Re: Rob's Coil Status
Subject: Re: Rob's Coil Status
From: MSR7-at-PO.CWRU.EDU (Mark S. Rzeszotarski, Ph.D.)
Date: Fri, 16 Feb 1996 10:50:54 -0500
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>Subject: Rob's Coil Status
>Well, I have finally had a chance to get to work on my coil.
>The Secoonday is complete:
>876 turns of 22AWG on 8"PVC form
>The OD oof the forrm ended closer to 8.50" with epoxy seal and all
>Copper ground plate as per Richard's suggestion.
>Top and bottom closed with 0.50" white plexi.
>Sealed ith another layer of two part epoxy.
>I have located my capacitors...
>I have three Maxwell Lab rated:
>tested at 0.0106uf
>Equiv. series ind.:0.02uh
>I also have four 40kv doorknob caps for use in the filter section.
>15Kv, 60ma times 2 for a total of 15kv -at- 120ma. (neon)
>I am going to start on the primary on Sunday...
Hello Robert and othe interested coilers,
I just completed winding a very similar coil: 8 inch diameter, 26.25
inch length, wound with 21 A.W.G. wire. After examining solenoidal, flat
spiral, and saucer shaped primary geometries, I have decided on a flat
spiral. (A saucer geometry would also work well.) I have .025 uF total
capacitance, and expect to operate at about 150 kHz, which is similar to
My primary will consist of 3/8 inch soft copper tubing in a flat
spiral with an inside diameter of 12 inches, and turn to turn spacing of
0.75 inches. Initially, I will use 50 feet, but am making the coil former
larger so I can extend this to about 75 feet later, as I expect to
eventually operate around 100 kHz. I will initially have about 10 turns,
and expect to operate around turn number 9 for 150 kHz. At the moment, I am
still in need of some plastic for the coil former, so construction of this
coil is on hold. Other coil construction continues, however. BTW, If you
build a coil similar to this, expect to operate it with the bottom turn of
the secondary about 2-3 inches above the primary turns, yielding a coupling
coefficient of about 0.2 or so.
Mark S. Rzeszotarski, Ph.D.