Re: Wire Length (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sat, 16 Dec 2006 13:28:15 EST
From: Mddeming@xxxxxxx
To: tesla@xxxxxxxxxx
Subject: Re: Wire Length (fwd)

 
In a message dated 12/16/06 11:25:51 A.M. Eastern Standard Time,  
tesla@xxxxxxxxxx writes:

Subject:  Re: Wire Length

Let me see if I am getting this right.  For any  given wire length and number 
of turns-per-inch there is a unique solonoid  height-to-diameter ratio at 
which maximum inductance occurs, and this H/D  ratio is approximately .9/1. 
Is that correct?

Gary  Peterson



Hi Gary,
 
     Actually, it is the H/R ratio that is  0.9/1.0  H = 0.9 R,  or H = 0.45 
D that gives the  maximum inductance for a solenoid. One can manipulate the 
variables to show  that a given wire length and TPI determine a unique coil size 
 using THIS ratio.
    The problem with a coil of this ratio is the very  high voltage gradient 
(dV/dh) and the very short separation between the topload  and the primary. 
    It can likewise be shown that maximum inductance of  a flat coil occurs 
when the ratio of inner radius to outer radius is  77/165. Here again, the 
length and turns TPI uniquely determine the size once  the ratio is fixed at THIS 
value. Not many coilers use flat secondaries,  and maximizing the inductance 
of a primary would not be an objective, since  you want to keep Ls/Lp high for 
voltage gain, so this is more of a mental  exercise than a practical building 
guide.
 
Hope this helps.
 
Matt D.
 
Matt D.