Miniature Circuit Breakers (MCB) in Automobile Engineering
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SARDAR PATEL INSTITUTE OF
TECHNOLOGY, PILUDARA
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Prepaid by :
Karan H. Rupareliya (130680102042)
Prajesh Aakhaja (130680102001)
Pintu ( 130680102043)
(Branch: Automobile Engineering)
undefinedMCB
(Miniature Circuit Breaker)
Topics :
Introduction
Principle of Operation
Construction
Classification
Application
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A Miniature Circuit Breaker is an
Electromechanical Device
which operates
and disconnects the circuit when the
current reaches a pre determined value
(High current).
An MCB is a replacement or most modern
substitute for a conventinal rewirable fuse
with most accurate efficient system in
overload and short circuit
.
Principle of Operation
MCB is a device which operate on the two
principles for the protection against
overload and short circuit :
1) Thermal for normal overload
Protection
2) Magnetic for short circuit protection
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The thermal
operation of miniature
circuit breaker
is achieved with a
bimetallic strip whenever continuous over
current flows through MCB, the bimetallic
strip is heated and deflects by bending.
This deflection of bimetallic strip releases
mechanical latch.
As this mechanical latch is attached with
operating mechanism, it causes to open the
miniature circuit breaker contacts.
But during short circuit condition, sudden
rising of
electric current
.
Miniature circuit breaker
Construction :
Miniature circuit breaker construction
is very
simple, robust and maintenance free. Generally an
MCB is not repaired or maintained, it just replaced
by new one when required. A miniature circuit
breaker has normally three main constructional parts.
These are :
1) Frame of Miniature Circuit Breaker
2) Operating Mechanism of Miniature
Circuit Breaker
3) Trip Unit of Miniature Circuit Breaker
1)
Frame of Miniature Circuit
Breaker :
The Frame of
Miniature Circuit
Breaker is a molded
case.
This is a rigid,
strong, insulated
housing in which the
other components
are mounted.
2
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The Operating Mechanism of Miniature Circuit
Breaker provides the means of manual opening and
closing operation of miniature circuit breaker.
It has three-positions "ON," "OFF," and "TRIPPED".
The external switching latch can be in the
"TRIPPED" position, if the MCB is tripped due to
over-current.
When manually switch off the MCB, the switching
latch will be in "OFF" position.
In close condition of MCB, the switch is positioned
at "ON".
3)
Trip Unit of Miniature Circuit
Breaker :
The Trip Unit is the main part,
responsible for proper
working
of miniature circuit breaker
.
Two main types of trip
mechanism are provided in
MCB.
A bimetal provides protection
against over load current and
an electromagnet provides
protection against short-circuit
current.
C
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o
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MCB are classified into two series :
1)
L series MCB for lighting circuits
:
Suitable for resistive load installation with low
and steady currents like heaters, ovens, geysers,
GLS lamps, electric irons, etc.
The L series MCBS are also used protection of
distribution equipment like wires, cables,
metering equipment etc.
2)
G- series MCB for motor
circuits
:
It is suitable for use in installation with high
inrush current peaks which require closer
overload protection.
These include inductive loads such as motors,
air conditions, transformers, halogen lamp,
fluorescent lamps, sodium vapour lamps ,
machine tools etc.
Application Of MCB
:
MCB are required in homes, offices, shops
distribution boards for protection of
individual circuit and complete wiring
system in that building through main circuits.
MCB are sightly more expensive than fuses
but this is offset by the fact that no cost is
involved in resetting them after operation
and it is very quick & simple process.
They are being used extensively these days
and are virtually replacing the traditional
rewirable fuses.
References
U.A PATEL (2013-2014)
MAHAJAN (2013-2014)
BOOKS INDIA PUBLICATION (2013-
2014)
T
H
A
N
K
Y
O
U
…
Learn about Miniature Circuit Breakers (MCB) used in Automobile Engineering, including their principle of operation, construction, and application. MCBs serve as efficient replacements for traditional fuses, providing overload and short circuit protection through thermal and magnetic mechanisms. The construction of MCBs involves three main parts: the frame, operating mechanism, and trip unit. Discover the essential features and functions of MCBs for enhanced safety in electrical circuits.
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Presentation Transcript
SARDAR PATEL INSTITUTE OF TECHNOLOGY, PILUDARA Prepaid by : Karan H. Rupareliya (130680102042) Prajesh Aakhaja (130680102001) Pintu ( 130680102043) (Branch: Automobile Engineering) Guided by : Vaishali D.Patel
MCB (Miniature Circuit Breaker)
Topics : Introduction Principle of Operation Construction Classification Application
What is MCB? A Miniature Circuit Breaker is an Electromechanical Device which operates and disconnects the circuit when the current reaches a pre determined value (High current). An MCB is a replacement or most modern substitute for a conventinal rewirable fuse with most accurate efficient system in overload and short circuit.
Principle of Operation MCB is a device which operate on the two principles for the protection against overload and short circuit : 1) Thermal for normal overload Protection 2) Magnetic for short circuit protection
1) Thermal for normal overload Protection : The thermal operation of miniature circuit breaker is achieved with a bimetallic strip whenever continuous over current flows through MCB, the bimetallic strip is heated and deflects by bending. This deflection of bimetallic strip releases mechanical latch. As this mechanical latch is attached with operating mechanism, it causes to open the miniature circuit breaker contacts. But during short circuit condition, sudden rising of electric current.
Miniature circuit breaker Construction : Miniature circuit breaker construction is very simple, robust and maintenance free. Generally an MCB is not repaired or maintained, it just replaced by new one when required. A miniature circuit breaker has normally three main constructional parts. These are : 1) Frame of Miniature Circuit Breaker 2) Operating Mechanism of Miniature Circuit Breaker 3) Trip Unit of Miniature Circuit Breaker
1) Frame of Miniature Circuit Breaker : The Frame of Miniature Circuit Breaker is a molded case. This is a rigid, strong, insulated housing in which the other components are mounted.
2) Operating Mechanism of Miniature Circuit Breaker : The Operating Mechanism of Miniature Circuit Breaker provides the means of manual opening and closing operation of miniature circuit breaker. It has three-positions "ON," "OFF," and "TRIPPED". The external switching latch can be in the "TRIPPED" position, if the MCB is tripped due to over-current. When manually switch off the MCB, the switching latch will be in "OFF" position. In close condition of MCB, the switch is positioned at "ON".
3) Trip Unit of Miniature Circuit Breaker : The Trip Unit is the main part, responsible for proper working of miniature circuit breaker. Two main types of trip mechanism are provided in MCB. A bimetal provides protection against over load current and an electromagnet provides protection against short-circuit current.
Classification : MCB are classified into two series : 1) L series MCB for lighting circuits : Suitable for resistive load installation with low and steady currents like heaters, ovens, geysers, GLS lamps, electric irons, etc. The L series MCBS are also used protection of distribution equipment like wires, cables, metering equipment etc.
2) G- series MCB for motor circuits : It is suitable for use in installation with high inrush current peaks which require closer overload protection. These include inductive loads such as motors, air conditions, transformers, halogen lamp, fluorescent lamps, sodium vapour lamps , machine tools etc.
Application Of MCB : MCB are required in homes, offices, shops distribution boards for protection of individual circuit and complete wiring system in that building through main circuits. MCB are sightly more expensive than fuses but this is offset by the fact that no cost is involved in resetting them after operation and it is very quick & simple process. They are being used extensively these days and are virtually replacing the traditional rewirable fuses.
References U.A PATEL (2013-2014) MAHAJAN (2013-2014) BOOKS INDIA PUBLICATION (2013- 2014)
