Re: Magnet Wire Sources

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


On your upper base assembly add a small drilled and tapped 1 x 1 inch x 3/8
inch thick piece of brass.  The sec coil should also have a brass stud out
it's base so it will screw into the brass plate.  A small separate hole is
drilled and tapped for ground wire attachment.

Make the stud on your sec coil extra long, like 2-3 inches long.

Now you can slip a tight piece of thickwall tygon tubing around it, gently
bend the tubing 90 degrees, and slip the other end over a variable slow
speed elec. drill or small DC gearmotor.

This will allow you to run the sec coil up and down while it's running so
you can see the dramatic effects of coeff. of coupling adjustment to spark
output.

After you do this with your proposed 8 inch coil please report back to the
list the results of your experiments.  I'm betting with an 8 inch dia. coil
you will require an elevation of around 5 inches (first lower turn to sec to
horizontal plane of primary measurement).  Let us know your results.

Other experimenters may wish to try this with their 4, 6, 10, 12, 16 inch
coilforms.

We make a lot of 18 inch dia. coils and found 7 inches to be the most
effective coeff. of coupling.  For our 24 inch dia. coils it requires 9
inches for best performance.

Most experimenters way over-couple their coils and lose performance that
they are not even aware is available.

Happy coiling,

Dr. Resonance

 >
 >  > Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
 >  > If you're having tracking problems there is the definite possibility
that
 >  > your coeff. of coupling is too tight.  With a 3-4 inch dia. coil
usually
 > the
 >  > sec. starts 1.5 - 2 inches above the horizontal plane of the primary.
 > With
 >  > a 6 inch form the sec. rise to 3.5-4 inches above the primary plane.
 >  > Inner turn to primary to coilform distance is 1.5 inches.
 >
 >      Yeah, my K is very high on this coil (it's an 8 inch). I have been
 > running the bottom sec turn about 1/4 inch above the pri plane for several
 > months now. I set up up as tight as I could get it without racing sparks
and
 > ran it that way for quite a while. Pri/sec clearance is your standard 1.5
 > inch.  I was bitten by the same thing that got several of us in the past-
 > small., invisible fire on the back side of the coil form. I'll definitely
be
 > kinder to the new secondary, but it's been a lot of fun to push "model #1"
 > to the limit. At least I can say the power supply is now pretty bullet
 > proof. Only the secondary ever catches on fire anymore. It's almost boring
 > to power it up because I "know" they won't be any silicon shrapnel ;)
 >
 >  > I don't have the chart handy.  You should check with the mfgr as there
is
 > a
 >  > slight variation between mfgrs and the thickness they use.
 >
 >      http://www.wiretron-dot-com/magnet.html has a little piece of software
that
 > provides charts for the various types (at least what they sell). It
appears
 > that "heavy" build has an OD of .0276 +/1 about 2% for 36 TPI, which
sounds
 > about right.
 > #20 comes out at 28 TPI which is dead on with coil #1.
 >
 >      Thanks for the help!
 > db
 >
 >
 >