I had to repair a 12" dia secondary with a similar problem, and another with
a 2 inch cut across the turns. In each case I took off all damaged turns,
then drilled a small hole in the open area. I cut each adjacent turn to
about 2" longer than the length to reach the hole, stripped the wire back
about 1 1/2 inches and stuck both ends into the hole. Then I reached inside
the secondary and twisted the wires until they were tight on the outside.
That leaves a wire reaching diagonally across the damaged area. You can
fold over the twisted ends, but the interior of the coil has only a
longitudinal E-field, so it should not corona. The repairs both worked, but
the 2" wide one had corona from the diagonal wire and was the source of a
few sliding sparks on the coil. I built a nice container for the coil out
of a cardboard concrete form tube.
In each case, we were able to rewind each section using the same joint
technique at each end.
Good luck!
---Carl
-----Original Message-----
From: Scott Bogard
Sent: Wednesday, September 17, 2014 8:38 PM
To: Tesla Coil Mailing List
Subject: [TCML] Emergency Secondary repair, also archives down???
Hey all.
So I finally burnt up my first secondary coil, (hopefully my last
also) and I was going to show it off on Saturday (not a paid gig, but still
I'd rather not disappoint). I was going to look up the accepted procedure
on repairing them in the archives like a good boy, but they didn't work on
my machine, I got a 404 error... Well the error occurred when I tried to
"search the site including archives". Anyway, is there any last second
pointers for the uninitiated? The coil is a 4*18 wound with 28 AWG, is
there any chance of saving her? The turn got hot and smoked a bit, before
glowing red, it is pretty bad, but the damage seems confined to about 3
turns or so, about 2/3rds up the side, it suffered a fall at some point and
despite re-coating it with polyurethane, well you know the story.
Scott Bogard.
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