KPS TL300 Manual De Instrucciones página 31

(2) Measurement of earth voltage.
Earth voltage measurement should be done before measurement of earth resistance to check the amount of earth
voltage, as voltage more than 10 V is likely to cause larger error in the measurement of earth resistance. In this case, cut
the measured object from the power supply and wait until the earth voltage drop for another measurement.
(3) Measurement of earth resistance
Rotate the switch to 2 POL position, press down the key of MEASURE to start the measurement, with the key
LED turned on and glittering. When the measurement comes to the end automatically, the buzzer will give a sound, the
key LED will go off and the data will be held automatically.
Attention: ＞LIMIT4000Ω displayed on LCD warns that the auxiliary earth resistance of the auxiliary earth
rods is so high that the current can not flow across the meter. Check if the test leads become loose and the amount
of the earth resistance of the auxiliary earth rods.
(4) Value measured
Re, value of the earth resistance measured by Bi-pole method, equals the sum of re, the earth resistance of earth
rods, and RX, the real earth resistance of the object measured; therefore, RX=Re-re, meaning that the real resistance of
the object measured equals Re minus re.
4.3 Measurement of the resistance by Tri-pole method
Potential Drop Method is used by the meter for the measurement of the earth resistance. Particularly, RX, the earth
resistance is figured out by first allowing I, the rated current, to flow between E, the object measured (the earth rods) and
C, the current pole, then measuring V, the potential difference between E and P, the voltage pole.
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