On Sat, 16 Feb 2013 10:13:55 -0500, Existential Angst wrote:

What are the pro's/cons of each?

One pro for caps is that they are cheaper! The AVR ditty for my unit
would cost another near-$400.
The pro for AVR is, presumably, much tighter voltage regulation with
load.

But mebbe AVR has its limits ito ruggedness?

The voltage swing on my genset is 250 - 230 V, 0-50 A. Units with AVR
claim 1-2% regulation.

Should I spring for the AVR? If a major outtage occurs, I'll be running
cnc equpment from it.

Do you have a link to a site that sells the AVR ditty? If it's
regulating the field current of the generator in response to the
generator voltage, and if all the genset does is rely on the motor's
governor for speed regulation, then it should give better regulation.

But I can only speak from a combination of a deep knowledge of control
systems theory, a reasonably deep knowledge of how generators work and
how Briggs and Stratton engines work, and a near total ignorance of how
people actually put these things together in practice.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com