Tuning Questions

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

Original poster: JOSEPH CACCIATORE <jocatch-at-us.ibm-dot-com> 


<<<<<<<<<<<<<<<Third attempt to get this posted>>>>>>>>>>>>>


I am now in the process of tuning my new coil. Short videos and pictures at 
my site, http://www.joecool-dot-org/joes_tesla_coil.htm.

The software is telling me that I need 15.75 turns on the primary, I 
currently have 14.5. Before I add the extra wire and start adjusting I was 
wondering how sharp of a "Q" is a tesla coil circuit? I would not expect it 
to be very narrow. In other words I don't expect to see much difference 
adding or removing one turn. Instead of adding another turn or two why 
can't I just reduce the size of the toroid (the major diameter that is, 
still using 4" duct)? Using heating duct, it is very easy to do. Are there 
any adverse affects reducing its size?

I also noticed that grounding the case of the NST and the bottom of the 
secondary to earth ground didn't make much difference in spark. Adjusting 
the spark gap doesn't seem to make much difference either unless I go too 
wide or too narrow although I didn't make any actual measurements for 
either test. Adding a sharp point to the toroid, like a piece of wire, 
gives me about 18" sparks. Without the wire I get small break outs all 
around the toroid. I don't know with a 12,000v,
30ma NST how much bigger I should expect. I will be playing around with the 
# of primary turns to see. Is there any way to ball park measure the 
differences during tuning other than visual?

JC