Re: Secondary ground terminations

Subject:      Re: Secondary ground terminations
       Date:  Tue, 10 Jun 1997 20:25:18 -0700
       From:  Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization: Stoneridge Engineering
         To:  Tesla List <tesla-at-pupman-dot-com>
 References:  1

Tesla List wrote:
> Subject:  Secondary ground terminations
>   Date:   Tue, 10 Jun 97 09:12:44 EDT
>   From:   Gary Lau 10-Jun-1997 0908 <lau-at-hdecad.ENET.dec-dot-com>
>     To:  tesla-at-pupman-dot-com
>     CC:  lau-at-hdecad.ENET.dec-dot-com
> Thanks to all who replied to my Pri/Sec spacing question.
> I've just completed the winding of my secondary and have to deal
> with terminating the ends before I can coat the coil.  I have
> read the R. Quick documents suggesting terminating the bottom of
> the secondary with a flush-mounted copper plate just below the
> bottom winding on the sec. tube, and attaching the earth ground
> connection to this plate using a rubber band.  While I can
> appreciate the durability and low corona discharge qualities of
> this approach, the integrity of the connection seems marginal
> when compared with the efforts one should make in providing a low
> impedance ground path.
> I was planning on plugging the base of my sec tube with a 3/8-
> 1/2" disk of Plexiglass with a 1/4-20 threaded insert in the
> center, and gluing a second 3/8" disk above this insert to
> insulate and plug the insert hole.  The insert would be used to
> mount the secondary assy.
> Would it be reasonable to use this insert as a ground connection,
> running a thin copper strip radially outward on the base of the
> lower disk from the insert to the bottom tail of the secondary?
> Gary Lau
> Waltham, MA


This approach should work like a champ! The strip avoids excessive eddy
current losses that would come with using a conductive disk or ring. A
flat strip of copper (easiest to solder to) or aluminum flashing should
work very nicely.

Safe coilin' to you!

-- Bert --