On Fri, Apr 16, 2010 at 10:25 AM, Reimer, Mark <[email protected]> wrote:
> I’ve done some (or tried to) research on the differences between APC Backups
> vs Smart-UPS ...
Off the top of my head:
Manageability (you mentioned this): Both model lines can signal
"power failure" and "low battery voltage" to the PC, but the Smart-UPS
models can report battery life, input voltage, load level,
temperature, and many more things. The PC can also command the
Smart-UPS models to do self tests, shut off, etc. They can also
accept a network card, which is great for monitoring battery status of
UPSes in seldom-visited wiring closets.
Output waveform: The Smart-UPS models output "real" 60 hertz sine
wave alternating current when on battery. The Back-UPS models output
a stepped approximation. Various types of loads will perform poorly,
not work at all, malfunction, or even by damaged if they don't get
"real" AC. For example, some types of test equipment, some AC motors,
some TVs, some clocks. The switching power supplies in most modern
computer and network equipment often won't care, though.
Transfer time: Smart-UPS models transfer to battery in less than one
AC cycle, which for almost all equipment means "instantly". Back-UPS
models take several cycles. Again, how much this matters depends on
your equipment.
Voltage correction: The cheaper Back-UPS models are either passing
line current, or they're on battery. Nothing else. The Smart-UPS
models all have voltage correction features, so if voltage sags or
surges slightly, the UPS will correct voltage to 120 VAC nominal,
rather than tripping over to battery. Depending on the typical power
quality at the point of service, this may make a big difference.
APC's branding for this is "AVR" ("Automatic Voltage Regulation").
Same applies to SmartPro vs OmniSmart, practically word-for-word,
except Tripp-Lite has a different brand name for voltage correction
("Power Trim", I think.)
You will additionally see a third tier from Tripp-Lite and some
other vendors, which Tripp-Lite calls "online" and some other vendors
call "double conversion". (APC does not offer double conversion in
anything smaller than a refrigerator-sized UPS.) These types of UPSes
*always* run the load off the inverter, and continuously
trickle-charge the battery. During an outage, the battery just stops
charging. This yields true instant transfer time (since there is no
transfer), and very clean power. Noise, harmonics, etc., are wiped
out. Overkill for most stuff, but you'll see it used on truly
critical infrastructure (such as life support equipment, and the
public telephone network).
Does any of this matter to you? Chances are, no. If you've got
sensitive loads, poor power quality, or you want remote monitoring,
then yes.
-- Ben
~ Finally, powerful endpoint security that ISN'T a resource hog! ~
~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
