UPDATED: LTR causes arcing to primary?

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

Original poster: "Brett Error by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bretterror-at-hotmail-dot-com>

Thanks for the tip.  However these "racing arcs" seemed to have disappeared 
when I added your filter:

http://hot-streamer-dot-com/TeslaCoils/Misc/NSTFilt.jpg

Note that I did make one modification.  I didn't connect the terminal to NST 
ground yet because I'm concerned about it also being attached to RF ground.

I realize that the filter shouldn't really have anything to do with 
eliminating the "racing arcs", but in any case that problem is gone.  I 
don't know if it was adding the filter or something else that changed in the 
process of rebuilding the coil.  Now, however, I have a problem of seemingly 
a much more serious nature.  I have arcing between the base of the secondary 
coil where the ground cable attaches and the inner windings of the primary 
coil. There is roughly an inch and the nearest point between the secondary 
and primary coils.

This arc has several forms:

- Type one: At first, when I had the center post of the safety gap connected 
to RF ground, every time the safety gap would fire I would also get an 
explosive arc from the bottom of the coil.  This is a high-powered arc and 
looks a lot like the safety-gap arc.

- Type two: Because the arcs seem related, I disconnected the center post 
from RF ground.  This didn't stop the arcs, but they did appear less 
frequently, and much lower power.  Just thin white arcs occasionally jumping 
from the base of the secondary to the primary.

- Type three: I'm not sure what I've changed (I've been tinkering and trying 
to tweak different settings) but now the arc is different again.  It is thin 
and purple, and is not intermittent.  As soon as the coil is powered the arc 
appears and stays until power is extinguished.  All the other arcs have been 
much more intermittent.

I've tried raising the secondary several inches to put more space between 
the secondary and the primary and it did help the arcing a little bit.  Also 
by adding insulation (electrical tape) I've also been able to somewhat curb 
the arcing.

Anyone have any ideas what might be happening here?  Again, previously when 
I ran the coil with a capacitance almost at resonance I don't think I had 
this problem.  This is something new that has shown up after the addition of 
a LTR capacitor and Terry's filter.

I could try to get more aggressive with insulation, or even remove a wind or 
two off the inside of the primary coil, but I'm afraid I might be treating 
the symptoms instead of the real problem.

Thanks in advance,

Brett


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: LTR causes arcing to primary?
>Date: Sat, 27 Oct 2001 12:47:59 -0600
>
>Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
>Hi Brett,
>
>It sounds like the primary to secondary coupling is too high which causes
>these "racing arcs" along the secondary coil.  simply raise the secondary
>coil up away from the primary (maybe an inch).  This increases distance
>will reduce the coupling a little and eliminate the problem.
>
>Cheers,
>
>	Terry
>
>
>At 05:54 PM 10/27/2001 +0000, you wrote:
> >I recently built a tesla coil that worked BEAUTIFULLY.  However, I built 
>it
> >with a capacitance on the primary tank that was almost exactly resonant.
> >Although the coil worked beautifully, it was short lived.  After less 
>than
> >10 minutes of run time, the caps burst into flame.
> >
> >The coil is about 4.5 inches outer diameter, and about 21 inches of wind
> >length.  Because the coil is relatively long and skinny, I did not 
>believe I
> >would need to add a strike rail to the coil.  And previously when I ran 
>the
> >coil, it worked beautifully until the capacitors failed.
> >
> >I just completed my LTR cap (about 1.5 X resonance) and plugged it into 
>the
> >coil.  I get streamers, but the secondary coil also arcs occasionally 
>down
> >its length just a couple of centimeters from the surface of the coil.  I
> >don't think it is arcing to the primary coil, because the discharge is so
> >close to the surface of the secondary coil.  I'm not sure exactly what is
> >going on and I don't want to run it too much to investigate because I 
>don't
> >want to risk a failure.
> >
> >Any idea what might be causing this if all I've changed was the 
>capacitor?
> >Is it likely arcing to the primary coil or is something else likely going
> >on?  Would a strike rail help this problem?
> >
> >Thanks in advance for your suggestions.
> >
> >Brett
> >
> >_________________________________________________________________
> >Get your FREE download of MSN Explorer at 
>http://explorer.msn-dot-com/intl.asp
> >
>
>


_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn-dot-com/intl.asp