[R-390] Another Capacitor Question

[Tisha Hayes]

Some people are perfectly willing to run right up against the rated
values on components. I really do not feel comfortable on doing that
and usually when I am approaching +/- 10-15% of whatever value
(capacitance, resistance, voltage, wattage, etc...) I am usually
upsizing the component.

Much of it depends upon duty cycle, the criticality of the application
and the inherent risk of the device. Since a capacitor is an energy
storage device that can fail catastrophically and cause cascading
failures in other components my personal inclination would be to go
with a 1000 V component.

You still may be able to use those 630 V capacitors if you create a
series/parallel combination of caps to get to the desired capacitance
value. You would end up with a capacitor array that would be rated for
a max voltage of 1260 volts and take up four times the number of
components (and space) to do the same thing. It does depend upon what
sort of deal you got on pricing/ availability (eg.. if it is in my
parts box it is essentially "free" to me and I do not worry about the
cost).

Running a 630 volt capacitor in a 600 volt system... yea, you probably
will be able to get away with it and 95% of the time it will never
become an issue. For me, it is the 5% of the time that gets me antsy
feeling.

-- 
Ms. Tisha Hayes/ AA4HA
-
“But what is liberty without wisdom, and without virtue? It is the
greatest of all possible evils; for it is folly, vice, and madness,
without tuition or restraint.”   Edmund Burke