How to Correctly Use a Clamp Ammeter to Measure Load Current
1. Select the appropriate gear. The principles of file selection are:
(1) When the measured current range is known: select the gear that is larger than the measured value but closest to it.
(2) If you don’t know the range of the current to be tested: you can first set the current to the highest level for testing.
2. The tester should wear gloves, put the meter on the flat end, open the jaws, let the wire under test enter the jaws and then close the jaws. The wire under test should be located in the center of the space inside the jaws.
3. Correct reading: According to the gear used, read the reading on the corresponding scale line.
4. When measuring small current, if you measure at the lowest gear, the deflection angle of the needle is still very small (the deflection angle of the needle is small, which means that the relative error of its measurement is large), and the lowest range gear of the meter is below 10% of the full scale value , allowing the wire to be wound around the jaws for a few turns, and after the jaws are closed, read the reading. At this time: the current value on the wire = reading / number of turns (calculation of the number of turns: how many wires are inside the jaw, count as how many turns).
5. After measuring a large current, before measuring a small current, the jaws should be opened and closed several times for demagnetization;
Use of clamp ammeter
(1) Matters needing attention when using clamp ammeter
①Estimate the size of the preliminary measured current before measurement, and select the appropriate range.
② When measuring, the current-carrying wire to be tested should be placed in the center of the jaws to avoid errors. For the measurement of the wire with less current, in order to improve the accuracy, if the conditions permit, you can also wind the wire under test several times, and then put it into the jaw for measurement. The actual current value is equal to the reading of the meter divided by the number of wire coils.
③ If there is noise during the measurement, it means that the jaws are not in good contact with the wires. You can open and close the jaws again. If the noise still exists, you can use gasoline to clean the jaws before measuring.
(2) Measurement operation method
① AC power measurement. Turn the switch to ACA1000A gear. Leave the switch in the relaxed position. Press the trigger to open the jaws, grip a wire, and read the value. If the reading is less than 200A, turn the switch to ACA200A to improve the accuracy of the reading.
② AC and DC voltage measurement. When measuring DC voltage, turn the switch to DCV1000; when measuring AC voltage, turn the switch to ACV750V, and keep the switch in a relaxed state. Connect the red test lead to the "VΩ" terminal, the black test lead to the "COM" terminal, then connect the red and black test leads to the circuit under test in parallel, and the read value is the actual voltage of the circuit.
③Measurement of resistance. Turn the switch to the electric resistance of the appropriate range. Leave the switch in the relaxed position. The red test lead is connected to the "VΩ" terminal, and the black test lead is connected to the "COM" terminal. Connect the red and black test leads to both ends of the measured resistance, and the read value is the actual resistance value of the measured resistance.
Note: When measuring online resistance, the line should be powered off and the capacitor connected to the resistor should be discharged.
④Continuity test. Turn the switch to 200Ω, connect the red test lead to the "VΩ" terminal, and the black test lead to the "COM" terminal. If the buzzer in the meter sounds, it means that the resistance between the red and black test leads is less than 50±2.5Ω.
