[SunRescue] exploding sun psus

Scott Newell rescue at sunhelp.org
Thu Dec 7 13:15:04 CST 2000


>Man I have been there. Anybody ever seen what happens when a 5 farad
>capacitor blows? No five pico-farad or micro-farad, 5 farad. It's pretty
>damned impressive. That was in a very large, very old public address system,
>and the smell and mess were pretty awful lemme tell ya.

5 farads (!).  Are you sure?  I've seen caps (supercaps?) intended for
non-volatile memory backup at 1F or so, but they're all rated at 5V or less
and have enough internal impedance to make the maximum pulse current output
pretty anemic.

I've also seen some reports in the trade mags about recent progress in
multi-farad sized caps double layer 'ltyics (Maxwell ultracaps?) with great
output pulse ability, but again, only at low voltages.

Seems to me any very large, very old, PA system would be running vacuum
tubes, and the power supply filter caps would each be in the 100s to low
1000s of microfarads.  Significant energy storage to be sure, but I just
have a really hard time believing an old PA system had a 5F cap in it.


newell




More information about the rescue mailing list