On Fri, 07 Sep 2007 14:37:58 GMT Noozer <dont.spam@me.here> wrote:
|
| "kony" <spam@spam.com> wrote in message
| news:2dd2e39g86vtkcf8lmmt655ieccvi6tu5f@4ax.com...
|> On Fri, 07 Sep 2007 09:04:51 GMT, "Noozer"
|> <dont.spam@me.here> wrote:
|>
|>>Might be a dumb question, but the expensive part of a UPS is converting
|>>the
|>>AC to DC for storage, then back to AC for use.
|>>
|>>Why not put the UPS *after* the PSU... three (?) mini UPS's actually - 5v,
|>>12v and 3.3v... and the -5v, etc if necessary. It could possibly even
|>>mount
|>>into a 5.25" drive bay.
|>>
|>>Sounds simple, doesn't it?
|>>
|>
|>
|> You write about putting it in a 5.25" bay which would
|> require very small batteries, meaning it couldn't have much
|> runtime. If long runtime for a system (only, including no
|> monitor or other peripherals if not powered by the system)
|> is not required, then we avoid the expensive larger,
|> traditional UPS, and can instead use one of the basic
|> commodity $40 types.
|
| True, but I'm thinking of something that would let the PC run for a 10
| second interruption, then signal the PC to hibernate. Probably looking at
| about 2 minutes of run time. No extra loads like monitors or printers to
| worry about either.
|
| Considering how much people rely on PC's I'm surprised that there isn't a
| better power solution than the 120v AC UPS's.
|
| ...not to mention that most consumer UPSs put out really crappy power and
| don't do ANYTHING to protect against power surges/etc.
That's becaus emost consumers don't want to pay all the extra cost of a
better power supply. They want the lowest prices. Manufacturers want to
keep getting a profit. The end result is you get what you pay for.
Some better power supplies _will_ ride through very short (less than one
second) power blinks just from the capacitors inside. If you overrate
the power supply (for example use an 800 watt one when 250 would have
been enough) you'll get bigger capacitors and maybe even 2 or 3 seconds
ride time. That's only good if the power comes back on real fast, not
enough for a clean hibernate.
There are power supply units that use DC input, like 12 volts or 48 volts.
Other voltages used in other markets might also be available (28, 36, and
72 volts). Some of them can take a wide voltage swing as well, giving you
plenty of range by using batteries aimed at the top voltage.
Note that these voltages are not the choice for most power efficiency.
Designing a data center for the most efficient use of power would likely
involve a 360 volt DC bus feeding each machine. The lower current would
mean less loss on the bus. Because power supplies actually convert the
voltage UP to around this level first, before converting back down to the
voltages the mainboard and devices use, a smaller more efficient power
supply could be used in each machine when the source voltage is in this
range. But such a setup would be far too hazardous for typical home use
(that is, not something sold commercially for a consumer market, even
though an engineer hobbyist might have no problem with it).
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net /
spamtrap-2007-09-29-0832@ipal.net |
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