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Re: Primary coil
Original poster: "M G" <gt4awd@xxxxxxxxx>
Hi, thanks for the replies. Matt D, I will only be using a 9kv 30ma
NST for the coil. Should I still add the HDPE plastic or will it be
ok? I think the supports are at a 35 degree horizontal angle, but I
am not sure of the difference between the two. I cut the bottom of
the supports to a 35 degree using an angle cutting table saw.
Ed, I had just assumed the epoxy was flammable. The package confims
that it is not flammable. I do care about how good the primary looks,
and tried my best to make it look nice and even. Mounting another
piece of wood or some plastic on top is what I will probably do.
John, the supports are made of wood. I had some wood stakes laying
around, and used them. Yes, I did cut notches in the wood.
---------[ Received Mail Content ]----------
Original poster: <mailto:FutureT@xxxxxxx>FutureT@xxxxxxx
>I was wondering if this is going to affect the coil
>
>performance a lot, or if my primary should be fine?
Matt,
None of that matters. It will work fine.
>Is the perfect, circular, shaping of most well built
>
>primary coils for performance reasons, or is it
>
>just nice to look at?
Just nice to look at.
>By the way, what should I do to hold the wire in place?
well you could drill holes in the wood near the wire, and put
a plastic tie-wrap at each spot where the wire crosses the wood.
Or (i think i saw notches in the wood?), you could put a long
piece of plastic over the wires along the wood to hold the wires
in the slots. Hold the plastic to the wood with some plastic
screws. The wood is flammable too. The supports look like wood to me
maybe it's not?
John
Original poster: Ed Phillips
<<http://mail.lycos.com/Mail-bin/send_mail.form.cgi?TO=evp@xxxxxxxxxxx>evp@xxxxxxxxxxx>
>I was wondering if this is going to affect the coil
>
>performance a lot, or if my primary should be fine?
Won't affect the performance at all.
>Is the perfect, circular, shaping of most well built
>
>primary coils for performance reasons, or is it
>
>just nice to look at?
Just for looks and "pride of ownership". Important points but
only of importance after the gadget works to your satisfaction.
>I could use wood/metal epoxy but it is flammable. That is what
>I used to attach the primary supports to the wood base.
I'm not aware that there's any flammability problem with epoxy -
it's high temperature stuff and almost indesctructible. You can get
by without anything holding the wire inplace but a couple of
ideas. You could mount a piece of wood on top of each of the formers
or else, if you don't care about looks, just hot melt glue. It's
great stuff and if you're not already using it you should get some
and try it. Quick and easy for lots of jobs.
>Thanks,
>
>Matt
Ed
Original poster: <mailto:Mddeming@xxxxxxx>Mddeming@xxxxxxx
Hi Matt,
The irregularities in your primary may not significantly affect
your coils performance, except that tuning may be a difficult because
the impedance does not vary smoothly, and the actual inductance and
thus resonance may vary considerably from any calculated value in
proportion to the amount of deformity.
>From the angle of the photos, it is difficult to tell if you
have 35 deg. up from the horizontal or 35 deg. out from the vertical.
If it's 35 deg. out from vertical, you may have a higher tendency to
flash over or have racing sparks on the secondary surface. Of more
concern though, are the wooden supports: Above ~8-10 kV, wood, which
is a passable insulator at low voltages, becomes increasingly and
unpleasantly conductive as voltage increases, due to moisture
retained in the cell structure. Wood also tends to absorb moisture
from the air, which can change its properties on a daily basis. If
you must use wood, it needs to be baked to remove all possible
moisture (<5%) and then immediately and completely coated with a
waterproof insulating sealant, then the wires carefully inserted. If
the wire scrapes the coating off, you may get arcing into the wood.
Instead, I would recommend that you get some HDPE plastic. The white,
waxy-looking cutting boards sold in kitchen supplies are fine. Cut it
into 3/4 in. strips, make the wire slots in it, and then attach it to
the edge of your wooden supports so that the wire does not come into
contact with the wood.
Hope this helps,
Matt D.
Original poster: "M G"
Hi everyone, I finished making my primary coil. It has
eleven turns using 10 ga. solid copper wire. The turns
are spaced at least half an inch, and the coil is on a
35 degree angle.
The spacing is fine, but the coil is uneven at parts.
The 10 ga. wire was not the easiest to shape right.
I was wondering if this is going to affect the coil
performance a lot, or if my primary should be fine?
Is the perfect, circular, shaping of most well built
primary coils for performance reasons, or is it
just nice to look at?
http://img167.imageshack.us/img167/6384/1000122be1.jpg
http://img167.imageshack.us/img167/2487/1000121qa2.jpg
By the way, what should I do to hold the wire in place?
Right now its just pressed agianst the wood inside the
slots. If it were to fall the coil would be ruined. I could
use wood/metal epoxy but it is flammable. That is what
I used to attach the primary supports to the wood base.
Thanks,
Matt
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