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Re: spark gap muffler? -> More tuning questions.
Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>" <vanyo-at-echoes-dot-net>
I'm pretty certain they're phased right; I'll check again, but I tested
each against each of the others in the beginning.
I am tripping the house breaker pretty often. As I mentioned in a
previous post (quoted below), I think two of my 15/60's have internal
PFC caps - otherwise I'd be tripping the breaker immediately, I think.
>> Here's a link to a two page PDF file from the manufacturer. Page
>> 2 lists "normal power factor" and "high power factor" models, and
>> the ones I have are model 15060 PC. If you compare their 15060 P
>> and 15060 PC models, the only difference is Primary VA (890 vs.
>> 495) and Input Amp (7.72 vs. 4.13) (and 3 lbs weight difference).
The gap blower motor does slow down significantly when I turn the variac
to the NST's up. My next step will be to:
1) Put the blower motor on a seperate line, and,
2) Put the NST's on a 30 amp 240 volt line, being quite careful to not
let the variac past 50%.
My biggest question still is how much effect wind has on streamer
length, and I geuss too it depends on how much wind. I would think a
streamer could follow a light breeze, just as the spark from a jacobs
ladder follows the hot ionized air rising.
Also, I've been waiting to run at night (since it has to run outdoors),
thinking that I won't be able to see the streamers in daylight, yet I
often see pictures of running coils in well lit rooms.
Well, I'll try sturdying up my supply line and see how that works out.
Tesla list wrote:
> Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> 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
> MA, USA
> 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?
> Bill V.
> 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
> 120V side.
> Capacitor: A Maxwell 30 kV, 0.06 uF cap (model # 37321).
> Static Spark Gap: 9 copper pipes mounted in a blower box, with
> adjustable spacing.
> 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"
> spacing on
> 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).