5 Steps to Using a Clamp Meter
(1) Correctly select the clamp ammeter according to the type and voltage level of the measured current. When measuring the current of a high-voltage line, a high-voltage clamp ammeter that matches its voltage level should be selected.
(2) Correctly check the appearance of the clamp ammeter, whether the jaws are closed and the condition of the meter is normal. If the pointer is not at zero, perform mechanical zero adjustment.
(3) Select the appropriate range of the clamp ammeter according to the measured current. The selected range should be slightly larger than the measured current value. If you do not know the magnitude of the measured current, you should choose the maximum range to estimate first.
(4) Measure correctly. When measuring, press the wrench tightly to open the jaws. Put the wire under test into the center of the jaw, loosen the wrench and close the jaw tightly.
(5) After reading, open the jaws, withdraw the measured wire, and set the gear to the highest current gear or OFF gear.
Measurement example: measure the operating current of the cage-type asynchronous motor in operation. According to the magnitude of the current, it can be checked to determine whether the motor is working normally, so as to ensure the safe operation of the motor and prolong its service life. First of all, correctly select the voltage level of the clamp ammeter, check whether its appearance insulation is good, whether it is damaged, whether the pointer swings flexibly, whether the jaw is rusted, etc. Estimate the rated current according to the motor power to select the range of the meter. When measuring, it can be measured once for each phase or once for three phases. At this time, the number on the meter should be zero (because the sum of the three-phase current phasors is zero). When there are two phase wires in the jaw, the meter will display The value is the current value of the third phase. By measuring the current of each phase, it can be judged whether the motor is overloaded (the measured current exceeds the rated current value), whether there is a problem inside the motor or the power supply voltage, that is, whether the three-phase current imbalance exceeds 10%. limit.
