RE: Small coil questions?

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

Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com> 

Comments interspersed:

 >Original poster: "Kreso" <kreso.bukvic-at-kc.htnet.hr>
 >
 >I have to make final work in my school. Il make a tesla coil.
 >I ordered 4kv38 ma transformer but it will be centertapped not
 >like transformers you use for competition. i have these questions:

Centertapped shouldn't matter at all.  Of course you'll have to not ground 
the inside of the primary as I did.

 >1. Can i make helical primary? Will it work so good like
Gary-s mini tc?

I have seen my flat primary overcoupled on my mini coil, so there's no 
doubt that a helical primary can easily overcouple.  I suppose you could 
build it well below the base of the secondary, but a flat primary would be 
far more compact and tidy.

 >2. Il make a secondary 50 mm diameter, 1100 turns of 0.2 wire.
 >Will it be good is this the same as Garys secondary?

That's precisly what I used.  Sounds fine to me!

 >3. Il use 10 kvac 20 kvdc caps bank at resonant rise. Will cap-s hold up?

The voltage rating certainly sounds adequate.  It's not clear what 
capacitance you have or what the dielectric/construction is, and this 
matters a lot.  If you're setting your cap value to be mains-resonant with 
the NST, OK, but be very careful to set the gap properly or the resonant 
rise WILL zing your caps.  Personally, I've gotten the best results with 
about 2X the mains-resonant value.

Regards, Gary Lau
MA, USA