mirror of https://github.com/tLDP/LDP
1024 lines
44 KiB
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1024 lines
44 KiB
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<?xml version="1.0"?>
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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [
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<!ENTITY howto "http://www.tldp.org/HOWTO/">
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<!ENTITY mini-howto "http://www.tldp.org/HOWTO/mini/">
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<!ENTITY home "http://www.catb.org/~esr/">
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]>
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<article id="index">
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<articleinfo>
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<title>UPS HOWTO</title>
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<authorgroup>
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<author>
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<firstname>Eric</firstname>
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<othername>Steven</othername>
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<surname>Raymond</surname>
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<affiliation>
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<orgname><ulink url="&home;">Thyrsus Enterprises</ulink></orgname>
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</affiliation>
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</author>
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<author>
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<firstname>Nick </firstname>
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<surname>Christenson</surname>
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</author>
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</authorgroup>
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<revhistory id="revhistory">
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<revision>
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<revnumber>2.2</revnumber>
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<date>2007-05-22</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Minor update with more info about battery types.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.1</revnumber>
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<date>2005-09-28</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Link fixes.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.0</revnumber>
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<date>2005-08-15</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Merged in material by Nick Christenson.
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</revremark>
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</revision>
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<revision>
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<revnumber>1.3</revnumber>
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<date>2005-08-17</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Fix a bad link.
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</revremark>
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</revision>
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<revision>
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<revnumber>1.2</revnumber>
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<date>2004-10-28</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Remove a bad link.
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</revremark>
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</revision>
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<revision>
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<revnumber>1.1</revnumber>
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<date>2004-02-21</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Add a little deployment advice, and stuff on other technologies.
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</revremark>
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</revision>
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<revision>
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<revnumber>1.0</revnumber>
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<date>2003-10-07</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Initial release.
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</revremark>
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</revision>
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</revhistory>
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<abstract><para>
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An Uninterruptible Power Supply (UPS) is an important thing to have
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if you live in an area where power outages are at all common,
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especially if you run a mail/DNS/Web server that must be up 24/7. This
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HOWTO will teach you things you need to know to select a UPS
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intelligently and make it work with your open-source operating system.
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</para>
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</abstract>
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</articleinfo>
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<sect1 id="introduction"><title>Introduction</title>
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<sect2 id="purpose"><title>Why this document?</title>
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<para>An Uninterruptible Power Supply (UPS) is an important thing to
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have if you live in an area where power outages are at all common,
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especially if you run a mail/DNS/Web server that must be up 24/7. The
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aging power grid in the U.S. has made this a more urgent issue than it
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used to be even for American hackers, but everyone is vulnerable to
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outages caused by storms and other natural phenomena. This document
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covers both the software and hardware aspects of protecting
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yourself.</para>
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<para>The advice in this document is aimed primarily at small
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installations — one computer and one UPS. Thus we'll focus on
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consumer-grade UPSes, especially those designed for home and
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small-business use. If you are a data center administrator running a
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big server farm, there is a whole different (and much more expensive)
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range of technologies we'll do no more than hint at here.</para>
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<para>The people who contribute to this document can speak only about
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equipment they have experience with. This may reflect a bias toward or
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against certain brands, features, functions, etc. Please keep in mind that
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the suggestions, brand names and functions here are by no means exhaustive,
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or even necessarily applicable to your situation. Also, if you have
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information that is not in this document, please submit it to the
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maintainer listed above. If you submit information, please say whether
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you'd like it to be attributed to you or not. We are more than glad to give
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credit to the fine people who helped with this document, but we want to
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respect the anonymity of those people who would prefer it.</para>
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</sect2>
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<sect2 id="newversions"><title>New versions of this document</title>
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<para>You can also view the latest version of this HOWTO on the World Wide Web
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via the URL <ulink url="&howto;UPS-HOWTO.html">
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&howto;UPS-HOWTO.html</ulink>.</para>
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</sect2>
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<sect2 id="license"><title>License and Copyright</title>
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<para>Copyright (c) 2003,2006 Eric S. Raymond.</para>
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<para>Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.2
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
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A copy of the license is located at <ulink url="http://www.gnu.org/copyleft/fdl.html">www.gnu.org/copyleft/fdl.html</ulink>.</para>
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<para>Feel free to mail any questions or comments about this HOWTO to Eric
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S. Raymond, <email>esr@snark.thyrsus.com</email>. But please don't ask me
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to troubleshoot your general UPS problems; if you do, I'll just
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ignore you.</para>
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</sect2>
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</sect1>
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<sect1><title>An Overview of Power Protection</title>
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<para>Power protection guards your equipment against blackouts,
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brownouts, surges, and spikes. All these events are anomalies in the flow
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of mains power that can damage your electronic equipment.</para>
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<para>A <emphasis>blackout</emphasis> is a complete interruption of
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power; some literature considers a voltage drop below about 80V to be a
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blackout as well since most equipment will not operate below that
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level.</para>
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<para>A <emphasis>dropout</emphasis> is a very short (less than one second)
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blackout.</para>
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<para>A <emphasis>brownout</emphasis> or <emphasis>sag</emphasis> is a
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decrease in voltage levels which can last for periods ranging from
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fractions of a second to hours. This can be caused by heavy equipment coming on
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line such as shop tools, elevators, compressors etc. Also occurs when
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utility companies deliberately do this to cope with peak load times.</para>
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<para>A <emphasis>spike</emphasis> is a tremendous increase in voltage over
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a very short period of time often caused by a direct lightning strike on a
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power line or when power returns after a blackout.</para>
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<para>A <emphasis>surge</emphasis> is a substantial increase in voltage
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lasting a small fraction of a second, often caused when high powered
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appliances such as air conditioners are switched off.</para>
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<para>There are three levels of power protection available to the
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home computer user. The levels are:</para>
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<orderedlist>
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<listitem><para>Surge Suppressor</para></listitem>
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<listitem><para>Line Conditioners</para></listitem>
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<listitem><para>Uninterruptible Power Supplies</para></listitem>
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</orderedlist>
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<para>While this HOWTO mainly focuses on UPSs, we'll start with some basics
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about the other two kinds of power filtering to help you understand where
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UPSes fit in. This is useful even though plummeting UPS prices have made
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the low-end alternatives less interesting than they used to be.</para>
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<sect2 id="surge"><title>Surge suppressors</title>
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<para>These are basically a fancy fuse between the source and your
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hardware; they clamp down spikes, but can't fill in a low voltage
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level or dropout.</para>
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<para>This is a bare minimum level of protection that any piece of
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expensive electronics should have. Note that this applies to more
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than just AC power; surge suppressors are available for (and should be
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used on) phone lines, and RS-232 and parallel connections (for use on
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long lines; generally not needed if the devices are colocated with the
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computer and all devices are protected from outside sources). Note
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also that <emphasis>all</emphasis> devices connected to your computer
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need to be protected; if you put a surge suppressor on your computer
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but not your printer, then a zap on the printer may take out the
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computer, too.</para>
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<para>An important fact about surge suppressors is that <emphasis>they
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need to be replaced if they absorb a large surge</emphasis>. Besides
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fuses, most suppressors rely on components called Metal-Oxide
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Varistors (or MOVs) for spike suppression, which degrade when they
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take a voltage hit. The problem with cheap suppressors is that they
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don't tell you when the MOV is cooked, so you can end up with no spike
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protection and a false sense of security. Better ones have an
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indicator.</para>
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<para>You can buy surge suppressors at any Radio Shack; for better prices, go
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mail-order through Computer Shopper or some similar magazine. All of
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these are low-cost devices ($10-50).</para>
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</sect2>
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<sect2 id="conditioners"><title>Line Conditioners</title>
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<para>These devices filter noise out of AC lines. Noise can degrade
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your power supply and cause it to fail prematurely. They also protect
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against short voltage dropouts and include surge suppression.</para>
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<para>The Tripp-Lite 1200 I used to have was typical of the better class of
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line conditioners; a box with a good big soft-iron transformer and a couple
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of moby capacitors in it and <emphasis>no</emphasis> conductive path
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between the in and out sides. With one of these, you can laugh at
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brownouts and electrical storms. A fringe benefit is that if you
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accidentally pull your plug out of the wall you may find you actually have
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time to re-connect it before the machine notices (I did this once). But a
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true UPS is better.</para>
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<para>Netter Trey McLendon has good things to say about Zero Surge
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conditioners. He says: "Our systems at work [...] have been protected for
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2.5 years now through many a violent storm...one strike knocked [out] the
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MOV-type suppressors on a Mac dealer's training setup across the street
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from us. The Zero Surge just sort of buzzed when the surge came in, with
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no interruption whatsoever. The basic principle is this: ZS units slow
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down the surge with a network of passive elements and then sends it back
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out the neutral line, which is tied to ground <emphasis>outside at the
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box</emphasis> by code. MOV units shunt the surge to ground <emphasis>at
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the computer</emphasis>, where it leaps across serial ports, network
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connections, etc. doing its deadly work."</para>
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<para>Price vary widely, from $40-400, depending on the power rating
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and capabilities of the device. Mail-order from a reputable supply
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house is your best bet. Line conditioners typically
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<emphasis>don't</emphasis> need to be replaced after a surge; check to
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see if yours includes MOVs.</para>
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</sect2>
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<sect2><title>Uninterruptible Power Supplies</title>
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<para>The remainder of this document will focus on UPSes. A UPS does three
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things for you. First, it filters the power your machine sees, smoothing
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out spikes and voltage fluctuations that can stress or even damage your
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electronics. Secondly, it provides a certain amount of dwell time in the
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event your power goes out entirely — this can often get you through
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brownouts and short blackouts. Third, when the UPS is about to run out of
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power it can arrange a graceful shutdown of your computer so that no
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unpleasant things happen to your disk filesystems. While the risks of
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unexpected shutdown are much lessened in these days of journalling
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filesystems like Linux's EXT3 or JFS from what they once were, ensuring a
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clean shutdown is still a valuable contribution to any system
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administrator's peace of mind.</para>
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<para>Here's what a UPS will do for you:</para>
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<orderedlist>
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<listitem><para>Absorb relatively small power surges.</para></listitem>
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<listitem><para>Smooth out noisy power sources.</para></listitem>
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<listitem><para>Continue to provide power to equipment during line
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sags.</para></listitem>
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<listitem><para>Provide power for some time after a blackout has
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occurred.</para></listitem>
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</orderedlist>
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<para>In addition, some UPS or UPS/software combinations provide the
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following functions:</para>
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<orderedlist>
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<listitem><para>
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Automatic shutdown of equipment during long power outages.
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</para></listitem>
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<listitem><para>
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Monitoring and logging of the status of the power supply.
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</para></listitem>
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<listitem><para>
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Display the Voltage/Current draw of the equipment.
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</para></listitem>
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<listitem><para>
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Restart equipment after a long power outage.
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</para></listitem>
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<listitem><para>
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Display the voltage currently on the line.
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</para></listitem>
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<listitem><para>
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Provide alarms on certain error conditions.
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</para></listitem>
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<listitem><para>
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Provide alarms on certain error conditions.
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</para></listitem>
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</orderedlist>
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<para>Many pronounce UPS as "ups", but most of the literature seems to
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favor "you pee ess", since they use "a UPS" instead of "an UPS". This
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document will try to follow the literature. Neither pronunciation will get
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you laughed at by those who are experienced in the field.</para>
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</sect2>
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</sect1>
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<sect1><title>UPS Basics</title>
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<sect2><title>How To Select A UPS</title>
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<para>UPSes are nowadays very inexpensive. In the U.S. in 2006, quite
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capable ones are available for less than $100, and prices are heading
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down. In fact prices are so low now that we're not going to walk you through
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the elaborate optimization step that would have been important
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even two or three years ago, of estiming the watt dissipation of your
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computer and matching it to a UPS rating. Instead we'll explain
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why this would be a waste of effort and how to buy in a simpler
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and more effective way.</para>
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<warning>
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<para>Bear in mind that the UPS systems that you're likely to buy in a
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store or computer catalog are <emphasis>not</emphasis> intended for safety
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or life-critical equipment. These devices should be considered to be pieces
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of consumer electronics. As such, the number-one basis on which most of these
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devices compete with each other is on price, not quality.</para>
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<para>Cost-effectiveness is more important to UPS vendors (because it
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appears to be more important to their customers) than ultimate
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reliability. If your life depends on computer uptime, you need a special
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purpose, online, big, redundant, expensive system. These systems are beyond
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the scope of this document. When you buy a UPS at your local computer
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store, you are <emphasis>not</emphasis> buying this sort of system.</para>
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</warning>
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<para>UPSes are rated by the watts a full battery can put out before
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it drains. However, they are marketed using a VA (voltage-amps)
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figure; often, consumer-grade UPSes don't even specify a wattage on
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the box where you can see it. This is because the VA figure is larger
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and looks sexier. As a rule of thumb. assume the wattage is half of
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the VA rating; for an explanation of the complexities involved (if you
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care) see the white paper <ulink
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url='http://sturgeon.apcc.com/whitepapers.nsf/URL/WP-17/$FILE/WP17.pdf'>Understanding
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Power Factor, Crest Factor, and Surge Factor</ulink> on the APC
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website.</para>
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<para>But even if you know the watt rating of the UPS, it is the ratio of
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that figure with the wattage dissipation of your computer that
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controls the dwell time. Your dissipation is hard to predict; it can
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even be effected by things like the size of monitor you use (big ones
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can be quite power-hungry).</para>
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<para>Manufacturers try to get around this technical thicket by
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putting an expected dwell time on the box. But they exaggerate and
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even lie about their dwell times a lot (this is called
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<quote>marketing</quote>). What they'll do is quote you the dwell
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time you would get driving a bare minimum system with the disk drives
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shut off and a tiny monitor, in much the same way laptop manufacturers
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lie about their battery dwell times. The more honest UPS
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manufacturers give you a little table showing expected dwell times for
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different system configurations (<quote>desktop</quote>,
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<quote>tower</quote>, etc.). As a rule of thumb, assume you will get
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about 50% of the dwell time listed on the box for your configuration
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type.</para>
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<para>My advice is to forget the numbers game. Just go online or to
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your local computer store and buy one of the higher-end consumer or
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home-office models from APC, Best, Tripp-Lite, Belkin, or some other
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reputable manufacturer. Go ahead and grab the model with the longest
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dwell time, highest watt rating, or biggest VA number you can find;
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the premium for it is not likely to be more than $75 over the
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bargain-basement model. I guarantee you will feel very good about
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your decision not to pinch pennies come your first extended power
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outage.</para>
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<para>Perhaps a more compelling reason it is better to over-buy
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capacity rather than ending up with a UPS that is too weak for your
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power drain is that overstrained UPSes can fail in ugly ways,
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including catching fire and exploding.</para>
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<para>Be sure you get a <firstterm>line interactive</firstterm> UPS
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rather than the older <firstterm>standby</firstterm> or
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<firstterm>SPS</firstterm> type. The older technology doesn't
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actually filter your power through the battery, so you're not assured
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of good voltage conditioning. The main advantage of an SPS (low cost)
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has been eroded now that line-interactive UPSes are so inexpensive.
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There are other UPS types, but they are either obsolescent or targeted
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at large data-center installations. For a detailed discussion of the
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different UPS types, see <ulink
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url='http://sturgeon.apcc.com/whitepapers.nsf/URL/WP-1/$FILE/WP1.pdf'>The
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different types of UPS systems</ulink>, a white paper on the APC
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site.</para>
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<para>Another important consideration is how your UPS will communicate
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with your computer. Do not buy a serial line UPS (one that
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communicates via an RS-232C cable). These are passing out of use in
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favor of UPS designs that use USB or Ethernet, for the very excellent
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reason that RS-232C interfaces are flaky, difficult to configure,
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and difficult to debug. Ethernet is overkill for this application;
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UPSes simply don't need that kind of bandwidth. We recommend sticking
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with USB, which is well-matched in price/performance to this job
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and relatively easy to troubleshoot.</para>
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<para>Until recently there was an important distinction between
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<firstterm>smart</firstterm> and <firstterm>dumb</firstterm> UPSes.
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Dumb UPSes did voltage-level signaling through individual pins; smart
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ones used the link as a primitive character channel and could pass
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more status information over it. But if you avoid RS232C UPSes you
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will never see a dumb one; indeed, it is likely that by the time you
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read this no dumb UPses will be in production any longer.</para>
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<para>Some UPSes advertise that they deliver a sinusoidal waveform. Those
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that don't may be delivering something more like a square wave or a very
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noisy sine wave. There are differing schools of thought about how
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important this is. One school of thought holds that one should always run
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equipment on the best approximation of sinusoidal input that one can, and
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that deviations produce harmonics which may either be interpreted as signal
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if they get through a power supply, or may actually damage the
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equipment. Another school holds that since almost all computers use
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switching-type power supplies, which only draw power at or near the peaks
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of the waveforms, the shape of the input power waveform is not
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important.</para>
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<para>Who's right? We don't know. Nick's opinion is that sinusoidal output
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is worth the extra money, especially for on-line UPS systems that
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|
continually provide their waveform to the computer; Eric is inclined to
|
|
doubt it matters much with modern power supplies. If you don't know that
|
|
your equipment has a switching-type power supply, you certainly might want
|
|
to think twice before buying a low quality UPS.</para>
|
|
|
|
<para>Personally, I (Eric) like APC UPSes (nether Eric nor Nick has any
|
|
connection with the company). But this is not the kind of widget for which
|
|
manufacturer makes a whole lot of difference as long as you stick with one
|
|
of the reputable brands.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Deploying your UPS and other devices: the total picture</title>
|
|
|
|
<para>Our recommendation for a production Unix environment is a
|
|
configuration like the following:</para>
|
|
|
|
<orderedlist>
|
|
<listitem><para>An UPS for the computer system. </para></listitem>
|
|
<listitem><para>Surge suppression on all phone lines, and also on
|
|
serial/parallel lines that leave the room.</para></listitem>
|
|
<listitem><para>Line conditioners on any devices not connected to the UPS. If
|
|
you do take a power hit, it's cheaper to replace a $50 line
|
|
conditioner than a $1500 laser printer.</para></listitem>
|
|
</orderedlist>
|
|
|
|
<para>If this is too expensive for you, then downgrade the UPS to
|
|
a line conditioner like the TrippLite. But don't go without at least
|
|
that. Running unprotected is false economy, because you
|
|
<emphasis>will</emphasis> lose equipment to electrical storms —
|
|
and, Murphy's Law being what it is, you will always get hit at the
|
|
worst possible time.</para>
|
|
|
|
<para>One thing to note is that you typically shouldn't put a laser printer
|
|
on the brownout-protected sockets in a UPS — toner heaters draw
|
|
enough current to overload a UPS and cause a shutdown within
|
|
seconds. Modern UPSes generally have some plugs that are marked
|
|
surge-suppressed but not filtered through the battery; plug your
|
|
printer into one of those.</para>
|
|
|
|
<para>A UPS should be wired directly to (or plugged directly into) the
|
|
AC supply (i.e. a surge suppressor is neither required nor suggested
|
|
between the wall and the UPS). In addition, a surge suppressor
|
|
between the UPS and the equipment connected to it is redundant.</para>
|
|
</sect2>
|
|
<sect2><title>Software Assistance</title>
|
|
|
|
<para>Your UPS communicates with your computer so it can gracefully
|
|
shut the computer down when an outage has lasted too long for the
|
|
battery to cope. In order for graceful shutdown to actually happen,
|
|
your computer needs to have a background process — a daemon, in
|
|
Unix terms — watching whatever messages come over the UPS cable
|
|
for the one that says <firstterm>terminate</firstterm>. Then it
|
|
needs to tell the operating system to shut down.</para>
|
|
|
|
<para>Your UPS probably comes with a CD full of such software. Throw
|
|
it away, as (a) most of it will be useless bits written for Windows
|
|
systems, and (b) in the unlikely event you get Linux software it will
|
|
almost certainly be stale binaries for a version you don't run.</para>
|
|
|
|
<para>Back in the days of dumb serial-line UPses, there used to be
|
|
about half a dozen different open-source UPS monitor daemons:
|
|
<application>apcd</application>, <application>dumbupsd</application>,
|
|
<application>genpowerd</application>.
|
|
<application>powerd</application>, <application>smupsd</application>,
|
|
<application>usvd</application> and more. These were fairly stupid
|
|
programs for a simple job. Many required you to hand-wire a custom
|
|
RS232C cable to get around various evil things that UPS manufacturers
|
|
did to their ports in order to lock in customers.</para>
|
|
|
|
<para>Those days are gone. USB UPSes get rid of the cable-hacking and
|
|
hardware klugery, but require a bit more smarts from a monitor daemon.
|
|
Accordingly the field has narrowed considerably. There appear
|
|
to be only two such projects left standing.</para>
|
|
|
|
<para>The <ulink url='http://www.networkupstools.org/'>Network UPS
|
|
Tools</ulink> project is a generic UPS monitor daemon that aims to
|
|
communicate intelligently with all current UPS designs.</para>
|
|
|
|
<para><ulink url='http://www.apcupsd.org/'>apcupsd</ulink> is a daemon
|
|
specifically designed for communicating with UPSes made by APC, the
|
|
American Power Corporation.</para>
|
|
|
|
<para>Both are solid, well-run projects. Their development groups are
|
|
mutually friendly, and there has been occasional talk of a merger.
|
|
Awkwardly, the <application>apcupsd</application> project is in many ways
|
|
the more featureful of the two, with, among other things, better USB
|
|
support and better documentation — but the NUT tools have a cleaner
|
|
architecture, more developers, and acceptance in Red Hat and other major
|
|
distributions.</para>
|
|
|
|
<para>My advice is simple; run <application>apcupsd</application> if
|
|
you buy an APC UPS, and the NUT tools if you buy anything else. RPMs
|
|
and Debian packages (which will modify your system's boot sequence
|
|
appropriately as well as installing the daemon binaries) are available
|
|
for both, so installation should be easy either way.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Preparing Your System For Auto-Reboot</title>
|
|
|
|
<para>If you are using your UPS to try to keep a DNS/Web/mailserver up
|
|
24/7, you will want to make sure the machine can be configured to
|
|
boot automatically when it is powered up.</para>
|
|
|
|
<para>This is not the normal behavior of most computers as shipped
|
|
from the factory. Normally after the power is cut and restored, you
|
|
must explicitly press a button for the power to actually be turned
|
|
on. You can test your computer by powering it down; shutting off the
|
|
power (pull the plug); then plugging the cord back in. If your
|
|
computer immediately starts up, good. There is nothing more to
|
|
do.</para>
|
|
|
|
<para>If your computer does not start up, manually turn on the
|
|
power (by pressing the power on button) and enter your computer's
|
|
SETUP program (often by pressing DEL during the power up sequence;
|
|
sometimes by pressing F10). You must then find and change the
|
|
appropriate configuration parameter to permit instant power
|
|
on.</para>
|
|
|
|
<para>Normally, this is located under the <emphasis
|
|
role="bold">BOOT</emphasis> menu item, and will be called something
|
|
such as <emphasis role="bold">Restore on AC/Power Loss</emphasis> or
|
|
<emphasis role="bold">Full-On</emphasis>. The exact words will vary
|
|
according to the ROM BIOS provider. Generally you will have three
|
|
options: <emphasis role="bold">Last State</emphasis>, <emphasis
|
|
role="bold">Power On</emphasis>, and <emphasis role="bold">Power
|
|
Off</emphasis>.</para>
|
|
|
|
<para>Some BIOSes do not support such an option. This is idiotically
|
|
bad design, but it does happen. If so, your only practical remedy is
|
|
to get a new motherboard.</para>
|
|
|
|
</sect2>
|
|
</sect1>
|
|
<sect1 id='testing'><title>Testing Your UPS</title>
|
|
|
|
<para>To test your UPS, throw the circuit breaker with the UPS on it to
|
|
simulate and outage and see how the transition goes. Note that in general
|
|
testing an UPS by pulling the plug from the wall is not a good
|
|
idea. Electronics like to always have a good ground reference. If you
|
|
unplug a UPS, it's still powered but now has what electricians call a
|
|
"floating ground". Not only can this be bad for electronics, but it can be
|
|
quite dangerous as well. It is likely that unplugging just about any UPS
|
|
for a short amount of time isn't likely to result in disaster (don't take
|
|
our word for it, though!), but in all cases, throwing a circuit breaker
|
|
would be a better thing to do.</para>
|
|
|
|
<para>It might be useful to install a GFI (Ground Fault Interrupter) on your
|
|
UPS-covered outlets to facilitate this testing without having to throw a
|
|
breaker, especially if you don't have your UPS protected machines on an
|
|
isolated circuit (which you probably should). These are the sockets found
|
|
in most modern kitchens and bathrooms with a red and a black button. You
|
|
push the latter to cut power and the former to restore power.</para>
|
|
|
|
</sect1>
|
|
<sect1 id='maintaining'><title>Maintaining Your UPS</title>
|
|
|
|
<para>Make sure the UPS keeps in contact with its electrical ground at all
|
|
times. Don't overload it. If it shows signs of misbehavior or
|
|
malfunction, yank it until it's repaired, or replace it.</para>
|
|
|
|
<para>Your UPS has a battery inside it. Usually it is a lead-acid
|
|
type (those are the least expensive for the manufacturer), but both
|
|
lithium and gel-cel batteries are sometimes used.</para>
|
|
|
|
<para>The battery is by far the most vulnerable and failure-prone part
|
|
of your UPS. If you have your UPS long enough, you will probably have
|
|
battery problems. Once every six months to a year or so you should
|
|
recalibrate your UPS's battery sensor, and once every several years
|
|
you will have to replace the batteries.</para>
|
|
|
|
<sect2><title>Service contracts</title>
|
|
|
|
<para>Some consumer-grade UPSes, and all UPSes designed for serious
|
|
data-center use, can be bought with vendor service contracts. These don't
|
|
make sense for low-end units that can be replaced cheaply from a local
|
|
electronics store. If you're an IT shop with a bunch of UPSes scattered
|
|
over a campus, a service contract might make sense, depending on circumstances.
|
|
If you have a larger UPS in the 5-10 KVA range, a service contract may be a
|
|
valuable hedge against extended downtime.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Extending battery life</title>
|
|
|
|
<para>To extend your battery life, (a) avoid deep discharges, and (b)
|
|
don't expose them to extremes of heat, cold, or humidity.
|
|
Unfortunately there is not much you can do to avoid deep-discharging
|
|
your UPS other than living in an area where power outages are few
|
|
and short.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Recalibrating Your UPS</title>
|
|
|
|
<para>Your UPS's dwell-time calibration will lose accuracy over the life
|
|
of the battery. The usual symptom of this problem is that the UPS
|
|
overestimates the dwell time it has remaining during outages, but
|
|
occasionally it can also lead to an actual bad-battery condition going
|
|
undetected and very odd symptoms as a result.</para>
|
|
|
|
<para>UPSes have a recalibration procedure built into their firmware.
|
|
It generally involves deep-discharching and recharging the battery
|
|
while the UPS is in a special test mode. Your recipe for triggering
|
|
such a recalibration will vary according to your UPS software.</para>
|
|
|
|
<para>You always need to do this when you install new batteries (see
|
|
below). It is a good idea to do it once every six to twelve months
|
|
as routine maintenance, but no more often than that; as we noted
|
|
previously, deep discharges shorten your battery life.</para>
|
|
</sect2>
|
|
|
|
<sect2><title>Replacing Your Batteries</title>
|
|
|
|
<para>All modern UPSes have a low-battery alarm and run a periodic
|
|
self-test; they will alert you when replacement is needed. Usually
|
|
they both flash an indicator and make an alarm sound. If you have a
|
|
monitoring daemon set up, they will alert it and you will probably get
|
|
warning mail. If you ignore the alarm it will time out, but be
|
|
repeated at intervals.</para>
|
|
|
|
<para>You will occasionally get a false alarm. It's a good idea, if you
|
|
get an alarm, to explicitly trigger a UPS self-test the next day and see if
|
|
the alarm goes away (the procedure for doing this varies depending on
|
|
your UPS software). If the alarm is persistent, you need to replace
|
|
the batteries.</para>
|
|
|
|
<para>It has been reported that bad batteries can also produce symptoms
|
|
that mimic inverter failures or wonky control electronics. Even if
|
|
your UPS is displaying epileptic symptoms like repeating alarms and
|
|
flashing panel lights, a bad battery is the first thing to
|
|
suspect.</para>
|
|
|
|
<para>UPS manufacturers would of course prefer that you replace your
|
|
entire UPS when the batteries die, since they make more money that
|
|
way. But in fact there is nothing unique or magic about UPS batteries.
|
|
They are standard types also used for other applications such as
|
|
powering marine electronics, with standard connectors. You can buy
|
|
them from sources other than the UPS manufacturer, and sometimes replace
|
|
them with equivalents that are better and less expensive.</para>
|
|
|
|
<para>It's best to wait until the low battery alarm before ordering a
|
|
replacement; keeping batteries on the shelf reduces their life unless
|
|
you keep them fully charged.</para>
|
|
|
|
<para>Do not throw old batteries in your regular trash! They contain
|
|
toxic metals and acids. Be kind to your environment and hand them to
|
|
a qualified party for recycling. Most battery dealers will cheerfully
|
|
do this for you. If not, your local garbage company or waste-disposal
|
|
authority can explain to you how and where to turn them in
|
|
safely.</para>
|
|
|
|
<para>Many UPS models use gel-cel batteries in standard formats like 12.0
|
|
V, 7.2Ah (151x64x94 mm). Warning: Many manufactors sell two or three
|
|
different types: standard use, cyclic use and high-current use. UPSes
|
|
require high-current and some UPS don't work well with batteries for
|
|
standard use, because the voltage goes low too early under high load (the
|
|
UPS turns off too fast or the output voltage drops so that the computer
|
|
turns off). Standard batteries are for alarm devices, emergency lights or
|
|
things like that. For instance Panasonic sells the "LCR127R2PG1"
|
|
(standard), and "UPRW1245P1" (high current), Fiamm the "FG20271" (standard)
|
|
and "FGH20902" (high current), CSB the "GP1272" (standard) and "HR 1234W"
|
|
(high current).</para>
|
|
|
|
<para>Below, you will find some suggestions for buying replacement
|
|
batteries. One <emphasis>important</emphasis> note of caution: at
|
|
least one user purchased one of the aftermarket batteries noted below
|
|
and found out that they would not fit into his unit. This required
|
|
cutting and soldering and other very undesirable things, so be
|
|
extremely careful in measuring your batteries — including every
|
|
millimeter of the terminal connections, which can cause
|
|
problems.</para>
|
|
|
|
<para>Although you can do a hot swap of your batteries while the
|
|
computer is running, it may not be very satisfactory, because the unit
|
|
will not know that the batteries have been swapped and your monitor
|
|
daemon will continue to show a low-battery indication. To correct
|
|
this situation, you must do a discharge and recharge of the
|
|
battery. At that point the battery should be calibrated better.</para>
|
|
|
|
<para>It may take several discharges and recharges of new batteries
|
|
before they reach full capacity and the dwell-time calibration is
|
|
accurate. If your UPS contains two or more battery units and your
|
|
monitoring software reports separate voltage levels for them, one way
|
|
to tell is to watch the divergence in voltage levels. As the cells
|
|
reach nominal full capacity, their voltages should converge.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Buying Batteries</title>
|
|
|
|
<para>APC makes "Replacement Battery Units" for each of the
|
|
SmartUPS models, but they sell them directly only in the U.S. Your
|
|
local Yamaha SeaDoo shop (if you have one) carries 35 ampere-hour deep
|
|
cycle marine batteries that are direct replacements for the kind APC
|
|
uses in many of its models. These are gel-cel and will double the
|
|
runtime and/or cut your recharge time in half. Here are some West
|
|
Coast sources:</para>
|
|
|
|
<programlisting>
|
|
Jet Works
|
|
1587 Monrovia Ave.
|
|
Newport Beach CA 9266?
|
|
Tel: +1 714 548-5259
|
|
|
|
J-W Batteries, Inc.
|
|
Tel: +1 714 548-4017
|
|
|
|
WPS 49-1200
|
|
GEL-CELL KB-35 BATTERY
|
|
</programlisting>
|
|
|
|
<para>The company I've heard most strongly recommended (by Carl
|
|
Erhorn, a core developer on the <application>apcupsd</application>
|
|
project) is called Battery Wholesale Distributors of Georgetown,
|
|
Texas. If you have questions, you can reach them by phone at (800)
|
|
365-8444, 9:00AM to 5:00PM (their local time), Monday through
|
|
Friday. Carl reports having gotten email from them on the weekends,
|
|
although the office is not open then.</para>
|
|
|
|
<para>The web site, with current pricing, is <ulink
|
|
url="http://www.batterywholesale.com">www.batterywholesale.com</ulink>.
|
|
They will ship outside of the US, they take all the usual credit
|
|
cards, and they accept orders by phone or Web.</para>
|
|
|
|
<para>Carl reports that BWD has found manufacturers who make batteries
|
|
in the standard case sizes, but have additional capacity over original
|
|
UPS batteries. Often, the difference is as much as 15% or so, and this
|
|
can result in additional runtime. It's a nice upgrade for a minor
|
|
increase in price.</para>
|
|
|
|
<para>BWD is also 'green-aware', in that they encourage you to
|
|
recycle your old batteries, and will accept the old batteries back
|
|
from you if you cannot find a local place that recycles them. You
|
|
pay the shipping but other than that, there is no charge.</para>
|
|
|
|
<para>Carl says <quote>I've been very pleased with their
|
|
products, service, and pricing. I hope you find them as helpful to
|
|
you as I do. I've been dealing with them since about 1994, and have
|
|
never been disappointed. The owner of the place also is very good
|
|
on technical issues, so if you have questions on their products, he
|
|
can get as technical as you need to go.</quote></para>
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1><title>Vendor information</title>
|
|
|
|
<para>Note: Many of these manufacturers make specialty systems for
|
|
large data centers, not the consumer-grade UPSes that we cover in
|
|
most of the rest of this document.</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.apcc.com/">American Power Conversion</ulink></term>
|
|
<listitem><para>
|
|
APC is the largest manufacturer of small UPSes (<2000 VA)
|
|
and has a whole line
|
|
of UPS systems (mostly line interactive), software, and
|
|
power system accessories which can be purchased directly
|
|
from them or via many retail
|
|
outlets around the United States and overseas.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.belkin.com/index.asp">Belkin</ulink></term>
|
|
<listitem><para>
|
|
Belkin makes a lot of computer connectivity products,
|
|
including UPSes.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.clary.com">Clary Corporation</ulink></term>
|
|
<listitem><para>
|
|
Clary sells UPS products and specializes in emergency,
|
|
military, and life support systems. They also sell
|
|
management software and accessories.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.controlledpwr.com/">Controlled Power Company</ulink></term>
|
|
<listitem><para>
|
|
Controlled Power produces UPS systems, power conditioners,
|
|
voltage regulators and transformers. Equipment can be
|
|
ordered direct.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.powerware.com/USA/default.asp">Eaton Powerware</ulink></term>
|
|
<listitem><para>
|
|
Eaton Powerware includes the product line that was formerly
|
|
Best Power, Inc.. They produce many types of UPS systems.
|
|
more advanced line interactive systems, and ferroresonant
|
|
line interactive systems as well as software, PDUs, and
|
|
power system accessories.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.gotoemerson.com/main/default.asp">Emerson Electronics</ulink></term>
|
|
<listitem><para>
|
|
Emerson is a big electronics conglomerate. Its claim to
|
|
fame in the UPS world is that it's the parent company to Liebert.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.powersource.net/">Energy Technologies, Inc.</ulink></term>
|
|
<listitem><para>
|
|
Energy Technologies provides power devices (including UPSes)
|
|
for physically demanding customers, including military and
|
|
vehicle uses. Most if their UPS systems seem to fall in
|
|
the 600 to 6000 VA range.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.exide.com">Exide Electronics</ulink></term>
|
|
<listitem><para>
|
|
One of the bigger players in the data center sized UPS
|
|
system industry, Exide also makes more modest sized
|
|
on-line and line interactive systems. Exide products
|
|
can be purchased direct or from their distributors.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.gamatronic.com/">Gamatronic Electronic Industris, Ltd.</ulink></term>
|
|
<listitem><para>
|
|
We're told these guys are the largest UPS manufacturer
|
|
in Israel and the Middle East. Their product line runs
|
|
the gammut from 1000 VA to 150 kVA systems.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.geindustrial.com/industrialsystems/gede/index.html">General Electric Industrial Systems</ulink></term>
|
|
<listitem><para>
|
|
Yup, GE makes UPSes from 300 VA up to MVA systems.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.intellipower.com">IntelliPower, Inc.</ulink></term>
|
|
<listitem><para>
|
|
Intellipower sells on-line UPS systems and management software.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.liebert.com/">Liebert</ulink></term>
|
|
<listitem><para>
|
|
A subsidiary of Emerson Electronics (see above), Liebert
|
|
is probably the largest manufacturer of large (10 kVA +)
|
|
UPS systems. Also well known for their other data center
|
|
products including power distribution units and HVAC
|
|
products. They also make smaller UPS systems (300 VA on
|
|
up), but these are not nearly as popular.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.mgeups.com">MGE UPS Systems</ulink></term>
|
|
<listitem><para>
|
|
MGE UPS Systems sells UPS systems from 300 VA to the very
|
|
large and additional power equipment.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.meau.com/eprise/main/Home/home">Mitsubishi Electric Automation</ulink></term>
|
|
<listitem><para>
|
|
Mitsubishi Electric Automation seems to specialize in
|
|
larger (> 5 kVA) UPSes, but they make them as small as
|
|
1 kVA.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.oneac.com/home.asp">Oneac</ulink></term>
|
|
<listitem><para>
|
|
Oneac sells line interactive and online UPS systems with
|
|
software in the US and UK. They were acquired by the
|
|
Chloride Group (see Chloride Power, below) in 1998.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.opti-ups.com/">OPTI-UPS</ulink></term>
|
|
<listitem><para>
|
|
OPTI-UPS makes standby, line-interactive, and online UPS
|
|
systems ranging from 375 VA to 8000 VA.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.philtek.com/">Philtek</ulink></term>
|
|
<listitem><para>
|
|
Philtek makes inverters and other similar power system
|
|
components.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.waber.com/">SL Waber</ulink></term>
|
|
<listitem><para>
|
|
SL Waber sells mostly UPS systems including the Tripp Lite
|
|
brand name as well as a wide assortment of surge suppression
|
|
and other power accessories.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.toshiba.com/">Toshiba</ulink></term>
|
|
<listitem><para>
|
|
Toshiba sells a lot of things, including UPSes. They sell
|
|
online UPSes from 1400 VA to the 300 kVA range. One of
|
|
Toshiba's product lines are UPSes specially designed to
|
|
automatically configure themselves to work with both US
|
|
(60 Hz) and European (50 Hz) power.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.p3international.com/">P3 International</ulink></term>
|
|
<listitem><para>
|
|
P3 International makes a number of cool consumer electronics
|
|
devices, but as far as this document is concerned, the
|
|
most interesting is an easy-to-use and relatively
|
|
inexpensive power monitoring device called "Kill A Watt".
|
|
When you can't or don't want to use a good break-out cable
|
|
and ammeter, this device is a good choice for measuring
|
|
power consumption.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.power-innovations.com/">Power Innovations International, Inc.</ulink></term>
|
|
<listitem><para>
|
|
Power Innovations sells online UPS systems ranging from
|
|
500 VA to 400 kVA.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><ulink url="http://www.chloridepower.com/">Chloride Power</ulink></term>
|
|
<listitem><para>
|
|
Chloride Power is a relative newcomer to the U.S. market
|
|
but has much more experience and is better known in Europe.
|
|
For the US market Chloride produces online UPS from the 700
|
|
VA to 3000 kVA range, and what look like they might be
|
|
standby systems from 300 VA to 650 VA.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>There are a lot of companies in this space, and there's no way that
|
|
we can list all of them. We try to include most of the best known companies
|
|
along with a few niche players that might be of interest to the readers of
|
|
this document. Let me know if there are important companies that we haven't
|
|
included.</para>
|
|
</sect1>
|
|
|
|
<sect1><title>Bibliography</title>
|
|
|
|
<para>One critical source of information on power protection is the IEEE
|
|
"color book" series, especially the following:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>The Emerald Book, IEEE Recommeded Practice for Powering and Grounding Electronic Equipment, Std. 1100-1999, 1999.</para></listitem>
|
|
<listitem><para>The Gold Book, IEEE Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems, Std. 493-1997, 1997.</para></listitem>
|
|
<listitem><para>The Green Book, IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems, Std. 241-1990, 1990.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
</sect1>
|
|
<sect1><title>Acknowledgements and Related Resources</title>
|
|
|
|
<para>Substantial portions of this document, notably the bits on
|
|
maintaining your UPS, were originally part of the
|
|
<application>apcupsd</application> documentation. The project
|
|
maintainers have graciously permitted me to re-use them here. Other
|
|
parts were part of my <ulink url='&howto;/Unix-Hardware-Buyer-HOWTO/'>Unix
|
|
Hardware Buyer HOWTO</ulink>.</para>
|
|
|
|
<para>There was a previous UPS HOWTO by Harvey J. Stein, last updated
|
|
in 1997. It was so out of date that I ended up using none of it.</para>
|
|
</sect1>
|
|
</article>
|
|
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|
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