How useful is the clamp ammeter?
The clamp ammeter is composed of a current transformer and an ammeter. The iron core of the current transformer can open when the wrench is tightened; the wire through which the measured current passes can pass through the core and the measured circuit wire becomes the primary coil of the current transformer, in which the passing current is induced in the secondary coil. current.
Usually when measuring current with an ordinary ammeter, the circuit needs to be cut off and shut down before the ammeter can be connected for measurement. This is very troublesome, and sometimes a normally operating motor does not allow this. At this time, it is much more convenient to use a clamp ammeter, which can measure the current without cutting off the circuit.
The clamp meter can be changed to different measuring ranges by turning the switch. However, it is not allowed to operate with power on when shifting gears. Clamp meters generally have low accuracy, usually level 2.5 to level 5. For ease of use, the meter also has switches of different ranges to provide the functions of measuring current and voltage at different levels.
Clamp meters were originally used to measure AC current. , but now it also has the functions of a multimeter, which can measure AC and DC voltage, current, capacitance, diode, transistor, resistance, temperature, frequency, etc.
Clamp ammeters can measure photovoltaic DC current and inverter output AC current. Special attention should be paid to the fact that some clamp ammeters do not have DC function. The jaws must be closed tightly and the range cannot be changed while charging.
Clamp ammeter reading
1. Select the gear and range. Turn the meter switch to the DC current "mA" position, and select the range correctly according to the size of the current being measured. When the magnitude of the current is not known, in order to prevent the current from being too large and exceeding the measurement range, the test can be performed at the highest DC current level first. If the measurement range is too large, reduce the measurement range until the measurement range is appropriate.
2. Connect in series to the circuit. When measuring current with a multimeter, the test leads must be connected in series with the current, and the red test lead is connected to the high potential end of the circuit, and the black test lead is connected to the low potential end of the current.
3. Reading method:
(1) Correctly select the scale mark for reading.
(2) Convert current value: Current value = number of scales pointed by the pointer × range size/maximum value of the selected scale.
