AEMC GROUNDFLEX 6474 User Manual

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AEMC GROUNDFLEX 6474 User Manual Manual pdf 13 page image

GroundFlex™ Adapter Model 6474 116474To the Model 6472NOTE: To increase measurement sensitivity, we recommend when possible,wrapping a maximum number of turns (up to 4) around the structure.3. Set the INPUT SELECTION switch accordingly. You can measure the currentflowing through one GroundFlex™ sensor (1, 2, 3, or 4), or through severalsensors (1, 2 or 1, 2, 3), or through all of the sensors (1, 2, 3, 4).4. Select how many times the sensor is wrapped around the conductor to bemeasured (from 1 to 4 turns) using the SENSOR TURNS switch.5. Set the SENSITIVITY switch to the desired sensitivity: x1/10, x1, or x10. Thechoice of sensitivity depends on the expected current value. As a precaution,always start with the lowest sensitivity, x1/10, and increase it as needed.2.3.2 Making a Measurement (Resistance of Legs)1. Place auxiliary electrodes H (Z) and S (Y) on opposite sides of the pylon, asfar away as possible (100 - 150 ft) and, if possible, perpendicular to the high-voltage line (depth is not important). This will eliminate interference with themeasurement by stray voltages or currents induced under the high-voltageline.2. In order to avoid electromagnetic interference, it is best to unwind the fulllength of each cable from the reel, to keep the cables as far apart as possibleon the ground, taking care not to form loops, and to avoid placing the cablesnear or parallel to metallic conductors (cables, rails, fences, etc.). Effects ofinterference are measured in milli-ohms.3. Connect these auxiliary electrodes to terminals H (Z) and S (Y).4. The terminals ES (Xv) and E (X) must be connected to a conducting metallicpart of the pylon located above the GroundFlex™ sensors. This ensures mea-surement of the current flowing downward and towards the earth (otherwise,you would measure the current flowing upward, from the earth to the tip of thepylon).