Re: Primary shield (fwd)

---------- Forwarded message ----------
Date: Tue, 19 May 98 15:43:41 EDT
From: Gary Lau  19-May-1998 1520 <lau-at-hdecad.ENET.dec-dot-com>
To: tesla-at-pupman-dot-com
Subject: Re: Primary shield (fwd)

Arcs are ingenious.  If there's any path possible to where they want to
go, they'll find it, especially if there is a solid surface to follow.
Straight lines are not required.  In the case you illustrated, I suspect
that the arc will either go out to the outer edge of the shield and then
down, or, through the hole the secondary passes through.  If you try to
make the shield very wide and somehow seal the secondary-to-shield crack,
it may work, but then it would be difficult to impossible to experiment
with adjusting the secondary height.  And if there are any screw holes in
the shield, the arc will find them!

It's generally not to difficult to protect one's primary.  A proper
toroid will direct most of the arc horizontally and a strike rail should
catch any deviant arcs.

Gary Lau
Waltham, MA USA

>Date: Tue, 19 May 1998 15:07:30 +0300
>From: Marco Denicolai <marco-at-vistacom.fi>
>To: tesla-at-pupman-dot-com
>Subject: Primary shield
>One question is bothering me: this might be a stupid one...
>Because I have read often that a discharge from the secondary stroke the
>primary and damaged something, isn't it possible to shield the primary
>with a sheet of acryl (or other plastic)?
>I tought to cover the primary with a sheet of 5 mm acryl plastic and, on
>the top of it, place the strike rail.
>Could it possibly work?
>               -----------
>              |           |         toroid
>               -----------
>                |       |
>                |       |
>                |       |
>                |       |
>          *     |       |     *     strike rail
>         ------------------------   acryl shield 
>          * * * |       | * * *     primary (3 turns shown)
>       ---------------------------- coil base
> Marco Denicolai                   Vista Communication Instruments, Inc.
> Hardware Development Manager      www.vistacom.fi   
> marco-at-vistacom.fi                 Kaisaniemenkatu 13 A
> fax:    +358-9-622-5610           SF-00100 HELSINKI
> phone:  +358-9-622-623-15         Finland
>   Remember, Murphy was an optimist! I am not...