AEMC 3640 User Manual

26 Digital Ground Resistance Tester Model 3640 and 4610
Distance from Y to Ground Electrode
Resistance
Overlapping Effective
Resistance Areas
XY
Z
Ground
Electrode
Under Test
Auxiliary
Potential
Electrode
Auxiliary
Current
Electrode
Figure 13
Now consider Figure 14, where the X and Z electrodes are sufciently
spacedsothattheareasofeffectiveresistancedonotoverlap.Ifweplot
theresistance,measuredwendthatthemeasurementsleveloffwhen
Yisplacedat62%ofthedistancefromXtoZ,andthatthereadingson
eithersideoftheinitialYsettingaremostlikelytobewithintheestablished
toleranceband.Thistolerancebandisdenedbytheuserandexpressed
asapercentoftheinitialreading:±2%,±5%,±10%,etc.
Resistance
Distance from Y to Ground Electrode
Effective
Resistance
Areas Do
Not Overlap
XY
Z
Ground
Electrode
Under Test
Auxiliary
Potential
Electrode
Auxiliary
Current
Electrode
D
62% of D
38% of D
Resistance of
Auxiliary Current
Electrode
Resistance of Earth Electrode
Figure 14

AEMC 3640 Specifications

General

Brand	AEMC
Model	3640
Category	Test Equipment
Language	English