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Generally speaking, there are five typical types of power problems that
affect electronic equipment.
They are:
BLACK-OUTS, SAGS, SURGES, SPIKES and NOISE.
| A.
Black-Out |
A
total loss of utility supply due to excessive demands on the power grid,
storms, lightning strike or nearby construction work and human error
results in a catastrophic loss of all current work, possible loss of
file allocation table resulting in loss of all data on the hard drive,
and the file corruption.
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| B.
Sags |
A
short term decrease in voltage which results in the computer being
starved of power. This can be caused by the start-up power demands of
lifts, electronic motors and other nearby industrial equipment causing
keyboards to lock up, PC's to reboot, operating system crashes and data
corruption.
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| C.
Surge |
A
short-term increase in voltage as extra voltage from lifts, electronic
motors, etc. is dissipated through the mains. This can cause components
to be put under stress decreasing both the reliability and working life
of your equipment. Permanent damage to components can occur leading to
lost productivity while repair or replacement occurs.
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| D.
Spike |
An
instantaneous dramatic rise in voltage often caused by damage to power
lines or lightning strikes nearby causing catastrophic damage to
hardware such as damaged motherboards fractured hard drives and damaged
network interface cards.
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| E.
Noise |
| Electro-magnetic
interference or radio frequency interference disrupts smooth mains
supply causing random errors to be introduced into data files and
executable programs. Noise can be generated by lighting, industrial
equipment, lifts, and other cables nearby.
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Types
of UPS |
| In
general, there are three types of UPSs which offer different levels of
support and protection. Optional software is available to provide
automatic, unattented shut-down of file servers and workstations. |
| Off
Line UPS |
A
off-line UPS will filter noise, surges and spikes from the utility power
before passing it to the load. The battery which stands off-line (and
therefore does not see the normal utility power) is charged on a required
basis. When power failure is detected switch is activated and the power is
supplied from the battery
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| Line
Interactive UPS |
Line
Interactive UPS combine some of the advantages of stand by units with
those of on line units. Normal power passes through the noise filters and
surge suppressors before going into an inverter, part of which is on-line
all the time. The inverter acts as a battery charger under normal
conditions but on power failure will provide battery back-up.
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| On
Line UPS |
With
On-Line systems the input current passes through their major components
all the time. A steady nominal output is obtained and if the line falls or
goes outside of the input limits, the battery will instantly carry on
delivering power to the load.
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