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M71
User Manual
26 pgs732.05 Kb0

HT instruments M71 User Manual

ENGLISH
User manual
Copyright HT ITALIA 2007 Release EN 1.01 - 21/02/2012
M71
1. SAFETY PRECAUTIONS AND PROCEDURES ......................................................... 2
1.1. Preliminary instructions ..................................................................................................... 3
1.2. During use ........................................................................................................................ 3
1.3. After use ........................................................................................................................... 3
1.4. Definition of measurement category (OVERVOLTAGE) .................................................. 4
2. GENERAL DESCRIPTION .......................................................................................... 5
3. PREPARING THE INSTRUMENT ............................................................................... 5
3.1. Initial check ....................................................................................................................... 5
3.2. Power supply .................................................................................................................... 5
3.3. Calibration ......................................................................................................................... 5
3.4. Storage ............................................................................................................................. 5
4. WORKING INSTRUCTIONS ....................................................................................... 6
4.1. Instrument description ...................................................................................................... 6
4.1.1. SWITCHING ON ............................................................................................................................. 7
4.1.2. AUTO POWER OFF ...................................................................................................................... 7
4.2. Auto mode ........................................................................................................................ 7
4.3. EARTH 2W:Two-wire earth resistance measurement ...................................................... 8
4.3.1. EARTH 2W- ZERO SETTING OF CABLES ........................................................................................ 8
4.3.2. EARTH 2W- MEASUREMENT PROCEDURE .................................................................................. 10
4.3.3. MESSAGE DESCRIPTION FOR EARTH 2W MEASUREMENT ............................................................ 12
4.4. EARTH 3W: Three wire earth resistance measurement ................................................. 13
4.4.1. EARTH 3W- ZERO SETTING OF CABLES ...................................................................................... 13
4.4.2. EARTH 3W- MEASUREMENT PROCEDURE .................................................................................. 15
4.4.3. MESSAGE DESCRIPTION FOR EARTH 3W MEASUREMENT ............................................................ 17
5. MAINTENANCE ........................................................................................................ 19
5.1. General ........................................................................................................................... 19
5.2. Battery replacement ........................................................................................................ 19
5.3. Cleaning .......................................................................................................................... 19
5.4. End of life ........................................................................................................................ 19
6. TECHNICAL SPECIFICATIONS ............................................................................... 20
6.1. Technical features .......................................................................................................... 20
6.1.1. SAFETY STANDARDS ................................................................................................................... 21
6.1.2. GENERAL FEATURES .................................................................................................................. 21
6.2. Environment .................................................................................................................... 21
6.2.1. ENVIRONMENTAL CONDITIONS ..................................................................................................... 21
6.3. Accessories .................................................................................................................... 21
7. SERVICE................................................................................................................... 22
7.1. Warranty terms ............................................................................................................... 22
7.2. After sales service .......................................................................................................... 22
8. PRACTICAL REPORTS FOR ELECTRICAL TESTS ................................................ 23
8.1. Earth resistance measurement in TT systems ............................................................... 23
8.2. Earth resistance measurement, volt ampere metric method .......................................... 24
EN – 1
M71
1. SAFETY PRECAUTIONS AND PROCEDURES
This instrument was designed in compliance with the IEC/EN61557-1 and IEC/EN61010-1 guidelines relative to electronic equipment.
For your own safety and to avoid damaging the instrument you are recommended to follow the procedures described in this manual and read
carefully all instructions preceded by this symbol .
Before and during measurements keep to the following instructions:
• Do not take voltage or current measurements in wet places
• Do not take measurements in the presence of explosive gas and combustibles or in
dusty places
• Avoid any contact with the circuit under test even though you are not taking any measurement
• Avoid any contact with exposed metal parts, unused measuring terminals, circuits etc.
• Do not take any measurement whenever anomalous conditions occur such as
deformations, breaks, leakages, blind display etc
• Pay utmost attention when taking measurements of voltage higher than 25V in special places (building yards, swimming pools, etc.) and higher than 50V in ordinary places due to the risk of electric shock.
The following symbols are used in this manual:
CAUTION: refer to the instruction manual. An improper use may damage the instrument or its components as well as endanger the user.
CAUTION
High voltage danger: risk of electric shock.
AC voltage or current
DC voltage
Double insulation.
EN – 2
M71
1.1. PRELIMINARY INSTRUCTIONS
• This instrument has been designed for use in environments with pollution degree
• It can be used for voltage and current measurements on electrical installations with
CAT III 240V to earth and maximum voltage of 415V between inputs
• The instrument can be used on electrical installations type TT, TN and IT industrial, civil, medical, zoo-technical both under ordinary conditions where contact voltage limit is 50V, and under special conditions where contact voltage limit is 25V
• You are recommended to respect the usual safety regulations aimed at protecting you against dangerous currents and protecting the instrument against improper use
• Only the original accessories supplied along with the instrument guarantee compliance with the safety standards in force. They must be in a good conditions and, if necessary, replaced with identical ones
• Do not test nor connect to any circuit exceeding the specified overload protection
• Do not take measurements under environmental conditions exceeding the limits
indicated in this manual
• Make sure that batteries are correctly installed.
1.2. DURING USE
You are recommended to read carefully the following instructions::
CAUTION
Failure to comply with warnings and instructions may damage the instrument and/or its components as well as injure the operator.
• When the instrument is connected to circuits never touch any unused terminal
• Do not measure in the presence of external voltages. Although the instrument is
protected, an excessive voltage may cause malfunction
• Avoid submitting the instrument to voltage while measuring (i.e. a test lead slipping off the measuring point accidentally touching an energized point).
CAUTION
If the “low battery” symbol is displayed during use interrupt testing, switch off the instrument and replace batteries following the procedure described in
§ 5.2.
1.3. AFTER USE
• Turn off the instrument pressing ON/OFF key after using it
• If you expect not to use the instrument for a long time remove batteries.
EN – 3
M71
1.4. DEFINITION OF MEASUREMENT CATEGORY (OVERVOLTAGE)
Standards IEC/EN61010-1 (Safety requirements for electrical equipment for measurement, control and laboratory use, Part 1: General requirements) define what a measurement category (usually called “overvoltage category”) is. At § 6.7.4: Measuring circuits it quotes:
Circuits are divided into the following measurement categories:
• Measurement category IV is for measurements performed at the source of a low- voltage installation.
Examples are electricity meters and measurements on primary excess current protection devices and ripple control units.
• Measurement category III is for measurements performed in the building installations.
Examples are measurements on distribution boards, circuit breakers, wiring, including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installations, and equipment for industrial use as well as some other equipment, for example, stationary motors with permanent connection to fixed installations.
• Measurement category II is for measurements performed on circuits directly connected to the low voltage installations.
Examples are measurements on household appliances, portable tools and similar equipment.
• Measurement category I is for measurements performed on circuits not directly connected to MAINS.
Examples are measurements on circuits not derived from MAINS, and specially protected (internally) MAINS-derived circuits. In the latter case, transient stresses are variable; for this reason, the norm requires that the transient withstand capability of the equipment is made known to the user.
EN – 4
M71
2. GENERAL DESCRIPTION
This instrument, whether used according to the instructions given in this manual, will grant you accurate and reliable measurements. Thanks to a development of newest conception assuring double insulation and overvoltage category III you will enjoy the highest safety.
The instrument is capable of performing the following measurements:
EARTH 2W: Two-wire earth resistance measurement . EARTH 3W: Three-wire earth resistance measurement.
3. PREPARING THE INSTRUMENT
3.1. INITIAL CHECK
This instrument was checked both mechanically and electrically prior to shipment. All possible cares and precautions were taken to let you receive the instrument under perfect conditions.
Notwithstanding we suggest you to check it rapidly to check any damage which may have occurred during transport. Should it be the case please contact immediately the manufacturer HT or your local dealer.
Make sure that all standard accessories mentioned in the enclosed packing list are included in the packaging. In case of discrepancies contact your dealer.
Should you have to return back the instrument for any reason please follow the instructions mentioned in § 7.
3.2. POWER SUPPLY
The instrument is powered by batteries (see § 6.1.2). When batteries are low, the low battery indication is displayed. To replace/insert batteries follow the instructions indicated in § 5.2
3.3. CALIBRATION
The instrument complies with the technical specifications contained in this manual and such compliance is guaranteed for 12 months from purchase date.
3.4. STORAGE
After a period of storage under extreme environmental conditions exceeding the limits let the instrument resume normal measuring conditions before using it (see § 6.2.1).
EN – 5
M71
4. WORKING INSTRUCTIONS
4.1. INSTRUMENT DESCRIPTION
CAPTION:
1. Inputs
2. Display
3. ON/OFF key
4. CAL key
5. Switch of test mode
6. AUTO key
7. GO key
CAL
AUTO
GO
Fig. 1: Instrument's front panel
Key to switch on and off the instrument.
CAL key to effect zero setting of cables under modes EARTH-2W e EARTH­3W.
AUTO key to start/stop the mode detecting critical measuring conditions (high electric noise) with automatic updating of measuring time.
GO key to start measurement.
Switch to select measuring mode.
EN – 6
M71
4.1.1. Switching on
When switching on the instrument a brief tone is audible along with display of all segments for about one second. Subsequently the last firmware version as well as the last selected measuring mode are displayed before switching off.
4.1.2. Auto Power OFF
To save battery life the instrument automatically turns off 5 minutes after last pressure of keys. To resume operation turn on the instrument pressing the start key.
4.2. AUTO MODE
Starting up this mode the instrument will alter the measuring time to fit to the testing conditions detected.
CAUTION
• If the instrument detects an “electrical noise” lower than 0.5Vrms before testing, it will adopt the “standard” test duration (approx. 13 s)
• If the instrument detects an “electrical noise” higher than 0.5Vrms before testing, it will extend the test duration (approx. 25s) to increase the outcome stability even under severe measuring conditions
EN – 7
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