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From: kaufman@neon.Stanford.EDU (Marc T. Kaufman)
Newsgroups: comp.periphs
Subject: Re: UPSes
Keywords: UPS
Message-ID: <1991Mar20.013017.4138@neon.Stanford.EDU>
Date: 20 Mar 91 01:30:17 GMT
References: <1991Mar19.200553.13176@athena.cs.uga.edu>
Organization: Computer Science Department, Stanford University, Ca , USA
Lines: 22

In article <1991Mar19.200553.13176@athena.cs.uga.edu> weinri@athena.cs.uga.edu (Kevin Weinrich) writes:
>Has anyone read any good articles about UPSes in any of the journals?
>I'm considering putting a SPARCstation 1+ and/or a 4/330 on a UPS, and
>I'm confused by all the electrical terms.  One unit is called a
>"BEST MD500 vA" -- does this mean it handles 500 volt-Amperes?  Is
>that the same as .5 kvA?  On the back it says 4.1 amps.  What should this
>mean to me?  My monitor says 2.5A.  Thanks in advance for steering me
>in the right direction.

I use a BEST MD500 for my Mac.  It is not only a UPS, but is a full-time
line conditioner, as it uses a ferro-resonant transformer to isolate the
computer from the line.  Because the inverter is on the INPUT to the
transformer, the output never sees even as much as 1/2 cycle dropout.  The
parameters to control the BEST are set and read out via an RS232 port.

It isn't cheap, though.  The 500 is about $900.

The fuse ratings on your monitor and computer represent about 150% of the
maximum load, with all memory and peripherals running, etc.  My Mac + monitor
+ 2 disks represents about 250 watts.

Marc Kaufman (kaufman@Neon.stanford.edu)