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Re: Here are my current specks: Was I give up!
In a message dated 8/22/00 2:11:57 PM Central Daylight Time, tesla-at-pupman-dot-com
writes:
<< Subj: Here are my current specks: Was I give up!
Original poster: "Garry F." <garryfre-at-pacbell-dot-net>
Garry,
My comments are all IMHO. Also, I have built a successful bipolar coil but
never a 1/4-wave coil
of your configuration: BUYER BEWARE.
lots of snips
>>As I mentioned before, I built it according to plans from sciencefirst-dot-com
but it did not work as advertized (Oh what a surprise).<<
I have never heard anything good said of this outfit
>>NST is the same in all cases 9,000 volt at 30 MilliAmps<<
At only 270 Watts I don't think you need the line chokes. Let's get things
simple.
>>Given this NST, I caculate the Impedance as being 300,000 ohms<<
>> I caculate that I need an .088pf capacitor or since I have two in series,
I will need two about
176uf each.<<
Uh Uh. A pico is 10 EE-12. You write 8.8 EE - 14 uF. Do you mean 0.0088 uF
equal to 8.8 EE-9 uF?
C = 1/ 2pi x 60 x 300,000 Ohms = 0.0088 uF. I would use a 0.01 uf MMC.
>> My current caps are aluminum flashing stacked<<
I know nothing of one of these contraptions. To me, they are unreliable and
dangerous. I would toss the aluminum plates into my toy box and build a nice
MMC. Someone else will probably have a
more constructive and tactful opinion. :-))
I think you wrote that you are using Brent Turner's book.
Please refer to the BASIC TESLA COIL SCHEMATIC on page 58.
>> The caps are in series with the primary winding and the other
end goes to one side of
the spark gaps. This isolates the primary from the rest of the circuit as
far as the 60 cycle current
is concerned. The primary is center tapped in the center after tuning
through a third choke with the
same configuration as the other two.<<
Garry, this paragraph is totally confusing and has no resemblance to the
schematic on page 58
of Turner's book.
I can assume that you really mean the HV primary consisting of the capacitor,
the SG, and the
40 turns of # 14 wire which are connected to the HV secondary of your NST.
Your description places everything on the LV 120 V primary side of the NST. I
do not think this is what you intended
to say. Your description gets totally out of control when you describe the
caps (more than one)? being in series with the primary winding and the other
end goes to one side of the spark gaps (more than one)?
>> Finally, I tried two brass doorknobs. Flat surface area inside the same
PVC
joint with the same fan.
Result was a significant improvement in performance to the tune of 16"
sparks. The best yet!!<<
This is not bad, actually it is very promising because things are probably
not as bad as your
description infers.
>> The next morning, I turned it on and the gap would only fire sporatically.
So, I closed the gap a bit
and by the time I got some reliable firing the sparks were quite a bit
weaker. They were thinner and
much shorter, with less bang and noise from the toroid.<<
I get the vibes that your capacitor is not taking an adequate charge.
You can very carefully test your NST by first making sure the power is OFF.
Connect one end of a
piece of HV lead to one terminal of the NST, strip the other end and tape the
wire to a long (12-inch)
piece of wood. Do not touch the wire. With the power ON, bring the end of the
wire to the NST
case. You should be able to draw out 1.5 to 2 inches of bright juicy arc. If
this works for both
terminals the NST is good.
>> I am most impressed with the kind and never harsh
replies I got from this
group. You should all be proud.<<
Yes, the Tesla group is the greatest. I again urge you to study-study-study,
and ask plenty of questions. No flaming on these pages.
Hope some of this helps. Also hope I got some of it right. :-))
Happy day,
Ralph Zekelman