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Re: [TCML] Notes on first SRSG...



Hello.
You can get a SRSG to run at a different bps rate if the timing is wrong, in my case I can get a 200 bps SRSG to run at 100bps (only at low power and for an experiment, as it is not a viable and safe way to do things) so you most likely had it running wrong before. You never mentioned what your original bps rate was. I presume it was 240bps as your using an NST, in which case you may have had 120bps. and now the timing is correct it runs at 240bps. It will also sound a lot different as well.

Phil

--------------------------------------------------
From: "Joe Mastroianni" <joe@xxxxxxxxxxxxxx>
Sent: Sunday, July 04, 2010 11:00 PM
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Notes on first SRSG...

Photos coming. I advanced the timing about 20 degrees and everything seems peachy. Also narrowed the spark gaps and can get breakout at much lower voltages. Reconnected the 3rd bank of 18 caps and up to 25nf total. Looking good.

More to come.

Joe


On Jul 4, 2010, at 9:33 AM, Gary Lau wrote:

I'd like to amplify one of the points John made below that I failed to
mention in my reply.  Even with a well-made Freau phase adjuster, it is
still necessary to make an initial trial and error ballpark mechanical
adjustment between the motor shaft and disk or motor and cradle. Any Freau
adjuster has a limited range and it needs to be somewhat close.

Please post some photos, as there are any number of other issues that can be
a factor that we just have no visibility into.  Also, more info on your
motor and gap arrangement may be useful.

Regards, Gary Lau
MA, USA

On Sun, Jul 4, 2010 at 11:36 AM, <futuret@xxxxxxx> wrote:

Joe,

Are the rotary gaps set close enough together for reliable firing? If the
electrode spacing
is too wide, the rotary will only fire at a high variac setting. Of course
if the electrodes
are tungsten and are set too close they can crash and break off.  In any
case
the coil should begin firing at a lower variac setting I would think. 25nf
should be
OK for a 15/60 NST.  25nf should not be too large to fire reliably.

The phase setting for the SRSG can only be set by adjusting for longest
sparks.
It cannot be adjusted using a scope because the firing timing depends on
the
exact characteristics of the NST and the cap value.  The phase setting
should
not be set without the resonator in place.  That can damage the caps and
won't
work anyway.  You may be able to get in the general ballpark range using
a scope, but I didn't bother in my own work.

The phase controller gives only partial phase range.  If you get best
results
at the end of the phase controller variac range, then you'll need to rotate the motor itself some in it's mounting cradle, or shift the rotor relative
to the
motor shaft to get the proper range. Of course the phase setting will be very different for the 25nf cap and for the 18nf cap. This may be why you
got better results with the 18nf cap (or part of the reason).

If you watch the rotary spinning under fluorescent light, you'll be able to
see if it's truly running in sync (just the rotary alone, no Tesla coil
firing).
The light pattern will rotate if you lower the rotary voltage so it drops
out
of sync, and you can hear the hunting sound when it's almost syncing
as you raise the voltage.  (I'm referring to the motor voltage not the
phase shifter variac setting).  You can just unplug the motor and you'll
see the light pattern start rotating, then freeze when you plug the
motor back in and it syncs.  Some people have a very very very hard
time seeing these patterns under fluorescent light however.
(Maybe you did all these verifications tests already).

The sound of the system should be 120 BPS, not 60 BPS.  You should
be getting 56" sparks or so if you're using a step up type variac
(140volts).

I'm surprised the variac has to be turned up so high for the static gaps
to fire.  Maybe the static gaps are set too wide?  I'm assuming you
have the coil tuned correctly at the primary tap.  I didn't verify using
JAVA TC or anything.  You'll probably need to tune outward by a turn
or two more than JAVA TC suggests, because JAVA TC doesn't
account for spark loading effects on the tune point.

John










-----Original Message-----
From: Joe Mastroianni <joe@xxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sat, Jul 3, 2010 11:02 pm
Subject: [TCML] Notes on first SRSG...


HI All,

I got my first SRSG running today. Some notes, and maybe you experienced

fellows can enlighten me on the phenomena I'm observing --



- Running a 15/60 NST.  17 turns of 1/4" x 1/4" refrigeration line as
primary.

22" tall, 30GA, 4" dia secondary.   25nf MMC (3 banks of 18  0.15mf by
2kV).

Tophat is an 18" x 4.5" spun toroid. Using 2 variacs - one in John Freau's

phase-shift configuration, and one for primary power.



- Experimented running with the static gap and 25nf, instead of 18nf on
the

MMC.  With 25nf on the MMC the variac has to be an nearly 120V for the
static

gap to fire.   It's kind of all or nothing.  Turning on the primary is
around

the 13th turn in this configuration



- Switched to the rotary gap - difficult to "tune" the SRSG phase in this

configuration, because you either get it to fire, or not, with max power on
the

power variac.  Lots of trial and error.



- Tried tuning the phase without the coil resonator connected to the SRSG.
Sort

of works...think I got it firing right.



- Took the 3rd bank of the MMC off - and lowered the total tank cap to
18nf.

Now the gap fires at lower voltages, and I can tune the phase. Though now
I'm

worried I should switch back to the 25nf capacitance to avoid blowing
something.



With 18nf capacitance and the SRSG rotating in what I think is a reasonable
sync

phase with utility power - I'm getting some really great results. Sparks
are

bright and "mean" sounding - full of what I presume to be 60hz buzz.



Is there any reliable way to tune the phase of the SRSG with a scope (or

without) - without having to rig up some kind of optical strobe sensor?



Thanks to all for the help!



Joe_______________________________________________

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Regards
Phil Tuck

www.hvtesla.com
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