capacitor failing

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

Original poster: "Laurence Davis by way of Terry Fritz <twftesla-at-qwest-dot-net>" <meknar-at-hotmail-dot-com>

(apologies for the simple question)
my homemade cap failed. pe/aluminum in mineral spirits.
60mil poly in 10 6 mil sheets with roofing aluminum for plates.

there are four caps in the tank. the caps are connected in parallel.
assuming 500v/mil dielectric strength for PE, that gives 30kv rating.
some have said 400v/mil for PE, which gives 24kv rating. whatever.
each cap at 7.2nf.

I had thought the cap was rated at a minimum of 24kv.

(since i've already proved i'm weak in the ohms law area :)

the cap (since it was wired in parallel) was THEN actually rated
at 6kv.  24kv / 4 = 6kv.

am i correct that it was actually 6kv instead of 24kv?

following that the voltage rating is an inverse relationship
to capacitance...  well sort of.

an example to be clear:
3 capacitors.  100v -at- 100uf.

in series...   300v -at- 33uf
in parallel...  33v -at- 300uf

in series...   ctot = ((c1 + c2 + c3)/3)/3
               vrat = c1v + c2v + c3v

in parallel...  ctot = c1 + c2 + c3
                vrat = ((c1v + c2v + c3v)/3) / 3
where c1v = c1 voltage rating.

larry.