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- Archive-name: UPS-faq
- Version: 1.7
-
-
- Uninterruptable Power Source (UPS) FAQ.
- VERSION 1.8, November 4, 1994.
-
-
- 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: none known
-
- 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, 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.
- ------------------------
-
-
- 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 800 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:
- Apparently Sola repackages Deltec UPS systems.
- I have no other information.
- ------------------------
-
-
- 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
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- Please note that I take full blame for any errors or omissions.
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