Re: (Re) Wire Length (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Tue, 19 Dec 2006 18:33:43 -0800
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: (Re) Wire Length (fwd)

Hi Jared,

Tesla list wrote:

>Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>
>
>
>---------- Forwarded message ----------
>Date: Tue, 19 Dec 2006 05:05:06 -0500
>From: Jared Dwarshuis <jdwarshuis@xxxxxxxxx>
>To: Pupman <tesla@xxxxxxxxxx>
>Subject: (Re) Wire Length
>
>Hi: Bart
>
>I have not wound any flat secondary (yet).
>
Sorry, I thought you had.

> I am wondering if the inductance can be roughly calculated as:
>
>L =   [4 pi x 10^ -7  x (wire length)sqrd] / [ 4 pi Radius ]
>  
>
Using your equation (SI units), I came up with 0.005853 H. Javatc came 
up with .004165 H in a linear distribution and .004849 H at resonance 
assuming the coil is 50" above the floor and not loaded. Hard to say 
which is close to reality. A spacewound secondary like this hasn't been 
measured yet that I'm aware of. We will find out with measurement.

>They say that Tesla used wood boiled in linseed oil, I have not tried this.
>If i were to do this (for reproduction purposes) my choice of wood would be
>spruce or similar softwood. I say this because many hardwoods
>(especialy wood from tropical enviroments) have minerals in the grain that
>are likely to be somewhat conductive. ( teak is horrible, you can see sparks
>when the carbide blade hits the mineral pockets)
>  
>
I have the wooden runners and used hard oak. The reason for that is 
mostly cosmetic. But as far as actual runners, I used a thin slotted 
plexiglas for that purpose. No need to go backwards in history regarding 
high voltage design. Tesla actually grooved the runners with curved 
insets for the cotton insulated wire. I can only imagine he used some 
sort of adhesive as I can't think of any other way to set the wire in 
place in those grooves.

Take care,
Bart