Re: Doorknob capacitors for primary?

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

Original poster: Mddeming-at-aol-dot-com 

In a message dated 12/20/03 9:52:39 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:
Original poster: brent meyer <res095fx-at-verizon-dot-net>

I was wondering why I don't see many coilers using ceramic "doorknob" HV
caps for their tanks?  Are they more prone to failure?  I just happened upon
a parcel of 18  570pF 40KV caps, and I bought the lot of them. I'll be
running them on a 15KV 60 NST.   I'm looking to build a bipolar coil using a
nice pair of  5 1/4 by 31 inch long fiberglass coil forms I just found, and
was wondering if I should have to incorporate some kind of blast shields
into the designŠ

Hi Brent,
     I tried using doorknob caps on one of my first small coils. They were 
4700pf 20 KV caps in parallel with a 10KV 23 ma OBIT. In my experience, the 
dielectric tended to be very prone to HV spike punctures, but to fail 
quietly rather than explosively, after a few hours run time.

Matt D.