AEMC instruments 6422, Руководство пользователя

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Ground Resistance Testers Models 6422 & 6424 23
2.3.1.1 Position of the Auxiliary Electrodes in Measurements
The goal in precisely measuring the resistance to ground is to place the auxiliary
current electrode H far enough from the ground electrode under test so that the
auxiliary potential electrode S will be outside of the effective resistance areas of
both the ground electrode and the auxiliary current electrode. The best way to
find out if the auxiliary potential rod S is outside the effective resistance areas is
to move it between E and H and to take a reading at each location. If the auxiliary
potential rod S is in an effective resistance area (or in both if they overlap),
by displacing it, the readings taken will vary noticeably in value. Under these
conditions, no exact value for the resistance to ground may be determined.
On the other hand, if the auxiliary potential rod S is located outside the effective
resistance areas, as S is moved back and forth the reading variation is minimal.
The readings taken should be relatively close to each other, and are the best
values for the resistance to ground of the ground E. The readings should be
plotted to ensure that they lie in a “plateau” region as shown below.