The correct use of clamp ammeters should pay attention to these three points
Due to the fact that clamp type ammeters can measure the current in a circuit without cutting it off, they are widely used. Proper use of clamp type ammeters should generally pay attention to the following issues:
(1) Choose the correct gear.
Before measuring the current, it is necessary to roughly estimate the magnitude of the measured current based on the size of the load and select the appropriate range. When it is impossible to estimate, a larger range can be used first, and then a suitable range can be changed based on the magnitude of the measured current. But when shifting gears, the measured wire should be placed outside the clamp of the clamp ammeter.
(2) The placement position of the measuring wire should be correct.
When measuring the current of the wire, the measured current carrying wire should be placed in the center position inside the clamp; When measuring the current, remove the movable magnet from the jaws and place one wire of the motor in the center of the jaws.
(3) Usage environment.
Try to stay away from strong magnetic fields (such as energized autovoltage regulators, magnets, etc.) and use a clamp type ammeter to reduce the impact of magnetic fields on the clamp type ammeter.
Precautions when using clamp type ammeters
(1) Due to the clamp type ammeter being in contact with the measured circuit, it is necessary to check the insulation performance of the meter before measurement. The shell should be undamaged and the handle should be clean and dry.
(2) When measuring, insulated gloves or clean wire gloves should be worn.
(3) When measuring, attention should be paid to maintaining a safe distance between all parts of the body and the charged body (the safe distance for low-voltage systems is 0.1-0.3 m).
(4) A clamp ammeter cannot measure the current of a bare conductor.
(5) Strictly select clamp type ammeters according to voltage levels: clamp type ammeters with low voltage levels can only measure current in low-voltage systems and cannot measure current in high-voltage systems.
(6) It is strictly prohibited to switch the gear of the clamp ammeter during the measurement process; If it is necessary to shift gears, the tested wire should be removed from the jaws before changing gears.
Usually, when using a regular ammeter to measure current, it is necessary to cut off the circuit and connect the primary side of the ammeter or current transformer in series to the circuit being tested. When using a clamp ammeter for measurement, the measurement can be carried out without cutting off the circuit.
