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On 2/23/21 7:12 AM, Adam James wrote:
Adam Here, None of my business, But perhaps a concern.
Before building my first TC I read all about capacitors and watched a few
videos on overcharged capacitors and how they can fail rather dramatically!
On curts setup, with the bucket Capacitor and an 80k to 100k sustained
charge would it be possible for that thing to go "boom"?
AJ
The failure mode on bucket caps is cracking of the glass, or arcing over
(then cracking the glass). They really don't store enough energy to be
more "exciting" than that. The usual failure is from dielectric heating
aggravated by localized heating from corona. The glass is a pretty
lossy dielectric (same problem with large glass plate capacitors that
were popular in the 1950s and 1960s) - as it gets hot, the loss goes up
(pretty quickly - after all molten glass is a good conductor) - the
hotter spots get lossier, which gets them hotter, until the thermal
stress cracks them. Once a crack starts to form, then the problem gets
even worse.
Bucket caps are also notorious for corona discharge, even at NST
voltages (20kV)
Fortunately, failures usually just result in a bucket full of broken
glass, salt water, oil and aluminum foil. And maybe a small fire, if
you're unlucky.