Over-coupled or under-insulated?

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

Original poster: "Chris Roberts by way of Terry Fritz <teslalist-at-qwest-dot-net>" <quezacotl_14000000000000-at-yahoo-dot-com>


Hi all,

I have been running my 6 inch coil for about 2 weeks now with no problems 
with the caps. (woo hoo!!) I guess we finally found the problem. However, 
during fourth light, the secondary started sparking along itself. (yes, it 
was tuned) I thought it was overcoupled and raised the secondary a bit. 
Then higher, and higher... The bottom turn of the secondary now sits about 
5 inches above the primary, and the two innermost turns on the primary were 
cut out. (this leaves me with a 9.25 inner diameter) The secondary stopped 
sparking for a while, but has started back up again. So I get a strong 
feeling that this is not a problem of coupling. I was suspicious of the 
tiny amounts of dust that is embedded in the polyurithane, (I now know not 
to re-coat after letting the coil sit for a while) so I removed all of the 
spray-on polyurithane with paint thinner, and am currently putting on 
several coats of varathane. Do you think t! his will be enough to stop 
those racing sparks? If this works, would you recommend that it would be 
safe to lower the secondary back to its original spot? Thanks.


-Chris