PPT ON MCB

THIS PPT WILL HELP YOU TO UNDERSTAND HOW THE "MCB"
CONSTRUCTED AND IT"S FUNCTION WITH IT"S PARTS.

1. MINIATURE CIRCUITBREAKER
(MCB)
by
S. SanthoshKumar
14125A0231

3. Objective
To understand the components, working principle of
Miniature Circuit Breaker (MCB), and its
advantages over traditional fuse.

4. Contents
•Introduction: history and its use
•Function
•Construction of MCB
•Working Principle
•Advantages
•Application
•Comparison : Fuse Vs MCB
•Conclusion

5. Introduction
•Thomas Edison developed the idea for a
circuit breaker in 1879.
•Granville Woods improved upon the design
and invented the automatic circuit breaker in
1900.
•Cutter Manufacturing Company manufactured
the first circuit breakers in Philadelphia in
1904.

6. Functions
•Switching Function: On/Off
•Protection Function: Overloads/Short Circuits

7. CONSTRUCTION
OF
MINIATURE CIRCUIT BREAKER

8. Cross-Sectional View

9. Main Parts of MCB
THERMAL UNIT MAGNETIC UNIT

10. Parts of MCB
ARC-CHUTES KNOB

11. Parts of MCB
INCOMING AND OUT GOING
TERMINAL INSIDE OF MAGNETIC UNIT

12. WORKING PRINCIPLE
OF
MINIATURE CIRCUIT BREAKER

13. On/Off Positions

17. Arc Formation
Arc-Chute

19. Comparison: MCB Vs fuse
MCB
(Miniature Circuit Breakers)
FUSE
1MCB trips off in case of
excessive load.
Fuse melts/fuses in case of
excessive load.
2MCB is to be just put-on after
correcting the fault in wiring.
Fuse needs to be replaced with a
new one.
3Since we do not change the
MCB, there is no risk of putting
on the MCB/switch even if the
fault is not correctly repaired.
There is a risk of putting on the
switch in case; due to ignorance
higher capacity fuse-wire is
positioned.
4Compact, small equipment. Porcelain base and top. Not
attractive.
5Works on Bi-metal expansion or
induced magnetism.
Works on melting/fusing due to
high temperature.
6Relatively costlier than fuse.Relatively cheaper than MCB.

20. Advantages over fuse
•Easily identify the faulty zone of electrical
circuit
•Simple to resume supply
•Better Interface: knob
•Electrically safer
•More sensitive to current than fuse
•Reusable
•Less maintenance and replacement cost.

21. Applications
•Home Electrical Panels
•Ground Fault Trip Mechanism
•Lights
•Industrial Applications
•Heaters

22. Conclusion
Miniature Circuit Breakers are more effective
than traditional fuse.

23. Thank You