RE: capacitors and equalizing resistors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mccauley, Daniel H by way of Terry Fritz <teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>


I disagree.  Resistors are almost always used as passive equalization
devices when large storage capacitors
are wired in series.  If not, unequal voltages can develop across these
capacitors (typically electrolytic, and tantalum
super-capacitors) and ultimately destroy them.  For pulse-conditions you are
correct, but for DC operation, resistors are
used for both voltage equalization across series capacitors and as bleeder
resistors.

Dan



 > If I may whine about one of my peeves - Referring to the resistors as
 > "equalizing" perpetuates the misunderstanding that they determine the
 > voltage division between series-ed caps.  The resistors are
 > far higher
 > impedance than the reactance of the caps at 60 Hz and have no
 > bearing on
 > the voltage division.  They are strictly for bleeding off
 > charges that
 > accumulate asymmetrically on series caps, for reasons that
 > frankly, are not
 > understood.  They should be referred to as bleeder resistors.
 >
 > Gary Lau
 > MA, USA