Re: Odd coil behavior

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

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


Before running the coil again, remove the top endpiece and carefully look
inside either outdoors in bright light or with a strong flashlight.  It's
probably arcing down the inside of the coilform.  If this is happening you
will be able to see the tracking marks.  You need to sand it down very
thoroughly and then add 2-3 coats of  Glyptal to seal the tube against the
usual suspect --- atmospheric molecular moisture adhesion.  I always coat 3
coats inside and outside prior to winding and then 4 coats of Dolph's AC-43
after winding.  It's specially formulated and much better than any
polyurethane coatings.  It dries very hard and thoroughly impregnates the
winding.

Your cap might be dying also --- internal arcing.

Someone on the list recently mentioned some type of plastic insulation that
could be easily pealed off later for re-coating.  This is terrible.  It
means that to an electron there is a space as large as the grand canyon
between the wires enamel insulation and the polymer coating he used.  The
overall effect is that the coating he used wasn't contributing anything of
value with regard to insulating the magnet wire.  In fact, it might only
contribute to capturing atmospheric moisture.

If you have a coating thats impossible to remove then you have one of the
best.

We use 1/4 inch arylic sheet cut into a circle and siliconed in place ---
usually one disk 5 inches up from the bottom and a second disk 7 inches down
from the end of the coilform.  This also helps in any coil where the spark
length exceeds the winding length of the secondary coil.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > My coil has been running for quite a while with no problems untill
 > recently. I never changed anything so it's not something new that's the
 > problem. The coil used to run moderately consistant the entire time but
now
 > it will run great for a while, then fizzle out and give almost nothing for
 > several seconds, then pick back up for a little while, etc. I would think
 > that this would be inefficient quenching that is causing this, but I
 > haven't changed the spark gap for as long as it's been on the coil.