[comp.sys.mac.misc] Info request on UNINTERRUPTIBLE POWER SOURCES

ostroff@Oswego.EDU (Boyd Ostroff) (06/13/90)

In article <19664.2670c5cf@oregon.uoregon.edu> slee@oregon.uoregon.edu writes:
>I'm moving to a place that's pretty susceptible to summer thunder storms
>and power outages.  What's your learned opinion of uninteruptible power
>systems (UPS)?  

I don't have one on my mac at this time, but have one on my AT&T 3B1 unix
box.  I definintely wouldn't run a unix machine without one (from experience).
I live out in the "middle of nowhere" and have lots of power problems.
Since I got my UPS I can keep my system up for months at a time without 
problems.

They tend to be pretty pricey, Kensington for instance 
>sells them for $270-$950.  

I have a Tripp-Lite BC-325, which can handle 325 watts (should be enough
for most macs).  I paid $300 for it a year ago from Jameco, but if you
want the best deal, pick up a copy of Computer Shopper Magazine and look
through the ads - I've seen this model for ~$250 there.

>What's the difference between brands and 
>sizes on these things?  

I'd suggest doing what I did.  Fill out the "reader service card" from a
computer magazine (like Byte) for all the companies which advertise these
things.  I ended up with tons of brochures and specs.  I picked the Tripp-Lite
for the cost vs. features ratio. The main differences are in the
transfer time, the type of wave (square vs. synchronized steps) the
battery capacity (amp-hours) and the wattage rating.  Don't confuse the last
two - the wattage rating just determines how big an inverter the unit has
and how much load you can connect to it - it doesn't necessarily reflect on
how long it will operate your computer.  I doubt that transfer time will
be a problem with the typical mac power supply.

Actually the term "UPS" (uninterruptable power supply) is probably not 
accurate.  Mine is technically called a BBS (battery backup system).  This
means that normally your computer is running of the AC line while the 
battery is trickle-charged.  In the event of a power failure, power is
transferred to the battery/inverter in a couple milliseconds.  This is the
most common setup; there are also full-time UPS'es which always power the
computer off the battery/inverter.  This requires a much beefier setup and
is very expensive, but you don't have any transfer time problems and your
power is always filtered with the battery as a buffer.

>Any opinions, experiences, or references to 
>articles reviewing UPSs?  

Byte Magazine did a very good article on "PC Power Protection" about 2 years
ago - sorry I don't have it handy.

>I just want it for a single computer, so it 
>seems likely that the smallest model would be appropriate. True?  

Probably; depends on what you're trying to accomplish.  If you just want to
protect against quick brownouts, or want to have a few minutes to do a 
shutdown during a blackout that should be fine.  Just to give you an idea,
my 3B1 is MC68010-based micro with 2 MB RAM, a 67MB miniscribe disk, fan,
monitor and external 2400 baud modem - should be similar to a Mac II in its
power requirements.  I was very surprised to get 3 hours of backup time
during a power outage recently.  For a $300 UPS, I'm quite pleased!
If you just have a Mac Plus or SE, a 200-watt model would probably be 
sufficient and might save you $50 or $60, but I'd go for the 300 watt
unit anyway in case your needs change in the future....

>How 
>about the cheapest?  Are they pretty much a generic good?

Just like anything else, there are good ones and bad ones.  Do a little 
research and take your best shot.  Good luck!

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