voltage rating on capacitor

[thl748]

I have a 4uf capacitor, working AC voltage 480v at 400 Hz and 600 VDC.
I'd like to know the working AC and DC voltage at 60 Hz

 

[Skogsgurra]

480 V AC 60 Hz.

Don't understand what you mean by DC voltage at 60 Hz.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[waross]

DC offset? If you may encounter DC offset you may consider keeping the peak voltage below 600 volts. That may result in a a greatly reduced maximum allowable applied voltage.
It depends, if the voltage rating is dependent on the maximum voltage that may be applied to the capacitor DC offset may be a problem.
If the maximum voltage is limited by capacitor heating, (I am thinking of motor starting capacitors that will overheat if energized continuously at the rated voltage) then the capacitor may be able to withstand some DC offset.
Or, "AC and DC voltage at 60 Hz" may be just misstated. grin

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DHambley]

I'm guessing that you mean, "AC with a DC offset". The peak voltage of 480VAC is 679V. The DC offset plus your peak sine voltage must be less than 679V. For good reliability the voltage needs to be a lot less than this. Some reliability specs require lower than 50%, some are OK with 90%. This depends on what your customer requires.

 

[zappedagain]

I'm curious... where have you seen a spec of 90%? Is that from consumer electronics that only has to last 1-3 years?

John D

 

[Skogsgurra]

It is something that different producers of electronic devices seem to select according to application. A general purpose electrolytic capacitor is mostly used at around 70 % of rated voltage.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[DHambley]

zappedagin, It was just an example for him; I shouldn't have said "spec". I have never seen a derating guidline which whould call out 90%. What I HAVE seen are parts in cheap commercial electronics which are stressed right at (or even above) 100% though.

 

[zappedagain]

Thanks. That makes a lot more ssnse.

Z