Max Surge Voltage Ratings on Modern Can Caps - anybody know those specs?

[lassoharp]

I have only seen a Max Surge Voltage spec printed on a hand full of vintage electrolytic caps but am assuming they were applicable to ones with no such printed spec.  Many commercial amps tapered the working voltage rating on the preamp nodes sometimes up to 100WV less than the high current nodes.  Fender ran 450V caps (two 16s in //) on a 330-340V winding in the Deluxe Reverb.

I haven't been able to find any surge voltage specs for any of the modern can cap maker's products and have always used the WV spec to stay within supply turn on peak numbers.

Anyone happen to know what, if any, peak voltages the modern can caps will safely take above their WV ratings?  Any DIY builds as working proof?


Are there any rules of thumb on this from the old days?  I imagine some caps were tougher than others.


Big caps are pretty cheap and we can always run them in series but sometimes it would be good to know how many of those 9 sec intervals of a given over voltage they can take before kicking the bucket prematurely.  5? 50? 500?  In the case I'm looking at it's about 586V peak on a 500V WV cap.

 

[PRR]

Google?

"capacitor Surge Voltage Ratings"

Chem-Con has a table here.

CDE has a paper showing how leakage varies with voltage, and how to compute estimated life from voltage and temperature.

Jianghai has a fine paper with much good explanation.

A fine paper by Otto Klug.

A typical good product-sheet has an explicit SVDC.

But the real question is: do you want it to live forever? Or do you expect/want to work on it again in the next few years? If it is a "plaything", or 90-day warranty, use whatever is pretty close. If you don't want to see the insides again soon, GROSSLY over-rate the cap. Even 2X the average voltage. Specifically: I like two 350V series (with good centering) on a 500VDC-550VDC supply. Two 450V would not be wrong.

 

[lassoharp]

Thanks for the article links.  That pretty much covers it.

This is for a DIY bench supply which will probably be tinkered with on a regular basis.  I doubt I would ever chance it that close on a repair job for a client, even if within spec sheet.


The Klug paper is excellent!