Subject: Uninterruptible Power Source FAQ
Date: 11 Jul 1995 20:34:55 GMT
Summary: Answers to FAQs about Uninterruptable Power Sources (UPS)

Version: 1.9


Uninterruptable Power Source (UPS) FAQ.
VERSION 1.9, July 11, 1995


Sections:
.01: What is this document all about?
..01: What is this document?
..02: How is this document made available?
..03: Who maintains this?
..04: Where did this information come from?
..05: How can I contribute?
..06: How may this document be distributed?
..07: Got anything else you'd like to add?
..08: Glossary.
.02: What is a UPS and how does is work?
..01: What is a UPS?
..02: How do you pronounce "UPS"?
..03: Vendor X says that (description) is a UPS, is it?
..04: Describe the types of UPS's?
..05: How can a UPS help me?
..06: What sort of stuff does a UPS do?
..07: How long can equipment on a UPS keep running?
..08: What is a "good" UPS?
..09: Support contracts on UPS's.
..10: Self maintenance tips.
..11: Is a UPS a glorified power strip?
..12: How important is the UPS output waveform?
.03: UPS monitoring/shutdown software.
..01: Can a UPS shut the computer down when power is low?
..02: Can I write my own shutdown routines?
..03: What freely distributable solutions are there?
..04: No UPS software works on my machines, what to do?
..05: What other software is out there.
.04: How big a UPS do I need?
..01: How are UPS sizes determined?
..02: What VA rating do I need?
..03: How do I determine this?
..04: What else should I consider?
..05: Can I use an UPS with a laser printer?
..06: What UPS sizes do you use on what equipment?
.05: Specific manufacturer's info.
..01: What vendors are there?
..02: UPS Hardware.
..03: UPS Software only.
..04: Other companies.
.06: Bibliography
.07: Acknowledgments

-----------------------------

01:
TOPIC:.What is this document all about?

01.01
Q:.What is this document?
A:.This is a FAQ document on Uninterruptable Power Sources.  It is 
.intended to provide a starting point for those people that want 
.to find out what they are, what they do, and what's available.

.Note that most of this document is very US-centric.  The power
.numbers, companies and services all emphasize US consumer 
.needs.  Sorry, but that's what I have to work with.  All the
.principles discussed here should be applicable just about 
.everywhere.

01.02
Q:.How is this document made available?
A:.Currently, its "home" is comp.misc.  It is also crossposted to 
.comp.unix.admin, comp.sys.sun.hardware, comp.sys.hp.hardware, 
.comp.sys.sgi.hardware, comp.sys.next.hardware, 
.comp.sys.ibm.hardware, comp.sys.dec, comp.answers and 
.news.answers.  This posting is automated and will occur on or 
.near the 10th of each month.  If there are other groups to 
.which this document should be posted, please let me know, but
.if I post it to every group where UPS questions get asked, that
.would be a lot of groups.  I'm open to suggestions.

.This document is also available via anonymous FTP.  The master
.sits on navigator.jpl.nasa.gov (128.149.23.82) in pub/doc/faq
.as the file UPS.faq.  It is also available via anonymous FTP
.from rtfm.mit.edu in: 
.pub/usenet-by-group/comp.misc/Uninterruptable_Power_Source_FAQ  

01.03.
Q:.Who maintains this?
A:.Right now, this document is maintained by Nick Christenson.  My
.preferred email address is npc@minotaur.jpl.nasa.gov, and I 
.would like it very much if questions regarding this document
.could have the word "UPS or UPS FAQ" or some such in the Subject
.line.  Note:  I am maintaining this on my own time, so please
.don't be upset if it takes a while for me to respond to your
.queries.  Also none of the information in here represents the
.views or has the blessing of any organization whatsoever.  The
.maintainer of the FAQ is to be held solely responsible for its
.contents.

01.04
Q:.Where did this information come from?
A:.Thankfully, many people have rallied to my cry to fill in
.the many gaps in my original draft.  This is now a group work,
.although I claim full responsibility for misstatements and 
.inaccuracies.  
.
01.05
Q:.How can I contribute?
A:.You should mail new information, corrections, suggestions, etc.
.to the current maintainer of this FAQ.  If you provide a suggestion,
.make sure you reference where the information is located in the
.document.  I guarantee that suggestions of the form "Change the
.word 'always' to 'almost always' in the part about surge suppression."
.will be ignored.

01.06
Q:.Are there any restrictions on distribution of this document?
A:.This document is copyright by the author.  You are encouraged 
.to distribute this document for any non-commercial purpose 
.as long as the contents remain unchanged and a pointer to 
.an up-to-date version is included.

01.07
Q:.Got anything else you'd like to add?
A:.Yes, now that you mention it.  The people who contribute to this
.document can speak only about equipment they have experience with.
.This may reflect a bias toward or against certain brands, features,
.functions, etc..  Please keep in mind that the suggestions, brand
.names and functions here are by no means exhaustive, or even 
.necessarily applicable to your situation.  Also, if you have 
.information that is not in this document, please submit it to 
.the maintainer listed above.  If you submit information, please
.say whether you'd like it to be attributed to you or not.  I am 
.more than glad to give credit to the fine people who helped with
.this document, but I want to respect the anonymity of those 
.people who would prefer it.

.One more caveat:  While the principles of UPS design and 
.maintenance are likely to be fairly universal, the power 
.figures in this FAQ are *very* US-centric.  Sorry, but 
.they're the only numbers I have.

01.08
Q:.Glossary
A:.This was contributed almost entirely by some kind soul.  I just
.cleaned it up a bit.

.Blackout: Complete loss of power. Some literature considers a voltage
.drop below about 80V to be a blackout as well since most
.equipment will not operate below these levels.

.Sag or Brownout: Decrease in voltage levels which can last for
.periods ranging from fractions of a second to hours. Can be
.caused by heavy equipment coming on line such as shop tools,
.elevators, compressors etc. Also occurs when utility companies
.deliberately do this to cope with peak load times.

.Spike: An instantaneous and tremendous increase in voltage often
.caused by a direct lightning strike on a power line or when
.power returns after a blackout.

.Surge: An substantial increase in voltage lasting a small fraction
.of a second, often caused when high powered appliances such as
.air conditioners are switched off.

.EMI/RFI Noise: ElectroMagnetic Interference and Radio Frequency
.Interference. Caused by, inter alia, lightning, generators,
.radio transmitters, industrial equipment.

.MOV: Metal Oxide Varistors used to control spikes.  These are
.common in Power Strips.  If you see more than two, you likely
.have a fairly decent Power Strip.  They look like largish disk
.capacitors.

.Inverter: Circuitry that converts DC battery power to AC power
.required by most computer equipment.

.Surge Protector: Circuitry consisting of MOVs, capacitors, rod-core
.inductors etc. for suppressing surges and spikes usually embedded
.in a power strip.

.Line Conditioner: A transformer that attempts to smooth out
.fluctuations in input voltage to provide near uniform output
.voltage or voltage waveform.


02: 
TOPIC:  What is a UPS and how does is work?

02.01
Q:.What is a UPS?
A:.An Uninterruptable Power Source is a device that sits between
.a power supply (e.g. a wall outlet) and a device (e.g. a computer)
.to prevent undesired features of the power source (outages, sags,
.surges, bad harmonics, etc.) from the supply from adversely 
.affecting the performance of the device.  

02.02
Q:.How do you pronounce "UPS"?
A:.I pronounce it "ups", but most of the literature seems to favor
."you pee ess", since they use "a UPS" instead of "an UPS".  This
.document will try to follow the literature.

02.03
Q:.Vendor X says that (fill in description) is a UPS, but it's 
.different that what you describe above.  Who's right?
A:.There really is no standard definition of what a UPS is.  
.Anything ranging from a 9 volt battery backup in a clock radio
.to a building/compound wide backup generator has been called
.a UPS by someone.  The majority of this document refers to
.objects larger than a beer can and smaller than a desk that
.help devices remain temporarily operational when changes to the 
.power they receive would otherwise interrupt their function.

.Maintaining power to a minicomputer (like a VAX 11) is beyond
.the scope of this document.  This FAQ deals with UPS equipment 
.that can be installed by a computer owner/administrator.  If you 
.have requirements that large, you need to talk to a qualified 
.electrician.

02.04
Q:.Can you give me some more information on this?
A:.(Kindly provided by Don Deal, Don.Deal@oit.gatech.edu, my additions
.are in [square brackets] )

.The UPS industry is made up of many manufacturers, and there is 
.a lack of standard terms within the industry.  I think this 
.sometimes borders on deliberate misdirection. (It's a jungle out 
.there!)

.There are basically three different types of devices, all of 
.which are occasionally passed off as UPSs.

.1. Standby power supply (SPS). In this type of supply, power is 
.usually derived directly from the power line, until power fails. 
.After power failure, a battery powered inverter turns on to 
.continue supplying power.  Batteries are charged, as necessary, 
.when line power is available.  This type of supply is sometimes 
.called an "offline" UPS.

.The quality and effectiveness of this class of devices varies 
.considerably; however, they are generally quite a bit cheaper than
."true" UPSs.  The time required for the inverter to come online,
.typically called the switchover time, varies by unit.  While some
.computers may be able to tolerate long switchover times, your
.mileage may vary.  [ Some articles in the trade press have claimed
.that their testing shows that modern PCs can withstand transfer
.times of 100ms or more.  Most UPS units claim a transfer time to 
.battery of about 4ms.  Note that even if a computer can stay up
.for 100ms, it doesn't mean that 100ms switchover is okay.  Damage
.can still be done to a computer or data on it even if it stays
.up. ]

.Other features to look for in this class of supplies is line 
.filtering and/or other line conditioners. Since appliances 
.connected to the supply are basically connected directly from 
.the power line, SPSs provide relatively poor protection from 
.line noise, frequency variations, line spikes, and brownouts. 

.[Some SPS's claim to have surge/spike suppression circuitry as 
.well as transformers to "boost" voltage without switching to 
.the battery if a modest voltage drop occurs. An example is the 
."APC Smart UPS" which claims it will switch to this boosting mode 
.if voltage drops below 103V (from the normal expected 120V) and 
.switches to battery only at 90V and below.  This, it is claimed, 
.allows operation of the equipment indefinitely under brownout 
.conditions as long as voltage does not drop below 90V.  I have
.not tested this, and would be interested in independent data.  
.There are other vendors products that make similar claims.]

.2. Hybrid UPS systems. I only know one vendor who sells them - 
.Best Power, Inc. The theory behind these devices is fairly simple. 
.When normal operating line power is present, the supply conditions 
.power using a ferroresonant transformer. This transformer maintains 
.a constant output voltage even with a varying input voltage and 
.provides good protection against line noise.  The transformer also 
.maintains output on its secondary briefly when a total outage occurs.  
.Best claims that their inverter then goes online so quickly that 
.it is operating without any interruption in power.  Other UPS 
.vendors maintain that the transition is less than seamless, but 
.then again it's not in their best interest to promote Best's products.  
.Best has a sizable part of the UPS market.

.[ Note:  According to some sources, ferroresonant transformers in an
.UPS system can interact with ferroresonant transformers in your 
.equipment and produce unexpected results.  The Moral:  Again, test
.before you buy.  -npc ]

.3. What I call "true" UPS systems, those supplies that continuously 
.operate from an inverter. Obviously, there is no switchover time, 
.and these supplies generally provide the best isolation from power 
.line problems.  The disadvantages to these devices are increased 
.cost, increased power consumption, and increased heat generation.  
.Despite the fact that the inverter in a "true" UPS is always on, 
.the reliability of such units does not seem to be affected.  In 
.fact, we have seen more failures in cheaper SPS units.  [ Note,
.though, that given the same quality inverter, you'd expect the
.one that runs least to last longest. ]

02.05
Q:.How can it help me?
A:.A UPS has internal batteries to guarantee that continuous power
.is provided to the equipment even if the power supply stops
.providing power.  Of course the UPS can provide power for a while,
.typically a few minutes, but that is often enough to ride out
.power company glitches or short outages.  
.Advantages:
..1) Computer jobs don't stop because the power fails.
..2) Users not inconvenienced by computer shutting down.
..3) Equipment does not incur the stress of another (hard)
..   power cycle.
..4) Data isn't lost because a machine shut down without
..   doing a "sync" or equivalent to flush cached or 
..   real time data.

02.06
Q:.What sort of stuff does a UPS do?
A:.A UPS traditionally can perform the following functions:
..1) Absorb relatively small power surges.
..2) Smooth out noisy power sources.
..3) Continue to provide power to equipment during line sags.
..4) Provide power for some time after a blackout has occurred.
.In addition, some UPS or UPS/software combinations provide the
.following functions:
..1) Automatic shutdown of equipment during long power 
..   outages.
..2) Monitoring and logging of the status of the power supply.
..3) Display the Voltage/Current draw of the equipment.
..4) Restart equipment after a long power outage.
..5) Display the voltage currently on the line.
..6) Provide alarms on certain error conditions.
..7) Provide short circuit protection.

02.07
Q:.How long can equipment on a UPS keep running after the power
.goes?
A:.How big a UPS do you have and what kind of equipment does it 
.protect?  For most typical computer workstations, one might 
.have a UPS that was rated to keep the machine alive through 
.a 15 minute power loss.  If you need a machine to survive 
.hours without power should probably look at a more robust
.power backup solution.  Even if a UPS has a very small load,
.it must still operate it's DC (battery) to AC converter, 
.which costs power.  A rough extrapolation from APC's 
.documentation, leads me to guess that a 2000 VA UPS can
.operate it's own converter (with no extra load) for just
.over 8 hours.  A 1250 VA UPS could run its converter for 
.about 5.  These are *very* rough guesses based on information
.provided by one vendor for one vendor.

02.08
Q:.Given the same vendor claims, how can I tell a "good" quality
.UPS from a "poor" quality UPS?
A:.Testing, testing, testing.  I can't emphasize this enough.  There
.are many good and bad units out there that call themselves UPS's.
.There are many good units that are wrong for your situation.
.Caveat Emptor.

.Some properties you might look for are:
.1) Sinusoidal power output.  In general, the closer the AC output 
.   of the UPS is to a sine wave, the better it is for your equipment.  
.   Many UPS units, especially the cheaper ones, deviate a great
.   deal from a sinusoidal output.  Some of them generate square
.   waves.  Waveform effects are dealt with in section 2.12.
.2) Does the UPS have a manual bypass switch?  If the UPS is 
.   broken or is being serviced, can you pass power through it to 
.   your equipment?  The last thing you want is for a broken UPS to 
.   be the cause of extra downtime.
.3) The more information about a UPS's operation you can get from
.   watching the unit itself, the better.  How much power (or 
.   percentage load) the equipment is drawing, how much battery
.   life is left and indications of the input power quality are
.   all very useful.
.4) Some newer UPS's can communicate with their monitoring software 
.   via network connection and SNMP!  This is wonderful *if* your 
.   network is on a UPS!  Also, beware, I have heard of dealers
.   advertising "Network UPS" monitoring where the network is 
.   the normal serial connection (no SLIP or PPP).  
.5) Does the UPS vendor offer support/maintenance contracts.  If
.   they don't even offer them, I would suspect the quality of the
.   equipment.

.If you do have a UPS that does not output a sinusoidal waveform,
.some manufacturers *strongly* urge you to not put a surge protector
.between the UPS and the computer.  The surge protector might mistake
.the non-sine waveform as a power surge and try to send it to ground.
.This could be bad for your UPS.  I don't know if this has happened
.or not, but I wouldn't chance it.

02.09
Q:.Should I make sure I have a support/maintenance contract for my
.UPS systems?
A:.Some people strongly recommend this, but to be honest, I don't 
.know how important it is.  I haven't had any UPS's long enough
.to have enough of them fail to know what the failure modes are
.likely to be.  Some people, with more experience than I in these
.matters, insist that a UPS support/maintenance contract is as
.important as your computer support/maintenance contract.  I can't
.argue with them.  In any case, it's almost certainly worth 
.pricing at any rate.

02.10
Q:.What sort of maintenance can I perform myself?
A:.One good thing you might want to do is periodically test the 
.UPS's and their failure modes.  A good time to do this might be 
.right after after a periodic level 0 backup.  Nobody is logged 
.in and you've got full backups of the machines.  Throw the 
.circuit breaker with the UPS on it to simulate and outage and 
.see how the transition goes.  Note that some UPS vendors suggest
.that testing an UPS by pulling the plug from the wall is *not*
.a good idea (Tripp Lite is one of them).  These UPS units like
.to have a good idea of what ground looks like.  It is likely that
.unplugging just about any UPS for a short amount of time would
.not be too dangerous (don't take my word for it, though!), but
.in all cases, throwing a circuit breaker would be a better thing
.to do. 

.It might be useful to install a GFI (Ground Fault Interrupter)
.socket to facilitate this testing without having to pull the plug,
.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.

.Those UPS units that use lead-acid batteries (that's most of 
.them, I'm told) do not have a battery memory and should be run 
.dry as few times as possible.  It's probably not a bad investment 
.to do this once on one UPS out of a largish batch to learn how 
.much UPS time you can expect in a real power outage.  Note:  
.depending on the manufacturer, UPS batters can be expected to 
.last between about 1 and 5 years before they ought to be replaced.

.As a UPS gets older, its battery life will become shorter.  Of
.course there's no way to reliably test how long it is without
.running the battery down and you don't want to do that because
.they have lead acid batteries.  <Sigh.>  All of these are very
.good reasons to get a support contract for them that includes
.periodic battery replacement.  At the very least, you can figure
.that the batteries will still be good at the end of the UPS 
.warranty figure, so that's a good place to start guesswork.
.
02.11
Q:.Isn't a UPS just a glorified power strip/surge protector with
.some batteries and a little power conditioning thrown in?
A:.Basically.  It's also got a power inverter and some other circuitry.
.It may also have a timer, thermometer or other gadgets.

02.12
Q:.How important is the UPS output waveform?
A:.That's a good question, and one is worthy of some debate.  One
.school of thought holds that one should always run equipment on
.the best approximation of sinusoidal input that one can, and that
.deviations produce harmonics which may either be interpreted as
.signal if they get through a power supply, or may actually damage
.the equipment.  Another school holds that since almost all 
.computers use switching-type power supplies, which only draw 
.power at or near the peaks of the waveforms, the shape of the 
.input power waveform is not important.  Who's right?  I don't 
.know.  My *opinion* is that sinusoidal output is worth the 
.extra money, especially for on-line UPS systems that continually
.provide their waveform to the computer.  Also, if you don't *know*
.that your equipment has a switching-type power supply, you might
.want to think twice before buying a low quality UPS.
.[ Some of this information from a great article in the October
.  1994 issue of LAN Magazine, check it out. -npc ]


03:.
TOPIC:.UPS monitoring/shutdown software.

03.01
Q:.If the power is out for a long time, I would like to have my
.computer automatically shut itself down gracefully before the
.UPS batteries die.  Can I do this?
A:.Yes.  Most UPS manufacturers support software that will do this 
.for some UPS's on at least some platforms.  Ask your UPS vendor 
.for details.
Q:.Okay, how about restarting the system for me once power returns?
A:.Fewer software products do this, but many do.  Again, ask your
.vendor.  I do not know of any freely distributable products that
.will do this.  It doesn't mean that they can't be built, but 
.vendor software is cheap enough (usually) that it's probably not
.worth building.

03.02
Q:.How does it work?  I'm a starving (fill in the blank) and I really 
.don't want to pay for software unless I absolutely have to.
A:.Usually, there is a serial connection running from a UPS into
.your computer.  The UPS sends information along the serial line
.as it goes.  If you can decode which pins contain which information,
.how the information is formatted and figure out what it wants to
.hear from the computer side, you're all set.  Make sure you have
.the right serial cable and know how the pins map between DB9 and 
.DB25 as both your computer and your UPS may take either.

.Since UPS units with network based monitoring capabilities are
.appearing on the market, we can hopefully get something that will
.communicate with those units.

.Here is a skeleton script provided by Joe Moss, joe@morton.rain.com.
.Definitely check this out as a starting point, but don't expect
.it to do anything meaningful without some work.


.---------start upsd.sh-------------
        #! /bin/sh

        # Shut down system in case of extended power failure

        # This should be the serial port to which the UPS is connected
        # This port must be set to block on open until the DCD line
        # is asserted - many UNIX systems have this determined by
        # the minor device number, if not, see if there is some way
        # to enable this behavior on your system
        PORT=/dev/ttya

        # Ok, this should block until there is a power failure

        : > $PORT

        # If we reach this point, we've lost power
        wall << EOF
        The sky is falling!! The sky is falling!!
        EOF

        # call shutdown (or init or whatever)
        exec shutdown
.-----------end--------------------

03.03.
Q:.Hmmm... that sounds kinda complicated.  Has someone already done
.this?
A:.Any solution would almost certainly be vendor specific.  However,
.some brave souls have provided partial functionality for certain
.vendors' UPS's.  I don't know the original source, but I have a
.copy available for anonymous FTP at navigator.jpl.nasa.gov in
.the pub/src/UPS directory as upsd.tar.Z.  I haven't tried it and 
.I don't honestly know if it even works.  

.Note:  Different UPS's produce different sorts of signals.  Just
.installing this already built package may require a great deal of
.work.  The cabling can be complicated, etc..  I would be 
.interested in hearing where this software does/doesn't work.

.Another good example, that probably works straight away for
.SunOS 4.1.X machines using APC Back-UPS devices, is also 
.available on navigator for anonymous FTP in the pub/src/UPS
.directory is pf.c.  It was written by Ronald Florence 
.(ron@mlfarm.com).  It looks like a nice framework for expansion
.to other OS platforms and UPS implementations.  Give it a try. 

03.04.
Q:.I can't find monitoring software that will work on my configuration.
.What should I do?
A:.Well, it seems you have a few choices:
..1) Build your own.  See item 03.02.
..2) Use something freely distributable.  See item 03.03.
..3) Lean on your UPS vendor to port to your platform.
..4) Try a different vendor that supports your platform.
..   See item 05.01.

03.05
Q:.What other software is out there?
A:.Software packages for UPS machines are getting more sophisticated.
.Most provide some level of power and status monitoring, but 
.lately there are more GUI's, more interactive packages, SNMP
.support, and even call-out paging.  See the software section
.05.03 for more info.


04:
TOPIC:.How big a UPS do I need?

04.01
Q:.How are the "sizes" of UPS's determined?
A:.Typically, a UPS has a VA rating.  The VA rating is the maximum
.number of Volts * Amps it can deliver.  The VA rating is not the 
.same as the power drain (in Watts) of the equipment.  Computers
.are notoriously non-resistive.  A typical PF (power factor: 
.Watts/VA) for workstations may be as low as 0.6, which means that
.if you record a drain of 100 Watts, you need a UPS with a VA
.rating of 167.  Some literature suggests that 0.7 may be a 
.good conversion factor, but this will depend heavily on the 
.machine.  WARNING:  Don't take my word for it!  Note:  Some UPS's 
.can continue to deliver power if the VA rating is exceeded, they 
.merely can't provide above their VA rating if the power goes.  
.Some can't provide power above their VA rating at all.  Some may 
.do something really nasty if you try.  In any case, I *strongly* 
.recommend not doing this under *any* circumstances.

04.02
Q:.How can I tell what VA rating I need for my equipment?
A:.First, when possible, get VA rather than wattage ratings.  See
.Q04.01 above.
.There are a couple of ways:
..1) Direct measurement.  You can get equipment to measure
..   the current draw of your equipment directly.  You may
..   or may not have access to this.  If you are part of an
..   organization that has it's own facilities/electrical
..   type people, they're likely to be able to do this.  They
..   might help you out if you ask nice.
..2) Compare notes.  If you know someone with the same setup
..   you're using, ask them what they use and how close they
..   are to the maximum VA rating.
..3) Use a chart.  Most vendors can help you out for common
..   equipment.  If you have an unusual setup, or mix 
..   vendors a lot, you're probably out of luck here.
..4) Use the equipment rating.  Most pieces of computer
..   equipment have a power rating on some back panel.  This
..   number is usually high, as it is necessary for the 
..   manufacturer to play it safe or they'll get sued.

.Note:  Method 1 is by far the best, method 2 and 3 are secondary,
.method 4 is usually overkill, but pretty safe.  There are some
.examples in section 4.6, but the information is probably worth
.what you paid for it :-)

04.03
Q:.Hmmm... seems like a tough thing to determine.
A:.Yeah, it can be.  It's also very important.  If you get a UPS 
.that's too big, then you've overpaid, but your equipment can 
.survive a longer outage.  If you get a UPS that's too small, 
.then you could be in deep trouble.  Therefore, I recommend that 
.you be conservative in buying these things, unfortunately, this 
.costs money.

04.04
Q:.What else should I consider?
A:.It would be nice to know how long your site's typical power 
.outages are.  In some places, with nice weather and a flaky
.power grid, the power is almost never out for more than 5 minutes,
.but this could happen quite frequently.  In this case, you may 
.as well use a UPS with a VA rating close to your equipment 
.rating with no extra batteries.  If your area has longer outages, 
.in the half hour or hour range, as is often the case in 
.thunderstorm country, you can either buy UPS's with multiples 
.of the VA rating of the equipment, since oversizing a VA rating 
.for a UPS has the effect of lengthening the amount of time your 
.equipment can stay up in case of a power outage, or you can buy 
.additional battery units for a smaller UPS.  You can probably 
.get away with doing simple math to determine how much longer a 
.larger UPS will keep your equipment running, but I recommend 
.running a few tests before committing to a large purchase 
.order.  Also, your UPS vendor will almost certainly be glad 
.to help you size the equipment you need.  If all else fails 
.and you guess wrong, or move equipment to a location with 
.different power status, you may be really, really glad if you 
.bought a UPS that can have additional battery packs added.
.
04.05
Q:.How about I use one of these UPS thingies for a laser printer?
A:.Don't *ever* do this.  If you ever measured the current draw
.of a laser printer during startup (and during printing) you'd
.be stunned at what it pulls.  All UPS manufacturers I know of
.tell you not to do this.

.Okay, I have to back down from this.  I know APC, just as an 
.example, now does rate some of their UPS units for use with 
.certain laser printers.  Not that I think this is a good
.idea, mind you.  In general, they are difficult to size and 
.rarely do they require the same level of uptime as servers.

.In any case, don't do this without specific approval of
.your UPS vendor.

04.06
Q:.So, what sorts of UPS sizes do you use on your equipment?
A:.BIG DISCLAIMER.  I disclaim everything about these figures.  
.At best, they are very, very rough.  Heck, I may be lying.  
.Don't trust them.  Here they are anyway.

.Note also, this is what the equipment apparently PULLS, not
.the UPS sizes that are on them.  Generally, I've been using
.UPS's that are about 2X the VA ratings shown.  At the very
.least, I would using UPS sized 1.5X the VA ratings here.

.400 VA:
.Sparc 2 with 3 600 MB disks, 1 200 MB disk, 1 exabyte 8200 
.tape drive, 19" color monitor.

.600 VA:
.HP 750 with 4 1.3 GB disks, internal 4mm tape drive and internal
.CD-ROM drive, external disk cabinet and 19" color monitor.

.500 VA:
.SPARC 2GX clone.  1 1.2 GB disk, 4 2.0 GB disks, 2 tape drives,
.1 CD-ROM drive, "big" monitor.

.300 VA:
.Sparc 2 clone with 100W power supply, internal 424 disk, 16"
.color monitor, external 1 GB disk drive.

.These are U.K. numbers, based on 240 V wall current.  Most of
.these VA numbers are very close to "American" VA numbers, but
.if my caveats weren't strong enough earlier... .

.100 VA:
.SGI Indigo R4400, 48 MB RAM, 1 GB int. disk, no graphics, no 
.monitor.

.580 VA:
.SGI Indigo R4400 configured as above with 17" Sony monitor plus
.3 19" monochrome X terminals.
.
.Another word of warning, don't assume that power requirements
.scale with compute power and number of peripherals, ESPECIALLY
.if they are different architectures.  Older equipment, CPU's,
.disks, monitors, whatever almost universally requires more
.power than new equipment.  For example, it seems that an HP
.9000/425e with 1 internal 420 MB disk and 19" color monitor 
.pulls a lot more power than a much more modern and much faster
.HP 9000/715 with an internal 1.3 GB disk, CD-ROM drive and 
.more modern 19" color monitor.  Again, the moral is don't assume.
.

05:
TOPIC:.Specific manufacturer's information.

05.01.
Q:.What vendors are there and what do they produce?
A:.Here is a very incomplete list, based only on what I know.
.Please give me information to expand it.  I make no claims
.as to the accuracy of this information.  It is mostly based
.on personal recommendations and vendor propoganda.

.Note:  The October 1994 issue of LAN Magazine has a great
.vendor list.  I have used it to update many of the entries
.here.  However, there is a lot of information available
.there that I don't have space to include here.  This 
.article is an excellent starting point for comparative pricing
.on UPS equipment.

05.02.UPS Hardware (and software) manufacturers:

.Company:..Acme Electric Corp.
....43 Argow Place
....Nanuet, NY 10954
.US Phone:..1-716-968-2400
....1-800-833-1373

.UPS Products:
..250 to 1400 VA standby UPS products, 1000 and 2000 VA
..on-line UPS products.  Shutdown/startup and SNMP 
..software for LAN Manager, Netware 3.x, 4.x, UNIX and 
..VINES.

.Contributed by:  Robert D. Freeman, rdf@thermo.chem.okstate.edu
..with additional information by npc.
.------------------------


.Company:..Advanced Electronic Systems, Inc.
....2005 Lincoln Way East
....Chambersburg, PA 17201
.US Phone:..1-800-345-1280
.Email:...None known

.UPS Products:
.Stediwatt UPS:  Designed specifically for use with NeXTSTEP.

.Contributed by:  Robert D. Freeman, rdf@thermo.chem.okstate.edu
.------------------------


.Company:..Alpha Technologies
.US Phone:..1-206-647-2360
....1-800-322-5742

.UPS Products:..
..600 to 15000 VA line-interactive UPS systems, SW
..with shutdown and SNMP support.  250 to 750 VA 
..standby UPS systems.

.Contributed by:  npc from LAN Magazine, October 1994.
.------------------------


.Company:..APC, American Power Conversion
.US Address:..132 Fairgrounds Road
....P.O. Box 278
....West Kingston, RI 02892
.FR Address:..4, rue Ste Claire Deville
....Zac du Mandinet-Batiment Espace
....LOGNES
....77447 MARNE LA VALLEE Cedex 2
....FRANCE
.US & CAN Phone:..1-800-800-4272
.Europe Phone:..(+33) 1.64.62.59.00
.World Wide Phone:.(401) 789-5735
.Email:...apctech@apcc.com
.WWW:...http://www.apcc.com

.UPS Products:
..Smart UPS in sizes up to 2000 VA.  The Smart UPS's do 
..monitoring and can shutdown multiple machines using the
..PowerChute software.  I recommend putting these on 
..computers.  SNMP adaptor can be installed.
..Back UPS same as Smart UPS except that you cannot 
..communicate interactively with the UPS and it will not
..support SNMP.  I recommend putting these on dumb equipment 
..like network equipment, X Terminals and Macintoshes (sorry, 
..I couldn't resist.).
..Matrix UPS a modular "fault-tolerant" system.  Any
..module, except the insulation unit, can be "hot-swapped" 
..at any time.  Also additional battery modules can be added, 
..again, while the system is running.  SNMP adaptor can be
..installed.
.Software:
..PowerChute, PowerChute PLUS.  They produce it themselves.  
..Supported on:  SunOS, HP-UX, SCO, AIX, AT&T UNIX,
..Interactive UNIX, XENIX, IRIX, and probably others by now.
.Contributed by:
..APC information contributed by Nick Christenson, 
..npc@minotaur.jpl.nasa.gov without consultation with
..APC.  Additional information provided by Joe Moss,
..joe@morton.rain.com.  I have no affiliation with APC 
..except as a satisfied customer.
..Updates contributed by Grant R. Bowman, grantbow@netcom.com.
.------------------------


.Company:..Best Power Technology, Inc.
....P.O. Box 280
....Necedah, WI 54646-9899
.US Phone:..1-800-356-5794
.Email:...None known

.UPS Products:
.FERRUPS:  Ferroresonant-Based, Line-Interactive UPS, sizes 
..from 500 VA - 18 KVA.  
..Features:  Standard power features, serial line
..communications, runtime monitoring, logging, 
..automatic shutdown with optional software, user
..configurable.
.FORTRESS:  Advanced, line-Interactive UPS, sizes from 360 
..VA - 2 KVA.
.PATRIOT:  Low-Cost Standby Power Systems, 250 VA - 850 VA.
.
.Contributed by:  Scott Pinkerton, spinkert@t4rta-gw.den.mmc.com
.------------------------


.Company:                Clary Corporation
        Address:                Clary Corporations
                                320 W Clary Ave
                                San Gabriel, CA 91776
        US Phone:               818 287-6111

        UPS Products:
        I'm not sure of the entire line, but their PC series includes
.[ On-line -npc ] UPS ranging from 400 to 1500 VA [ 450 to 2400 
.VA -npc] with surge and noise suppression.  Voltage regulation 
.to 3%, frequency to 1 Hz, RS232 signal output, LED load and 
.charge indicators.  Sine wave output, Alarm, etc.. 

.[ SW will do shutdown/startup and SNMP for LAN Manager, LAN
.Server, Netware 3.X, 4.X, Unix, VINES, Windows NT, and OS/2. 
.-npc ]

.Contributed by:  Ron Tansky, ron.t@bix.com who has no relation
..to Clary Corporation except as a user.
..Additions by npc from October 1994 issue of LAN Magazine.
.------------------------


.Company:..Controlled Power Company
....1955 Stephenson Hwy.
....Troy, MI 48083
.US Phone:..1-800-521-4792
....1-313-528-3700
.US Fax:...1-313-528-0411

.UPS Products:
..UPS, AC regulators, power conditioners.  They
..will do custom work.

..[ On-line UPS from 400 to 60000 VA.  Software
..with shutdown/startup and SNMP functions for
..AppleShare, LAN Manager, LAN Server, NetWare
..3.X, 4.X, UNIX, VINES and Windows NT -npc ]

.Contact: David Gerds (Sales)

.Contributed by: Donald McLachlan, don@mars.dgrc.doc.ca
..Additions by npc from LAN Magazine, October 1994.
.------------------------


.Company:..Data General

.UPS Products:
..Data General repackages another vendor's UPS's (from
..Exide?) with some sort of special cable.  They deserve 
..some mention since they provide UPS monitoring software 
..built in to the AViiON (their UN*X boxen) line.  It can 
..be managed through sysadm(1M).

.Contributed by:  Morris Galloway Jr., mmgall@presby.edu
.------------------------


.Company:..DELTEC
....2727 Kurtz St.
....San Diego, CA 92110-9980
.US Phone:..1-800-854-2658
.Email:...None known

.UPS Products:
.."Most technologically advanced *true* on-line UPS."
..[ 400 to 2200 VA line-interactive UPS systems.  
..Software with shutdown/startup and SNMP for 
..AppleShare, LAN Manager, LAN Server, NetBIOS,
..NetWare 3.X, 4.X, UNIX, VINES, Windows NT and OS/2. 
..-npc ]

.Contributed by:  Robert D. Freeman, rdf@thermo.chem.okstate.edu
..Additions by npc from October 1994, LAN Magazine.
.------------------------


.Company:..Easy Options IBM Corporation
.Address:..IBM Corporations
....Easy Options
....Dept. WC3J
....P.O. Box 2150
....Atlanta, Ga 30301-9948
.US Phone:..Unknown.
.
.UPS Products:
.UPS ranging from 250 VA to 600 VA with surge and noise suppression.
..Sine wave output, Test/Alarm, etc..
.These UPS's come with an insurance policy.  If your UPS damages
.your systems, they'll pay you up to $25,000..
.Software:  
.Works with APC's PowerChute software.

.I doubt that IBM is making their own UPS's rather than repackaging
.someone elses, but I'll be glad to post a correction if they are.

.Contributed by: Dave Gruhn, dgruhn@fuzzy.eskimo.com
..who has no relation to IBM, or Easy Options except as
..a satisfied customer.
.------------------------


.Company:..EFI Electronics
.US Phone:..1-801-977-9009
....1-800-877-1174
.
.UPS Products:
..400 to 1250 VA Standby UPS systems.  Software
..with shutdown/startup and SNMP for LAN Manager,
..LAN Server, NetWare 3.X, 4.X, UNIX, VINES, 
..Windows NT.

.Contributed by:  npc, from October 1994 issue of LAN Magazine.
.------------------------


.Company:..Elgar Power Systems Components
....9250 Brown Deer Road
....San Diego, CA 92121
.US Phone:..1-800-733-5427
....1-619-450-0085
.US Fax:...1-619-458-0267

.UPS Products:
..UPS, Line Conditioners, AC regulators.

.Contributed by: Donald McLachlan, don@mars.dgrc.doc.ca
.------------------------


.Company:..Emerson Electric Co., Computer Power Div.
.US Address:..9650 Jeronimo Road
....Irvine, CA 92718, USA
.UK Address:..Elgin Drive, Swindon
....Wiltshire SN2-6DX, England
.FR Address:..8, Rue de l'Esterel
....Silic 502
....94623 Rungis Cedex
....France
.IT Address:..SICE S.p.A. [Note national Name!]
....Via Rossini 6
....20098 San Giuliano Milanese
....Italy
.US Phone:..1-800-BACKUPS
.UK Phone:..+44 458 841898
.FR Phone:..+33 146 862336
.EMail:...n/a

.Products:
        Accupower GOLD Series:
                UPSes for 750, 1000, 1500, 2100 VA, the latter with
                external Batt Pack. Connector for {Power,Accu}Mon S/W.
                5 yr Batt Life. Good Display (3 Status LEDs, Load
                and Batt Charge LED Bargraphs). Switches positioned
                wrong (Main Power Switch on Front, Batt Check/Alarm
                off on Back - I'd prefer them the other Way 'round).
        other UPSes?
        PowerMon Software:
                Triggers for Outage, long Outage, Batt low. Uses one
                serial Connector. Logging and Warnings to Users.
                Requires special Cable (included in PowerMon Kit).
                NOTE: The "Batt low" Trigger does not work "on SunOS
                4.1.1 and above due to OS Limitations". >:-C I don't
                know whether this includes Solaris 2.x.
        AccuMon Software:
                Reported to support all Kinds of fancy Communication
                Items (gathering Power Line and internal UPS Data,
                test Batt Cap periodically and announce Batt Aging,
                switch off UPS on Computer Command, Logging 
..Facilities for all these Functions)
        Other Software?

.Contributed by: Jochen Bern, bern@kleopatra.Uni-Trier.DE
..who has no relation to Emerson.
.------------------------

.
.Company:..Exide
....8521 Six Forks Road
....Raleigh, NC 27615
.US & Canada Phone:.1-800-554-3448
....1-919-872-3020

.UPS Products:
..800 to 1500 VA On-line UPS systems.  Software
..does shutdown/startup and SNMP for NetWare 3.X, 
..4.X, UNIX, VINES, Windows NT
.
.Contributed by: npc from October 1994 LAN Magazine.
.------------------------


.Company:..Gamatronic Electronic Industries Ltd.
....P.O. Box 7369
....Jerusalem 91073
....Israel
.Israel Phone:..972-2-821777
.Israel FAX:..972-2-828875
.Email:...Gamatronic@Product.com
....Goren@Vms.huji.ac.il

.UPS Products:
..250 VA to 750 VA stand-by UPS systems.  On-line
..Smart UPS systems from 250 VA to 80 KVA with
..microprocessor controllers.  Shutdown/startup
..software for LAN manager, Novell, Unix, Windows NT.

.Contributed by: E. Finegold of Gamatronic.
.------------------------


.Company:..Hewlett-Packard

.UPS Products:
..HP used to resell Deltec and APC UPS units.  They
..will discontinue selling these as of April 1, 1995.
..They now have their own line of UPS productcs
..called "PowerWise UPS".

..PowerWise UPS are on-line units and come in 1000 VA 
..and 2100 VA sizes.  Shutdown software is available
..for HP-UX, AIX, Solaris, SCO, UnixWare, Windows NT, 
..NTAS, OS/2, Lanserver and NetWare.

.Contributed by:  Tom Myers, tvmyers@icdc.delcoelect.com
.Updated by:.npc, on information from Hewlett-Packard.
.------------------------


.Company:..Hipotronics Inc.
....Route 22
....Brewster, NY 10509
.US Phone:..1-914-279-8091
.US Fax:...1-914-279-2467

.UPS Products:
..UPS, Line Conditioners, AC Regulators.

.Contributed by: Donald McLachlan, don@mars.dgrc.doc.ca
.------------------------


.Company:..Intellipower
.US Phone:..1-714-587-0155

.UPS Products:
..650 to 1100 VA On-line UPS systems with
..software for shutdown/startup and SNMP for
..AppleShare, LAN Manager, LAN Server, NetWare
..3.X, 4.X, UNIX, VINES, Windows NT, AIUX, 
..NetWareLite, LANtastic

.Contributed by: npc from October 1994 LAN Magazine.
.------------------------


.Company:..Liebert Corportation
....1050 Dearborn Drive
....P.O. Box 29186
....Columbus, OH 43229
.US Phone:..1-614-888-0246
....1-800-877-9222
.US Fax:...1-614-841-6973

.UPS Products:
..250 to 600 VA Standby UPS, 600 to 2000 VA 
..Line-interactive UPS, 750 to 18000 VA On-line
..UPS systems.  Software does shutdown/startup
..and SNMP for AppleShare, LAN Manager, LAN Server,
..NetBIOS, NetWare 3.x, 4.X, UNIX, VINES, 
..Windows NT, OS/2.  Communications interface for
..SGI machines is available.

.Contributed by: George Elkins, elkins@nmrlab.cabm.rutgers.edu
..and npc from LAN Magazine, October 1994.
.------------------------


.Company:..Minuteman
.US Phone:..1-214-446-7363
....1-800-238-7272

.UPS Products:
..300 to 425 VA Standby UPS, 500 to 2000 Line-
..interactive UPS, 500 to 1000 VA On-line UPS.
..Software does SNMP for AppleShare, LAN Manager,
..LAN Server, NetWare 3.X, 4.X, UNIX, VINES,
..Windows NT.

.Contributed by: npc from LAN Magazine, October 1994.
.------------------------


.Company:..Oneac
.US Phone:..1-708-816-6000
....1-800-327-8801

.UPS Products:
..400 to 1800 VA Isolated Line-Interactive UPS
..with software that does shutdown/startup and
..SNMP for LAN Manager, LAN Server, NetWare 3.X,
..4.X, UNIX, VINES and Windows NT systems.

.Contributed by: npc from LAN Magazine, October 1994.
.------------------------


.Company:..Philtek Electronics Ltd.
....2471 Vauxhaul Place
....Richmond, BC
....V6V 1Z5  Canada
.Phone:...1-604-270-4642
.Fax:...1-604-270-8343

.UPS Products:
..UPS's.

.Contact: Bob Smedley

.Contributed by: Donald McLachlan, don@mars.dgrc.doc.ca
.------------------------


.Company:..Pylon Electronic Development
....5020 Fairway St.
....Lachine, PQ
....H8 1B8  Canada
.Phone:...1-514-633-8787
.Fax:...1-514-636-1970

.UPS Products:
..UPS's/Power conditioners, modular/industrial

.Contact: Graeme Turnbull
.
.Contributed by: Donald McLachlan, don@mars.dgrc.doc.ca
.------------------------
..

.Company:..Sola
.
.UPS Products:
..Sola apparently used to repackage Deltec systems.
..They have merged with Best Power Tech to form the
..new Best Power company, a unit of General Signal.

.Contribued by: npc, with updated information from Michael 
..Reget of Best Power.
.------------------------


.Company:..Square D-EPE/TOPAZ
.US Phone:..1-714-557-1636
....1-800-344-0570

.UPS Products:
..250 to 700 VA Standby UPS, 600 to 2000 VA
..Line-interactive UPS, 900 to 10000 On-line
..UPS.  Software does shutdown and SNMP on
..AppleShare, LAN Manager, LAN Server, NetBIOS,
..NetWare 3.X, 4.X, UNIX, VINES, Windows NT,
..OS/2.

.Contributed by: npc from LAN Magazine, October 1994.
.------------------------


.Company:..Superior Electric
.US Phone:..1-203-585-4500

.UPS Products:
..400 to 2200 VA On-line UPS.  Software does
..shutdown/startup on AppleShare, LAN Manager,
..LAN Server, NetWare, UNIX, VINES, Windows NT.

.Contributed by: npc from LAN Magazine, October 1994.
.------------------------


.Company:..Toshiba International Corporation
.US Address:..Industrial Division
....13131 West Little York Rd.
....Houston, TX 77041
.US Phone:..1-713-466-0277
.US Fax:...1-800-321-1412
.Canada Phone:..1-800-527-1204

.UPS Products:
..Single and three phase double conversion on-line UPS,
..from 600 VA to 50 KVA.  Serial line interface and
..auto-shutdown software available.

.Contributed by:  Seth J. Bradley, sbradley@scic.intel.com, 
..a very satisfied customer.
.------------------------


.Company:..Tripp Lite
....500 N. Orleans
....Chicago, IL 60610-4188
.US Phone:..1-312-329-1601
....1-755-5401
.Email:...None known

.UPS Products:
.On-line UPSs with pure Sine Wave output. [ 250 to 1250 VA
.Standby UPS, 250 to 2000 Line-interactive UPS, 300 to
.2000 VA On-line UPS.  Software does shutdown/startup, SNMP
.and RMON for AppleShare, LAN Manager, LAN Server, NetWare,
.UNIX, VINES, Windows NT, OS/2, LANtastic. -npc ]
.
.Contributed by:  Robert D. Freeman, rdf@thermo.chem.okstate.edu
..Additional info by npc from LAN Magazine, October 1994.
.------------------------


.Company:..Waber, Inc.
....(A division of SL Industries, Inc.)

.UPS Products:
.UPS 250, 500.  No other information on this company.

.Contributed by:  npc, from an advertisement for Fry's Electronics
..(of Manhattan Beach, CA) in the October 17, 1994 issue
..of MicroTimes.
..


05.03.Software products:

.Company:..ResponseWare Inc.
.US Phone:..1-800-673-4777
.Email:...responseguy@AOL.com

.Products:
.ResponseWare is software that performs a great number of
.services for UPS users.  ResponseWare uses a MS Windows
.console as its control point.  The console communicates 
.with both a UPS and the server.  It has built-in out call
.paging and they offer a remote monitoring service where 
.they can dial-in, diagnose problems and dispatch help.
.The software also can monitor temperature, humidity,
.security, life/safety, etc..

.ResponseWare works on Novell (NLM), AS/400, HP 9000, Sun,
.and VAX platforms.

.It works with APC, Best, Deltec, Exide, Liebert and TrippLite
.UPS products.

.Cost is $99 per server and $199 for the MS-Windows Console
.program.  Monthly monitoring charges begin at $99/month.

.Information provided by Bob Hunter of ResponseWare provides
.this information.
.------------------------


.On the NeXTSTEP front, there is a company called BenaTong (?)
.which sells a software package called PowerGuardian for NeXTSTEP
.only.  It will work with APC, TrippLite and UNISON UPS's.  If, 
.for example, you call APC and ask for PowerChute for NeXT, they
.will refer you to Power Guardian.

.Contributed by:  Chuck Bennett, (chuck@benatong.com) who works
.for this company.
.------------------------


.Also for NeXTstep, Max Hailperin wrote a package for monitoring
.Best Fortress UPS units called GACUPS.  It consists of a daemon
.and a GUI.  The daemon will shut the NeXT machine down gracefully
.and do logging.  It also answers queries from the GUI.  The GUI
.displays status information.  It should be available on the usual
.NeXTstep anonymous FTP sites.  One place you might want to check
.is in :  ftp://nova.cc.purdue.edu/pub/next/submissions/.  Any
.reports on how it works?

.Contributed by Max Hailperin (max@kolmogorov.gac.edu).




05.04.Other companies:  ITT Power System Corp
...  Digital Equipment Corporation.  (They probably
....repackage someone else's stuff, but 
....they're likely to support it and you
....can order it from their catalog.)

..I'd appreciate any information I can get on these.
..
06:
TOPIC:.Bibliography

.There are many good references and review articles on UPS
.information.  Some of the best sources can be found in 
.vendor information.  There is great reference material woven
.into their propoganda.  Some other good sources are:

."The Dranetz Field Handbook for Power Quality Analysis",
..1991, Dranetz Technologies, 1000 New Durham Rd., 
..Edison, NJ 08818, 1-908-287-3680.
."National Electrical Code Handbook", 1993, National Fire
..Protection Association, One Batterymarch Park, 
..P.O. Box 9101, Quincy, MA 02269, 1-617-770-3000.
."Grounding and Shielding in Facilities", 1990, by Ralph
..Morrison and Warren H. Lewis, John Wiley & Sons,
..New York, ISBN 0-471-83807-1.
."Battling Power Problems", by Alan Frank, LAN Magazine, 
..October 1994, pp 65-72, Miller Freeman, Inc..
."UPS Chart", by the LAN staff, LAN Magazine, October
..1994, pp 74-84, Miller Freeman, Inc..
.Hewlett-Packard has a White Paper on selecting a UPS.
..You may be able to get them to send it to you.
..A shortened version appeared as an aritcle in
..the January 9, 1995 issue of Electronic Engineering
..Times.


07:  
TOPIC:  Acknowledgements

.I would like to thank Charles Rhoades (cwr@zeus.jpl.nasa.gov) for
.his sage remarks on my draft of this document.
.I would like to thank Kevin R. Ray (kevin@kray.com) for sending me
.the freely distributable upsd software and Ronald Florence 
.(ron@mlfarm.com) for contributing the pf program. 
.Thanks also to Don Deal (Don.Deal@oit.gatech.edu) for a great
.many valuable suggestions and that great section on the types
.of UPS units.
.The following people have all made valuable contributions to this 
.document:
..Scott Pinkerton, spinkert@t4rta-gw.den.mmc.com
..Morris Galloway Jr., mmgall@presby.edu
..David E A Wilson, david@cs.uow.edu.au
..Edward Hartnett, ejh@larry.gsfc.nasa.gov
..Joe Moss, joe@morton.rain.com
..Kurt Hillig, khillig@chem.lsa.umich.edu
..Robert D. Freeman, rdf@thermo.chem.okstate.edu
..Jochen Bern, bern@kleopatra.Uni-Trier.DE
..Dave Gruhn, dgruhn@fuzzy.eskimo.com
..Steve Welch, smw@columbine.cgd.ucar.edu
..Ron Tansky, ron.t@bix.com
..Andrew J. Templin, nosilla@ohionet.org
..Chuck Bennett, chuck@benatong.com
..M.V.S. Ramanath, ram@sclara.qms.com
..Max Hailperin, max@kolmogorov.gac.edu
..Larry Moss, moss@cvs.rochester.edu

.Please note that I take full blame for any errors or omissions.

