"kevincw01" writes:

OK, fair enough. What about a power condition that does "AC
Regeneration", or is this the same as line voltage regulation you
spoke of.

That's probably referring to an "on line" UPS, which continuously
converts AC to DC, then back to AC using an inverter. This is larger
and more expensive (because the electronics have to run all the time,
not just when there's a power failure) but it still won't solve your
problem.

With an on-line UPS, the circuitry is designed to never discharge the
battery when AC power is available. So when your printer's fuser turns
on, it draws 400 W or so extra from the UPS, which will in turn draw
*more* than 400 W extra from the AC line. So it will have even more
effect on your lights.

The only way to prevent a UPS from affecting house voltage at all is to
unplug the UPS just before you start printing, so it doesn't draw any
power from the house and the batteries supply all the power. However,
you'll need a *big* UPS for this. It needs to be able to supply the
startup surge of the fuser, not just its steady-state running power.

Also note that most UPSes will operate for only 5 minutes or so fully
loaded - if you want to print long documents, you'll need one with more
battery capacity. When the batteries have been discharged, it takes
many hours for them to recharge, so you can't print very often. And,
finally, doing this very often will shorten the life of the batteries.

Dave