Accuracy requirements for clamp-on ammeters
(1) When measuring the current, the clamp ammeter gear should be appropriate, it is best to make the meter needle falls to the scale of the scale of 1/3 or more of the scale, because the deflection angle of the needle is too small, the scale value is not easy to distinguish, affecting the accuracy of the measurement.
(2) The measured wire should be placed as far as possible in the jaws of the central position, such as the measured wire is too oblique, the measured current in the jaws of the core of the magnetic induction intensity generated by the jaws will occur more substantial changes, directly affecting the accuracy of the measurement, generally due to the measured wire in the jaws of the improper position caused by the measurement error can be up to 2% -5%.
(3) In order to make accurate readings, should make the iron core jaws of the two sides of the tightly closed. If you hear the electromagnetic noise emitted by the jaws or grasp the clamp ammeter hand has a slight vibration of the feeling that the jaws end face combination is not tight, this time should be reopened, close the jaws of a time; if the murmur still exists, you should check the jaws end face with or without dirt or rust, if there should be cleared until the jaws combined with a good so far.
(4) for digital clamp ammeter, although in the use of the battery before had checked the battery power, but in the process of measurement, should also pay attention to the battery power situation, if the battery voltage is found to be insufficient (such as the emergence of a low voltage prompt symbols), must be in the replacement of the battery and then continue to measure; if the measurement site there is electromagnetic interference, it is bound to interfere with the measurement of the normal, it should try to exclude the interference. Can correctly read the measurement data, but also directly related to the accuracy of the measurement.
(5) for the pointer type clamp meter head, first of all, should recognise the selected gear, and secondly, recognise which scale is used. Observe the scale value pointed out by the needle, the eyes should be facing the needle and scale to avoid squinting and reduce parallax. Although the display of the digital head is more intuitive, but the effective viewing angle of the LCD screen is very limited, the eyes are too skewed when it is easy to read the wrong number, but also should pay attention to the decimal point and its location, which must not be ignored.
(6) Measurement of the temperature of the place of abnormal or drastic changes will affect the accuracy of the measurement. Because the temperature change will make the meter error increases, thus reducing its accuracy. Clamp ammeter affected by the temperature is mainly due to: due to temperature changes in the composition of the instrument key structural components of the material performance results. Such as changes in ambient temperature often make the instrument to produce a reaction moment of the elasticity of the hairspring changes, so that the instrument value of the consequent changes, but also the formation of the magnetic field of the magnetic field changes, so that the instrument's role in the change in the size of the torque. In addition, due to changes in ambient temperature, the resistance of the line constituting the instrument, as well as a variety of electronic components, semiconductor device parameters will produce changes, the end result will affect the accuracy of the measurement.
(7) Two or more wires cannot be clamped at the same time during measurement. Measurement of current less than 5A or less, in order to get a more accurate reading, if conditions permit, the wire can be wound around a few more times into the jaws for measurement, but the actual current value should be the reading divided by the number of turns of the wire put into the jaws.
