Re: sparks running down secondary - why?

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

Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>" <vanyo-at-echoes-dot-net>

Replying to my own message here - let me know if it makes sense.  :)

Tesla list wrote:
> 
> Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<vanyo-at-echoes-dot-net>
> 
> Last time I ran my coil, I got occasional loud snappy sparks running
> down the length of the secondary, as well as occasional firing of my
> safety gap.  Wondering what causes the sparks down the secondary, and if
> it's a problem?

Seems it depends on how I set my static gap.  If I narrow it a bit, the
arcs on the secondary (and the safety gap firing) stop - so that's what
I'm doing.

> The only change I made since my previous run (which was still
> underperforming, but perhaps due to wind - not sure - this is my first
> coil) was to hook my NST power supply (three 15/60's, two with internal
> PFC) to a seperate 20 amp line.  I could now run it without tripping the
> breaker.  I still plan on hooking it to a 30 amp 240 volt line, stepped
> down by variac to 120 volt.

Just tried it on the 240 volt 30 amp line, stepped down to 120 using the
variac.  Best sparks so far - very bright purple-white, but still short
- about 3 to 3/12 feet now.  But I'm still running outdoors with
somewhat of a breeze.  I'm hoping that the breeze is the problem.

> Oh, and the other change is a bigger topload.  Originally, I had a
> smaller toroid, and now have added a larger one on top.  I can run with
> just the larger.

Now I'm just using the single larger toroid.

BTW, I can confirm what someone else once reported - my secondary
retains an appreciable static charge for quite some time after being
disconnected from the rest of the apparatus.

> 
>         Thanks again,
>         Bill V.
> 
> Specs again:
> 
> Power Supply: Three 15/60 NST's (two have internal PFC), with Terry's
> protection filter on the
> high voltage side, and redundant line filters and a 50 amp variac on the
> 120V side.
> 
> Capacitor: A Maxwell 30 kV, 0.06 uF cap (model # 37321).
> 
> Static Spark Gap:  9 copper pipes mounted in a blower box, with
> adjustable spacing.
> 
> Secondary: 1000 turns of 22 awg, 6.5" (closer to 6 5/8) diameter, 27.5"
> winding length.  Countless coats of polyurethane.
> 
> Primary (just rebuilt): Flat spiral, 10 turns of 1/4" copper tube, 1/2"
> spacing on centers.  Inside diameter 9.5".  Tapped between 6 and 7
> turns.
> 
> Toroid: I have two toroids, both aluminum dryer duct, and constructed
> so  I can easily attach either or both.  The smaller is 6 inch cord with
> 14 inch center to center spacing, and the larger is 8 inch cord with 24
> inch center to center spacing.
> 
> Ground: 32" segment of copper clad iron ground rod.