Use a clamp meter to measure current Use a clamp meter to measure current, generally follow the following operations:
a. Estimate the range of the measured current and select the appropriate current gear. The selected current block should be larger than the measured current. If the current range cannot be estimated, the high current block can be selected for measurement first, and the small current block can be selected when the measured value is too small.
b. Clamp the wire under test. During measurement, press the wrench on the clamp meter, open the iron core, and clamp a wire in, as shown in Figure 2(a), the needle swings, indicating the magnitude of the current flowing through the wire. Pay attention when measuring: two wires cannot be clamped at the same time. The measurement method shown in Figure 2(b) is wrong. This is because the currents flowing through the two wires are equal in magnitude but opposite in direction. The directions of the magnetic fields are opposite and cancel each other out. The current value measured by the clamp meter will be 0. If it is not 0, it means that the currents flowing through the two wires are not equal, and the load has leakage (part of the current of one wire is insulated). The object with poor performance goes directly to the ground, not all of it flows to the other line) At this time, the value measured by the clamp meter is the leakage current value.
C. Reading. When reading, observe and write down the value that the needle points to on the "ACA (AC current)" scale line, and then perform a comprehensive reading with the number of gears. For example, in the measurement shown in Figure 2(a), the pointer points at 35 of the ACA scale line, and the gear is the current 50A gear. When reading, the maximum value of the ACA scale line 5 is regarded as 50, and 3.5 is 35. , that is, the current value flowing through the tested wire is 35A
