Re: Wire Length (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sat, 16 Dec 2006 17:35:46 -0800 (PST)
From: Mike <megavolts61@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Wire Length (fwd)

This max inductance can be usefull for maggie design,   but a spacewound secondary would probaby be required for the volts per turn issue.   Knowing the information....even if just for trivia cannot hurt though.
  Mike
   
   
   
  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.


 __________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com