Glass Caps

From:  Esondrmn [SMTP:Esondrmn-at-aol-dot-com]
Sent:  Tuesday, January 27, 1998 10:18 AM
To:  tesla-at-pupman-dot-com
Subject:  Re: Glass Caps

In a message dated 98-01-25 11:45:25 EST, you write:

<< Dear Readers,
 Anyone ever run a medium or large coil with a glass cap?  I'm trying 
 to figure out how bad the heating problem is at 1KVA and up.  I've 
 only built 3 small coils, all under 500VA.  All I've ever used is 
 glass caps, and I've only experienced one unexplained failure in a 
 foil & window glass cap on a 380VA coil.  A hasty autopsy revealed 
 glass panes laced with very fine, spider web-like cracks.  Might've 
 been due to thermal effects.  My current 450VA coil runs with salt 
 water bottle caps.  I think the water sinks so much heat, I'll never 
 be able to detect RF heating at such low power input levels.

My very first Tesla coil, built many years ago, used a flat glass plate cap
made from window glass with copper foil bonded to each side.  It did get hot
and two of them failed.  These were operated dry - no oil.  I was using a 12
kv 30 ma transformer.

Ed Sonderman