The structure of the current measuring part of the clamp multimeter
Regarding the structure of the current measurement part of the clamp multimeter, the current measurement part of the clamp multimeter is composed of the current transformer and the current measurement part of the multimeter. When using, turn the range switch to the appropriate current position, and the clamp multimeter must not measure high voltage line current.
The structure of the current measuring part of the clamp multimeter
The current measuring part of the clamp multimeter is composed of the current transformer and the current measuring part of the multimeter.
The iron core of the transformer has a movable part, which is connected with the handle. When in use, the movable iron core is opened by pressing the handle. Put the wire of the current to be measured into the jaws, release the handle to close the iron core.
At this time, the wire passing through the current is equivalent to the primary winding of the transformer, and an induced current will appear in the secondary winding, and its magnitude is determined by the working current of the wire and the ratio of the 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 current in operation.
Therefore, the calculated scale is used to reflect the current on the primary side. When there is current flowing through the wire, the pointer of the ammeter connected to the secondary winding will deflect proportionally, thereby indicating the value of the measured current.
When in use, turn the range switch to the appropriate current position. Holding the watch body and pressing the switch with your thumb, the jaws can be opened and the conductor under test is introduced into the center of the iron core.
Then, release the switch, the iron core will be closed automatically, and the current of the tested wire will generate alternating magnetic lines of force in the iron core, and the current value will be reflected on the meter, which can be read directly.
1. Before using the digital multimeter, read the instruction manual carefully to be familiar with the power switch function and the function of the limit switch, input jack, user jack, 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 change rule of the decimal point position.
Before measuring, carefully check whether the test leads are cracked, whether the insulation layer of the leads is damaged, and whether the test leads are inserted correctly to ensure the safety of the operator.
2. Before each measurement, check again whether the measurement item and the limit switch are in the correct position, and whether the input jack (or special socket) is selected correctly.
3. The meter will appear jumping number phenomenon when measuring, should wait for the displayed value to stabilize before reading.
4. Although there is a relatively complete protection circuit inside the digital multimeter, it is still necessary to avoid misoperations in operation. For example, use the current to block the voltage, use the electricity to block the voltage or current, and use the capacitor to block the charged voltage. capacitors, etc., so as not to damage the meter.
5. If only the highest digit displays the number "1", and other digits are blanked, it proves that the meter has been overloaded, and a higher limit should be selected.
6. It is forbidden to toggle the limit switch when measuring the voltage above 10OV or the current above 0.5A, so as to avoid arcing and burning the contacts of the transfer switch.
7. The number marked with the danger mark next to the input jack represents the limit value of the input voltage or current of the jack. Once exceeded, it may damage the instrument and even endanger the safety of the operator.
8. The clamp multimeter is not allowed to measure the current of the high-voltage line, and the voltage of the line under test cannot exceed the voltage level specified by the clamp meter (generally more than 500 volts) to prevent insulation breakdown and personal electric shock.
9. The measurement should estimate the magnitude of the measured current, select the appropriate range, and do not use the small range gear to measure the large current. 10. Before measuring, pay attention to the range switch to the corresponding AC current gear, and cannot use the voltage range and resistance. To measure the current, remember! Never use the resistance gear and the current gear to measure the voltage, otherwise, if you are not careful, the meter will be burned.
11. Only one wire can be clamped in each measurement. When measuring, the conductor under test should be placed in the center of the jaw to improve the accuracy of the measurement. It is best to flatten the watch body with your hand, and try not to let the wires rest on the jaws and the watch body.
12. After the measurement, the range switch must be rotated to the maximum voltage range position, and then the power switch must be turned off. to ensure safe use next time.
