Re: Location of Primary relative to Secondary???

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Steve,

Tesla list wrote:

> Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<srward16-at-hotmail-dot-com>
> I usually make the very first turn of the secondary, level with the inner
> turn of the primary.  Its usually as level as i can get them.  I would
> believe this to have the highest coupling, correct?

No, this is not the highest coupling. As the secondary is lowered further
into the primary, mutual
inductance and coupling will increase and will reach a maximum when the
primary is positioned in the
center of the secondary (assuming the secondary is helical). Continuing
further past the secondary
mid-point would start lowering mutual inductance and coupling back down.

If you want, you can type in ' bart85 ' in the JavaTC password box to load
the default coil into
JavaTC, then go down to the Primary Circuit Design. Mutual Inductance and
Coupling is "roughly"
calc'd and there is an input for changing the primary to secondary height.
Just change it to the
center of the secondary's coil length (about 20") and press the Calculate
button. Then put in
numbers above and below this. You'll always get the maximum mutual
inductance and coupling when the
primary is positioned in the center of the secondary - makes for a decent
demonstration.

http://www.classictesla-dot-com/java/javatc.html

Take care,
Bart