My question: does a line-interactive UPS provide better isolation from network blackouts, brownups, spikes & other instabilities than a simple standby UPS?
I guess that depends on how you, or rather the maker defines "simple". I would not put a "simple" UPS on my computers. To me, a simple UPS is a simple "backup power" device in the event of a full power outage. Something I might use for lighting, or... well I can't think of anything else - maybe a small TV to keep track of weather updates (I live in Tornado Alley, USA).
Note I said above, "a good
UPS with AVR". With a good UPS with AVR, it is the AVR - automatic voltage regulation that is the key feature of the UPS. Unlike a surge and spike protector, it does not simply "clamp" or chop off the tops of the sinewaves during high voltage anomalies (surges and spikes), it regulates, or attenuates the voltage back to within normal limits presenting the supported equipment with a fairly decent (stepped approximation sinewave) voltage. And note a surge and spike protector does absolutely nothing for low voltage anomalies (sags, dips and brownouts or extended sags - note that is brownout, not brownup) by using the batteries to boost the voltage, and the AVR to shape it as needed. Providing backup power in the event of a full power outage is only the icing on the cake for a UPS with AVR.
Now, like PSUs, there are cheap ones and good ones and I would never trust my expensive high speed digital electronics, and more importantly, my data, to a cheap power supply. So the same goes with a UPS.
Now, the ATX Form Factor PSU Design Guide
, paragraph 3.2.9 says an ATX power supply should be able to hold full power for 16ms after loss of power. A "good" UPS should be able to switch to batteries in 10ms or less.
I've been using UPSs for years, it's just that my current one, after having served for over 3.5 years has finally come to the end of its road.
Oh? The downside to all UPS is the batteries, typically sealed lead acid (SLA) batteries only last for, and must be replaced about 3 years - hopefully before you discover they can no longer hold a load. Are you sure the UPS is bad and not just the batteries?
Edited by Digerati, 24 August 2010 - 12:42 PM.