Re: Doorknob capacitors for primary?

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

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > 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 designS

	This subject has been discussed many times.  I've had good results
running about that same capacitance, although with fewer larger
capacitance and lower voltage units.  They do have low series resistance
which helps and more dielectric and hysteresis loss which doesn't.  They
will drift with temperature as the warm up.  However, if you keep the
runs short and are careful with the tuning I think you'll get
satisfactory results.

Ed