[AMPS] HV Power Supply Capacitors

[Tom Rauch (W8JI)]

km1h@juno.com wrote:

> >The equalizing resistors should be selected to equalize the voltage, so
> >you really have to know the leakage resistance tolerance of the
> >capacitors to pick the correct resistor.
> >The resistor should "swamp out" leakage tolerances. In general as low a
> >value as pratical is best because it insures more equal voltage division
> >even if one capacitor is more or less leaky than the rest.
> 
> Maybe a low value equalizing resistor was the norm back in ancient
> history but technology has advanced a lot since your days at Heathkit.
> The CDE 381LX series has a lower ESR  and ripple current rating at 120Hz
> and is half the size of the CGS style used in Ameritron amps. 

My point was the larger size capacitor dissipates heat better, and has a
higher ripple current rating for a given capacitance.

>From the 1995 North American Capacitor Company catalog:
 
The "ancient" CGS style 380 mfd used in Ameritron supplies has a ripple
current rating of 3.3 amperes and an ESR of .212 ohms typical (page 78).

A 390 MFD LX style has a ripple current rating of 2.2 amperes and an ESR
of .510 ohms (page 91).

I didn't follow your point of why you want to use a capacitor with lower
ripple current rating and more ESR in a capacitor input supply. Did I
miss something?

73 Tom



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