Presentation on Over-/under-voltage protection of electrical appliance

Sudden fluctuation in supply is a very big problem in industries and domestic applications. It causes a major loss for industries, offices and homes.
This project gives a low cost and powerful solution for this problem. This Circuit protects refrigerators ,ACs, Microwave ovens as well as other appliances from over and under voltage fluctuations.

1. Presentation on Over-/under-voltage protection of electrical appliance Submitted by: rakesh roshan(0701209329) nishant kumar(0701209350) abhishek pattnaik(0701209404) narayan singh(0701209288) ashish kumar nayak(0701209345 ) Under guidance of Er. Alice Pradhan

2. Introduction: Sudden fluctuation in supply is a very big problem in industries and domestic applications. It causes a major loss for industries, offices and homes. This project gives a low cost and powerful solution for this problem. This Circuit protects refrigerators ,ACs, Microwave ovens as well as other appliances from over and under voltage fluctuations.

3. Block diagram:

4. Circuit diagram

5. Simulated circuit diagram

6. Components: TRANSFORMER IC 7812 LM 324 (OPERATIONAL AMPLIFIER) RELAY ZENER DIODE npn TRANSISTOR RESISTORS ,CAPACITORS AND DIODES

7. TRANSFORMER Step down transformer 230V/12V Operating frequency is 50HZ. Voltage is converted from 230v to 12v. Current rating is 1A.

8. IC LM7812 (VOLTAGE REGULATOR) Output current in excess of 1A. Output Voltages of 12V. current Internal thermal overload protection. No external components required. Output transistor safe area protection. Internal short circuit limit.

9. IC LM324 (OPERATIONAL AMPLIFIER) Features : Large DC voltage gain:100 dB Wide power supply range: Single supply:3VDC to 32 VDC Dual supplies:±1.5VDC to ±16VDC Differential input voltage range equal to the power supply voltage Power drain suitable for battery operation Large output voltage swing:0VDC to VCC-1.5VDC

10. PIN CONFIGURATION (LM 324)

11. Its rating is 12v, 200 ohm ,1 c/o relay. Relay SPDT – Single Pole Double Throw. A common terminal connects to either of two others. Including two for the coil, such a relay has five terminals in total. A relay is an electrically operated switch .

12. A Zener diode is a type of diode that permits current not only in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the breakdown voltage known as "Zener knee voltage" or "Zener voltage“. Zener diode of rating 6.0 v and 6.8 v are used in the circuit. ZENER DIODE

13. BC 547 transistor is used in the circuit. Transistor is used to energise the relay when op-amp goes high. npn TRANSISTOR

14. Diodes Resistor capacitor RESISTORS ,CAPACITORS AND DIODES

15. APPLICATIONS: Industrial machinery House hold items like TV, refrigerator, AC Agriculture Motors Water pumps

16. ADVANTAGES: Highly sensitive Fit and Forget system Low cost and reliable circuit Complete elimination of manpower Can handle heavy loads up to 7A Auto switch OFF in abnormal conditions Auto switch ON in safe conditions

17. CONCLUSION: It is helpful in protecting electrical appliances in very effective way.

18. REFERENCE : www.wikipedia.org www.efy.com www.google.com

19. THANKs..