TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Traction Control of Electric
Locomotives
TECHSEM REPORT
Presented by
Dinesh Kumar Das
Roll # EE200117009
Under the guidance of
Mr Shyamalendu Mohanty
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
INTRODUCTION
• Driving forward of vehicle is called
Traction and the system, which employs
this type of mechanism is called Traction
system
• classified broadly into two groups namely:
(1)non-Electric traction systems
(2)Electric traction systems
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Requirements of an Ideal
Traction System
• High starting pulling effort in order to have rapid
acceleration.
• Equipment capable of withstanding large
temporary overloads for short periods.
• The locomotive should be self contained and able
to run on any route.
• Capability of withstanding voltage fluctuations
and temporary interruption of supply.
• Parallel running usually more than one motor (two
or four motors ) should be possible.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
ADVANTAGE OF ELECTRIC
TRACTION
.
•
•
•
•
•
•
Cheapness. It is cheapest method of all other methods of
traction.
Cleanliness. It is free from smoke and flue gasses
Maintenance cost. Maintenance and repair cost is about
50% of steam traction system.
Starting time. It can be started without loss of time.
High starting torque. This system uses of d.c. and a.c.
series motors which has a very high starting torque.
Braking. In electric traction , regenerative breaking is used
which feeds back 40%of the energy.
Saving in high grade coal. No coal is required for electric
traction.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
DISADVANTAGE OF ELECTRIC
TRACTION
• Higher initial expenditure.
• Failure of supply is a problem.
• Additional equipments are required for
breaking purposes.
• The electrically operated vehicles have to
move only on electrified track.
• Interference with telegraphs and telephone
lines.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
COMPONENTS OF AN A.C
LOCOMOTIVE
• CATENARY - This is the overhead wire of special cross-section.
• PANTOGRAPH - This is a device used for collecting current from the
catenary i.e. the over head lines.
• CIRCUIT BREAKERS - The function of circuit breaker is to disconnect
the engine from the line side in case of some fault
• ON LOAD TAP CHANGER - On load tap changer is used for varying the
output voltage for controlling the speed of motor
• TRANSFORMER - A tap changing transformer is installed in the
locomotive for stepping down the voltage according to the requirement of
traction motors
• RECTIFIERS - Semiconductor rectifiers are used for conversion of A.C
power into D.C power
• SMOOTHING REACTORS - Any ripples found on the output side of the
rectifier are eliminated by the smoothing reactor fitted after the rectifier.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
SEPEX
Short form of SEParate EXcitement of traction motors
where the armature and field coils of an electric motor are
fed with independently controlled current. This has been
made much more useful since the introduction of thyristor
control where motor control can be much more
precise. SEPEX control also allows a degree of automatic
wheel slip control during acceleration
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
THYRISTOR CONTROL
Schematic of AC Electric Locomotive Power System with
Thyristor Control and Separately Excited DC Motors
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
DC Choppers
Thyristor Control Circuit for DC Supply to DC Motors
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
AC TRACTION MOTOR
AC Locomotives with AC Drive
Schematic of Single Phase AC Supply Powering 3-Phase AC
Motors
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
AC Locomotives with DC Drives
Schematic of AC locomotive with Tap Changer Control
of Transformer Output
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
DC TRACTION MOTOR
It consists of two parts, a rotating armature and a fixed
field.
• The fixed field consists of tightly wound coils of wire
fitted inside the motor case
• The armature is another set of coils wound round a
central shaft.
• The armature is connected to the field through
"brushes" which are spring loaded contacts
pressing against an extension of the armature
called the commutator.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
The DC Traction Motor: How it Drives
the Axle
How a DC motor drives the axle through a pinion and gearwheel
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
DC Resistance Control
Simplified DC Traction Motor Power Control Circuit
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
DC Power Circuit
Schematic of Simple DC Traction Motor Power Control Circuit
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Field Weakening
DC Traction Motor with Field Weakening Circuit
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Braking in traction motors
• Dynamic Braking: where the motors become generators
and feed the resulting current back.
• It classified into two categories:
1 Plugging
2. Rheostatic Braking
3. Regenerative Braking
• PLUGGING: Generally plugging is applied by changing
the phase sequence of the three phase induction and
synchronous motor
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Rheostatic Braking
• The motors become generators and feed the resulting
current into an on-board resistance.
• When the driver calls for brake, the power circuit
connections to the motors are changed from their power
configuration to a brake configuration and the resistors
inserted into the motor circuit. As the motor generated
energy is dispersed in the resistors and the train speed
slows, the resistors are switched out in steps, just as they
are during acceleration.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Regenerative Braking
• the motors become generators and feed the resulting current
back into the supply system
• a train could use its motors to act as generators and that this
would provide some braking effect if a suitable way could be
found to dispose of the energy.
• Trains were designed therefore, which could return current,
generated during braking, to the supply system for use by
other trains.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
CONCLUSION
• no single motor is ideal for traction purposes. But; DC
Series Motors are most suitable for this work
• Power Electronics have been resorted to in a major way as
in case of thyristor control.
• Different types of braking for the traction system was
studied.
Presented by :: Dinesh Kumar Das (Roll # EE200117009)
TRACTION CONTROL OF ELECTRIC LOCOMOTIVES
Presented by :: Dinesh Kumar Das (Roll # EE200117009)