What are the skills in the selection of clamp ammeter
1. Selection of clamp ammeter
(1) First of all, it should be clear whether the measured current is AC or DC. The rectifier clamp ammeter is only suitable for measuring power frequency current with low waveform distortion and little frequency change, otherwise, large measurement errors will occur. For the electromagnetic clamp ammeter, since the deflection property of the movable part of the measuring mechanism has nothing to do with the polarity of the current, it can be used to measure both AC current and DC current, but the accuracy is usually relatively low . The accuracy of the clamp ammeter mainly includes 2.5 grades, 3 grades, 5 grades, etc., and should be selected according to the measurement technical requirements and actual conditions.
(2) For digital clamp ammeters, the readings of the measurement results are intuitive and convenient, and the measurement functions have also been expanded a lot, such as being able to measure resistance, diodes, voltage, active power, reactive power, power factor, parameters such as frequency. However, the digital clamp ammeter is not perfect. When the electromagnetic interference in the measurement occasion is serious, the displayed measurement results may have discrete jumps, making it difficult to confirm the actual current value; if the pointer clamp ammeter is used, due to The damping effect of the magnetoelectric mechanical meter itself makes it relatively slow to respond to strong electromagnetic field interference. At best, the hands produce a small swing, and its indication range is relatively intuitive. Relatively speaking, reading is not too difficult. .
2. Check before using the clamp ammeter
Focus on checking whether the insulating material (rubber or plastic) on the jaws is peeled off or cracked; whether the entire shell including the meter head glass is intact or not, these are directly related to the measurement accuracy and involve the performance of the instrument; To check whether the zero point is correct, if the needle is not at the zero point, it can be adjusted through the adjustment mechanism; for the multi-purpose clamp ammeter, it is also necessary to check whether the test line and the meter rod are damaged, and it is required to have good conductivity and good insulation; for digital clamp ammeters , It is also necessary to check whether the power of the battery in the watch is sufficient, and must be updated if it is insufficient.
