Re: primary mounting positions

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi David,

	I can think of three possible problems:

1.	The coupling between the primary and secondary may be too high.  People
are always trying to get greater primary to secondary coupling.  However,
there is a limit at about 0.2 where increasing the coupling further hurts
performance and starts to cause other problems.  With the primary in the
center of the coil, you would have to have the primary turns spaced fairly
far from the secondary just to keep the coupling reasonable.

2.	The voltage in the center of the secondary is roughly 1/3 the terminal
voltage.  So you would have very serious problems trying to keep the center
of the secondary from arcing to the primary.

3.	There will be a tendency for the coil to fight from going into a 1/2
wave mode instead of a 1/4 wave mode.  The coil would naturally want to
have the center grounded with the two ends at high voltage.  With a
grounded base and the primary in the middle of the coil, odd things may
happen...

You may want to try a true 1/2 wave coil where the two ends are terminals
and the center is basically grounded.  If you try this, be sure and let us
all know what happens!  The third item above could be really interesting!

Cheers,

	Terry


At 12:42 PM 7/4/00 +0000, you wrote:
>I need some help
>has any one tinkered with mounting a primary at middle point up secondary 
>thus taking full advantage of magnetic/electric feilds produced so if use 
>rough rule of pri dia= secondary height for optimum but calculate for 
>seconadr of double that is this feasable.
>any coments welcome
>Davis Brown
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