09,22,2026 16 views
Grounding resistance testerIt is a portable grounding resistance measuring instrument equipped with necessary accessories for testing. The instrument is equipped with two clamps, voltage clamp and current clamp. The voltage clamp excites an induced potential E in the tested circuit and generates a current I in the tested circuit. The instrument can measure the value of I through the current clamp. By measuring E and I, the value of R can be obtained using Ohm's law: R=E/I.
The specific testing method on site is as follows:
(1) When measuring the grounding resistance at the E-E terminals, short-circuit with a chrome plated copper plate and connect it to a 5-meter-long pure copper wire provided with the instrument. Connect the other end of the wire to the grounding body test point to be tested. When measuring the resistance of the shielding body, the chrome plated copper plate should be loosened, one E terminal should be connected to the grounding body, and the other E terminal should be connected to the shielding.
(2) The P-pillar is connected to a 20m pure copper wire that comes with the instrument, and the other end of the wire is connected to a pin.
(3) The C-pillar is connected to a 40m pure copper wire that comes with the instrument, and the other end of the wire is connected to pin 2.
The current technical requirements for grounding resistance tester testing
(1) The grounding resistance tester should be placed 1-3 meters away from the testing point, and should be placed steadily for easy operation.
(2) Each terminal post of the connector must have good contact and a secure connection.
(3) Two grounding electrode pins should be set at positions 20m and 40m away from the tested grounding body respectively; If two pins are connected by a straight line or wire, the grounding body to be tested should be basically on this straight line.
(4) Do not use other wires to replace the 5m, 20m, and 40m long pure copper wires provided with the instrument configuration.
(5) If the grounding resistance tester is taken as the center, the minimum angle between the two pins and the tester should not be less than 120 °, and they should not be set in the same direction.
(6) The soil for setting the two pins must be solid and cannot be placed on mud, backfill soil, tree roots, grass, or other locations.
(7) The grounding resistance test can only be conducted after 7 consecutive sunny days after rain.
(8) The grounding body to be tested should first undergo rust removal and other treatments to ensure reliable electrical connection.
Precautions for operating the grounding resistance tester
(1) The measurement of grounding resistance value should only be started after the tester is set up to meet the specifications.
(2) Before measurement, the grounding resistance knob should be turned to the maximum gear, i.e. x10 gear, and the knob for adjusting the grounding resistance value should be placed in the 6-7 Ω position.
(3) Slowly rotate the handle. If the pointer of the flow meter quickly deviates to the right from the 0 balance point in the middle, it indicates that the original range gear selection is too large. You can select the gear to x1. If the deviation direction is the same as before, you can select the gear to x01.
(4) After selection through step (3), slowly rotate the handle, and the pointer of the current meter shifts to the right from the 0 balance point, which indicates that the grounding resistance value is still too large. While slowly rotating the handle, the grounding resistance knob should slowly rotate clockwise. When the pointer of the current meter returns to 0, gradually accelerate the rotation speed of the handle, so that the handle speed reaches 120 rpm. At this time, the resistance value indicated by the grounding resistance multiplied by the multiple of the gear is the grounding resistance value of the grounding body. If the pointer of the current meter slowly deviates to the left, it indicates that the resistance value of the grounding resistance knob is lower than the actual grounding resistance value. It can be slowly rotated counterclockwise to increase the instrument resistance indication value.
(5) If the pointer of the flow meter does not jump steadily when the handle is slowly rotated, it indicates that the soil on the ground where the two grounding pins are set is not dense or there is poor contact at a certain joint contact point. At this time, the ground or each joint where the two pins are set should be rechecked.
(6) When measuring the grounding resistance of a static pressure pile with a grounding resistance meter, it is normal for the pointer of the current meter to have a slight left and right swing at the 0 point.
(7) When the pointer of the flow meter slowly moves to the zero balance point, the handle of the instrument generator can be accelerated, and the rated speed of the handle is 120 revolutions per minute. It is forbidden to accelerate the rotation speed of the handle when the pointer of the current meter still has a large deflection.
(8) The resistance level of the measuring instrument should be placed in the maximum position, i.e. x10 level, after use. Organize the three test wires that come with the instrument configuration, clean the dirt on the two pins, and place them safely.
