There are few things in computing that are as traumatic as watching your
computer screen shut down and realizing you haven't saved your data. If you
live in an area where storms, brownouts, or power surges are common, you'd
be wise to invest in an Uninterruptible Power Supply (UPS).
UPS devices are designed to protect electronic equipment like computers
against problems stemming from a temporary failure in the power supply. By
providing a constant source of electricity, a UPS can help prevent damage or
data loss that can occur with the unexpected shutdown of computers and other
UPS systems work by regulating the amount of electricity coming from the
outlet and boosting power to maintain a constant flow of electricity to the
connected equipment. This power boost is provided either by a transformer
that enhances a weak electrical flow or from an internal battery that substitutes for the normal power source in the event of failure. UPS units
also contain surge protectors, which may help prevent equipment damage
whenever there are sudden increases in the flow of voltage (power surges).
The power requirements of your equipment will determine the amount of backup
power you will need. It is generally recommended that a UPS have a capacity
that is at least 25% greater than the total power capacity requirements of
the connected equipment. For example, a desktop computer that runs between
180 VA (volt-ampere is the unit used to quantify power) to 280 VA should be
equipped with a 300 VA UPS. You can check how much power your equipment uses
by reading the plate on the back of the equipment. Keep your calculator
handy, since these plates won't necessarily list the power requirements in
the VAs that the UPS will use. If the power figure is given in amps, just
multiply this number by the line voltage (usually 110V in the United States).
Manufacturers report how long a UPS battery will last under full-load or
half-load conditions. Running under full load signifies that a UPS is working at its maximum capacity. A typical UPS should report a full-load
time duration of about ten minutes. Under half-load conditions, when the UPS
provides only half the power it is capable of generating, the time duration
is often more than three times as long.
Most UPS units are designed to provide approximately ten minutes of backup
power. This should be enough time to appropriately shut down the computer
while avoiding data loss and hardware problems. Since blackouts typically
last no more than a couple of minutes, this should also be enough time to
work right through most power failures. It should be noted, however, that
this action is not recommended.
Your best protection for power surges, brown-outs or storms is to purchase
an Uninterruptible Power Supply. If you do lose your power for a fraction of
a second, your computer won't even know it. And, if the outage is of a
longer duration, you have plenty of time to shut down your computer in an
orderly fashion - saving all the data you worked so hard to get.