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Re: SRSG firing problems

Hi Nathan, Scott,

> Original Poster: Bunnykiller <bigfoo39-at-idt-dot-net>
> it sounds like you are getting the inital surge of power
>thru your system for the first burst ...    your cap seems
> right for the tranny ...   a 15/60 needs about  .010 mF

I would say it is quite a bit too small for an SRSG. See
below for more comments.

> a 15/60 should produce about 24 + "  of streamer  ( i
> have no idea of what your secondary is )

I would say AT least. My coil´s best (at 900VA) was around
45" using a crude static gap.

> aka  you may have to move the motor ( CCW or CW ) in relation
>to the stationary gap ( stationary) posts ( like the timing on a
>distributor on a car)   if you consider the timing on a car compared
>to the timing of a coil  you need to have the rotory ( distibutor) in
>sync with the firing point of the spark plugs at top dead center of
>the cylinder ( aka top of the sine wave maybe a bit on the down
>side due to current lag)

Nice analogy, except that an engine needs lots of advance, because
gasoline is slow burning and you want the gas / air mix to achive
full pressure by the time the piston / con rod / crank assembly
reaches TDC. This is not the case with a mains reso cap SRSG
powered coil. It will reach firing voltage a LOT sooner (way
before "TDC").

> the buzzing all the time is the potential of electricty trying to fire
> off at the non conductive state of the gap system ( its trying  but no
> gap to fire to )     try moveing the motor 45 degrees left or right
> ...   see if that improves the output ...   then move back and forth
> till you see best output...

And this is the point, where I would NOT recommend such a
proceedure. Using a mains reso cap in a SRSG powered coil
is an *awful* combo. If you *just* turn the alignment time one
way or the other you´ll be more than likely to fry both the
cap AND the NST due to overvoltage. Sort of like timing a
modified engine w/o really knowing what is going on. Too
little timing and your headers will glow (or melt). Too much
timing and your engine will die from knock under load.

Nathan, you said you tried the cardboard and florouescent
lamp trick. You also said, you noticed a 4 line pattern. So
far, so good. However, you will see this on any induction
motor. What is important, is to check that the lines remain
stationary (a non sync motor will allow the pattern to slowly
revolve) AND that the lines appear in the same position
regardless of when you switch on the power. You can also
hear the motor *sync* into place. A normal induction motor
will start up and run quietly, whereas (esp. a modified) sync
motor will *snap* into sync. If you lower the voltage (via a
variac) you can hear the motor "hunt" as it tries to sync into
place. A *normal* induction motor is NOT a synchronous
motor.

What bothers me, is the fact that when you replaced your
SRSG with your old static gap, you no longer got your
original output spark length. I will assume you did tune your
coil to it´s FRes, so this behavoir would suggest to me that
something has changed in your setup. It could be something
as simple as Stan mentioned (a loose connection) or it might
well be that your NST or cap are shot. Did you actually
measure the 10nF? If so, I would remeasure the cap now.
But even if it still measures 10nF, it might well be that the
dielectric is failing under applied power. An ESR meter
might give you a clue. Do you have access to another cap
that you could test your setup with? What kind of cap are
you using? A rolled or flat homebrew poly cap just won´t
like the beating you are giving it. An MMC will take more
of a beating. If I were you, I would "rip" the setup apart
and reconnect and check every single connection for
corrosion or high resistance. Check your ground system.
Try connecting a high wattage halogen lamp between hot
and your ground. If it lights up to similar brilliance (yes, I
know, it IS a crude test), when connected normally (to N
that is) you can probably figure your ground is okay. The
key point is to use a HIGH wattage bulb. A normal 100W
bulb will light up on the worst ground, so this gives no real
clue. Aligning a SRSG (esp. with a mains reso cap) is a
tricky feat.  Richie Burnett had a neat setup, which used
halogen bulbs in place of the primary coil. This will save
your NST and cap while adjusting your gap. I may have
missed it, but did you post how your sync gap is built (i.e.
number of rotating & stationary electrodes, disk diameter,
electrode material, motor rpm and bps)?

Let us know what you turn up.


Coiler greets from Germany,
Reinhard