Re: heating a cap

On Sat, 5 Oct 2024 13:20:51 +0100, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

On 04/10/2024 00:36, john larkin wrote:

I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
cranked up the voltage. It started drawing a bunch of current at 105
volts, got hot, and folded back to 80 mA at 87v.
 
It got too hot to touch in a couple of minutes, after roughly 500
joules. Freeze spray let it go back up to 100 volts or so.
 
None of that seemed to damage it, so an electrolytic cap sort of has a
built-in MOV.
 

>
If you need a high temperature cap, these work and they're not horribly
expensive...
>
https://www.mouser.co.uk/datasheet/2/40/THJ-3165556.pdf

I reall want to absorb joules when a power supply is back-driven by a
load, like decelerating a motor for instance. So I want caps with a
lot of mass, or MOVs that can get very hot before they die.

The environment won't be very hot, but the cap (or MOV) will.