As several have already mentioned a UPS goes a long way toward saving you
from lots o' potential problems, grey hair and beating your head against
the wall.

Since 1990 I have been using a Best Ferrups 18KVA unit and it has been
absolutely fantastic at shielding the lab and instruments from transients,
spikes, etc. and carrying us through short power outages of the kind
experienced during a New England summer. Prior to this I used a
Gould-Deltec for many years in Southern California (which had much superior
local power). Outages are handled by Gel cell batteries and power
conditioning is accomplished by toroidal transformers and the batteries.
Long outages of course are just as problematic as if you did'nt have a UPS,
but having one allows a more controlled shut down during the short initial
time under battery power, rather than one catastrophic flipping of one
switch. The more batteries you buy, the more time you will be covered. The
more juice you draw the less time you will be covered. We have about 40
minutes with two mass specs and associated periferals. This gets us through
some but not all outages.

I have found that the down side to the unit (other than initial cost) is
that the batteries have to be replaced periodically and they are very
expensive. My battery bank costs about $2000+ to replace and I have
replaced them twice since initial installation. If one battery goes it
tends to draw the others down so you cannot replace the failed individual
battery, you have to go for the whole enchilada (all batteries in the
bank)! Other than this, my unit has been maintenance free.

Personally, I think the conditioning aspects are more important that the
back-up power aspects of the device.  If the power goes off for any
considerable length of time you are going to have to restart the
instruments anyways.  This really isn't that big a deal, but having quality
data, good precision, no spikes, happy computers and no"fried boards" is
much better for the psyche(w)!

My question to the experts is:  If the conditioning is done by transformer
on my UPS unit, why isn't my large transformer going from 120V (USA) to
240V (UK) enough to accomplish the task? Similarly the power supplies in
individual circuits should also be isolated via thier transformers, so why
do I need the expensive power conditioner? Empirically, I have seen the
benefits of a seperate unit, I just don't understand why. What's the scoop?
Best Regards,
Cap