AEMC 450.100, Руководство пользователя

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Digital Ground Resistance Tester Model 4500
• Disconnect the shorting strip from the X and Xv terminals.
• Arrange the electrodes in a straight line. Be sure that distances
between electrodes are identical: e.g. 3 meters between each
electrode (See Figure 18).
• The distance between poles is proportional to the average depth
of the soil sample you wish to make.
• The electrodes should be placed at a depth of approximately 6"
(0.15m), so that the depth is approximately 1/20th of the distance
between electrodes.
• Use leads to connect the X, Xv, Y, and Z electrodes to the respec -
tive terminals on the Digital Ground Resistance Tester.
• It is preferable to place the selector in a range position which
varies inversely in relation to the distance identified as “A”; in
other words, the farther apart the four electrodes, the lower the
test current should be.
• Press the “TEST” button.
• Read the resistance level (R) indicated on the display.
• In the event of difficulties in performing measurements, consult
the previous instructions concerning ground resistance measure-
ments.
• Apply the following formula in order to determine resistivity ( ρ ):
ρ = 2 π x 225 Ω x 3m
ρ = 4350 Ω m
Example: After inspection, the area to be investigated has been narrowed
down to a plot of ground approximately 75 square feet (22.5m
2
). Assume
that you need to determine the resistivity at a depth of 15ft. (450cm). The
distance “A” between the electrodes must then be equivalent to the depth
at which average resistivity is to be determined (15 ft, or 450cm). Using
the more simplified Wenner formula ( ρ = 2 π AR), the electrode depth must
then be 1/20th of the electrode spacing or 8-7/8" (22.5cm).
Lay out the electrodes in a grid pattern (Figure 20) and connect to the
Model 4500 as shown in Figure 19. Proceed as follows:
• Remove the shorting strip between X and Xv
• Connect all four auxiliary rods