tiple events. Most
data is stored on a
device, and it can be
used with software
that accompanies the
PQ meter. Some users today
would like to see power func-
tionality in a memory recorder
which would combine a trouble-
shooting device that can make
Dave Kadonoff, field sales engineer,
Ideal Industries, Sycamore, Ill., said any
equipment that is under the control of
logic circuits can be impacted by the loss of
control signals if PQ to the control unit is compromised.
“PQ issues are most commonly thought of as disturbances to
the purely sinusoidal waveform of 60 hertz and related amplitude for the appropriate rms voltage resulting in sags, swells,
distortion, spikes, literally any deviation from the pristine
waveform of sufficient magnitude (up or down) and duration
that can impact reliable function of load or shorten equipment’s
expected lifetime,” he said.
To find and categorize these distortions and the slightest of
deviations from a pure sine wave, many overlook the integrity
of the wiring and connections on electrical distribution systems.
“For example, hospital outlets are mandated to be tested
once a year for retention force,” Kadonoff said. “That’s good,
but only checks integrity to the length of the inserted prong.
To look further into the branch circuit, and all the way back to
the panel, an advanced receptacle/polarity checker combined
with a circuit analyzer is needed.
“By plugging the Sure Test into the outlet with the provided
standard three-prong connector, the existing voltage is measured, a 15 amp load is applied for slightly less than one cycle
to not disturb any sensitive electronics or trip any breakers,
even if there are already loads on the circuit. Then the voltage
is measured in the loaded state and voltage drop in percent is
calculated. Less voltage drop is desirable—the [National Electrical Code] recommends 3 to 5 percent or less. This provides an
immediate sense of the condition of the integrity of the branchcircuit wiring from the panel to that point and whether it can
support loads to design limits without causing excessive voltage drop,” he said.
Jim Huekels, account manager for Extech, a Flir company,
said PQ issues are generally perennial.
“Where we see changes are in today’s wider adoption of
variable speed drives and motor controls, as well as DC motors
in AC environments,” he said. “For energy efficiency, more
and more sensitive electronics are being employed to play an
important role in optimizing motors, pumps and other industrial electrical equipment. These pose a vulnerability to ‘dirty’
“The emerging Internet of Things approach
to industrial equipment
management adds another
dimension to vulnerabilities related to power
quality. Are industrial IP-networked monitoring
and control systems hardy
enough to withstand surges
from dirty power quality, or
do they represent an additional weak link?
“PQ testing should
be part of a well-defined
program. Basic test equipment used for PQ-related
testing includes insulation
resistance testers, voltage
and current data loggers,
and power clamp meters. All of these complement the primary
tools for PQ, the power and harmonics analyzers,” Huekels said.
Today’s PQ and harmonics analyzers can be used to provide a big picture of a site’s PQ conditions. With more than 30
metrics and functions, PQ analyzers offer a detailed view of
PQ and harmonics.
“Current capacities have increased with options up to 3,000
amperes, and data-logging capacity has increased with the flexibility of removable SD memory cards,” he said. “Displays have
improved with better contrast for improved viewing in both
dim and bright lighting conditions.
“Some power quality analyzers can store up to 30,000 sets
of records. Programmable sampling rates add flexibility to data
logging, and a SD card ensures a convenient, portable format
to transfer records,” Huekels said.
GRI FFI N, a construction and tools writer from Oklahoma City, can
be reached at firstname.lastname@example.org.
Ideal Sure Test
Extech PQ3470 three-phase
power and harmonic analyzer
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