project ppt

1. ELECTRIC LOCO SHEDn.c.r. KANPUR
(an unit of indian government)
Submitted to:
Mr. Md. Israr (SSE)
Submitted by:
Mr. SACHIN SINGH
M.P.E.C. KANPUR
1304620015
Project presentation on FAILURE OF FUSE & MCB

2. ELECTRIC LOCO SHED
KANPUR

3. CONTENT
• What is fuse
• Different types of fuse
• Fuse in electric loco
• Different types of fuse in loco
• Use of fuse in loco
• Failure of fuse
• Maintenance of fuse
• Circuit breaker
• Miniature circuit breaker
• MCB working principle
• MCB construction
• Trip unit of MCB
• Overload protection
• Advantage & disadvantage of MCB
• Characteristics of MCB

4. INTRODUCTION
o ESTABLISHMENT
o The Electric Loco Shed, Kanpur was established in 1965 with
the Electrification of Mughalsarai-Kanpur section. The shed
started functioning with a meager holding of 11 imported
WAM-1 type locomotives for Passenger services.
o It’s main purpose is of maintenance of
o WAP1,WAP4,WAP5,WAP7 ,WAG5, WAM4 engines.
o INITIAL COST
o Rs. 1.5 (IN CRORES)
o PRESENT LOCO HOLDING
o 201,(43-WAP4, 153-WAG7, 02-WAG-9 & 3-WAM4)

5. What is a fuse?
 A fuse is a device that
protects against damage from
excessive current. It contains
a short piece of wire made of
an alloy that melts readily.
 The flow of current through a
fuse causes the wire to heat
up and melts when excessive
current passes through the
fuse.
 A burned-out fuse which is
commonly called a "blown"
fuse must be replaced for the
circuit to function.

6. Different types of
fuses
Blade Type Fuses
Glass Fuses
SMT Fuses
Bolt-In Fuses

7. FUSE IN ELECTRIC LOCO
 NH fuses are types of
electrical resistors used as
sacrificial devices to
protect electrical circuits
in industrial related plant.
 NH fuses are easily
identified by their square
or oblong bodies combined
with blade style terminals.
 Due to their larger body
size they have higher
ratings comprising of up
to 1.25kA in sum total.

8. Different types of fuses in loco

9.  Fuse used in electric locos are different types such as
shown in figure. they are bigger in size heavier in
weight as compared to normal fuse.
 the construction of fuse is also different such as they
are made up by molding the winding or made up by
ceramics. they can survive for high voltage and high
current.
 the rating of fuse shown in figure is 1000V/1000A. the
resistance of fuse are very small such as in milliohm.
the resistance of fuse shown in figure is
0.0949mΩ/210C.

10. Use Of Fuse In Electric Loco
 The loco have six dc motor to run
these motor the dc supply is
required. The loco have a
pantograph which takes supply from
the main line which is generally a
25Kv line.
 A transformer is connected After the
pantograph to step down the supply
to probably 1000V.
 A bridge rectifier is connected in the
secondary side of the transformer.
The bridge rectifier used diode to
rectify the supply.
 The maximum number of diode
used in rectifier is 28 & the
minimum number of diode used is
12

11.  The fuse are connected in
parallel in each of diode to
protect it from damage. They
are connected in parallel of
each diode. When a fault
current occurs it diverted it
due to its small resistance.
 The anode & cathode are
mentioned in the box. It is
divided into two parts &
diode is settled in between of
the parts. The diode is works
as a bridge in between them.
The terminal of anode &
cathode is as a blade type.

12.  The given figure shows the
diode which is used to
rectify the AC supply into
DC supply. They are
circular in size & heavy in
weight.
 The anode & cathode are
mentioned in the diode.
They are not directly
connected to the
secondary side of
transformer.

13. FAILURE OF FUSE
 When the current due to fault is
very heavier & crosses the rating
of fuse then the fuse’s contact is
opened up.
 The fuse winding are in a box so
a mentor is unable to see the
fuse whether it us damage or
not.
 A indicator is holded upon the
surface of fuse it is near the
blade type terminals. When the
fuse is blown out the red pin
comes up which means the fuse
is damaged.
 The indicator is shown in the
red circle of the given figure.

14. MAINTENANCE OF FUSE
 When fuse is blown out the indicator indicates that by pin
mounted on the surface of fuse. The pin comes outside the
surface of fuse that means the fuse not more usable.
 So for the safe drive of train that’s the equipments will not
be damaged it has to replace by some another fuse. So
maintenance of fuse is done by replacing it by another fuse.
 The damaged fuse will not rectified again so that we can
not use it again means when a fuse is damaged it can not be
repaired by anyhow.
 So the only thing which is possible is replacing that fuse by
another new fuse.

15. What is a circuit
breaker?
 A circuit breaker is an
automatically-operated
electrical switch designed
to protect an electrical
circuit from damage
caused by overload or short
circuit. Its basic function is
to detect a fault condition
and, by interrupting
continuity, to immediately
discontinue electrical flow.

16. Miniature Circuit Breakers (MCB)
 As the name implies it is the miniature form of circuit
breaker.
 It can operated as an ordinary switch in
making/breaking the circuit on which it has been
applied on.
 It is easy to handle and provide complete safety to
human beings.
 They have vast range and small steps between rated
current, allow cables to be utilized fully.

17. MCB Working Principle
 There are two arrangement of operation of
miniature circuit breaker. One due to
thermal effect of over current and other due
to electromagnetic effect of over current.
 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.
 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, causes electromechanical
displacement of plunger associated with
tripping coil or solenoid of MCB.
 The plunger strikes the trip lever causing
immediate release of latch mechanism
consequently open the circuit breaker
contacts.
 This was a simple explanation of miniature
circuit breaker working principle.

18. MCB
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.

19. 3. Trip Unit
Of MCB
 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.

20. Overload protection
A bimetal strip is used: to protect the cable against
overload symbol:
 principle of the bimetal: in a Multi 9 circuit
breaker
bimetal
tripping
bar
bimetal
tripping bar
screw
calibration
strip
braid
NC45 NC100 / NC125

21. Choosing a circuit breaker
In conclusion
A circuit breaker is
determined by:
• rating
•breaking capacity
•number of poles
•Voltage
•tripping curve
•Standard
•Frequency
•type of load

22. Advantages of MCB
 It automatically switches off the electrical circuit
during abnormal condition of the network means in
over load condition as well as faulty condition.
 The fuse does not sense but Miniature Circuit
Breaker does it in more reliable way.
 MCB is much more sensitive to over current than fuse.

23. Characteristics of MCB
Disadvantages of MCB
 Rated current not more than 100 A.
 Trip characteristics normally not adjustable.
 Thermal or thermal-magnetic operation.
 Only one disadvantage of MCB over fuse is that this system
is more costlier than fuse unit system.

24. Thank you.