Kunshan ammeter manufacturer introduces the use and maintenance methods of ammeter and voltmeter

This paper describes the use and maintenance of ammeter and voltmeter

1. Select ammeter reasonably

(1) According to the accuracy requirements of the measured ammeter, the accuracy of the ammeter should be selected reasonably. Generally speaking, 0.1-0.2 class magnetoelectric ammeter is suitable for standard meter and precision measurement; Class 0.5-1.5 magnetoelectric ammeter is suitable for laboratory measurement; Class 1.0-5.0 magnetoelectric instruments are suitable for industrial and mining enterprises as electrical equipment operation monitoring and electrical equipment maintenance.

(2) Select the ammeter with corresponding limit according to the current of the side to be measured. If the measurement limit is too small, the ammeter will be damaged. In order to make full use of the accuracy of the instrument, the range of the instrument should be selected according to the principle of using the last quarter of the scale as far as possible.

(3) Choose the internal resistance of ammeter reasonably. The smaller the internal resistance of ammeter, the better

2. Inspection before measurement

Before measurement, check whether the pointer of the ammeter is aligned with the "0" mark. If not, adjust the "zero adjuster" to make the pointer return to zero.

3. Connection between ammeter and circuit under test

(1) When measuring, the ammeter should be connected in series to the low potential side of the circuit under test.

(2) When measuring DC, it is necessary to pay attention to the symbol of ammeter terminal button. For single limit ammeter, the measured current should flow into the ammeter from the terminal button marked with "+" and flow out of the ammeter from the terminal button marked with "-"; For multiple limit ammeters, the common terminal button marked with "*" is used. If other terminals are marked with "+", the measured current shall flow in from "+" terminal button and flow out from "*" terminal button; If the other end buttons are marked with the "-" symbol, the connection is the opposite of the above situation.

4. Correct reading

When reading, make the pointer stable before reading, and keep the line of sight perpendicular to the dial as far as possible. If the dial has a mirror, the pointer and the Shadow Protection of the pointer in the mirror should coincide to reduce the error.

5. Maintenance method

(1) Because the overload capacity of magnetoelectric ammeter is very small, we must pay attention to the polarity of the connecting circuit and the selection of the limit.

(2) If it is found that the pointer's reverse deflection or forward deflection exceeds the full scale mark on the scale in the measurement, the measurement shall be stopped immediately after the power is cut off, and the measurement shall be carried out after the correct connection or re selection of more limited ammeter.

(3) When the measurement is completed, the power supply should be cut off first, and then the ammeter should be removed from the measuring circuit and placed in a dry, ventilated and cool environment. For the microammeter and milliammeter with high sensitivity and accuracy, the positive and negative terminals should be connected by wires to protect the measuring mechanism of the instrument.

The operation and maintenance methods of voltmeter are similar to those of ammeter, and the following points should be noted:

(1) When measuring, the voltmeter should be connected to the circuit under test in parallel.

(2) Because the voltmeter and the load are in parallel, the internal resistance RV is required to be much larger than the load resistance RL.

(3) When measuring DC, connect the "-" button of the voltmeter to the low potential terminal of the circuit under test, and then connect the "+" button to the high potential terminal of the circuit under test.

(4) For the multi limit voltmeter, when the limit needs to be changed, the voltmeter should be disconnected from the circuit under test, and then the limit should be changed.