19 Jan
2012
19 Jan
'12
9:44 a.m.
Ian King wrote:
I've cited this research before in this thread,
and it states that the
common failure mode is that the equivalent series resistance (ESR)
increases, which contributes to other failure modes. "The wearout
process is rarely driven by evaporation and escape of the electrolyte
unless the safety vent is compromised due to high leakage current and
pressure buildup." Overvoltage is not likely to be a factor in an
existing system unless there has been some other failure in the power
supply,
Actually I don't see anything in that paper that contradicts my claims
that the oxide breaks down when the capacitor is not used under bias for
a long interval, nor that such an oxide breakdown reduces the effective
working voltage of the capacitor, leading to failure when used at the
original rated voltage.
I've seen other papers from capacitor vendors, possibly including CDE,
that discuss this problem. I don't have those papers handy at the
moment, so I'll have to dig around for them.