AEMC 6416 User Manual page 17

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PRINCIPLE OF OPERATION
Typically, a grounded distribution system can be simulated by the basic circuit
shown in Figure 3-1 or an equivalent to the diagram shown in Figure 3-2. If
voltage (V) is applied to any measured grounding electrode Rx through a
following equation:
1
V
= Rx +
I 1
n
Ri
i=1
Therefore, V/I = Rx is established. If I is detected and measured with V kept
constant, the measured grounding electrode resistance Rx can be obtained.
constant voltage oscillator. The resulting current is then sensed by a detection
commercial frequency (50/60 Hz) and high-frequency noise.
Example: If clamped around any grounding electrode in a multi-grounded
system, the measured value of the electrode under test will be the resistance
of that particular rod in series with the equivalent parallel resistance value that
the rest of the multi-grounded system represents. If an electrical system had
in series with the equivalent parallel resistance of the other 100 electrodes or 0.2
Clamp-on Ground Resistance Tester Model 6416
www.
Rx »
where, usually
.com
1
1
n
Ri
i=1
17
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