Re: UPS recommendations?
- From: w_tom <w_tom1@xxxxxxx>
- Date: Wed, 27 Jun 2007 15:21:30 -0700
On Jun 27, 1:53 am, Steve <h...@xxxxxxx> wrote:
Ok, here's a stupid question - other than being a better surge
protector, what does a UPS do? Does it come into play only if you
happen to be working at the computer when a surge hits? Then you get
a couple minutes to save your work and log off? Any other benefits?
Your original citation (visitinggeeks.com) is classic myths. That
author clearly does not have electrical knowledge. For starters,
brownouts do not harm computers. One power supply function: provide
all voltages to computer (even enough to perform a startup) when
incandescent bulbs are only 40% intensity - a severe brownout. If
power supply cannot maintain voltage (lights dim even lower), then
power supply 'system' simply shuts down computer. No damage. Even
demanded in Intel ATX specs and was required in 1970s industry
standards. Just another in a very long list of functions inside a
power supply even 35 years ago.
What does a plug-in UPS do? It provides power long enough to save
data. Typically has no hardware protection functions. It connects
computer directly to AC mains when not in battery backup mode. Does
that relay perform surge protection? Of course not.
It does claim surge protection. But color glossy sheets are where
half truths are promoted to the naive. For example, it does not
protect from a type of surge that typically does hardware damage. Its
protector component is typically so small as to be near zero
protection. But it does have protection. Just enough to post a half
truth on color glossies.
Go to its numerical specs - where useful numbers are found. No
numbers? Then a fact does not exist. Specs do not list protection
from each type of surge and numbers for protection? Otherwise you
might learn of many types of surges - including one that typically
does damage.
If numerical specs are useful, then a number defines power output
when in battery backup mode. For example, this 120 volt UPS outputs
two 200 volt square waves with a spike of up to 270 volts between
those square waves. Is that conditioned power? Since they are
selling products to layman whose eyes glaze over when the numbers
appear, then those layman don't bother to learn how 'dirty' that UPS
power is in battery backup mode. Those square waves are then called
'modified sine wave'. Again, 'experts' using 'word association' would
assume that is 'clean' electricity.
A "modified sine wave" may be so 'dirty' as to even harm some small
electric motors. But computers are far more robust. Computers
already contain internal protection making that 200 volt square wave
and 200+ volt spike irrelevant. A UPS that outputs such dirty power
is also called 'computer grade UPS'. Color glossies let the naive
assume that means 'clean' power. Sold by half truths and myths.
Many types of UPSes exist. Ones that perform various 'power
conditioning' include building wide systems located when power enters
a building - including a dedicated earth ground. No wonder they cost
$thousands. Where is that dedicated earthing wire on a plug-in UPS?
Does not exist since it performs only one UPS function - protect from
data loss.
How cheap are those plug-in UPSes? Well a car battery used every
day and exposed to all weather should last seven or nine years. Plug-
in UPSes are made so cheaply that its battery typically dies in three
years. Often costs more to replace a battery than to buy a new UPS.
They are that cheap - have that few actual functions. Sold on
numerous myths.
For reliable service, consider a laptop that already contains a UPS
and typically consumes less power. Need longer battery backup? Most
laptops can also support a second battery.
Do not chain batteries to a UPS. Risk from explosion and fire is
created. Again, serious UPSes costs many $thousands for good reason.
.
- References:
- UPS recommendations?
- From: Steve
- Re: UPS recommendations?
- From: Steve
- UPS recommendations?
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