1. Seminar On
Prepaid Energy
Meter
By
ROHIT BHATIA
10EMREE072

2. Introduction
 What is an energy meter ?
 What is a prepaid energy meter ?
 Why prepaid energy meter must be used ?

3. Working of house hold energy meter
 Driving system:-
 Consist of 2 electromagnets made of silicon steel laminations.
 Coil of one of the electromagnet (shunt magnet) is excited by load current known
as current coil.
 Coil of 2nd electromagnet (series magnet) is connected across supply & carries a
current proportional to voltage known as pressure coil.
 Copper shading bands whose position is adjustable are provided on central limb
to bring the flux exactly in quadrature with the applied voltage.
 Moving system:-
 Consist of an aluminum disc mounted on a light alloy shaft positioned
in the air gap between magnets.
 Shaft is pivoted on jewel bearings and a pinion engages it with
counting or registering mechanism.

4.  Braking System:
 Braking Torque is required to control the speed of moving system.
 A permanent magnet is positioned near the edge of the aluminum
disc to provide braking torque.
 This magnet induces eddy currents that produces the braking torque
proportional to the speed of moving system.
 Registering or Counting Mechanism:
 Records continuously a no. proportional to a the revolutions made by
moving system.
 Train of gears drives a series of 4 or 5 pointers.
 There are 2 types of registers – pointer type & cyclometer register .

5. Internal view of Induction type energy meter

6. DISADVANTAGES OF INDUTION TYPE ENERGY
METER
 Induce human error while noting down the
reading.
 Amount of electricity consume in rupees is not
displayed.
 Creeping can cause significant error.

7. Block diagram of Prepaid energy meter

8. Overall characteristics of prepaid energy meter
 Collection of revenues.
 Loading the credit revenue into the meter.
 Decrementing the revenue.
 Providing the alarm.
 Disconnection.
 Security of transactions.
 Unloading the revenue.

9. Components of prepaid energy meter
 EEPROM IC (Smart card)
 AT89S52
 16*2 LCD
 ULN2003
 AT2402
 Digital energy meter

10. EEPROM IC
 It is called as smart card.
 It is a electrical erasable & programmble read only
memory.
 It is to upload the amount recharge in form of
electrical energy.
 The contents are automatically deleted once it is
inserted inside the card reader.

11. AT89S52
 It belongs to family of microcontrollers.
 It has total 40 pins.
 32 I/O lines.
 8K flash memory ROM and 256K RAM.
 It operates at 33KHz frequency.
 Only pin nos 12,31,40,34-39,22,21,25,28 are used for
our purpose.

12. ULN2003
 ULN 2003 are high-voltage high-current Darlington
transistor arrays.
 It consists of seven NPN Darlington connection.
 It acts as a current amplifier circuit.
 It is used to run a high voltage/current peripheral
circuits.
 When input terminal is high it offers low
impedance path other wise it offers a high
impedance.
 Any two input and output are used for our
purpose.

13. AT2402 and 16*2 LCD display
 Chip is used to read data from EEPROM through
card reader.
 All the data are transmitted serially in 8 bit words.
 It also verifies the code prior to read
operation(PSC).
 16*2 LCD display has two row screen and each
row displays 16 digit at a time.
 It also acts as a tariff indicator, indicates amount
of electricity consume and remaining.

14. Pin Diagram of 24C02
Pin Name
A0 - A2
SDA
SCL
WP
NC
GND
VCC
Function
Address Inputs
Serial Data
Serial Clock Input
Write Protect
No Connection
Ground
Power Supply

15. Digital energy meter
 ADE7757:-It is a high accuracy electrical energy
measurement IC.
 7805(voltage regulator):-It is Use to regulated the
power supply in electronic circuits.
 MCT2E(Opto-coupler): -It is a component that
transfers electrical signals between two isolated
circuits by using light.

16. Working principle of digital energy meter
 Output in form of frequency.
 Energy consume proportional to output
frequency.
 Relatively cheaper meter.
 Human error are reduced while calculating.
 Opto-coupler is used for calculation of pulses.
 Output frequency can be selected for other
purpose also , such as running a stepper motor an
electromagnetic register.

17. Circuit diagram of prepaid energy meter

18. Benefits to consumers
 Pay as you go.
 No need to stand in queue.
 No surprising bills.
 No bill disputes.
 Allow customer to budget expenses.
 Help customer contribute towards energy
conservation.

19. Benefits to utilities
 Up front payment for electricity.
 Lower overheads.
 No billing hassles.
 No disconnection/reconnection.
 Tamper and fraud detection.
 Money and time based load connection and
disconnection.
 Load/demand control.

20. THANK YOU