ONE. The main structure and working principle of the prepaid electric energy meter.
The electronic components of the prepaid energy meter are mounted on a printed circuit board (PCB) and the upper cover is fixed with screws, one of which can be sealed with lead, and the terminal button cover is fixed with two special screws, on which can be sealed with lead.
The working principle of the energy meter is accomplished by two main functional blocks, one is the measuring system, the other is the special circuit processing system. The measuring system is a three-phase electronic watt-hour meter. Its working principle is: voltage sampling is completed by voltage divider, current sampling is completed by transformer, and the voltage and current signal after sampling is converted into power signal by Four Quadrant Analog multiplier. Users are required to pay for electricity at the electricity sales office of the power supply department. The amount of electricity purchased is written into the user's card on the motor sold and transmitted to the meter by the card. The high security of card encryption can protect users' reliable use. When the electricity consumption is exhausted, the relay in the table will automatically cut off the power supply circuit.

TWO. Installation method of prepaid electric energy meter
There are hook screw holes at the upper end of the base of the watt-hour meter, which can be fixed by M4 hook screw. There are two mounting holes at the lower part of the electric meter, which can be fixed on the wiring board by M4 *10 or M4 *12 screw. The bottom of the mounting meter should be fixed on a solid refractory wall. It is suggested that the mounting height be about 1.8 meters and there is no corrosive gas in the air.
The electric energy meter should be connected according to the wiring diagram, preferably with copper wire or copper wire connector.

THREE. What are the main features of the Prepaid energy meter?
Prepaid electric meter, also known as quantitative watt-hour meter, IC card watt-hour meter, in addition to ordinary watt-hour meter metering function, in particular, the user first buy electricity, after buying electricity can use electricity, if the user does not continue to buy electricity, then automatically cut off the power supply to stop.
With the increase of residential electricity consumption, prepaid watt-hour meter is more and more widely used. What are the main characteristics of prepaid watt-hour meter?

1. There is no need to initialize the newly installed and replacement direct reading energy meter.
2. The whole system does not need any power supply at ordinary times. It only needs instantaneous power supply when reading meter, and the data will never be lost.
3. When the open circuit and short circuit fault occur in the signal line, it does not affect the accuracy of the data. When the line returns to normal, the collected data is still consistent with the current counting value of the electric meter.
4. In the wet water meter, a unique patent sealing technology scheme is adopted to seal the sensor and the wheel in the transparent wheel box, which can be used in different water quality. This not only ensures that the reading of the meter is permanent and clear, but also ensures the long-term stability and reliability of the part of the electronic sensor.
5. There is no cumulative error in data acquisition, and there will be no error code in the acquisition of word wheel carry.
6. It is not affected by external voltage, light source, high and low frequency, magnetic field, water pressure and other environmental factors.