Clamp Meter Selection Guide
A clamp ammeter is a combination of a current transformer and an ammeter. The iron core of the current transformer can be opened when the wrench is tightened; The wire through which the measured current passes can pass through the open gap of the iron core without cutting, and the iron core will close when the wrench is released.
Working principle of clamp ammeter:
The tested circuit wire passing through the iron core becomes the primary coil of the current transformer, and current is induced in the secondary coil through the current. So that the ammeter connected to the secondary coil can indicate the current of the tested circuit. The clamp gauge can be changed to different ranges by shifting the switch. But it is not allowed to operate with electricity when shifting gears. Clamp gauges generally have low accuracy, typically ranging from 2.5 to 5 levels. For ease of use, there are also conversion switches with different ranges inside the meter for measuring different levels of current and voltage.
Selection guide for clamp current meter:
(1) Firstly, it should be clarified whether the measured current is AC or DC. The rectifier clamp ammeter is only suitable for measuring power frequency currents with low waveform distortion and little frequency variation, otherwise it will result in significant measurement errors. For electromagnetic clamp ammeters, the deflection property of the movable part of the measuring mechanism is independent of the polarity of the current. Therefore, it can be used to measure both AC and DC currents, but the accuracy is usually relatively low. The accuracy of clamp current meters mainly includes 2.5 levels, 3 levels, 5 levels, etc., and should be selected according to the measurement technology requirements and actual situation.
(2) For digital clamp current meters, the reading of their measurement results is intuitive and convenient, and the measurement functions have also been greatly expanded, such as being able to measure parameters such as resistance, diodes, voltage, active power, reactive power, power factor, frequency, etc. However, digital clamp current meters are not perfect. When electromagnetic interference is severe in the measurement environment, the displayed measurement results may experience discrete jumps, making it difficult to confirm the actual current value; If a pointer type clamp ammeter is used, due to the damping effect of the magneto electric mechanical meter head itself, its response to strong electromagnetic field interference is relatively slow, at best, the meter needle produces a small amplitude swing, and its reading range is relatively intuitive, making reading relatively easy.
