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Re: component sizing
Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Esondrmn-at-aol-dot-com>
In a message dated 2/19/01 10:19:48 PM Pacific Standard Time,
I am in the process of building my first coil and I have a few questions.
The secondary is 10.25" diameter on a PVC pipe. It has about 916 windings
of 20GA wire. For the Primary, I am planning on using 1/4" copper tubing
wound at a 15 degree inverse conical. the spacing between winding on the
primary is 1/2". I have not "wound" the primary yet, but I was planning on
15 windings. but I have notches in my supports for up to 17 winding. I
currently have 1 15/60 NST that I am planning on using to power it, but I
was going to try to get at least two more of them.
Now for the questions.
1. From Ed Sonderman's Excel spread sheet I was planning on trying to get
a tank cap with a value of around .028 uF. Does this sound correct, and if
so, what is the best way of obtaining the tank caps? I have a limited
budget, but I am also trying to make a very nice looking coil.
2. I wanted to make a RSG. I have access to some DC motors and
controllers, but I have seen a few places mention that an async-RSG is bad
news for NST's. should I stay away from the DC motors?
3. I have some 1 1/2" acrylic that I was planning to use for the rotor of
my RSG. I am planning on drilling and tapping 1/4-20 holes in it and using
threaded rod with acorn nuts on the ends for my electrodes. is this a good
plan or bad?
4. RF chokes. what are some good designs, and How do I size them?
5. what is the best method of constructing a toroid that would be large
enough for my coil?
Thank for your help
.028 ufd sounds too small for a coil of that size - but I did not run the
math. I have a 6.0" diameter coil, admittedly with large toroids on top, and
I use a .05 ufd cap.
I would definitely change the primary to flat v.s. conical and go with 17
turns. If I were building it, I would use 3/8" tubing. A coil this large
will probably see some serious power put into it some day.
Using nst power supplies, I would recommend starting with a RQ style
cylindrical static gap. It will work well and they are easy to build.
I built my first rotary gap as you are describing, with stainless steel acorn
nuts for contacts. You should use polycarbonate (Lexan) instead of acrylic.
I think an acrylic rotor will come apart.
My toroids are made from 6" diameter corrugated plastic drain pipe, wrapped
around a circular acrylic center disk and covered in clear plastic shipping
tape then aluminum tape. You can see them at my web site.