| 摘要 |
The "Ground Resistance Test" provides a circuit and test setup for measuring the resistance of earth grounds. The ground resistance test uses the central office battery from a working telephone pair to source current into the "Tested Ground". First the quiescent voltage (Vo) on the Tested Ground with respect to a removable ground rod is measured and recorded. Then the ring side of a working pair is connected to the Tested Ground and the office battery draws current (I) from the Tested Ground. The voltage (Vi) on the Tested Ground with respect to the removable ground rod is again measured with dc current flowing. Voltage fall Vf is computed as (Vi-Vo). The ohms (R) of the Tested Ground is then displayed as R=Vf/I. In the event that central office battery is unavailable, the Ground Resistance Tester will provide an optional current rod and internal battery source.
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