maximum
> amount of coupling (without racing sparks down the
> secondary) by using this technique. It is possible that
> you might be able to tighten your coupling a bit if your
> are not having racing sparks down the secondary or
> primary to secondary arc-overs. If you do tighten up the
> distance between the two windings, raising the secondary
> in small increments (1/4") can get you to the "best
> coupling" distance (my opinion).
> Bart
>
> Tesla List wrote:
> >
> > Original Poster: bob golding <yubba-at-clara-dot-net>
> >
> > Hi All,
> >
> > Have just been playing around with the coupling of my coil.
> > 9 Kv 60mA neon,
> > Conical 30 degree primary 9 turns 3/8" Cu,
> > home made flat plate cap 15 nF,
> > RQ gap 0.125" gap, vacuum quenced
> > 41/2" secondary 21" winding length, About 980 turns 23 AWG,
> > 19" x 4" toroid.
> >
> > I am getting 20" sparks to a grounded rod with the primary tapped at 8
1/2
> > turns. I started with the base of the secondary windings about 2" above
the
> > first turn of the primary. This gave 20" sparks. I then moved the
secondary
> > down to be in line with the first turn of the primary. This does not
seem
> > to have made any differance to the spark length. is this because the
coil
> > is too far out of tune? I did notice that safety gap activity is less
with
> > the secondary lower. Am I right in thinking that the coupling is at the
> > mininim when the the secondary is in line with the bottom turn of the
> > primary, therefore there is no point in adjusting the coupling below
this
> > point?, and that coupling is increased as the secondary is raised. How
> > much differance does the distance between the the primary and the
secondary
> > make?. At the moment I have about 1" I would find it hard to tighten
this
> > up due to the design of my coil.
> >
> > many thanks
> >
> > bob golding lightning without rain
> >
> > bob yubba.clara-dot-net
>