AEMC 721 User manual

11/03
99-MAN 100066 v2
Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments
15 Faraday Drive • Dover, NH 03820 USA • Phone: [phone] • Fax: [phone]
www.aemc.com • www.chauvin-arnoux.com
ICLAMP-ON HARMONIC METER
ENGLISH User Manual
721
600V
OFF
A
~
V
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!COM +
Model 721
HARMONIC METER
HOLD
MIN
MAX
PEAK
SMOOTH Hz RANGE THD
P
RECORD-PAUSE MAX MIN AVG
SMOOTH RANGE
HOLD
DF
%THD
Hz CF
RMS
PEAK
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AV
AV
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TABLE OF CONTENTS
1. INTRODUCTION ..............................................................3
1.1 Receiving Your Shipment..........................................................4
1.2 Ordering Information.................................................................4
2. PRODUCT FEATURES .....................................................5
2.1 Description................................................................................5
2.2 Control Features .......................................................................7
2.3 Digital Display Features............................................................8
2.3.1 Display and Error Indications........................................9
3. SPECIFICATIONS ..........................................................10
3.1 Electrical Specications ..........................................................10
3.2 General Specications............................................................12
3.3 Mechanical Specications ......................................................12
3.4 Safety Specications ..............................................................13
4. UNDERSTANDING ELECTRICAL HARMONICS .............14
4.1 Detection and Measurement...................................................20
4.2 Effects on the System.............................................................21
4.3 Transformer Derating..............................................................22
4.4 Meter Readings ......................................................................23
4.5 Crest Factor ............................................................................23
4.6 Limiting the Effects of Harmonics ...........................................24
5. OPERATION ..................................................................25
5.1 Current Measurements ..........................................................25
5.1.1 Ranging ......................................................................26
5.1.2 Analog Output – Vout..................................................26
5.1.3 Other Functions ..........................................................26
5.1.4 Bargraph .....................................................................26
5.2 Voltage Measurements ...........................................................27
5.2.1 Ranging ......................................................................28
5.2.2 Other Functions ..........................................................28
5.2.3 Bargraph .....................................................................28

5.3 THD Push Button: Power Quality Measurements...................29
5.3.1 %THD: Total Harmonic Distortion ...............................29
5.3.2 %DF: Distortion Factor ..............................................31
5.3.3 CF: Crest Factor .........................................................32
5.3.4 Bargraph .....................................................................32
5.4 Range Push Button: Manual Ranges .....................................33
5.5 Hz Push Button: Frequency Measurement.............................34
5.6 Peak/Smooth Push Button......................................................35
5.6.1 Smooth .......................................................................35
5.6.2 Peak............................................................................36
5.7 MIN/MAX Push Button: Recording Function...........................36
5.8 Vout – Analog Output..............................................................38
5.8.1 Output Level ...............................................................39
5.9 Summary of Accessible Functions..........................................39
5.10 Auto-Off Feature .....................................................................40
5.11 Troubleshooting ......................................................................40
6. MAINTENANCE .............................................................41
6.1 Cleaning..................................................................................41
6.2 Battery Test & Replacement ...................................................41
6.2.1 Battery Replacement ..................................................42
Repair and Calibration...........................................................................43
Technical and Sales Assistance ............................................................43
Limited Warranty ...................................................................................44
Warranty Repairs...................................................................................44

Harmonic Meter Model 721 3
CHAPTER 1
INTRODUCTION
Warning
These safety warnings are provided to ensure the safety of personnel and
proper operation of the instrument.
• Read this instruction manual completely before attempting to use or ser-
vice this instrument and follow all the safety information.
• Use caution on any circuit: Potentially high voltages and currents may be
present and may pose a shock hazard.
• The meter must not be operated beyond its specied operating range.
• Safety is the responsibility of the operator.
• Never open the back of the meter while connected to any circuit or input.
• Always make connections from the instrument to the circuit under test.
• Always inspect the instrument and accessory leads for serviceability prior
to use, and replace defective parts immediately.
• Do not use the meter or any test leads, BNC leads, connectors, probes or
clips if they look damaged.
• Never use the meter on electrical conductors rated above 600Vrms.
International Electrical Symbols
This symbol signies that the instrument is protected by double or
reinforced insulation. Use only specied replacement parts when
servicing the instrument.
This symbol on the instrument indicates a WARNING and that
the operator must refer to the user manual for instructions before
operating the instrument. In this manual, the symbol preceding
instructions indicates that if the instructions are not followed, bodily
injury, installation/sample and product damage may result.
Risk of electric shock. The voltage at the parts marked with this
symbol may be dangerous.

4 Harmonic Meter Model 721
1.1 Receiving Your Shipment
Upon receiving your shipment, make sure that the contents are consis-
tent with the packing list. Notify your distributor of any missing items. If
the equipment appears to be damaged, le a claim immediately with the
carrier and notify your distributor at once, giving a detailed description of
any damage. Save the damaged packing container to substantiate your
claim.
1.2 Ordering Information
Harmonic Meter Model 721............................................... Cat. #1208.52
Includes a 9V battery, two 5 ft (1.5m) leads, two test probes, two grip
probes, one insulated banana to BNC connector, a user manual and a
hard carrying case.

Harmonic Meter Model 721 5
CHAPTER 2
PRODUCT FEATURES
2.1 Description
The Harmonic Meter Model 721 combines the simplicity and familiarity
of digital clamp-ons with today’s critical information on power quality and
harmonics.
Operation is simple and direct, with no menus, calculations or complex
analyzer procedures. Select Amps or Volts on the rotary dial, connect, and
measure. The push of a button gives additional or more specic informa-
tion. You can troubleshoot and measure power quality with the ease of
using a digital clamp-on — simply, safely, and economically.
The Model 721 performs current and voltage measurements in True RMS,
and provides immediate readings of total harmonic distortion (%THD), dis-
tortion factor (%DF), crest factor (CF) and Peak of distorted currents and
complex voltages. It also gives the minimum, maximum, maximum Peak
and average measurement values so you can record for over 24 hours to
monitor daily uctuations. And, you can measure frequency (Hz) through
either the current or the voltage at any time.
In addition, the instrument’s analog output allows display of the current
waveforms on any oscilloscope or hand-held scope while measuring; or
the output may be used for loggers and recorders.
The Model 721 incorporates True RMS electronics and measurement
techniques to ensure correct and accurate readings on distorted wave-
forms. Use the Model 721 as a comprehensive tool for troubleshooting
as well as for daily measurements on circuits supplying traditional and
today’s nonlinear loads.
Beyond the absolute product ruggedness and overall design qualities
—the Model 721 is built with GE Lexan® and meets specic physical
standards — the instrument features a high level of safety. The Model 721
meets IEC 1010-1 Category III for 600 V ratings.

6 Harmonic Meter Model 721
The Model 721 is comfortable to hold, compact and easy to maneuver in
crowded breaker panels. The hooked jaw design facilitates clamping and
accommodates two 500 MCM conductors.
The AEMC Harmonic Meter Model 721 works as easily as a clamp-on mul-
timeter, while permitting True RMS voltage and current measurements.
The rotary switch selects the volt or ampere range and, beneath the large
LCD, ve push buttons provide direct access to additional key measure-
ment and power quality values.
The Model 721 high sensitivity accepts low input levels (300 mA and 300
mV) permitting power quality measurements on even low power or idling
equipment — an advantage not common to many instruments.

Harmonic Meter Model 721 7
2.2 Control Features
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1. Jaw assembly
Transformer jaws opens to 1.7" (43 mm)
Accepts two 500 MCM
2. Lever/Trigger
Opens or closes jaws
3. Display
Liquid crystal display, 9999 count
4. Min/Max
Selects Record mode for A, V, %THD, %DF, CF, Hz
Accesses the following values: Max, Min, AVG

8 Harmonic Meter Model 721
5. Peak/Smooth
Accesses the following modes:
• Smooth for 3-second averaging for easy readings on uctuating
signals.
• Peak measurement values (1 ms) for A and V
6. Hold/Data Hold
• Freezes last measured value on display
• Does not freeze bargraph or analog output
7. Rotary selection switch
OFF, Amps/Vout, Volts
8. Hz
Selects frequency measurement (A or V input)
9. THD
Accesses (in A or V) the following measurement modes:
• %THD (Total Harmonic Distortion referenced to the fundamental)
• %DF (Distortion Factor: THD referenced to RMS)
• CF (Crest Factor)
10. Range
Selects Auto Ranging or Manual Ranging measurement ranges
(A or V)
11. Voltage Jacks and Analog Output Vout
“COM” : black
“+” : red
2.3 Digital Display Features
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The combination digital/analog display gives measurements on a large
9999 count (3 digit) LCD display. A fast responding analog bargraph
display provides indications for trends or surges.
A Displayed when instrument is measuring TRMS amperes
V Displayed when instrument is measuring TRMS voltage

Harmonic Meter Model 721 9
Indicates that internal battery requires replacement
SMOOTH Indicates three second measurement averaging to
smooth uctuating signals
RANGE Displayed during manual range selection
HOLD Displayed when Hold function is activated
RECORD Blinks (1/second) during record mode
PAUSE Interrupts recording mode when Hold is activated in the
Record Mode
MAX Displays maximum measurement value
MIN Displays minimum measurement value
AVG Displays average measurement value
%THD % Total Harmonic Distortion
%DF % Distortion Factor
CF Crest Factor
PEAK Peak (1 ms) measurement (MAX Peak is available in
the recording mode)
Auto-Off feature disabled
Bargraph Analog bargraph for trend measurements A or V and
remaining battery life at power-up
2.3.1 Display and Error Indications
OL-- Input overload: > 999.9 V peak or > 999.9 A peak
– – – Input signal below measurement range
Input exceeds safety, measurement or operating range. The warn-
ing triangle is accompanied by a beeping alarm. Discontinue mea-
surement and refer to the specic function and specication section
in user manual.
Please note that the warning triangle will also be displayed if the
input signals are too low, or if the fundamental signal is not 50 or
60Hz.