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Murphy strikes home !



Hi all
We tried to tune our little tesla coil Tuesday night , but had little success 
with our 12 turn inverted cone primary (30 degree pitch). So tonight we tried 
it with our old solenoid wound primary.( 15 turns of #12 wire ,wrapped onto a 
4.75" spool.)
We were using a 4" metal tape wrapped foam ball as a top load. The spark gap 
was set to 4 gaps (0.020") and the safety gap was set to 2 gaps behind 
that(0.060-"- 0.080"). We were getting about 2" sparks to a ground wire held 
onto a 3' stick We would try a 15 to 20 second run shut down and try another 
tap down, seemingly with no improvement. Then, Then my youngest decided that 
we should change the top load to our 2" x 12" toroid. Without changing 
anything anything else boy did we get results. We got a 4" arc that traveled 
from the interior of the toroid down inside the primary spool and into our 
secondary . The arc burned through 2 layers of electrical tape and 5 coats of 
varnish. At the same time, the spark gap shorted out, or something along that 
line.

My question is: Why ? The toroid  should have been at near equal potential as 
the secondary. To produce such an arc would need ay least 30 thousand volts 
difference in potential.

Rich Sebzda, With Adam and Kevin in the caboose.
Your friendly neighborhood catscan repairman.