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RE: spark gap muffler? -> More tuning questions.
Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>
I use a single 15/60 NST with a .02uF cap, so yours is just a scaled up
version. At 140VAC in, my single NST pulls over 20 Amps from the wall,
though mine seems to be on steroids, even though I've made no shunt
modifications. Is it possible that you're seeing a substantial voltage
drop in your mains wiring when the variac is cranked? Also, is it
possible that one of your NST's is phased wrong?
Regards, Gary Lau
Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>"
OK, there seems to be a unanimous consensus - if the gap is louder than
the streamers, something's wrong. Well then, something's wrong.
I *am* still in the process of tuning it, and don't get to run it often
- I can only run outdoors, and it's been windy lately - I'm waiting for
a still night to try again.
Could it be that my cap is too large, even for LTR? I'm using 0.06uF
with three 15/60 NST's, whereas 0.045uF would be about right. How
significant is this?
If I can get my hands on another 15/60, I'll throw it on, but in the
Also, my spark gap is adjustable, but I'm thinking maybe I don't
understand the principle behind how to adjust it. Basically, what
effect does having the gap wide versus narrow have? I've noticed that
when it's wide, it seems to fire more erratically. If the gap is set
too narrow, how does that affact streamer length?
Is there anything else I should look at? I got sparks about 2 feet max
in a good breeze. Was it just the breeze, or is something else way off?
BTW, the specs again are:
Power Supply: Three 15/60 NST's, with Terry's protection filter on the
high voltage side, and redundant line filters and a 50 amp variac on the
Capacitor: A Maxwell 30 kV, 0.06 uF cap (model # 37321).
Static Spark Gap: 9 copper pipes mounted in a blower box, with
Secondary: 1000 turns of 22 awg, 6.5" (closer to 6 5/8) diameter, 27.5"
winding length. Countless coats of polyurethane.
Primary (just rebuilt): Flat spiral, 10 turns of 1/4" copper tube, 1/2"
centers. Inside diameter 9.5". Tapped between 6 and 7 turns.
Toroid: Aluminum dryer duct, 8 inch cord with 24 inch center to center
Ground: 32" segment of copper clad iron ground rod.
All interconnects are 1/4" copper tubing, with 1/16" thick polyethylene
insulation (3/8" o.d., 1/4" i.d. tubing), except I use welders cable to
my primary tap clip (both heavy and very flexible),
and 15kv rated high voltage wire from the power supply to either side of
the spark gap.
Misc: Strike rail (open loop).