Selection of clamp-on ammeters
(1) Firstly, it should be clear whether the measured current is AC or DC. Rectifier system clamp ammeter is only suitable for measuring the waveform distortion is low, the frequency change is not big frequency current, otherwise, will produce a large measurement error. For the electromagnetic system clamp ammeter, because of its measurement mechanism movable part of the deflection of the nature of the polarity of the current is not related to the current, therefore, it can be used to measure both AC current and DC current, but the accuracy is usually lower. Clamp ammeter accuracy mainly 2.5, 3, 5 and so on several kinds, should be selected according to the technical requirements of the measurement and the actual situation.
(2) For the digital clamp-on ammeter, the measurement results of the readings intuitive and convenient, and the measurement function has been expanded a lot, such as the expansion to measure resistance, diode, voltage, active power, reactive power, power factor, frequency and other parameters. However, the digital clamp-on ammeter is not perfect, when the measurement of electromagnetic interference is more serious, the display of the measurement results may be discrete jumps, thus making it difficult to confirm the actual value of the current; if you use a pointer clamp-on ammeter, due to the magneto-electric system of the mechanical head itself has a damping effect, which makes its own response to the stronger electromagnetic field interference is relatively slow, at best, is also the needle produces a At best, the needle will produce a small swing, the range of values is more intuitive, relatively speaking, it is not too difficult to read.
Clamp ammeter check before use
Focus on checking the jaws of the insulating material (rubber or plastic) with or without shedding, rupture and other phenomena; including the head glass, including the integrity of the entire shell, which are directly related to the measurement of safety and performance issues related to instrumentation; but also to check whether the zero point is correct, if the needle is not in the zero point can be adjusted through the adjusting mechanism aligned; for the multi-purpose type clamp ammeter, should also be checked to see if there is any damage to the test line and meter stick, the requirements of the Conductivity is good, insulation is intact; for digital clamp ammeter, but also need to check the table battery power is sufficient, insufficient must be updated.
