The function of a clamp ammeter-Reading of clamp ammeter
The function of a clamp ammeter
A clamp type 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 tested circuit wire of the iron core, which becomes the primary coil of the current transformer, and the current is induced in the secondary coil through the current.
When measuring current with a common ammeter, it is necessary to cut off the circuit and shut down before connecting the ammeter for measurement. This is very troublesome, and sometimes normal running motors are not allowed to do so. At this point, using a clamp type ammeter becomes much more convenient, as it can measure current without cutting off the circuit.
The clamp meter can be changed to different ranges by shifting the gears of the switch. However, it is not allowed to operate with power when shifting gears. The accuracy of clamp shaped watches is generally not high, usually ranging from 2.5 to 5 levels. For ease of use, there are also conversion switches with different ranges in the meter for measuring different levels of current and voltage.
The clamp meter was originally used to measure AC current., But now multimeter has some functions, such as measuring AC/DC voltage, current, capacitance, diodes, transistors, resistors, temperature, frequency, and so on.
Clamp type ammeters can measure photovoltaic DC current and inverter output AC current. It should be noted that some clamp type ammeters do not have DC function, and the clamp mouth should be tightly closed and cannot be changed with power.
Reading of clamp ammeter
1. Select the gear and range. Turn the meter switch to the DC current "mA" position and select the correct range based on the measured current. To avoid excessive current exceeding the range without knowing the magnitude of the current, it is recommended to first place it in the highest DC current range for testing. If the range is too large, reduce the range again until it is suitable.
2. String in circuit. When measuring current with a multimeter, the probe must be connected in series with the current, with the red probe connected to the high potential end of the circuit and the black probe connected to the low potential end of the current.
3. Reading method:
(1) Correctly select scale marks for reading.
(2) Converted current value: current value=the number of degrees indicated by the pointer × Range size/maximum value of the selected scale.
