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Re: Primary coil
Original poster: 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.
In a message dated 2/9/07 2:24:07 A.M. Eastern Standard Time,
tesla@xxxxxxxxxx writes:
Original poster: "M G" <gt4awd@xxxxxxxxx>
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/img167/6384/1000122be1.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