2. IntroductIon
It is a production unit owned by Indian railways , for which it manufactures
diesel–electric locomotive and its spares parts.
To meet the increased transportation needs of the Indian railways it was
established in collaboration with Ms ALCO( American Locomotive
Company), USA.
Founded in 1961, the D.L.W. rolled out its first locomotive three year later,
on January 3, 1964. It manufactures locomotives which are variants based on
the original ALCO design dating to 1960s and the GM EMD design of the
1990s.
It has evolved into an integrated diesel–electric locomotive manufacturing
plant, capable of building all components of the locomotive in-house,
including the engines, super structures, and fabricated bogies and under
frames.
3. dIesel’s advantages over steam
They can safely be operated by one person, making them ideal for
switching/shunting duties in yards.
The operating environment is much more attractive, being much quieter, fully
weatherproof and without the dirt and heat that is an inevitable part of operating
a steam locomotive.
Steam locomotives require intensive maintenance, lubrication and cleaning
before, during and after use.
The thermal efficiency of steam was considerably less than that of Diesel
engines.
4. dIesel-electrIc locomotIve
In a diesel-electric locomotive, the diesel engine drives an electrical
generator or alternator whose output provides power to the traction motors.
There is no mechanical connection between the engine and the wheels. The
important components of diesel-electric propulsion are :
Diesel engine ( 16 cylinder , two stroke )
The main generator or alternator
Traction motor
Control system consisting of the engine governor
Electrical or electronic component to control or modify the electrical supply
to the traction motions
Inverters
6. alternator
Alternators generate
electricity by the same
principle as DC generators,
namely, when the magnetic
field around a conductor
changes, a current is induced
in the conductor according
to faraday’s law of
electromagnetic induction.
7. synchronous speed
The output frequency of an alternator depends on the number of poles and
the rotational speed. The speed corresponding to a particular frequency is
called the synchronous speed for that frequency.
Poles Rpm at 50 Hz Rpm at 60 Hz
2 3000 3600
4 1500 1800
6 1000 1200
8 750 900
10 600 720
12 500 600
14 428.6 514.3
8. Governor
A device used to measure and regulate the speed of an engine.
The microcontroller based governor consists of a control unit mounted in
the drive cab and an actuator unit mounted on the engine.
The governor controls the engine speed based on throttle handle position.
Engine RPM is measured by a Tacho generator or engine speed sensor
mounted on the engine.
Digital PID control is used to control the fuel rack position dynamically ,
based on the selected notch on throttle handle and measure engine RPM .
A steeper motor drive is used to control the fuel rack of diesel engine .
9. A PID controller attempts to correct the error between a measured
process variable and a desired set point by calculating and then
outputting a corrective action that can adjust the process accordingly
and rapidly, to keep the error minimal.
The governor also controls the electrical load on the engine, so as to
limit horsepower at each notch to a present level, through an electrical
interface with the excitation system of the locomotive.
Air pressure is measured through a pressure sensor mounted in air
manifold, and movement of fuel rack is limited as a function of this
pressure so as to prevent incomplete combustion, black smoke,
excessive engine temperature, fuel wastage etc.
Lube oil pressure is continuously monitored and engine is shut down if
the lube oil pressure is less than the specified pressure so as to protect
the engine from damage due to malfunctioning of lube oil pump etc.
10. Control unit features
•No need of regular maintenance.
•Effective control for complete
combustion of fuel improves fuel
efficiency and reduces pollution.
•Continuous display of engine status
parameters.
•Online fault diagnostics and fault
message display.
11. aCtuator unit features
•16 bit microcontroller based design
•Steeper motor used for high
precision position control of fuel
rack
•Digital PID control.
•Tuning for each individual engine
is not required.
12. traCtion
Traction refers to the maximum frictional force that can be produced
between surfaces without slipping.
CoeffiCient of traCtion: The coefficient of traction is defined as the
usable force for traction divided by the weight on the running gear (wheels,
tracks etc)i.e.
Usable Traction = coefficient of Traction x Weight
As the coefficient of traction refers to two surfaces which are not slipping
relative to one another it is the same as Coefficient of static friction.
13. traCtion motor
• Electric motor providing the primary rotational
torque of a machine, usually for conversion into
linear motion.
•DC series-wound motors, running on
approximately 600 volts.
•The availability of high-powered
semiconductors such as thyristors has now made
practical the use of much simpler, higher-
reliability AC induction motors.
14. types of traCtion
1. DC traCtion: employed until the late 20th century in diesel-electric
traction units.
With DC, the most popular line voltages for overhead wire supply systems
have been 1,500 and 3,000.
The disadvantages of DC are that expensive substations are required at
frequent intervals.
The low-voltage, series-wound, DC motor is well suited to railroad traction,
being simple to construct and easy to control.
15. 2. AC TrACTion:
Three-phase AC motor traction became practicable in the 1980s.
With AC, especially with relatively high overhead-wire voltages (10,000
volts or above), fewer substations are required.
With commercial-frequency, AC systems, there are two practical ways of
taking power to the locomotive driving wheels:
1. By a static rectifier on the locomotive to convert AC supply into DC at low
voltage to drive standard DC traction motors
2. By a converter system to produce variable-frequency current to drive AC
motors
Thyristor or chopper are used to control the current supply to the motor.
16. bogie
A bogie is a wheeled wagon or trolley. In
mechanics terms, a bogie is a chassis or
framework carrying wheels, attached to a
vehicle.
Usually the train floor is at a level above the
bogies, but the floor of the car may be lower
between bogies.
17. Bogies serve a number of purposes:
1. To support the rail vehicle body
2. To run stably on both straight and curved track
3. To ensure ride comfort by absorbing vibration, and minimizing
centrifugal forces when the train runs on curves at high speed
Usually two bogies are fitted to each carriage, wagon or locomotive, one at
each end. Most bogies have two axles as it is the simplest design, but some
cars designed for extremely heavy loads have been built with up to five
axles per bogie.
18. reCTifiers
A rectifier is an electrical device that converts AC to DC, a process known
as rectification. Rectifiers have many uses including as components of
power supplies and as detectors of radio signals.
A device which performs the opposite function (converting DC to AC) is
known as an inverter.
Rectifiers are of two types:
a) half wave rectifier
b) full wave rectifier
19. CrAnes
A crane is a lifting
machine, generally
equipped with
a winder (also called a
wire rope drum), wire
ropes or chains and sheav
es, that can be used both
to lift and lower materials
and to move them
horizontally.
20. generAl ChArACTerisTiCs
Used to move loads over variable (horizontal and vertical) paths within a
restricted area
Used when there is insufficient (or intermittent) flow volume such that the
use of a conveyor cannot be justified
Provide more flexibility in movement than conveyors
21. engine TesTing
Types of TesTing
lubriCATing oil TesTing
Lubrication is done for better performance of the engine parts.
testing is done by checking the circulation of lubricant oil.
For rotating parts checking is done by seeing the returning path of the oil
i.e. checking not only the forward path but also the returning path.
RR40 is used as lubricating oil.
22. water testing
Water acts as a coolant for moving part of the engine because constant
movement or rotation causes various parts to heat up and water working as
coolant cooled down the concerned part.
Load testing
For load testing electrical load is provided to the engine. If there is any
abnormal sound then the engine is again tested for lubrication so that any
flaw which is there can be removed.
23. dwg2
DWG2 class 3100 hp diesel electric locomotive AC-DC transmission,
powdered with D.L.W. built 16 cylinder ALCO251C diesel engines is
exclusively designed for heavy freight service.
High adhesion two stage suspension design trucks minimize weight transfer
and provide a higher traction effort and excellent riding quality.
WDG2 is popular for the low and easy maintenance at extended periods,
reduced noise and exhaust emission, fuel saving safe operation.
24. generaL characteristics
Installed 3100 hp
Power input to traction under site condition 2750 hp
Gauge 1676 mm
PrinciPLe dimension
Locomotive weight 123000 kg
Nominal axel load 20500 kg
Wheel diameter 1092 mm
Maximum starting tractive effort 37884 kg
Fuel tank capacity 6000 liters
Max speed 100 km/hr
25. engine test oPeration sequence
Base inspection under screen and fitting over screen.
Water circulation.
Lube oil filling and check deflection crank shaft.
Lube oil circulation.
Pre run on no load 3 to 5 times of duration 10 to 30 min each 400 rpm.
Intermediate runs 12 runs of 30 min duration each from 400 to 1000 rpm.
Check over speed trip of recheck 3 times.
Check bake in nozzles and set tapped clearance.
Inspection before fist hour performance.
First hour performance on full load.
Base inspection.
Second hour performance on full load.
Attend defects of first hour performance.
Final base inspection.
Check engine deficiencies.
Engine clearance.
