The structure of the current measuring part of the clamp multimeter
The current measurement part of the clamp multimeter consists of a current transformer and the current measurement part of the multimeter.
The iron core of the transformer has a movable part and is connected to the handle. When in use, press the handle to open the movable iron core. Put the wire of the current being measured into the jaws, release the handle and close the iron core.
At this time, the wire passing the current is equivalent to the primary winding of the transformer, and an induced current will appear in the secondary winding, the size of which is determined by the working current of the wire and the ratio of the number of winding turns.
The ammeter is connected to both ends of the secondary winding, so the current it indicates is the current in the secondary winding, which is proportional to the working current.
Therefore, the calculated scale is used to reflect the current on the primary side. When there is current passing through the wire, the pointer of the ammeter connected to the secondary winding deflects proportionally, thus indicating the value of the measured current.
When using, turn the range switch to the appropriate current position. Hold the meter body and press the switch with your thumb to open the jaws and introduce the wire under test into the center of the iron core.
Then, when the switch is released, the iron core will automatically close, and the current of the measured wire will generate alternating magnetic lines in the iron core. The current value will be reflected on the meter and can be read directly.
1. Before using a digital multimeter, read the instruction manual carefully to familiarize yourself with the power switch function and the function of the limit switch, input jack, socket, and various function keys, knobs, and accessories.
In addition, you should also understand the limit parameters of the multimeter, the characteristics of overload display, polarity display, low voltage display and other indicator displays and alarms, and master the changing rules of the decimal point position.
Before measurement, you should carefully check whether there are any cracks in the test leads, whether the insulation layer of the leads is damaged, and whether the test leads are plugged in correctly to ensure the safety of the operator.
2. Before each measurement, you should check again whether the measurement items and the limit switch are in the correct position, and whether the input jack (or special socket) is selected correctly.
3. The meter will jump when taking measurements. You should wait until the displayed value stabilizes before reading.
4. Although the digital multimeter has a relatively complete protection circuit inside, it is still necessary to try to avoid operational malfunctions, such as using a current block to measure voltage, an electric block to measure voltage or current, and a capacitor block to measure charged components. capacitor, etc. to avoid damaging the instrument.
5. If only the highest digit displays the number "1" and the other digits are blanked, it proves that the instrument has been overloaded and a higher limit should be selected.
6. It is forbidden to turn the limit switch when measuring a voltage above 10OV or a current above 0.5A to avoid arcing and burning the contacts of the transfer switch.
7. The number with a danger mark next to the input jack represents the limit value of the input voltage or current of the jack. Once exceeded, the instrument may be damaged or even endanger the operator's safety.
8. The clamp multimeter is not allowed to measure the current of high-voltage lines. The voltage of the line under test cannot exceed the voltage level specified by the clamp meter (generally no more than 500 volts) to prevent insulation breakdown and personal electric shock.
9. When measuring, you should estimate the size of the current being measured and select an appropriate range. Do not use small ranges to measure large currents. 10. Before measuring, be sure to set the range switch to the corresponding AC current range. Do not use voltage ranges and resistors. Use the resistance setting or current setting to measure the current. Remember! Never use the resistance setting or the current setting to measure the voltage. Otherwise, if you are not careful, the meter will be burned.
11. Only one wire can be clamped for each measurement. When measuring, the wire under test should be placed in the center of the jaws to improve the accuracy of the measurement. It is best to flatten the meter body with your hands and try not to let the wires rest on the jaws and meter body.
12. After the measurement, you must turn the range switch to the maximum voltage range position, and then turn off the power switch. to ensure safe use next time.
