METREL MD 9272 User manual

Leakage Clamp TRMS Meter with
Power Function
MD 9272
Instruction manual
Bedienungsanleitung
Version 2.1.2; Code 20 752 381
KOMETEC Karl Oelkers e.K.
Mess- und Prüfgeräte · Shop
Mozartstr. 10 · D-88097 Eriskirch
T: 07541 / 955-1313 · F: 07541 / 955-1131
[email protected] · www.kometec.de

2
Distributor:
METREL d.d.
Ljubljanska cesta 77
1354 Horjul
Slovenia
E-mail: [e-mail]
web site: http://www.metrel.si/
Metrel GmbH
Mess und Prüftechnik
Orchideenstrasse 24
90542 Eckental -Brand
Germany
E-mail: [e-mail]
Internet: http://www.metrel.de/
Metrel UK
Test & Measurement
Unit 16, 1st Qtr Business Park Blenheim Road
Epsom
Surrey
KT19 9QN, GREAT BRITAINE-mail: [e-mail]
Internet: http://www.metrel.co.uk/
© 2015–2019 METREL
Mark on your equipment certifies that this equipment meets the requirements of all EU
(European Union) related regulations.
No part of this publication may be reproduced or utilized in any form or by any means without
permission in writing from METREL.

MD9272 Leakage Clamp TRMS Meter with Power Function
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Contents
English
1. General Instructions..................................................................................................4
2. Instrument Description..............................................................................................6
3. Description of Functions..........................................................................................11
4. Data Hold and Recording Mode..............................................................................18
5. Technical Specifications..........................................................................................19
6. Maintenance............................................................................................................22
Deutsch
1. Allgemeine Anweisungen........................................................................................24
2. Gerätebeschreibung................................................................................................26
3. Beschreibung der Funktionen .................................................................................31
4. Datenspeicherungsmodus ......................................................................................38
5. Technische Daten...................................................................................................39
6. Wartung ..................................................................................................................44
Slovensko
1. Splošna navodila.....................................................................................................46
2. Opis instrumenta.....................................................................................................48
3. Opis funkcij..............................................................................................................52
4. Načini zadrževanja podatkov ..................................................................................58
5. Tehnični podatki......................................................................................................59
6. Vzdrževanje ............................................................................................................62
7. Garancijska izjava...................................................................................................63

MD9272 Leakage Clamp TRMS Meter with Power Function General Instructions
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1.General Instructions
This instrument has been designed in accordance with IEC 61010 series standards that
regulate safety requirements for the electronic measuring equipment and current
measuring clamps. The user manual shall be read carefully in order to get the best
results from this equipment. Safety instructions shall always be followed.
Safety measures
General
•If the clamp-meter is used in a manner not specified in this user’s manual, the
protection provided by the equipment may be impaired!
•This equipment can be used to carry out measurements in the CAT.III1600V
environment.
•When using this clamp meter, the user should comply with all the safety
measures regarding:
- Protection against the electric current hazards.
- Protection of the clamp A-meter against incorrect use.
- Protection against electric shock hazard.
•For operator security, only the test probes supplied with the instrument shall be
used.
Do not use the clamp-meter and its accessories if any damage is detected!
During use
•Before carrying out any measurements, the instrument shall be warmed up for at
least 30 seconds.
•If the clamp-meter is used near any high level noise source, the screen might
become unstable or there may appear errors in display.
•The maximum limits of the input value shown in the technical specification tables
shall not be exceeded in order to avoid damage to the equipment.
•The rotary switch shall be in the correct position before starting a new
measurement.
•Exercise extreme caution when working near bare conductors or bus-bars. Any
accidental contact with the bare conductor may cause an electric shock.
•Work carefully with voltages higher than 60 VDC. or 30 VACrms to avoid a risk of
electric shock.
•The test probe(s) shall be disconnected from the circuit that is being tested
before changing the function.
•During measurement fingers shall always be kept behind the protection guard
(check point 2 of this manual)
•The battery shall be changed when the symbol is shown in order to avoid
incorrect measurement readings.
(1): Measurement protective category III covers measurements performed in the building installation.
Examples are measurements on distribution boards, circuit-breakers, wiring, including cables, bus-bars,
junction boxes, switches, socket-outlets in the fixed installation, equipment for industrial use, and some
other equipment, for example, stationary motors with permanent connection to the fixed installation.

MD9272 Leakage Clamp TRMS Meter with Power Function General Instructions
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Symbols
The symbols used in this manual and in the equipment are as follows:
Warning: check the instruction manual. Any incorrect use may cause damage to the
equipment or its components.
Earth
Complies with European Union Directives.
This equipment has double insulation.
Allows use with dangerous voltage conductors.
Instructions
•Before opening the equipment, the instrument shall be disconnected from any
source of electricity supply and it shall be ensured that the operator is free from
static electricity, as this could damage or destroy the internal components.
•Before using this equipment it shall be checked for proper operation; by turning
the rotary switch to A or V position and verification of a double beep and the
display activity.
•Any adjustment, repair or maintenance work on the clamp A-meter must only be
carried out by a qualified person, always taking into account the instructions in
this manual.
•A “qualified person” means somebody familiar with the installation, construction
and operation of the equipment, and with the risks implied. This person should be
trained and authorized to charge and discharge energy from the circuits and the
equipment in accordance with established practice.
•When the equipment is open, some internal components can retain dangerous
power, even after the equipment has been disconnected from the mains or
battery electricity supply.
•In the case of abnormal operation and/or performance, the equipment shall not
be used until it has been repaired and verified.
•The battery shall be removed from the clamp-meter if it is not going to be used
for a long period, and shall not be stored at a high temperature or in a humid
environment.
WARNING
This equipment is designed according to EMC standards for portable measuring and
test instruments. Regardless, it is recommended to disconnect the test leads during
clamp measurements, as a high radiofrequency electromagnetic field might be present,
which can negatively affect the accuracy of the measurement.

MD9272 Leakage Clamp TRMS Meter with Power Function Instrument Description
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2.Instrument Description
Become familiar with the equipment
1 Transformer jaws
2 Protection ring
3 Jaw opening trigger
4 Function switch
5 Keypad
6 LCD display
7 Terminals
Transformer clamps
Capture alternating current flowing through the conductor. Direct current cannot be
measured.
Keyboard
The keyboard consists of four push buttons. Table 1 describes the function of each one.
1
2
3
5
4
6
7

MD9272 Leakage Clamp TRMS Meter with Power Function Instrument Description
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Table 1. Keyboard
Key
Use
Function
F –Function
Any position of the
rotary switch
Function selection key. Depending on the
rotary switch position, the functions will
vary (refer to chapter 3).
Pressing this button cycles through the
various functions.
Hz
A and V, in the
RMS function only
Pressed for more than 2 s, alternates the
second display information from THD to
Hz.
H –Hold
Any position of the
rotary switch in all
the functions
except in PEAK
function
When pressed the memory mode is
activated and the value on screen kept
from updating.
Pressed again, the MAX mode is
activated for the register of maximum
values.
Next pressed, the MIN mode is activated
for the register of minimum values.
Pressed again returns to the normal
mode.
Light
Any position of the
rotary switch, in all
the functions
With a long press of the key (more than 2
s) the LCD screen back illumination is
turned on. 30 s after any button was
pressed, it switches off automatically.
Auto
A and V, in the
RMS function only
Cycles through manual ranges until the
Autorange is active again.
+
A and V in the
harmonic
measurement
function
Increases the number of harmonics to be
measured.
AC/DC
V, in the RMS
function only
Alternates between VAC. and VDC
measurements.
-
A and V in the
harmonic
measurement
function
Decreases the number of harmonics to be
measured.
Table 2. Rotary switch positions
Position
Function
OFF
OFF position.
A
Measurement of AC current up to 100 A.
V
Measurement of AC or DC voltage up to 600 V.
W
Measurement of power of up to 60 kVA, with limit at 100 A
and 600 V.

MD9272 Leakage Clamp TRMS Meter with Power Function Instrument Description
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LCD Screen
Data hold indication.
Maximum reading indication.
Minimum reading indication.
PEAK
Peak function, this is the fast sampling for maximum value of the
measured quantity, whether voltage or current.
Measurement of the phase angle of the current in reference to the
voltage.
Indicates that the current is in front compared to the voltage.
Indicates that the current is behind compared to the voltage.
Indication of loss, possibly due to insulation defects, only in the mA
measurement mode.
Indication of loss, possibly due to insulation defects and
accumulation of non-linear loads, only in the mA measurement
mode.
Indication of loss, possibly due to a high accumulation of non-linear
loads, only in the mA measurement mode.
Indication that the measured magnitude is expressed as a true
effective value.
CF
Crest factor measurement function is active for the given mode (V or
A).
AC
AC input indication.
DC
DC input indication.
mA, A
Miliamperes, Amperes.
V
Volts.

MD9272 Leakage Clamp TRMS Meter with Power Function Instrument Description
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VAr, kVAr
Reactive Volt amperes, Reactive Kilovolt amperes. Reactive power
measuring units.
VA, kVA
Volt amperes, Kilovolt amperes. Apparent power measuring units.
W, kW
Watts, Kilowatts. Active power measuring units.
%
Measurement of a percent value.
THD
Total harmonic distortion ratio
PF
Power factor.
HARMONIC
Indication of the measured harmonic.
Hz
Hertz, frequency measurement unit.
Indication that range is selected automatically.
Full battery.
Medium battery.
Low battery.
Battery is close to be discharged
Input
Table 3 shows the information on input.
Table 3: Input
Input
Description
COM
Input received by the black test probe as common reference.
V
Input received by the red test probe for the voltage and power
measurements.
Measuring power Measuring current Measuring voltage

MD9272 Leakage Clamp TRMS Meter with Power Function Instrument Description
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Standby Mode
If the clamp-meter is not used for a period of 15 minutes, the screen will go blank and
the clamp-meter will go into standby mode. To wake the clamp-meter from standby
mode, the rotary switch needs to be turned to the OFF position and then back to the
function to reactive the screen.
Accessories
•Test probes
•Batteries (2 AA 1,5V batteries)
•Instruction manual
•Carrying Case

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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3.Description of Functions
Measuring mA, A and V
The following sections explain the functions available in the current (mA and A) and
voltage (V) measurement mode (positions of the rotary switch in mA, A and V). To
select the desired function the Fkey shall be pressed repeatedly. For current
measurements (mA, A), it is recommended to disconnect the test leads (see “Warning”
section).
TRMS value measurement
In this function, we can see the measurement of the effective value of the current or the
voltage together with a second reading: the THD (total harmonic distortion ratio) or the
frequency of measured signal. The THD is a ratio of the higher frequency components
in the signal to the essential component (at 50 Hz or 60 Hz) expressed in percentage. A
high THD value indicates high distortion of the measured signal whilst a 0%THD
indicates that the measured signal wavelength is a pure sinusoid.
In this mode data hold is possible as well as the registering the maximum and minimum
values using the Hkey.
Frequency measurement
In this function, the frequency of the measured signal is displayed. Press the Fbutton
for more than 2 s in the TRMS measurement mode to enter frequency measurement
mode. To return to THD, press the same button again during more than 2 s.

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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Intelligent loss analysis (mA measurement only)
The clamp A-meter includes an algorithm that determines the cause of the current loss.
This mode is enabled only when current is measured in the mA range and TRMS
measurement is selected. In the TRMS measurement function, one or two icons will be
shown on the screen informing of the possible reasons for the loss.
This icon indicates that the loss is possibly due to a defect in
the equipment insulation.
These two icons indicate that the loss may be partially due to
defects in the insulation and partially to the accumulation of
non-linear loads.
This icon indicates that a loss is possibly due to a high
accumulation of non-linear loads.
Harmonic analysis
The clamp-meter measures harmonic content of the signal up to 19th component,
displaying the effective value and the harmonic number. A harmonic is a multiple of the
network base frequency. If, for example, the 3rd harmonic is measured on a 50 Hz
network frequency, this means measuring the magnitude (current or voltage) of the 150
Hz component.
In this function, the measurement of the effective value of any harmonic in the range of
1 to 19 range is executed. Initially displayed is the harmonic 1, but this can be modified
using the +and -keys. The display shows the effective value together with the
harmonic number (to the bottom of the screen).
In this mode, data hold and registering of maximum and minimum values is possible by
using the Hkey.
Harmonic analysis (percentage values)
Harmonics can be measured (1 through to 19) as a percentage of the fundamental (the
1st) harmonic, also called the fundamental frequency. Initially the harmonic 1 is
displayed but this can be changed using the +and -keys. The display shows the

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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percent of effective value together with the harmonic number (at the bottom of the
screen).
In this mode data retention and registering of maximum and minimum values is possible
by using the Hkey.
Crest factor
Measures value of crest factor of the input signal. The crest factor is the ratio of the
peak and the effective (or TRMS) value of a waveform. For a sinusoidal wave the crest
value is 1.41. The greater the difference between the peak and efficient RMS value, the
higher the crest factor is.
In this mode, data hold and registering of maximum and minimum values is possible by
using the Hkey.

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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Peak hold
In this function, the peak value of the waveform is shown. The peak value is the highest
measured value of the signal waveform and is usually higher than the effective value
(also known as the TRMS value). E.g. for a perfect sinusoidal signal the peak value is
1.41 times the effective value. Peak hold is executed with a faster sampling rate than
other measurements, catching pulses as short as 25 µs.
DC measurement (Voltage only)
In this function, the DC value of the waveform is shown. This mode is entered by press
the AC/DC button in the TRMS measurement function screen. To change back to AC,
press the same button again.
Manual range selection
By pressing the Auto button, the range mode changes from autorange to the different
manual ranges available. This function can be used in V and A mode. When the
autorange is not active, the icon is off.

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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Measuring Power
In the following sections, the functions available in the power measuring mode (position
W of the rotary switch) will be explained. To select the desired function the Fkey must
be pressed repeatedly.
Active power measurement
In this function the measurement of active power together with the measurement of the
power factor are shown on the screen. If the load is inductive, the symbol will
appear on the screen and if the load is capacitive, the symbol will appear on
screen.
In this function, the position of the voltage terminals and the jaw is taken into account;
the red terminal should be connected to the line terminal and the jaw should be
connected so that the current flows toward load in the direction indicated on the jaw. In
this mode, data hold and registering of maximum and minimum values is possible by
using the Hkey.
Reactive Power Measurement
In this function the measurement of reactive power is shown together with the
measurement of the power factor. If the load is inductive, the symbol will appear
on the screen and if the load is capacitive, the symbol will appear on screen.

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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In this function, the position of the voltage terminals and the jaw is taken into account;
the red terminal should be connected to the line terminal and the jaw should be
connected so that the current flows toward load in the direction indicated on the jaw. In
this mode, data hold and registering of maximum and minimum values is possible by
using the Hkey.
Apparent Power Measurement
In this function the measurement of the apparent power together with the measurement
of the power factor are shown. If the load is inductive, the symbol will appear on
the screen and if the load is capacitive, the symbol will appear on screen.
In this mode data hold and registering of maximum and minimum values by using the H
key is possible.
Phase difference measurement
In this function the phase difference measurement between the voltage and the current
is shown in degrees. The position of the voltage terminals and the jaw should be taken
into account: the phase line should be connected to line (red) terminal and the jaw
should be connected so that the current flows towards the load in the direction indicated
on the jaw. If this is not the case the phase angle difference shown will not be correct.

MD9272 Leakage Clamp TRMS Meter with Power Function Description of Functions
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MD9272 Leakage Clamp TRMS Meter with Power Function Data Retention Mode
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4.Data Hold and Recording Mode
To access the data hold mode, press the Hkey. By pressing the key repeatedly the
HOLD, MAX and MIN modes can be selected. The three recording modes are available
in all the measuring functions except in the peak measurement.
HOLD Mode
In this mode, last measured value is frozen on the screen. The symbol also appears
on the screen.
MAX Mode
In this mode, the maximum value measured is shown since mode activation is
displayed. The symbol is on. Before using this function, the clamp-meter should
be connected properly (see section 3).
When recording the value, the difference between the peak value and the maximum
value should be taken into account: the maximum value holds the highest measured
value on the screen, whilst the peak value shows the highest absolute value of the
waveform.
MIN Mode
In this mode, the minimum measured value is shown on the screen. The symbol
will be shown. Before using this function, the clamp should be connected properly (see
section 3)

MD9272 Leakage Clamp TRMS Meter with Power Function Technical Specifications
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5.Technical Specifications
General specifications · Environment conditions:
Measurement Category –clamp-
meter
CAT III 600V
Measurement Category –Test
Lead
CAT III 600V
Maximum Current1
100 A
Pollution degree:
2
Altitude
< 2000 m
Operation temperature
0 ºC –40 ºC (<80 % H.R., <10 ºC without
condensation)
Storage temperature
10 ºC –60 ºC (<70 % H.R., extract batteries)
Temperature coefficient:
0.1 (of specified precision) / ºC (<18 º C or >28 º
C)
Functioning principle:
Sampling of signal at high speed
Data update on screen:
twice a second
Screen:
3 3/4 + 3 digits LCD screen
Range selection:
Automatic and manual selection
Over-range indication:
-0L- is shown on the LCD screen, fast beep
Polarity indication:
“-“ is shown automatically
E.M.C.:
Meets EN 61326-1:2013, EN 61326-2-2:2013
Safety:
Meets EN 61010-1:2010, EN 61010-2-32:2012,
EN 61010-2-033:2012, EN 61010-031:2015
Power supply:
3 V
Type of batteries:
2 x 1,5 V AA, alkaline batteries
Consumption:
5 mA average, depending on function.
Duration of the batteries:
200 - 400 h. (batteries 2000 mAh)
Dimensions:
185 mm x 62 mm x 42 mm
Weight:
Aprox. 210 g (without battery)
(1) This equipment cannot be exposed to currents above the limit

MD9272 Leakage Clamp TRMS Meter with Power Function Technical Specifications
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Measurement specifications
Current and voltage
Automatic ranging within the same function.
TRMS value
Function
Range
Resolution
Accuracy
mA,
A
40 mA
0.01 mA
± 0.8 % of reading ± 3 digits
400 mA
0.1 mA
± 0.8 % of reading ± 3 digits
4 A
0.001 A
± 0.8 % of reading ± 3 digits
40 A
0.01 A
± 1 % of reading ± 3 digits
80 A
0.1 A
± 1.2 % of reading ± 3 digits
100 A
0.1 A
± 5 % of reading
V
40 V
0.01 V
± 0.5 % of reading ± 4 digits
400 V
0.1 V
± 0.5 % of reading ± 2 digits
600 V
1 V
± 0.5 % of reading ± 2 digits
THD
0 … 99.9 %
0.1 %
± 2 % of reading ± 3 digits
100
… 999 %
1 %
± 2 % of reading ± 3 digits
Note: the specifications are valid for waveforms with fundamental frequency between 45
Hz and 65 Hz and crest factor < 3.
DC voltage
V
40 V
0.01 V
± 0.5 % of reading ± 4 digits
400 V
0.1 V
± 0.5 % of reading ± 2 digits
600 V
1 V
± 0.5 % of reading ± 2 digits
Frequency
Hz
45 - 500 Hz
0.1 Hz
± 0.05 % ± 1digit
Harmonics
N: harmonic component 2 ÷ 9th
Measuring range
Accuracy
IhN < 10 % IRange
± 0.15 % × Irange ± 3 digits
10 % IRange < IhN < 100 % IRange
± 1.5 % × IhN ± 3 digits
N: harmonic component 10 ÷ 19th
Measuring range
Accuracy
IhN < 10 % IRange
± 0.3 % × Irange ± 3 digits
10 % IRange < IhN < 100 % IRange
± 3 % × IhN ± 3 digits
IRange: Nominal clamp current (RMS)
IhN: measured current of Nth harmonic component
N: harmonic component
N: harmonic component 2 ÷ 9th
Measuring range
Accuracy
UhN < 3 % URange
± 0.1 % × Urange ± 2 digits