[ARC5] HV oil caps - keep or not ?

[Richard Knoppow]

    They are paper dielectric with oil. The oil tends to prevent 
the paper from electrolyzing, i.e. what makes newspaper turn 
brown. They are generally very long lived although all paper caps 
are life limited.
    One purpose of the BCB type oil is that it has a very high 
flash point and does not burn easily.
    Oil filled caps can develop leaks due to degraded seals at 
the terminals. If they don't leak oil they will have a very long 
life.
     I had an incident with PCB filled transformers many years 
ago. I was living in the SF valley then and a distribution 
substation in Burbank blew up. It was during extremely hot 
weather, too much A/C going. The power went out and stayed out 
for almost two weeks. I took my bike and rode over there. The 
explosion had blown the iron doors off the building. Eventually 
flat bed trailers showed up with large transformers on them. Lots 
of warning signs posted to stay away. Eventually, it got fixed 
but I think its now open air. Anyway, I don't live in the SFV any 
more but have quite irregular power where I am.
     I would not be too concerned with the caps. Find a capacitor 
tester that is capable of measuring both series and parallel 
resistance. Caps can have reasonable series resistance but still 
be "leaky" i.e., have low parallel resistance. Watch out for 
stored charge. Paper caps are pretty good about this but you can 
still get a hit off old HV caps that have been stored without a 
short of some sort across the terminals. If the cap has physical 
leakage, i.e. is leaking oil, dispose of it as a hazardous waste.

On 1/14/2022 3:25 PM, Hubert Miller wrote:
> The Pyranol oil is a nonissue with me. The chance of the power 
> supply being in a fire is much less
> 
> likely than me being struck by lightning, which is itself very 
> remote. I was just wondering, as these
> 
> are rather large caps for the capacity, compared to lytics, 
> whether to keep. One thing about them,
> 
> they don't need reforming after 20 years, or 50 years, or….
> 
> -Hue Miller
> 
> 
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL