Circuit BreakersA circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected.

1. Circuit
Breakers
Basics of Biomedical
PREPARED
BY ATHEENA PANDIAN

2. Presentation Flow
TOPICS TO BE DISCUSSED
What is Circuit Breakers?
Need
Parts
Construction
Working
Types
Applications
1.
2.
3.
4.
5.
6.
7.

3. What is Circuit
Breakers?
It is an automatically operated
electrical switch designed to protect
an electrical circuit from damage
caused by excess current from an
overload or short circuit.

4. Parts
a frame,
operating mechanism,
interrupting structure,
trip unit, and
terminal connections.
Circuit Breakers basically
contain five components —
1.
2.
3.
4.
5.

5. Construction
Their construction is mainly divided into
three parts, i.e., fixed contacts, moving
contact and arc shield which is placed
inside the arc interrupting chamber.

6. WORKING PRINCIPLE
Circuit breaker essentially consists of
fixed and moving contacts. These
contacts are touching each other and
carrying the current under normal
conditions when the circuit is closed.

7. NEED OF CIRCUIT BREAKER
Overload
Short Circuit
Earth
In order to keep our electrical
components & system safe, it is
mandatory to protect our system
against the below faults. This leads to
the need of circuit breaker.
1.
2.
3.

8. Vacuum circuit
breakers
Air circuit
breakers
SF6 circuit
breakers
MEDIUM-VOLTAGE
CIRCUIT BREAKERS
1.
2.
3.
Bulk oil
Minimum oil
Air blast
Vacuum
SF6
CO2
HIGH-
VOLTAGE BREAKERS
(classified by the medium
used to extinguish the arc)
1.
2.
3.
4.
5.
6.
Types
CIRCUIT BREAKERS
Miniature circuit
breaker (MCB)
Molded Case Circuit
Breaker (MCCB)
Low-voltage power
circuit breakers
LOW VOLTAGE CIRCUIT
BREAKER
1.
2.
3.

9. LOW VOLTAGE
CICUIT BREAKERS
It is one which is suited
for circuits rated at 600
volts or lower. One of the
most commonly
used low-
voltage air circuit
breakers is the molded
case circuit breaker

10. MEDIUM VOLTAGE
CICUIT BREAKERS
These are the ones which
operate on voltage levels
around 400 volts to 15kV
approximately. The reason
they are named so is that
extremely
low voltage conditions are
not suitable for them to
operate properly, neither a
very high voltage helps
them perform their
operation accurately.

11. HIGH VOLTAGE
CICUIT BREAKERS
Electrical power
transmission networks are
protected and controlled by
high-voltage breakers

12. The circuit breaker is a
switching device which also
offers protection by tripping &
cutting off the supply to load
in case of fault. Primarily the
circuit breakers are used for
switching of different kinds of
load in Industries, Buildings,
Commercial Complexes, and
Hotels etc.
CIRCUIT BREAKER
Applications

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