HT2302 Digital Ground Earth Resistance Tester with LCD Backlight for Electric Power Communication Laboratory Item Type: Ground Resistance Meter Material: ABS Model: HT2302 Battery: 1.5V AAA x 8 Battery (Battery Not Included) Purpose: Ground resistance tester is used to measure the ground resistance value of various devices in power, communications, anti thunder protection, towers, electromechanical, radio and television, buildings, troops, laboratories, factories, water affairs, large workshops, railways, industrial and mining enterprises and other departments . At the same time, it can also measure soil resistivity and voltage, which is an alternative to traditional grounding meters. Support Language: English Basic Parameters: 1. General Specifications Measurement Method: The measurement of grounding resistance uses constant current conversion method, using a test current with a frequency of about 800Hz and a magnitude of about 3MA, and the measurement of grounding voltage uses the average numerical rectification method. Operating Temperature and Humidity: 0-40℃, Relative Humidity Below 85% Storage Temperature and Humidity: -10-50℃, Relative Humidity Below 85% 2. Technical Specifications Accuracy: ± (% Reading + 7) Baseline Conditions: Ambient temperature 18℃-28℃, relative humidity not more than 80%. Ground Resistance 0-29.99Ω ±(2%rdg+6d) 0.01Ω 30.0Ω-99.9Ω ±(3%rdg+3d) 0.1Ω 100Ω-999Ω ±(3%rdg+3d) 1Ω 1.00kΩ-4.00kΩ ±(3%rdg+3d) 10Ω Voltage to Ground 0V-200V (50/60Hz) ±(1%rdg+5d) 0.1V How e: 1. Ground Voltage Measurement Turn the rotate switch to the "voltage to ground" position, and insert the test wire into the E and P/S jacks. The other end of the test line is connected in parallel to the voltage source or load for measurement, and the voltage value will be displayed on the LCD screen. 2. 2 pole method of grounding resistance measurement (simple measurement) This method is a measurement method that does not use an auxiliary grounding rod, and uses the existing known minimum grounding resistance as the auxiliary grounding electrode, such as metal buried objects such as metal water pipes, the common grounding of commercial power supplies or the building anti thunder rod as the auxiliary grounding electrode. The measurement steps are as follows: (1) First detect the ground voltage Measure the ground voltage before measuring the ground resistance, and check whether there is ground voltage in the measured device according to the "ground voltage measurement" method. If there is a connection voltage and it exceeds 10V, it will cause a relatively large error in the measurement of the grounding resistance. Please cut off the power supply of the tested object, wait for the ground voltage to drop before measuring. (2) Measurement of grounding resistance Rotate the dial switch to the "two-pole method" position, connect the meter to the device to be measured, press the "measure" button to start the measurement, the "measure" button lights up and flashes, the measurement automatically stops, the buzzer sounds once , "Measure" key light goes out, the measured value Re is automatically kept on the display, and the measurement result is read. Note: If the measured value exceeds the range, it will display >LIMIT4000Ω, which means that the auxiliary grounding resistance of the auxiliary grounding rod is too large and the current cannot flow through the meter. Please confirm whether the test wire is loose and the grounding resistance of the auxiliary grounding rod. (3) Calculate the grounding resistance value When measuring the ground resistance of the two-pole method, the measured value Re is the addition of the ground resistance value re of the auxiliary ground electrode and the real ground resistance value Rx, so the measured value Re minus the value of re is the value of the real ground resistance Rx: Rx (grounding Resistance value) = Re (measured value)-re (ground resistance value of auxiliary grounding electrode). 3 pole method of grounding resistance measurement (accurate measurement), this instrument uses the potential difference method to measure the grounding resistance value. The potential difference method is to flow AC rated current 1 between the measured object E (ground electrode) and C/H (current electrode), measure the potential difference V between E and P/S (voltage electrode), and then calculate the ground resistance Value Rx method.