Ideal 61920 Manuel D’Utilisation
5. Measurement Theory
This instrument can measure the earth resistance to earth in multi-earthed system. Let's regard earth resist-
ance under test as Rx, and the other earth resistances as R1, R2, …Rn.
ance under test as Rx, and the other earth resistances as R1, R2, …Rn.
Of these earth resistances, R1, R2, …Rn can be considered connected in parallel and can be regarded as a
combined resistance Rs. The Rs can be regarded small enough against Rx since combined resistance con-
sists of several resistances. Following is an equivalent circuit diagram of this scenario.
combined resistance Rs. The Rs can be regarded small enough against Rx since combined resistance con-
sists of several resistances. Following is an equivalent circuit diagram of this scenario.
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ND 5417-1 61-920 Ins 9/26/06 8:49 AM Page 9