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Re: Formless Secondary

Hi Kevin,

No, you're not wasting your time if you are having fun.  However, if you are 
trying to build the ultimo secondary, you probably are.  Any secondary you 
make on approved materials like acrylic or polyethylene are going to produce Q 
factors far above the Q of the primary circuit.  These two Q factors behave 
something like resistors in parallel.  You know, if you have 1000ohms in 
parallel with 20ohms, the 1000ohm resistor isn't really contributing much to 
the resultant value.  The formula for system Q (which I have posted many times 
before) is:

    Qsys = 2 * (1-K) * (Qp * Qs) / (Qp + Qs)

where:
Qp & Qs are the primary and secondary Q factors
K is the coefficient of coupling (typically 0.05 to 0.2)

If you build a really really good primary circuit, you will get Qp = 50 
(about).  The typical well made secondary's Qs = 150.  Plugging these numbers 
into the formula (assume K = 0.1) gives Qsys = 68.  Now, if you succeed in 
building an absolutely balls out screeeeeemin' secondary with a Qs of 400 
(which you won't), the SYSTEM Q (Qsys) will increase to 80.  This translates 
to a power processing efficiency increase from 72% to 75% for all that effort. 
 This is the efficiency at which power is coupled from primary to secondary 
and vice versa, not the efficiency of output spark power to input power.

Well, I hope that wasn't too long winded for you, but I could have just said 
"yes, you're wasting your time." and left it at that, but you probably 
wouldn't have appreciated that too much.  My point (as always): INCREASE THE 
PRIMARY Q and you will go much farther in increasing Qsys.  The best way to do 
that is to wind a low frequency secondary coil (40-100KHz) that will require 
the largest possible primary inductor to tune it.  This slants the primary L/C 
ratio up and increases primary Q dramatically.

Boy, I sure say that a lot.

Zap,
Mark

========================================================================
>
>What is the dissapation factor of polyeurathane, varnish, epoxy and behr 50.
>Since this is now my form, it is an important factor now isn't it?
>Which one is stronger, what are the +- of each?
>I am a test systems PCB designer in the testing lab at Delco Electronics for
>vehicle instrument clusters, I can test the strength but do not know how to
>test
>dissapation factor. (we can test about everything imaginable, we have
>electron
>microscopes, test chambers of all types,emc, emr,sound,&light rooms,finding
>out somthing new every day)
>
>Input from anyone is greatly appreaciated.
>
>                               Kevin M. Conkey