MI 3290 Earth Analyser Tests and Measurements
92
11.3.3 Schlumberger method Measurement
Place the two earth probes (ES and S) at a distance d from one another and place the
second two earth probes (E and H) at a distance a from ES and S probes. All probes must
be placed on a straight line and to a depth of b, considering the condition b << a,d. Distance
d must be between 0.1 m and 49.9 m and the distance a must be a>2*d. Connect the cables
to the probes, then to terminals H, S, ES, and E.
E a r t h
H
S
ES
E
MI 3290 Earth Analyser
a
G
V
A
S - probe
ES - probe
E - probe
H - probe
d a
b
Figure 11.46: Schlumberger method example
Schlumberger method with unequal distances between test probes:
where:
R
e
..................................... Measured earth resistance in 4-pole method
a
....................................... Distance between earth probes (E, ES) and (H, S)
d
....................................... Distance between earth probes (S, ES)
b
....................................... Depth of earth probes
π ....................................... Number π is a mathematical constant (3.14159)
To Next Page
Loading...
