cages Re: [TCML] 4'-5' tesla coil sparks?

[dave pierson <dave_p@xxxxxxxxxxx>]

> The cage (which should go ALL around the coil, including under it) 
> serves as the ground. There's no need to ground to some other ground 
> (other than the electrical safety ground).
 
> Even a pretty big mesh works fine for this.

> However, bear in mind that a Faraday cage doesn't do much for magnetic
> 
> fields, so don't count on it to keep fields under the ANSI C95.1 
> limits, you need to rely on just plain old distance.

     Just so.
     Having done detailed work on Faraday cages, a couple of notes:

     Edges between segments, around 'doors', etc, need attention.  How
     much varies with the frequency: Tesla coils being LF may do
     fine with 6 footish between bonding points.  (There's
     detailed math: higher freq requires closer bonding points.
     6 footish should do, but....)

     As noted 'ground', literally is not real relavant IF the
     cage is 'rfi' tight.

     IMPORTANT:
     VERY important is that ALL wiring in and out of cage be
     handled correctly.  Anything 'inside' WILL pick up 'strays'
     and cheerfully conduct them OUTside.  All wires must run
     thru filters at the cage wall with 'zero length' connections
     to that wall.  Attention to details is important to keeping
     strays where they belong.  Ferinstance: if a line filter
     is just plunked into a run of cable anything riding the
     outside can radiate around the filter. 

     best
      dwp
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