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Introduction Our current household watt-hour meters are all active watt-hour meters. It records the active energy consumed by electrical appliances, and does not record reactive energy. The heating elements such as ordinary light bulbs and electric furnaces consume only active energy. . So how much A is suitable for a household electric meter? How big of an electric meter should a home install? Generally, the rated current of household electric meters should not be greater than 10 amps. The specific situation will also be determined according to the needs. Below, we will introduce the capacity selection and installation of some household electric meters.
Introduction to the types of electric energy metersElectric meter classification
Electric energy meters are instruments used to measure electric energy, also known as watt-hour meters, fire meters, kilowatt-hour meters, which refer to instruments that measure various electrical quantities, commonly known as electricity watt-hours Table, fire table. [Household Electricity Meter Wiring Diagram]
By use: industrial and civil meters, electronic standard meters, maximum demand meters, multi-rate meters
By structure And working principle: induction type (mechanical type), static type (electronic type), electromechanical integrated type (hybrid type)
According to the nature of the power supply: AC meter, DC meter
According to the accuracy level: common ordinary table: 0.2S, 0.5S, 0.2, 0.5, 1.0, 2.0, etc.
Standard table: 0.01, 0.05, 0.2, 0.5, etc.
According to installation wiring Mode: direct access, indirect access
According to electrical equipment: single-phase, three-phase three-wire, three-phase four-wire electric energy meter. [Three-phase four-wire meter wiring diagram]
Types of household electricity metersElectric meter classification How to choose household electricity meters
The household appliances need electricity , and electricity needs to be metered, and electricity metering is necessary to use a watt-hour meter. How to choose the right watt-hour meter? The selection of the watt-hour meter should be determined according to the load. That is to say, the capacity or current of the selected watt-hour meter is determined according to the size of the load in the calculation circuit. If the capacity or current is selected too large, the watt-hour meter cannot rotate normally, which will affect the accuracy of the measurement results due to its own errors. ; If the capacity or current selection is small, the watt-hour meter may be burned. Generally, the total load power of the selected watt-hour meter should be 1.25 to 4 times the actual total power consumption. Therefore, before selecting the capacity or current of the watt-hour meter, it should be calculated first. For example, if you use 4 lighting lamps at home, it is about 120 W; if you use electrical appliances such as televisions and refrigerators, it is about 680 W; try to use the current capacity of the watt-hour meter. From this we get: 800×1.25=900(w) or 800×4=3200(W), the load wattage of the watt-hour meter used is between 900 and 3200 W. It is more appropriate to choose a current capacity of 10 to 15 A.
When choosing a watt-hour meter, in addition to considering the current capacity, it is also necessary to pay attention to the inherent quality of the meter, especially whether the lead seal on the watt-hour meter case is damaged. Generally speaking, the watt-hour meter should be checked for accuracy before leaving the factory. After passing the inspection, seal the detachable parts of the watt-hour meter, and users are not allowed to open the seal without permission. If the lead seal is damaged, it must be re-calibrated by the relevant department before it can be used.
How much amperage is a general household electric meter
Selection of the capacity of the electric meter: The capacity of the electric meter should be selected between 20~120% of the rated current of the electric meter, and the single-phase 220V lighting device should be 5 amps per kilowatt, three-phase 380V power consumption should be calculated at 1.5 amps or 2 amps per kV.
The size of the current of the electric meter: the rated current of the general household electric meter should not be greater than 10 amps. This is because:
When the power factor is 1, the starting current of the meter is about 0.5~1% of the rated current, so a 10A meter will only start when a current of 0.05~0.1A passes through. Turning, its power is equivalent to 12~24 watts on the 220V line. Although an electric meter is a precision instrument, there is still unavoidable mechanical resistance when it is rotated. When starting to rotate, the accuracy of the meter is not high in this case because the motive torque is not much different from the mechanical resistance.
A calibrated meter can only guarantee that under the rated voltage, when the current is within the range of 10~100% of the rated current, and the power factor is 0.5~1, its error will not exceed 1 ~2%. That is to say, a 10A meter can only achieve accurate measurement when the load is 110~2200 watts. At present, the wattage of electricity in general households does not exceed this range. If the nameplate current of the electric meter exceeds 10A, the purpose of the measurement standard will not be met, so it is not suitable for use.
Installation of the electric meter
1. The electric meter should be installed on the wall or switch board that is not easily affected by vibration, and the distance from the ground should be between 1.7~2 meters;
2. Install the electric meter The place should be clean, dry, and free from strong magnetic fields, and should be located in an obvious place for reading and monitoring;
3. The electric meter should be installed in places susceptible to mechanical damage, dirt and touch Inside the box;
4. The meter should be installed vertically, and the allowable deviation should not exceed 2°;
Power-on inspection: power-on to check whether the power meter is working properly. If there are abnormal phenomena such as non-rotation, reversal and excessive error, the reasons should be analyzed and eliminated. Most of these faults are caused by wiring errors. The reason for the reversal may be that the polarity of the voltage and current coils are reversed, the polarity of the current and voltage transformers are reversed, or the load may be abnormal. For example, in the load of a three-phase active watt-hour meter, when a motor with a larger capacity overspeeds, the motor becomes a generator operation, and the active watt-hour meter will reverse.
Calculate and check the operation of the electric meter: The electric meter should be calculated and checked after it has been put into use for a period of time. Sometimes, although the wiring is wrong, it is difficult to observe the operating state of the watt-hour meter alone. Therefore, it is necessary to calculate according to the power, power factor and working time of the load, and compare the calculation result with the reading of the watt-hour meter to confirm the reliable operation of the watt-hour meter. .
Electric meter classification
For electric meters, everyone may feel familiar and unfamiliar. Everyone has at least one electric meter in their home. But many people only know that the electric meter is an instrument used to measure the number of electricity, and they do not know how the electric meter looks. Therefore, in our real life, we often see some people copying the electricity for a few kilowatts of electricity, that is, a few dollars. The electricians at the meter clashed and even refused to pay the electricity bill. The following will tell you how the smart meter looks:
The first type: General straight-forward single-phase and three-phase meters can directly read the number minus the last one The reading is the power at this stage. The incoming wire of the straight-type meter is thicker, and it is carefully observed that it is not connected through the transformer.
The second type: The three-phase electricity meter is connected by the current transformer connection. Ratio, there is a current transformer on the nameplate, which is marked with a number ratio of 5, such as 100/5150/5, etc., the number read on the meter multiplied by the current ratio is the measured amount of electricity, and the accuracy must be added to the variable. loss and line loss.
The third type: Single-phase electricity meters measure the electricity of three-phase electricity. The power reading method is to read the number on the meter by 3 by connecting the meter directly. If the meter is connected through a transformer, the number of the meter should be multiplied by the current multiple of the transformer and then multiplied by 3.
The fourth type: The smart meter has only one LCD screen. If it is a single-phase, it will directly display the total power and remaining power, which can be read directly. If it is an IC card meter, only the LED display is a single graphics card meter. There will be a small red dot on the meter. If the red dot jumps to the total usage, it is the total usage, and if it jumps to the remaining location, it 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.
Finally, I want to tell you that stealing electricity and leaking electricity is illegal and immoral. I remind consumers, especially those who like petty and cheap, that they should pay on time in their daily electricity consumption. Electricity bills, do not steal electricity and leak electricity. If you see the behavior of stealing electricity and leaking electricity, you should report it in time and be a good citizen who abides by the law.
Electric meter classification
Smart meter is a rapidly developing meter category. Traditional smart meter users hold IC cards to the power supply department to pay for electricity, and the power supply department uses the electricity sales management machine to The purchased electricity is written into the IC card, and the user holds the IC card and swipes the non-contact IC card in the induction area (referred to as swiping the card, the same below), then the power supply can be turned on, and the card can be removed after the power is supplied. When the remaining power in the meter is equal to the alarm power, the power off alarm (or buzzer alarm) will be triggered. At this time, the user can restore the power supply by swiping the card in the induction area; when the remaining power is zero, the power will be automatically switched off. The electricity can be restored only when the card is used to pay for electricity again. The new smart meter has achieved bank and network power supply, and users can purchase electricity through the business window of the power company, cooperative banks, third-party electricity sales agencies and the network, which greatly facilitates users.
Main functions
1. Pre-paid function: pre-charge electricity bills, and automatically switch off when the remaining electricity is zero.
2. Closing and opening method: There are two specifications of internal switch and external control switch.
3. Memory function: The data in the table can be saved for 10 years in case of power failure.
4. Display function: dual display, the meter displays the accumulated power consumption, and the LED display shows the remaining power and other information.
5. It can detect the flow that cannot be detected by ordinary electric meters (such as sockets, wiring boards, etc.). Accurate billing.
6. The intelligent price adjustment mode can intelligently adjust the price for users who consume too much electricity, so as to achieve the effect of energy saving and emission reduction.
Specifications
1. Accuracy level: 1.0, the basic error, starting and creeping meet the requirements of the national standard.
2. Current specification: 2.5(10)A 5(20)A 10(40)A 20(80)A 30(120)A
3. Meter constant: 1600imp /kWh 800imp/kWh
4. Power consumption <1.0W
5. Patented non-contact (radio frequency) IC card technology: using the world’s most advanced radio frequency IC card and Base station technology, fully sealed, non-contact, moisture-proof, waterproof, anti-attack, anti-theft, anti-magnetic, anti-interference performance.
6. Data voting error correction technology: each data in the table is stored in five places. If the data is wrong, it can be corrected in other places, so that the data is absolutely reliable and foolproof. .
Features
1. No manual meter reading is required, which is beneficial to modern management. The use of IC card electricity meters avoids many inconveniences caused to customers by manual meter reading and door-to-door charging, and historical electricity purchase data can be saved, which is convenient for customers to query.
2. It fully reflects the commodity attributes of electricity. Implement electricity purchase first and then use electricity, customers can purchase and use electricity in a planned way according to their actual needs, and there will be no late fees due to arrears and unnecessary expenses.
3. Solved the problem of difficult charging. It can well solve the charging problem of scattered residential customers, temporary electricity customers, and customers who often default on bills.
4. The IC card meter has a variety of anti-theft functions, small starting current, no creep, wide load, low power consumption, straight error curve, good stability during long-term operation, beautiful appearance, Small size, light weight and easy installation. High accuracy: fully electronic design, built-in imported special chip, the accuracy is not affected by frequency, temperature, voltage high-order harmonics.
5. Long life: using SMT technology, optimized circuit design, no need to adjust the circuit after the whole machine leaves the factory.
6. Low power consumption: adopt low power consumption design to reduce power grid line loss.
7. Pre-purchased power; IC card transmits data to realize data readback, including: readback of total power, remaining power, accumulated power purchase in the meter, total power purchase times and other information.
8. Store table constants, initial values, user addresses, names and other information.
9. Overload alarm power off, residual power alarm, remind users to purchase electricity in time.
10. Technical parameters: The long-life base table is adopted to prolong the service cycle.
Installation and use
When installing the prepaid smart meter, the installation position should be kept vertical and connected according to the wiring diagram.
1 Open the cover of the terminal button box of the electric energy meter, then connect the wiring of each terminal button according to the wiring diagram, and turn on the power.
2 The user inserts the pre-purchased power IC card into the watch in the direction of the arrow on the card (the metal contact faces to the left), the display first displays F1 and then displays the purchased power, and then displays F2 steadily and then the display shows the original The sum of the remaining power plus the newly purchased power is the current remaining power. At this time, the IC card can be removed and the display will turn off. (For example, when the remaining power in the meter is lower than the displayed alarm power, the display is always on, and when the sum of the original remaining power in the meter and the power in the power purchase card is greater than 9999kWh, the power in the card will not be input to the meter and will still be stored in the card.)
3 When the user uses electricity, the pulse indicator will flash accordingly.
4 During the normal use of the prepaid electricity meter, the purchased electricity will be automatically calculated in decreasing order. When the remaining power in the electric energy meter is less than 20 degrees, the display will display the current remaining power to remind the user to purchase electricity. When the remaining power is equal to 10 kWh, the power outage reminds the user to purchase electricity once. At this time, the user needs to insert the IC card into the electric energy meter to restore the power supply once. When the remaining power is zero, the power supply is stopped.
5 One meter and one card. After each new purchase of electricity, users can only insert their own electricity meter to input valid electricity once.
6 The display of the prepaid electricity meter is usually off. If the user needs to check the remaining electricity, he can insert the IC card into the electricity meter, and it will display F1 to purchase electricity and display zero, and F2 to display the remaining electricity.
7 Every time the user inserts the IC card into the prepaid meter, the meter will write back all the user’s electricity consumption on the IC card. When the user purchases electricity next time, the electricity sales management system will read the IC card data Aggregate and check whether users are using electricity legally. Electricity inspectors can also use the inspection card to check the user’s electricity consumption.
8 The power supply management department sets the user’s maximum electricity load according to the actual situation. When the actual power load exceeds the set value, the power supply will be stopped, and the meter display will display “E2”, reminding the user to reduce the power load. The user needs to insert the IC card into the power meter to restore the power supply.
Types of common problems to be solved Problem 1: Burnt smell in the bakelite junction box
There are two main reasons for the burnt smell in the bakelite junction box at the bottom of the dial: First, during installation or replacement When the circuit wire is connected, the fixing screw in the box is not tightened. When the electrical load of the electrical appliance increases, the screw column will heat up due to poor contact, and the bakelite box will be burned out and accompanied by a burning smell. The solution is very simple. After removing the terminal cover of the lower limb surgery, pull down the main switch knife, remove all the power leads, use the knife again to scrape off the residue of the wire ends, put them into the terminal posts, and tighten all the screws to eliminate the fault.
Another reason is that the quality of the wires connected to the meter from the room is poor, which causes an oxide layer between the copper column and the wire (especially the meter installed in a humid and unventilated place is prone to Such problems), thereby increasing the resistance value and causing the contacts to heat up and damage the junction box. At this time, the oil in the junction box should be completely removed and the wires should be replaced. Sometimes when the electrical equipment exceeds the actual ampere value of the meter, not only the junction box will be damaged, but the meter may also be damaged by strong current. Replace the watt-hour meter in case the meter is damaged or an electrical fire occurs.
Question 2: Self-rotating when no-load
The meter will rotate by itself when no-load, that is, all electrical equipment and lighting fixtures in the house are not in use, and the aluminum plate of the meter is still rotating or slowly crawl. Generally speaking, when the power supply voltage is 80% to 110% of the rated value, the rotation of the aluminum plate of the electric meter will not exceed one circle, which is a normal range (that is, the turntable rotates one circle clockwise), but if the aluminum plate rotates slightly more than It means that there is leakage in the meter circuit, and an electrician should be asked to check and deal with it. If there is no leakage, it is the fault of the meter itself, and it should be sent to the power department for maintenance or a new meter in time.
Question 3: There is a “squeaking” sound during operation
When the watt-hour meter is running, there is a slight “humming” sound, which is a normal phenomenon. However, if there is an irregular noise in the watch, it is caused by the aging of some accessories inside the watch, the loosening of some components of the electromagnetic field, or the lack of oil in the rotating gear. It should be sent to the power department for verification and replacement of vulnerable parts. Sometimes, when the meter is in serious overload operation, it will also produce irregular noises. Some electrical appliances should be turned off in time to prevent damage to the meter.
Question 4: The aluminum plate stops rotating or does not skip the word A: kitchen storage and kitchen storage, function: lotion is a kind of transparent liquid kitchen storage and kitchen storage, function: lotion is a transparent liquid Liquid makeup kitchen storage storage kitchen storage, role: make-up… Question 5: How to test by yourself if the meter is inaccurate
Usually, if you suspect that the meter is inaccurate, you can use the following methods to test it. Generally, the sign of the electric meter is marked with the number of revolutions of the aluminum plate per kWh of electricity consumed. If lighting a 100-watt light bulb continuously consumes 0.1 degrees of electricity per hour, it means that the aluminum plate should rotate 300 times, and the aluminum plate should rotate about 5 times per minute on average. After this simple test, we can know whether the meter is running normally. When the test result and the actual error are very large, it should be suspected that there is a problem with the meter.
