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Nowadays, many households have replaced mechanical electronic meters with smart meters. The smart meter is the smart terminal of the smart grid. There are four values on the meter, which represent peak, peak, flat and valley. At present, the smart meters in households are generally single-phase meters, so how do single-phase smart meters read degrees? How to wire a three-phase four-wire meter? Meter classification
1. By purpose: Active energy meter, reactive energy meter, maximum demand meter, standard energy meter, multi-rate time-of-use energy meter, prepaid energy Meters (coin-operated, magnetic card, electric card), energy consumption meters, multi-function energy meters and smart energy meters.
2. According to the working principle: Induction type (mechanical type), static type (electronic type), electromechanical integrated type (hybrid type).
3. According to the nature of the access power supply: AC meter, DC meter.
4. According to the structure: Integral type, split type.
5. According to the access phase line: Single-phase, three-phase three-wire, three-phase four-wire electric energy meter.
6. According to the accuracy level: Ordinary installed electric energy meter (0.2S, 0.5S, 0.2.0.5.1.0, 2.0 class) and portable precision electric energy meter (0.01, 0.05, 0.2 grades).
7. According to the installation wiring method: Direct access, indirect access.
The principle of the electric meter
First, after the electric energy meter is connected to the circuit, an alternating current is generated in the voltage coil and the current coil, and the alternating current generates an alternating magnetic flux in its iron core; The changing magnetic flux produces eddy currents in the aluminum plate; thirdly, the eddy current in the aluminum plate is acted by the force in the magnetic field, which makes the aluminum plate rotate; finally, the rotation of the aluminum plate drives the counter, and the power consumption is reflected in digital form .
When the power consumed by the load is larger, the alternating current generated in the voltage coil and the current coil is larger, the eddy current generated in the aluminum plate is larger, and the rotating torque of the aluminum plate is larger, so that its The more counts; on the contrary, when the power consumed by the load is smaller, the alternating current generated in the voltage coil and the current coil is smaller, the eddy current generated in the aluminum plate is smaller, and the rotating torque of the aluminum plate is smaller, so its count is also smaller. less.
Electric energy meter models
At present, the forms and functions of electric energy meters are diversified, and the names of the models are also different from major manufacturers. Conventional active energy only uses two letters to indicate its function and purpose. Other electronic energy meters with special functions use three letters to indicate their functions and uses.
The model of the electric meter is generally written from the category code, group code, function code, design serial number, etc. The general electric energy meter category code is D. The group code is usually divided into: A (ampere-hour meter), B (standard), D (single-phase electric energy meter), F (volt-hour meter), J (DC), S (three-phase three-wire), T (three-phase three-wire) Four lines), X (reactive). Function codes are usually divided into: F (time-of-use billing), S (electronic), Y (prepaid), D (multi-function), M (pulse), Z (maximum demand). Design serial numbers are numbers. Examples are as follows:
Wasion Electric Energy Meter: DDS102 Single-Phase Electronic Active Electric Energy Meter
Kelu Electric Energy Meter: DDS720 Single-Phase Electronic Electric Energy Meter
Hangzhou Huali : DDS28 single-phase electronic energy meter, DDS28-1 single-phase electronic energy meter
The way to take it is to connect the meter directly. The number on the meter is multiplied by 3. If the meter is connected through a transformer, the number of the meter is multiplied by the current multiple of the transformer and then multiplied by 3.
How to check the degree of the three-phase four-wire meter
The three-phase meter is connected by the current transformer connection. There are 10 wires in the meter, and the current ratio of the connected current transformer should be observed. There is a current ratio on the nameplate of the current transformer, which is marked by a number ratio of 5, such as 100/5, 150/5, etc., the number read on the meter multiplied by the current ratio is the measured amount of electricity, and the accuracy must be added Up change loss and line loss.
How to read the degree of the smart meter
The smart meter has only one LCD screen. If it is single-phase, it will directly display the total power and remaining power, and you can read it directly. If it is an IC card meter, only the LED display is a single card meter, and there will be a small red dot on the meter. The red dot jumps to the total use, which is the total use, and jumps to the rest, which is the surplus. Dual graphics card table, read above or below. Three-phase prepaid meter for direct reading. Multiply the reading of the mutual inductance meter by the multiplier of the mutual inductance.
Three Phase Four Wire Meter Wiring Diagram
Flip over the terminal cover, You can see the wiring diagram of the three-phase four-wire meter. Among them, 1, 4 and 7 are connected to the S2 terminal of the secondary side of the current transformer, that is, the current incoming terminal;
3, 6, and 9 are connected to the S1 terminal of the secondary side of the current transformer, that is, the current outgoing terminal;
2, 5, and 8 are connected to the three-phase power supply respectively.
10 and 11 are connected to the zero terminal. For safety, the S2 end of the current transformer should be connected and grounded.
Note that the current measurement sampling of each current transformer must be Voltage sampling is kept in the same phase, that is, 1, 2, and 3 are a group; 4, 5, and 6 are a group; 7, 8, and 9 are a group.
Precautions for installation of household electric meters
1. The amperage of the electric meter should be suitable for the total wattage of household electrical appliances. It is more appropriate to use a 2.5 amp meter in general households.
2. The voltage of the meter must conform to the voltage of the power supply. If the voltage of the power supply is 220 volts, a 110-volt meter cannot be used, otherwise the voltage coil of the meter will be burned out and cause an accident.
3. The meter should be installed in a dry location, not above the kitchen or gas stove.
4. The installation height of the meter should be appropriate. The height of the meter center from the ground is 1.5-1.8 meters.
5. The meter should be installed on the wooden board for power distribution, and should be firmly installed on a reliable and dry wall, not on the door frame or the wooden wall.
6. The wire connection must be firm, and the connection should not be loose or poorly connected, otherwise it is easy to generate sparks and be dangerous.
Household electric meter selection skills Total nuclear load power
Turn on the total power of all electrical appliances in your home, and also need to consider the total nuclear load power of which appliances will be purchased next to select the specifications and models of the electric meter so as to meet the long-term requirements. time requirements.
Electricity meter function
The electric meter now has many kinds of functions, such as active meter, reactive meter, mechanical meter, electronic meter, demand meter, multi-function meter, peak-valley time-sharing meter and so on. Here you need to look at the specific use requirements. Today’s multi-function electronic watches can integrate a variety of measurement functions, but they are expensive. General mechanical watches can measure one or several functions individually, and the price is relatively cheap. The key depends on the need.
Metering Accuracy
Under different requirements, the required accuracy of the meter is also different. For general household electricity, it is sufficient to use a meter with an accuracy of 2.0 or higher, while in large enterprises, a meter with an accuracy of 0.5 or even 0.2 is needed. The higher the accuracy, the higher the price. This also depends on the needs of use.
Product quality
Under the same conditions as other factors, the quality of the product is very important, and it does not mean that the expensive one must be good, and the good must be expensive. Ensure quality and avoid adverse consequences.
Safety Tips for Electric Meters
1. Use appropriate fuses instead of other metal wires. The function of the fuse is to cut off the power supply in time to ensure safety when a short circuit or serious overload fault occurs in the circuit. The choice of fuse should be considered according to the maximum power used or the current value of the watt-hour meter.
2. Avoid overloading the watt-hour meter, otherwise it will not only cause inaccurate measurement, but also may burn the watt-hour meter or even cause a fire. For example, if the nameplate of the watt-hour meter is marked with “5(20)A”, the maximum value of household electric current cannot exceed 20A.
3. The old watt-hour meter should be sent to the metering department for verification. Before replacing the watt-hour meter, its appearance should be checked, and there should be no obvious defects in appearance. If it is a new watt-hour meter, not only the lead seal is required to be intact, but also the factory inspection certificate must be attached. After installation, it can be used normally and count from zero. If it is an old watt-hour meter, it should be sent to the metering department (in the past, it was sent to the power supply department for verification) for inspection, and it should be sealed with lead before it is used.
4. Regularly check the watt-hour meter. After a period of use, due to various reasons, there is a problem of inaccurate measurement. Therefore, it should be calibrated regularly, usually every 3 years.
Top 10 Electric Meter Brands
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