RE: [TCML] Sucker Gap

["Lau, Gary" <Gary.Lau@xxxxxx>]

Hi Phillip,

I found exactly the same thing occurring on my sucker gap.  I detailed the observation on my sucker gap web page http://www.laushaus.com/tesla/onegap.htm:

(Start of quoted text)  I performed an experiment to better observe the arc geometry in this gap. By disconnecting the tank components and having the NST output arc directly into the gap, the arc runs at a much lower current, and is less brilliant and safer to look at. The result was not at all what I expected. Rather than forming a ring between the two reducer faces originating at the copper half-torus, 95% of the arc was in a slender line precisely centered in the holes through the brass reducers. I couldn't see where this line of arc terminated so I replaced one of the PVC pipes with a clear acrylic pipe. The arc did not extend beyond the downwind (closest to the vacuum motor) end of the reducer (not surprising), but did stay centered throughout the fitting. The connection between the arc and the fitting was also surprising. The best way to describe it is like a bottle brush. The main arc travels down the center of the brass reducer, like the handle of the brush. Then, the arc connects to the reducer through a very large number of much smaller arcs, perpendicular (or nearly so) to the main arc, like the bristles of the brush, over the length of the reducer. (End of quoted text)

My theory is this.  I'm guessing (WAG) that the air density is lowest along the central axis where the low power arcs were observed.  Low density air is more easily ionized than higher pressure ambient air, so that's where the ionization occurs.

As to why the short, high current arc occurs between the electrode faces, while the low current arc occurs in a slender line through the axis of the gap - this is a mystery to me.  Perhaps we simply can't see what's happening with the tank circuit configuration, since it's too bright to observe safely.  Or, maybe that all arcs START where the gap is physically shortest (between the electrode faces), but progress thereafter to the low pressure areas.  But in the high powered config with the tank circuit, the energy is gone right after the initial bang?

But the short answer is that I think your gap is operating normally.

Regards, Gary Lau
MA, USA




> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Phillip Slawinski
> Sent: Wednesday, July 23, 2008 9:37 PM
> To: Tesla Coil Mailing List
> Subject: [TCML] Sucker Gap
>
> I just hooked up my new NST to my sucker gap to test gap width.  A very odd
> thing happened.  It had what appeared to be a power arc inside despite the
> vacuum motor running.  There was a 2mm thick plasma rod in the very middle
> of the electrodes that extended down the tube.  With every other transformer
> I have a ring of blue sparks forms around the outside.  Only a half circle
> of blue sparks formed this time, in addition to the plasma in the middle of
> the gap.  Could this be a sign that my sucker gap ... sucks?  Perhaps it's
> time to upgrade to a rotary?  If it can't even quench the NST without a cap
> there's no way it can quench it with one, right?
>
> Has anyone else seen this before?

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