Clamp Ammeter
A clamp meter (clamp meter) is an instrument that integrates a current transformer and an ammeter. It is an important branch of a digital multimeter. Its working principle is the same as that of a current transformer to measure current. The clamp meter is composed 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 opening of the iron core without cutting it, and the iron core is closed when the wrench is released. The circuit wire under test passing through the iron core becomes the primary coil of the current transformer, in which the current is induced in the secondary coil by passing the current. So that the ammeter connected to the secondary coil will have an indication-----measure the current of the line under test.
The clamp meter can be changed to different ranges through the shift of the switch. However, it is not allowed to operate with power on when shifting gears. The accuracy of the clamp meter is generally not high, usually 2.5 to 5 grades. For the convenience of use, there are also switches of different ranges in the meter for measuring different levels of current and measuring voltage.
The clamp meter was originally used to measure AC current, but now the multimeter has all the functions it has, which can measure AC and DC voltage, current, capacitance, diode, triode, resistance, temperature, frequency, etc.
A clamp meter is a meter used to measure the magnitude of the current in a running electrical line, and it can measure the current without interruption. It is an electrical instrument specially designed to measure AC high current.
Clamp ammeter is also called clamp meter, and Taiwan is more called hook meter.
Clamp-on ammeter is a convenient test instrument (also known as non-destructive measurement) to detect current without cutting off the circuit by clamping the wire.
Analog pointer multimeters and digital multimeters cut off the circuit to detect the current, while the clamp-type ammeter is only clamped on the outer skin of the energized wire to detect the current. The operation is simple, and it can safely detect large currents without directly connecting the circuit.
Clamp meters, multimeters and insulation resistance meters all have analog pointer and digital.
Standard detection range: AC and DC are around 2A to 200A or 400A, and there are products that can detect a high current of 2000A;
There are also leakage detection products that can detect small currents of several mA, and products that can detect true RMS (True RMS) of non-sine waves other than sine waves such as transformer power supplies and switching power supplies.
Clamp Meter Essentials
1: Detection object
According to different detection objects, AC current, DC current, or leakage current to select the model;
2: Detectable size of the largest conductor
With the testing site, there are different specifications from 21mm diameter to 53mm diameter.
3: Is it necessary to detect the true value?
A clamp ammeter using the average value method cannot correctly detect non-sinusoidal circuits such as motors and transformer circuits. To detect such circuits, a true RMS clamp ammeter should be used.
4: Other functions
Not only can detect the current, but also the detection function and recording output in one model.
Clamp meter classification
According to its structure and use, it is divided into transformer type and electromagnetic system.
Commonly used is a transformer type clamp ammeter, which consists of a current transformer and a rectifier system instrument. It can only measure AC current. The deflection of the movable part of the electromagnetic instrument has nothing to do with the polarity of the current, so it can be used for both AC and DC.
