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Use and precautions of grounding resistance tester

time:2020/8/11   source:华天电力  reading:606 time

Grounding resistance tester use method and matters needing attention

How to use the ground resistance tester:

The first step is to place the equipment at different positions of the development level, check whether the current meter pointer information is on the center line, or adjust the center line to zero.

In the second step, the "magnification" is set at the maximum magnification, the generator crank rotates slowly, while rotating the "carousel measurement", the center line of the galvanometer pointer.

Earth Resistance Tester.png

In the third step, when the pointer of the galvanometer is close to a balance, accelerate the crank of the generator so that it can reach more than 120 revolutions per minute. At the same time, adjust the "measurement dial" to make the pointer point to the center line. If the “scale” reading is less than 1, the magnification should be set to a smaller multiple, and the “measurement scale” should be adjusted to obtain the correct reading. Finally, when filling out this record, the additionality test points and the sequence of the test points should be planned Numbering.

Pay attention to safety matters for the grounding resistance tester:

The grounding wire should be disconnected from the protective equipment to ensure the accuracy of the measurement results. When it rains and the soil absorbs too much water, the measurement cannot be controlled when the climate, temperature, pressure, etc. change drastically, and there should be no stray current and polarized soil near the measurement pole. The probe is from underground water metal pipes, cables, and the larger main body of the railway, where the current is greater than 10m, and the voltage should be greater than 50 meters. If the metal body is not connected to the ground network, the distance can be shortened by 1/2 to 1/3.

Note that insert the current electrode into a soil to make the ground rod at zero potential. Use insulated cables to avoid leakage. When testing different parts of the body, we must not have electrolytes and rotted bodies to avoid illusions. The soil resistivity should be selected during the test, such as early winter or dry summer.

At any time, to check the accuracy of the instrument (measurement unit, used to determine once a year), when the sensitivity of the galvanometer is too high, the voltage potential probe can be inserted into the shallow lever of the soil. When the sensitivity of the galvanometer is insufficient, the moisture In the probe.

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