Re: flat coil ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Chris Swinson wrote:

> I am just about to build a large flat secondary coil.  The wire
> length will be 2000ft, the wire dia is 1.6mm. I *think* this will
> be 500 turns at about 4foot dia. 

> Does anyone know the self C of the coil ?

Bart wrote:

> I simply input (in inches) the I.D. (0.125), the wire diameter
> (0.063), the wire spacing (0.0034, this is the insulation
> thickness between closewound turns ... (339 turns) 

Using Bart's dimensions, tssp software calculates:

For center grounded, rim hot:

  1/4 wave resonance: 117 kHz
  Effective series L: 54 mH
   Effective shunt C: 34.6 pF
    Energy storage C: 40.0 pF
         Max current: 135% of center terminal current,
                      at 65% of radius
          Max V/turn: At 85% of radius

For rim grounded, center hot:

  1/4 wave resonance: 149 kHz
  Effective series L: 59 mH
   Effective shunt C: 19.3 pF
    Energy storage C: 26.7 pF
         Max current: 180% of rim terminal current, 
                      at 88% of radius
          Max V/turn: At 85% of radius

Clearly, the center-hot configuration ought to make the best use
of your primary bang energy.  In both configurations 80% of the
voltage rise occurs over the outer 50% of the radius.

Bart wrote:
> and I for one would be interested in doing these exersizes again
> after we know the actual dimensions.

And I for two.  
--
Paul Nicholson
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