Digital clamp ground resistance meter

　　The CA6415 precision clamp-type ground resistance meter is an instrument that can measure ground resistance conveniently and quickly. This measuring instrument does not need to use auxiliary grounding probes during measurement, nor does it need to interrupt the grounding of the device to be measured. As long as the clamp is clamped on the grounding wire or the grounding probe, the grounding resistance of the grounding body can be measured. This model can also be used for current measurement. The high sensitivity can measure leakage current as small as 1mA, and the neutral line current can reach 30A (effective value). This function is very important when the grounding network to be measured contains large clutter signals and harmonics that will affect the power quality. The clamp-type ground resistance meter provides alarm and memory storage functions. In the alarm mode, if the measured value exceeds or falls below the input setting value, an alarm sound signal will be generated; the memory function can store 99 sets of values ​​(resistance or current) to facilitate the analysis and verification of the measured values ​​in the future. The stored data and alarm setting values ​​can still be saved after the power is turned off.

　　(1) Key functions and LCD display information The appearance of the CA6415 precision clamp-type ground resistance meter is shown in Figure 1.

Figure 1 Appearance of CA6415 precision clamp ground resistance meter

　　The panel key functions are shown in Figure 2. When set to data storage and alarm setting, pressing the increase or decrease key can change the set value. The LCD display information is shown in Figure 3.

　　Figure 2 Panel button functions

 

　　Figure 3 LCD display information

　　(2) Measurement principle The measurement principle of the clamp-on ground resistance meter is shown in Figure 4. It uses the principle of current transformer for measurement. The closed grounding loop is equivalent to the primary winding of a transformer. If a known voltage U is provided, the current in this loop is

　　Figure 4 Clamp ground resistance measurement