Article View: comp.sys.next.hardware
Article #130Re: NeXT Uninterruptible Power Supply recommendations
From: Doug McClure
Date: Sat, 31 Oct 1992 23:21
Date: Sat, 31 Oct 1992 23:21
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3959 bytes
In <1croojINN3c2@darkstar.UCSC.EDU> isbell@cats.ucsc.edu (Art Isbell) writes: >What rated capacity is recommended for a NeXT Cube with an external floppy and >CD-ROM drive and a modem (I think I'd need to keep all of these running during >a power failure). NeXTanswers reports that an idling Cube draws less than 150 >watts of power (maybe around 115 W., but I can't recall for sure). My >peripherals are low-power devices, so I would think that my VA load would be no >more than 300 (I think volt-amps = 1.4 * watts). I don't want to buy a bigger >UPS than I really need, although I guess I could run longer on a larger UPS. Since I have a very similar setup and just got a UPS, I think I'll comment. Plus add some extra for other folks. I have a NeXT Cube, external hard drive, modem, and soon will have a CD-ROM drive. I currently own a 660VA BEST Fortress UPS. It runs currently at about 40% load and will probably hit 45-50% with the CD-ROM. And I get about 25-30 minutes of backup time. Remember to consider if you have an OD drive, that'll chew up some more power. Anyways, the BEST catalog has this to say about determining the Volt/Amps (VA) rating you should get and this should apply to any UPS. 1) List **ALL** equipment that will be protected by the UPS. 2) Check the voltage and amps, then multiply them together to get your VA rating for that device. If it gives just a figure for Watts, multiply that by 1.4. 3) Add up all VA requirements. 4) Give room for growth. Mutiply by 1.25 to get a 25% growth factor. This will be the total value for a VA requirement. Now when I talked to BEST they told me that even though they tell you this is how you should calculate it, more often than not, manufactures specifications for power consumption is for the absolute greatest possibly that you can consume. For a NeXT Cube that would be 300W at 5A. A fairly large load. You can therefore lower your VA requirement some. But you definitely want some room to spare, powerwise, for your UPS. For me, the next model down would have been a 460VA unit which would have sufficed but would have been operating at about 85-90% capacity. Not good. >I'd also like to get a UPS with maintainable batteries (apparently the sealed >maintenance-free batteries supplied with many UPS's eventually fail because >they dry out, so the ability to add water periodically could extend battery >life by a factor of 2 - 4). BEST uses sealed ones. But they also offer some kind of warranty that covers their batteries. >Any guidance, words of wisdom, suggestions, etc. would be appreciated. I will >summarize to the net. I've been extremely happy with my BEST Fortress. It is a sleek efficient model. It has a nice readout display that you can change various paramaters of it's operation, it offers a very nice advanced communications off a RS-232 port, which you can buy software for to shutdown your computer. You can check voltage in, out, runtime, %loads, and more. They have been given great ratings for a number of people, Their staff are very easy to deal with and very glad to help you out. Even though they sell their own software for communicating with their UPS's, they will gladly give you documentation on exactly what you can do across the communication port so you can work with them. I would highly recommend BEST products to anyone looking for a UPS. -doug
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Newsgroups: comp.sys.next.hardware Path: arc1-ca.pugleaf.net!sparky!uunet!sun-barr!ames!purdue!mentor.cc.purdue.edu!sage.cc.purdue.edu!asd From: asd@sage.cc.purdue.edu (Doug McClure) Subject: Re: NeXT Uninterruptible Power Supply recommendations Message-ID: <Bx0E8B.6Cx@mentor.cc.purdue.edu> Keywords: UPS Sender: news@mentor.cc.purdue.edu (USENET News) Cc: isbell@cats.ucsc.edu Organization: Purdue University References: <1croojINN3c2@darkstar.UCSC.EDU> Date: Sat, 31 Oct 1992 23:21:46 GMT Lines: 69