In article ,
Meat Plow wrote:

My generator is 2500/3250 surge like
yours. And it is brushless. But there was nothing I could do to filter
the output well enough where my two 1000va APC UPS units would come
back off battery.

I've read elsewhere that the problem with generators and UPS units, is
that the generator doesn't hold an exact 60 Hz. You might find a
generator's frequency will range as much as 63 Hz to 59 Hz from no load
to full load. The UPS likely depends on a crystal controlled oscillator
to determine if 60 Hz power is present.

I wonder if inverter generators like the little Honda EU1000i, will work
with a UPS?

Fred