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   Before conducting high-voltage power tests, power workers need to perform grounding work. To measure the soil resistivity, they must first measure the grounding resistance, which requires a ground resistance tester. So how do you troubleshoot a ground resistance tester?

    1. The meter pointer does not move, including when checking battery voltage and during measurement with the ground resistance tester, the pointer does not move, but the "OK" light is on. The fault is caused by a burnt meter head or a disconnected connection between the meter head and the circuit board. Open the meter panel and manually move the pointer. If the pointer cannot return to zero automatically, the meter head is damaged by shock; otherwise, solder off the meter head and measure it with a multimeter in resistance mode. If it is open circuit, the meter head is burnt. Then use the multimeter in current/voltage mode to measure the original meter head connection points. Press the voltage check button on the ground resistance tester. If the multimeter shows a voltage, the instrument fault is caused by a damaged meter head, and it can be repaired by replacing the meter head. If the meter head is intact, open the instrument casing and check the meter head wiring; if disconnected, reconnect it.

   Such faults are usually caused by excessive vibration during use or transportation. Therefore, this instrument should be protected from shock during use and transportation to avoid unnecessary damage.

     2. The battery voltage is normal but grounding resistance measurement cannot be performed. This fault is usually caused by problems in the switching power supply, AC/DC conversion, and constant current output section. Use a frequency counter to measure the C port. If there is no 820Hz AC output, check this part of the circuit step by step, from the output transformer, switching transistor, oscillator circuit, etc., to find the faulty part and replace it with new components to repair.

    3. The battery voltage is normal but when measuring grounding resistance, the measurement data is inaccurate with large errors. This fault is usually caused by problems in the detection signal filtering and calibration circuit. A common cause is damage to the filter inductor T1; replacing the T1 inductor can fix it.

    4. When measuring with the ground resistance tester, the measurement data fluctuates, sometimes accurate and sometimes not. This phenomenon usually indicates no fault in the ground resistance tester; the problem lies in poor connections between the resistance tester and the ground stakes (auxiliary electrodes) and the tested grounding body. Common issues include broken wires or loose connections at the joints of the three connecting wires, leading to poor conductivity. If during use you find that the wires are disconnected from the metal pieces at both ends, be sure to solder them firmly with solder to ensure normal measurement operation of the instrument.

Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.