Re: RE- Secondary wire & insu

Subject:      Re: RE- Secondary wire & insu
       Date:  Mon, 9 Jun 1997 09:42:03 +1200
       From:  "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Organization: Wellington Polytechnic, NZ
         To:  tesla-at-pupman-dot-com

Re close-wound vs space-wound,
                               There is actually not a huge 
difference between them. You can view a space wound coil as being a 
close wound coil wound with thinner wire. Spacewound has it all over
closewound when it comes to well-bolstered turn-turn insulation, but 
as some recent experiments of mine show, voltage breakdown is 
probably the least of your worries in getting a good coil going. 
Consider: If the voltage is approaching that which will tax the wire 
insulation, the coil would be shooting sparks straight from top to 
bottom. IMO it is only because coils are typically run at voltages 
somewhat less than this limit that the streamers can reach out and 
grow to many times the "voltage length".
    This last weekend I tried the now-bolstered 2.5" high litz coil 
on the minisystem I am playing with and the single shot length (low 
rep rate) exceeded the winding height - just. There was a faint 
corona visible on the outside of the coil varnish. Increasing coupling 
beyond that point made it shoot straight up and down with no hope of 
streamer growth.