[Amps] Oil-caps delating 2/3 ratings?

[Barrie Smith]

> Recently an old man told me that all of the caps are energy storage jobs
> and they are usually derated for continuous duty to about 2/3 rating.
> I thank him very much.
>
> I am using cheap 32uF 4500V GE non-pcb caps.
> Should I use it at 3000V maximum?
> Fortunately I am using this potential level now.
> If someone use 16uF 7500V Arioso caps like Henry,
> maximum working voltage should be 5000V?
>
> Would you please tell me the reason for the "2/3 derating"
> practically when using them for our linear amps?
>
> For a long time I had a question why GE had not indicate working
> voltage and test voltage but only "4500V".
>
> Additionally anyone did a destructive/non-destructive test on it?
> Seemingly they are sustainable at 5kV, but if the number 2/3 work
> their life should be very short.

Han:

Totally by accident I ran a pair of these caps at 6500 volts for several
minutes.  Nothing bad happened.

I still use that pair of caps in power supply that runs 4200 volts no-load.

As they say, YMMV.

73, Barrie, W7ALW