LEM LH41 User manual

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International Electrical Symbols
Caution! Refer to this manual before using the meter
Meter is protected by Reinforced or Double Insulation
CONTENTS Page
1 INTRODUCTION..................................... 2
2 SPECIFICATIONS .................................. 3
2.1 Electrical Data ...................................... 3
2.2 General Data ........................................ 3
3 OPERATING INSTRUCTIONS ............... 4
3.1 Switch On ............................................. 4
3.2 Zero Adjustment ................................... 4
3.3 Current Measurement ........................... 4
3.4 Data Hold............................................... 4
3.5 Auto Power Off...................................... 4
4 SAFETY .................................................. 5
5 BATTERY REPLACEMENT ................... 6
6 WARRANTY............................................ 6
7 OTHER PRODUCTS............................... 7
Issue 1. 05/99

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1. INTRODUCTION
The LH41 current clamp meter has been designed for
reliable and accurate non-intrusive measurement of DC
and AC currents using advanced Hall Effect technology.
Measurement features include:
•Non - intrusive AC and DC current measurement
•1mA resolution
•Average responding, RMS calibrated
•Autoranging/ Autozeroing
•Data Hold
•Low battery indicator
•Auto Power Off
HOLD
LH 41
AUTO
40A
ZERO OFF ACDC
Fig. 1

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2. SPECIFICATIONS
2.1 Electrical Data
(All accuracies stated at 23°C ± 1°C)
LH41
Measuring Range............... 0 - 40 A DC or AC pk
Autoranging........................ 4A / 40A
Resolution.......................... 1 mA in 4 A range
10 mA in 40 A range
Accuracy
Basic Accuracy .................. ± 1.3% rdg ± 5 digits
Temperature coefficient ..... ± 0.05% of rdg / °C
Frequency range................ DC in DC
40 Hz to 400 Hz in AC
Overload capacity.............. 150 A
Dielectric strength.............. 3.7kV RMS. 50 Hz 60s
(EN61010-2-032 Cat III, 300V Pollution Degree 2)
2.2 General Data
Operating temperature....... 0°C to +50°C
Storage temperature with
Battery removed................. - 20°C to + 60°C
Power supply ..................... 9 V, Alkaline battery
PP3, NEDA 1604 or
IEC6LR61
Battery life.......................... 15 hours dependant on
duty cycle
Display............................... 4000 count
Characters......................... 10 mm high
Mechanical
LH41
Dimensions........................ 184 x 71 x 31 mm
Max. jaw capacity............... 19 mm ø cable
Max. jaw opening............... 20 mm
Weight ............................... 235 g

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3. OPERATING INSTRUCTIONS
Refer to Fig. 1 for the main operating features of the
meter.
3.1 Switch On
Move the switch from the OFF / HOLD position to either
DC or AC to select the required mode of operation.
3.2 Zero Adjustment
When in DC mode the display zero may change due to
thermal shifts and other environmental conditions. An
auto zero adjustment is provided. Proceed as follows to
perform the adjustment:
•Ensure that the instrument is away from the current
carrying conductor and that the jaws are closed
during the adjustment cycle.
•Select the DC position of the power switch.
•Use the auto zero button to zero the display if
necessary.
The auto zero button can be used to null the effects of
the earth's magnetic field on DC measurements.
3.3 Current Measurement
Select as required the DC or AC measurement option
using the power switch.
If necessary adjust the DC display to read zero as
described in section 3.2. Clamp the jaws of the
instrument around the conductor ensuring a good
contact between the closing faces of the jaws.
Observe and take measurements as required. Positive
output indicates that the current flow is in the direction
shown by the arrow on the instrument.
3.4 Data Hold
To activate the data hold, turn the power switch to the
OFF / HOLD position. The data will be held on the
display for approximately 10 seconds.
3.5 Auto Power Off
The meter will power down automatically after
approximately 8 minutes of inactivity.

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4. SAFETY
This product conforms to the latest directives
concerning safety and electromagnetic compatibility.
•European Low Voltage Directives 73/23/EEC and
93/68/EEC
•European EMC Directives 89/336/EEC and
93/68/EEC
Safety Standards
BSEN61010-1: 1993. General Requirements.
Safety requirements for electrical equipment for
measurement, control and laboratory use.
BSEN61010-2-032: 1995. Particular requirements for
hand held current clamps for electrical measurement
and test.
EMC Standards
RF Susceptibility
EN50082-1: 1992 3V/m Residential, Commercial and
Light Industry
RF Emissions
EN50081-1: 1992 Residential, Commercial
and Light Industry
FCC Part 15 Class B
This product is designed to be safe under the following
conditions:
− indoor use
− altitude up to 2000m
− temperature 0°C to +50°C
− maximum relative humidity 80% for
temperatures up to 31°C decreasing linearly
to 40% relative humidity at 50°C.
Use of the meter on uninsulated conductors is limited
to 300V RMS or DC and frequencies below 1kHz.
This meter complies with the requirements of the above
safety standard for 300V Cat III Pollution degree 2
Safety in its use is the responsibility of the operator who
must be a suitably qualified or authorised person.
Users of this equipment and or their employees are
reminded that Health and Safety Legislation require
them to carry out valid risk assessments of all electrical
work so as to identify potential sources of electrical
danger and risk of electrical injury such as from
inadvertent short circuits.

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Do not use the instrument if any part of it appears to be
damaged or if a malfunction of the instrument is
suspected.
When using the instrument ensure that your fingers are
behind the protective barrier see Fig. 1
Clean the case periodically by wiping it with a damp
cloth and detergent. Do not use abrasive cleaners or
solvents. Do not immerse the instrument in liquids.
5. BATTERY REPLACEMENT
When the Low Battery symbol is illuminated in the
display the minimum operating battery voltage has
been reached. Refer to Fig.1. and use the following
procedure to replace the battery.
Unclamp the meter from the conductor, turn it off using
the OFF / Hold power switch. Loosen the captive
screw which secures the battery cover. Lift the cover
through 30°and pull it clear of the instrument body as
shown in Fig1. The battery is then accessible.
Replace the battery and re-fit the battery cover and
fasten the screw.
Replacement with other than the specified type of
battery will invalidate the warranty. Fit only Type 9 V
PP3, Alkaline (MN1604 ).
6. WARRANTY
Your LEM HEME clamp on current meter is guaranteed
for one year from the date of purchase against
defective material or workmanship. If the meter fails
during the warranty period, we shall at our discretion,
repair or replace it with a new or reconditioned unit
provided we are satisfied that the failure is due to
defective material or workmanship. To make a claim
under warranty, the meter should be returned to us,
postage prepaid, with a description of the defect. The
use of a battery, other than that specified invalidates
this warranty.
SAFETY WARNING
Before removing the battery cover,
make sure that the instrument is
remote from any live electrical circuit.

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Goods alleged by the buyer to be defective shall not
form the subject of any claim for injury, loss, damage,
or any expense howsoever incurred whether arising
directly or indirectly from such alleged defects other
than death or personal injury resulting from the seller‘s
negligence.
No condition is made or to be implied nor is any
warranty given or to be implied as to the life or wear of
goods supplied or that they will be suitable for any
particular purpose or for use under specific conditions,
notwithstanding that such purpose or conditions may be
made known to the seller.
7.OTHER PRODUCTS
The LEM group offer a wide range of non-invasive
transducers, probes and instrumentation for the
measurement and analysis of current, voltage and
power.
Since the introduction of the world’s first digital AC/DC
clamp-on ammeter in 1982, LEM HEME has continued
to provide innovative test and measurement solutions
encompassing current measurement from 5mA to
2000A.
LEM HEME policy is one of continuous product
improvement and the company
reserves the right to revise the above
specifications without notice.