[TCML] Bipolar coil winding

[Bert Hickman]

Jim Mora wrote:
> Hello Fellow Coilers,
> 
> I am beginning winding my first "1/2" wave bipolar horizontal coil. There
> seems to be a difference of opinion on the DIRECTION of wind when I get to
> the center (1/2" gap). I know twins are wound in opposite directions. It
> seems to me that since the solenoid primary is 180 degrees out of phase end
> to end, the direction should carry on the same??? Can a few of you that have
> made these please check in with what works the best?

Same direction - a single solenoid or a pair with a gap (but wound in 
the same direction). If wound on separate formers, the latter setup also 
allows you to independently adjust coupling.

> 
> I would like to have some agreement before I get to the half way point.
> 
> The secondary is 2.25" acrylic, 27" total wind, 30AWG, 6:1 ratio, approx 900
> turns to the center. The primary solenoid will be wound on a 8.25" acrylic
> tube with 3/16" CU tubing on .25 to .375" spacing to allow taping. I will
> likely add a 3" tube to encase the secondary. There will be ~ 12x3" toroids
> on each end and the usual adjustable sweeping centered electrodes on 3/8"
> tube. I have numerous transformers in this power range to experiment with.
> It would seem the power would want to double from a smallish coil like this
> in 1/4 wave. Thoughts? 

A 9/30 or 12/30 should provide ample power. Use the main spark gap to 
limit max power output.

> 
> I wouldn't normally wind such a thin secondary, but I have the acrylic on
> hand and want to be able simply demonstrate this coil to small groups
> without the worries of a ground or wayward arcs.
> 
> Thanks Much,
> Jim Mora
> 
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> 

Bert
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