My coiler-buddy Andi (Andreas Saile) has developed an SRSG-Strobe-Tuner, on
the base of an powerful LED, by which it is possible to adjust the
electrodes exactly to whatever optimum firing angle one likes. We presumed,
a good starting angle adjustment could have been calculated, by means of a
PSPICE simulation of the TC. A small description of the Strobe-Tuner can be
downloaded from my website, at:
https://hvchbs.zeitgenossen.ch/Downloads/Strobe_SRSG_Tuner.pdf
We have successfully applied this "cold" = "off HV" tuning with the B&W
coil.
The John Freau phase adjuster allows the fine tuning of the coil, when HV is
life, and seems almost "a must" for us. The most helpful measurement in this
context, seems monitoring the primary cap voltage, by means of a potential
transformer and oszilloscope. - Well, just varying the phase, monitoring
spark performance and listening to the sound of the coil/rotary is also a
good way...:-)
Regards
Kurt Schraner
Basel, Switzerland
-----Ursprüngliche Nachricht-----
Von: Tesla <tesla-bounces@xxxxxxxxxx> Im Auftrag von Steve White
Gesendet: Dienstag, 23. Oktober 2018 02:30
An: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Betreff: Re: [TCML] SRSG strobe
I know that using an optical sensor with an oscilloscope provides a very
precise way to insure that the flying electrodes line up with the stationary
electrodes at whatever phase angle on the 60 Hz power line that you pick on
the oscilloscope. Now, whether or not that is the optimum firing point may
be a different matter. On my pole-pig powered coil which runs at 240 BPS,
the firing angles of 0, 90, 180, and 270 degrees which I set with my
oscilloscope did indeed seem to be the optimum. I built a very nice John
Freau style phase adjuster to make fine adjustments. When I used it to vary
the phase angle from the one that I set with the oscilloscope, I saw no
difference in streamer performance or quality. Maybe the effect is much
greater with a 120 BPS NST-powered system. Some posters have suggested that
a 240 BPS system is closer in performance to a ARSG because it fires 4 times
per cycle where firing points may not be as critical.
Steve White
Cedar Rapids, Iowa
----- Original Message -----
From: "Gary Lau" <glau1024@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Monday, October 22, 2018 5:09:07 PM
Subject: Re: [TCML] SRSG strobe
What exactly is the goal here? Assuming that you're successful in getting
the timing light to sync and fire 120PPS, that still gives no useful
information as to whether the RSG is set to fire at the optimum phase angle.
The best you can hope for is confirmation that the motor is in fact
synchronous and that the phase can be varied. I'm unaware of any means to
set the phase other than varying the phase and monitoring spark performance.
The optimum phase of the RSG relative to the mains phase will vary with
primary cap size and Variac setting, there's no fixed "best"
setting relative to mains peak. That's why the variable Freau SRSG
controller* is such a godsend - it's always something that you'll want to
tweak. In my experience, the SRSG phase is super-critical at 120BPS,
there's a clear increase in spark performance as I retard the firing, up
until a critical point, and then it becomes unstable, so I back it off a
tad.
As far as protecting the NST, a safety gap in parallel is mandatory in
parallel with the RSG.
For a simpler means of viewing the phase of your SRSG relative to mains
phase, attach a small magnet to the shaft, and mount a small, high turns
count inductor so that the magnet sweeps past it. Scope the voltage across
the inductor and sync the scope to the line. You should see induced voltage
blips with each sweep of the magnet, and you should see that waveform shift
as you vary the phase of the SRSG.
*See my RSG web page - http://www.laushaus.com/tesla/sync_gap.htm
Regards,
Gary Lau
MA, USA
<snip>
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