Application Note

4 Fluke Corporation Stepping up to power quality tools
The Harmonics function
Selecting Harmonics from the menu provides the
level of each harmonic current in the system. Har-
monic currents are multiples of the fundamental
60 Hz frequency. Different harmonic levels present
different problems. In a single-phase system,
the presence of the third harmonic is common.
This harmonic current can cause overheating in
neutral conductors and transformers and, as with
all harmonics, it will tend to distort the funda-
mental sine wave. Pay attention to total harmonic
distortion (THD) for voltage. It must be 5 percent
or less at the service entrance, but may be higher
when closer to individual loads. Press the arrow
key to move the cursor and note the level of each
harmonic current as the cursor passes along the
harmonic graph.
Recording voltage over time
As electronic and larger motor loads cycle off
and on in a distribution system, they can present
problems for single-phase equipment. Large
inrush currents can cause voltage to sag. Quite
often it is not one particular power quality event
that causes electronic equipment to malfunction.
It is sometimes a series of two or more events. For
example, the sag in voltage by itself may not be
an issue for certain equipment but other nearby
equipment with less immunity may be severely
affected. Since it is usually impossible to tell
exactly when equipment will start, draw large
inrush currents and create voltage sags, the Fluke
43B allows for recording of these values over time.
The Harmonics screen supplies valuable information on current flows
created in the system by nonlinear loads that add heat and distort
the 60 Hz sine wave.
With the cursor
over the 3rd
harmonic, values
for distortion
created by this
harmonic are
indicated
The 3rd harmonic
is measured at
179.9 Hz, which is
1.32 amps and
26.7 % of the
60 Hz amperage
The bars provide
a graphical
representation of
the magnitudes
of the various
harmonic currents
The Fluke 43B has additional
functions to facilitate trouble-
shooting in the field. The
analyzer can measure ohms,
test for continuity and check
capacitor values. Temperature
can be measured in degrees
Celsius or degrees Fahrenheit. A
scope function is also available,
allowing for troubleshooting of
electronic equipment. Addition-
ally, up to twenty screenshots
can be saved in the instrument
and later reviewed or down-
loaded to a computer for analysis
with the FlukeView
®
software.
In today’s modern electri-
cal environment, problems that
were once overlooked can no
Additional troubleshooting with the Fluke 43B
longer be ignored. Network
communication devices, per-
sonal computers and specialized
single-phase loads from medi-
cal equipment to copy machines
must all function properly. Iden-
tifying and isolating the source
of power quality problems that
prohibit the proper functioning
of this equipment is the job of
the electrical professional. For
those responsible for solving
such power quality issues, the
use of a single-phase power
quality analyzer is invaluable.
For those desiring to break into
the field of power quality, the
Fluke 43B Power Quality Ana-
lyzer is a logical choice.
Recording transient conditions
The single-phase power quality analyzer also
allows for recording of transient conditions. A
transient is a short-duration spike along the volt-
age sine wave. High energy level transients can
occur from lightning strikes and utility switching.
Lower energy level transients can occur within a
facility as different loads cycle. While high energy
level transients can cause immediate failure of
electrical equipment, lower level transients can
cause damage over time—resulting in unexplained
premature failure of equipment.
Fluke Corporation
PO Box 9090, Everett, WA 98206 U.S.A.
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa [phone] or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.fluke.com
©2010 Fluke Corporation.
Specifications subject to change without notice.
Printed in U.S.A. 10/2010 3931841A A-EN-N
Modification of this document is not permitted
without written permission from Fluke Corporation.
Fluke. Keeping your world
up and running.
®