HT GroundTest M71 Скачать руководство пользователя страница 11 | Manualshive

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HT GroundTest M71 Скачать руководство пользователя страница 11

GroundTest

M71

EN – 10

4.4.2. EARTH 2W- Measurement procedure

CAUTION

The instrument can be used for voltage and current measurements on
installations with overvoltage category equal to CAT III 240V to earth and
maximum voltage of 415V between inputs. Do not connect the instrument to
installations whose voltages exceed the limits indicated in this manual.
Exceeding such limits may cause electric shock to the user and damage the
instrument.

Fig. 3: Example of instrument's wiring for two-wire earth measurement

Fig. 4: Example of instrument's wiring for 2-wire earth measurement (only for TT systems).



Whenever it is not possible to drive rods into the ground to take a three-wire

measurement (i.e. In historical centres) it is possible to use the simplified two-wire
method which gives an excess value for the sake of safety



To carry out the test a suitable auxiliary rod is necessary; a rod is defined “suitable”

when its earth resistance is negligible and is independent of the earth installation under
test



In Fig. 3 a lamp post is used as auxiliary rod. However a water pipe or any metal body

driven into the ground is suitable provided that the above mentions requirements are
met



Only in case of a TT system a neutral conductor can be used as auxiliary earth rod

(see Fig. 4).

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Содержание GroundTest M71

Страница 1: ... Copyright HT ITALIA 2016 Release EN 2 00 10 05 2016 ENGLISH User manual ...

Страница 2: ...TH 2W Measurement procedure 10 4 4 3 Message description for EARTH 2W measurement 12 4 5 EARTH 3W Three wire earth resistance measurement 13 4 5 1 EARTH 3W Zero setting of cables 13 4 5 2 EARTH 3W Measurement procedure 15 4 5 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 ...

Страница 3: ...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 pl...

Страница 4: ... 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 Wh...

Страница 5: ...ples 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...

Страница 6: ... 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 d...

Страница 7: ... Instrument s front panel 4 2 FUNCTION KEYS DESCRIPTION ON OFF Key to switch on and off the instrument CAL key to effect zero setting of cables under modes EARTH 2W e EARTH 3W 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 ...

Страница 8: ...tes after last pressure of keys To resume operation turn on the instrument pressing the start key 4 3 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 electrica...

Страница 9: ... cells Fig 2 Instrument s wiring for zero setting of cables under mode EARTH 2W 1 Press the instrument s start key 2 Select function EARTH 2W pressing the left arrow key 3 Connect the red cable the blue cable and the green cable to the corresponding instrument s input terminals The instrument shall keep the same operating features during all measurement stages Any cable extension or replacement as...

Страница 10: ...g the positive outcome for zero setting and displays again the initial screen by the symbol CAL Symbol CAL indicates that the instrument was calibrated this symbol is displayed for each subsequent measurement even though the instrument is switched off and on again 8 If during cables zero setting the value measured is higher than 2 the instrument interrupts such setting procedure removes the previo...

Страница 11: ...ent s wiring for 2 wire earth measurement only for TT systems Whenever it is not possible to drive rods into the ground to take a three wire measurement i e In historical centres it is possible to use the simplified two wire method which gives an excess value for the sake of safety To carry out the test a suitable auxiliary rod is necessary a rod is defined suitable when its earth resistance is ne...

Страница 12: ... is assumed to be affected by electric noise press the AUTO key to select the corresponding mode 4 Connect the red cable and the green cable into the corresponding instrument s input terminals 5 Connect the crocodiles to the test leads 6 When necessary symbol CAL missing or use of a new set of cables carry out zero setting of cable resistance see 4 4 1 7 Connect the instrument s terminals to the c...

Страница 13: ...emits a long sound tone indicating an anomalous condition then displays the initial screen again This message indicates that the measured resistance is lower than that of measuring cables and that a further zero setting procedure is to be carried out 4 When measuring if terminals voltage is higher than 6V the instrument does not effect the test A long sound tone is emitted indicating an anomalous ...

Страница 14: ...he instrument s start key 2 Select function EARTH 3W pressing the right arrow key 3 Connect the red cable the blue cable and the green cable to the corresponding instrument s input terminals The instrument shall keep the same operating features during all measurement stages Any cable extension or replacement as well as additional crocodiles may nullify previous zero setting so requiring to repeat ...

Страница 15: ...bol CAL Symbol CAL indicates that the instrument was calibrated this symbol is displayed for each subsequent measurement even though the instrument is switched off and on again 8 If during cables zero setting the value measured is higher than 0 3 the instrument interrupts such setting procedure removes the previous offset value and does not display the symbol CAL until a cables zero setting is suc...

Страница 16: ...ace the ampere metric probe terminal H blue wire at a distance equal to five times the diagonal of the earth installation and the volt metric probe terminal S red wire at a distance equal to about 2 5 times the diagonal of the earth installation For large sized installations place the ampere metric probe terminal H blue wire at a distance equal to the diagonal of the earth installation and the vol...

Страница 17: ...Connect the crocodiles to the test leads 6 When necessary symbol CAL missing or use of a new set of cables carry out zero setting of cable resistance see 4 5 1 7 Connect the instrument s terminals to the circuit under test see Fig 6 8 Press GO key to start measurement 9 Display example of earth resistance and disruptive voltage measured values Should disruptive voltage have been higher than 0 5V i...

Страница 18: ...emits a long sound tone indicating an anomalous condition then displays the initial screen again This message indicates that the measured resistance is lower than that of measuring cables and that a further zero setting procedure is to be carried out 4 When measuring if terminals voltage is higher than 6V the instrument does not effect the test A long sound tone is emitted indicating an anomalous ...

Страница 19: ...wires as well as their integrity If the problem still exists connect two or more auxiliary rods in parallel and pour some water around the rods in order to make a better ampere metric probe that is the ground rod connected to the blue wire 8 If the ampere and volt metric circuits terminal S and H show a too high resistance value the side message is displayed Check connection of blue red and green ...

Страница 20: ...ation shall be carried out by qualified people only Before replacing batteries disconnect test leads from the circuit under test to avoid electric shock 1 Disconnect all cables from input terminals 2 Turn off the meter pressing ON OFF key 3 Remove battery compartment cover 4 Remove all batteries and replace them with 4 units having the same features see 6 1 2 keeping to the indicated polarity sign...

Страница 21: ...ding to IEC EN61557 1 Earth Resistance measurement Range Resolution Accuracy Disturbance 3Vrms 3Vrms Disturbance 6Vrms AUTO mode triggered 0 01 19 99 0 01 2 rdg 3dgt 4 rdg 10dgt 20 0 199 9 0 1 200 1999 1 2 00 19 99k 0 01k 20 0 49 9k 0 1k 3rdg 3dgt 6 rdg 10dgt Measurement frequency 110Hz 1Hz Test current 12mA Open circuit voltage 25Vrms Resistance values of the voltmetric Rp and ampermetric probes ...

Страница 22: ... V alkaline batteries type AA LR6 Low battery indication symbol Errore Non si possono creare oggetti dalla modifica di codici di campo is displayed Battery life approx 500 measurements Auto Power OFF after 5 minutes of idleness Display LCD 53mm x 53mm 2x2inches 6 2 ENVIRONMENT 6 2 1 Environmental conditions Reference temperature 23 C 5 C 73 F 41 F Operating temperature 0 40 C 32 F 104 F Relative h...

Страница 23: ...g Any repair that might be necessary as a consequence of service actions carried out by unauthorised personnel Any change to the instrument carried out without the explicit authorisation of the manufacturer Use not provided by the instrument specifications or in the instruction manual The content of this manual cannot be reproduced in any form whatsoever without the manufacturer s authorization Ou...

Страница 24: ...ing time test of the RCDs A AC RCDs S A AC see Ia Tripping current in 5s of the RCD rated tripping current of the RCD in case of RCD S 2 I n 50 Safety limit voltage reduced down to 25V in special environments If the installation is protected by an RCD the measurement shall be effected upstream or downstream the RCD short circuiting it to avoid its tripping These methods even though not presently p...

Страница 25: ...of the area limiting the earth installation Place the voltage probe at approximately half way between the earth rod and the current probe finally measure voltage between both of them Fig 7 Measurement of earth resistance for small sized earth rods Use several rods in parallel and moisten the surrouding ground if the instrument does not manage to supply the current necessary to perform the test due...

Страница 26: ...way between the rod and the current probe later moving the probe to both the earth rod and the current probe Fig 8 Earth resistance measurement for medium and large sized earth rods The measuring method allows to define the specific resistance till the depth corresponding approximately to the distance a between two rods If you increase the distance a you can detect deeper ground layers and check t...

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