Working Principle and Model of Electric Meter (4)
Metering of electrical energy
Electric energy measurement unit
Active energy meter kW h (commonly known as degree 1kw. h=3.6×10 to the 6th power numerically represents the electric energy consumed by an electrical appliance with a power of 1kw working for 1h)
Reactive energy meter kvar h
Character wheel counter window (LCD display window):
The integer and decimal places are of different colors, with a decimal point in the middle; each character wheel has a multiplication factor (when there is no decimal point). The LCD display of the multi-function meter has two integer and decimal places.
level of accuracy:
Relative error, represented by a number inside a circle
Nominal current and rated maximum current:
Calibration current: marked on the table as the base current value for calculating the load: I b
Rated maximum current: The electric energy meter can work normally for a long time, and the error and temperature rise fully meet the requirements of the maximum current value: Imax
Rated voltage: single-phase electric energy meter label: 220V
There are three marking methods for three-phase meters:
A. Direct access three-phase three-wire: 3×380V
B. Direct access three-phase four-wire: 3×380/220V
Electric energy meter constant: The proportional number of the relationship between the electric energy recorded by the electric energy meter and the number of revolutions of the turntable or the number of pulses: r/kWh; imp/kWh
What should be paid attention to when using the watt-hour meter
1. The wiring of the watt-hour meter is more complicated. Before wiring, the voltage terminal and the current terminal of the watt-hour meter must be distinguished, and then connected according to the instructions.
2. The accuracy of the watt-hour meter can only be guaranteed if it works under the conditions of rated voltage and rated current of 20~120% of rated frequency of 50 Hz.
3. The watt-hour meter should not work when the current is less than 5% of the specified current and about 150% of the specified current.
4. The watt-hour meter that has been out of use for half a year should be re-calibrated
5. When installing the watt-hour meter, it should be more than 0.5 meters away from the thermal system, 0.7~2.0 meters away from the ground, and strive to be installed vertically.
