Power 101
Power
problems can quickly interrupt the traffic
flow of
data across an enterprise, cripple business operations, and place
your infrastructure at risk. By first understanding these power
problems, you will ensure that you select the right solution.
Here are
some of the most common power supply problems and their likely
effects on sensitive electronic equipment:
A
power surge
takes place when the voltage is 110% above normal. The most common
cause is heavy electrical equipment being turned off. Under this
condition, computer systems may experience memory loss, data errors,
flickering lights, and equipment shutoff.
High-voltage
spikes
occur when there is a sudden, rapid voltage peak of up to 6,000
volts. These spikes are usually the result of nearby lightning
strikes, but there can be other causes as well. The effects on
vulnerable electronic systems can include loss of data and burned
circuit boards.
Switching
transients
take place when there is a rapid voltage peak of up to 20,000 volts
with a duration of 10 microseconds to 100 microseconds. They are
commonly caused by arcing faults and static discharge. In addition,
major power system switching disturbances initiated by the utilities
to correct line problems may happen several times a day. Effects can
include memory loss, data error, data loss and component stress.
Power sags
involve
voltages 80 to 85 percent below normal for a short period of time.
Possible causes are heavy equipment being turned on, large
electrical motors being started, and the switching of power mains
(internal or utility). A power sag can have effects similar to those
of a power surge, such as memory loss, data errors, flickering
lights and equipment shutoff.
Electrical line
noise
is defined as Radio Frequency Interference (RFI) and Electromagnetic
Interference (EMI) and causes undesirable effects in the circuits of
computer systems. Sources of the problem include electric motors,
relays, motor control devices, broadcast transmissions, microwave
radiation, and distant electrical storms. RFI, EMI and other
frequency problems can cause data error, data loss, storage loss,
keyboard lockup and system lockup.
A
frequency variation
involves a change in frequency from the normally stable utility
frequency of 50 Hz or 60 Hz, depending on the geographic location.
This may be caused by erratic operation of emergency generators or
unstable frequency power sources. For sensitive electronic
equipment, the result can be data corruption, hard drive crash,
keyboard lockup and program failure.
A
brownout
is a steady lower voltage state. An example of a brownout happens
during peak electrical demands in the summer, when utilities can’t
always meet the requirements and must lower the voltage to limit
maximum power. When this happens, computer systems can experience
data corruption, data loss and premature hardware failure.
Power failure
or
blackout
is defined as a zero-voltage condition that lasts for more than two
cycles. It may be caused by the tripping of a circuit breaker, power
distribution failure or utility power failure. This condition can
lead to data damage, data loss,
file corruption and hardware damage.
Power Protection
Devices
