Is this Normal SRSG behavior?

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

Original poster: "Jeremy Scott by way of Terry Fritz <twftesla-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>

Hey folks,

I just completed my first SRSG:

o 1800 RPM teletype motor (1/14hp
o 8 rotating electrodes
o rotating electrodes are .25" MIG welder tips
o electrodes spaced 3" apart
o 2 stationary electrodes are .25" carriage bolts.

Sandwiched inbetween the two discs is a plate of
aluminum that electrically connects all of the
rotating electrodes when they are screwed in.

Mechanically, this gap appears to work well.
It comes up to speed and is very stable and
balanced.

I have not yet hooked in my capacitor bank,
or tried my 4.5" coil with it. I have however,
put 15Kv across the gap and let it run without
the tank circuit.

What I have noticed is that there is this
orangy flame around the arc that drags on
for about an inch or so past the electrode
"presentations" when the the
power level nears 50% to max.
(adjusted with variac.) Keep in mind this
is just with the NST, no capacitor feeding
the spark. (NST is about 15Kv/60ma)
It does 'beat' at about 240hz, which means
it is making and breaking the spark, but
there is a lot of other screeching noise
with it too.

I have the rotating electrodes spaced about
1/16" of an inch away from the stationary ones.

I guess my question is, do I have a problem
quelching this gap when this orangy corona
appears? (Why is it orange? Is this the
zinc/aluminum burning off the carriage bolts?)

Some things I can think that might be wrong:

o space between electrodes is too small.
   allows operation at lower voltages but
   may be too close to allow proper quenching.

o 3" diameter for 8 electrodes may be too small.
   switch to 4 electrodes?


So what do you think?

Thanks