Summer training report report on diesel locomotive works Varanasi
SUBMITTED BY:SHIVAM ALOK VIVEK CHOUDHARY CHOUDHARY EN (7TH SEM) IIT(GZB)
Introduction
It is a production unit owned by Indian I ndian railways , for which it manufactures diesel – electric locomotive and its spares parts. – electric
To meet the increased transportation needs of the Indian railways it was established in collaboration with M\s ALCO( American American Locomotive Company), USA.
Founded in 1961, the D.L.W. 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 – electric plant, capable of building all components of the locomotive in-house, including the engines, super structures, and fabricated bogies and under frames.
Diesel – electric locomotive were introduced to exploit their versatility, low maintenance requirements and cost effectiveness as compared to steam engine.
Got its first ISO certification in 1997 and ISO-9001 and ISO-14001 in December 2002.
With technology transfer agreement from manufacturers such as GM-EMD, DLW today produces advance locomotives having output range from 2600 to 4000 hp.
It has supplied locomotives to other countries such as Sri Lanka, Bangladesh, Malaysia, Tanzania and Vietnam etc.
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
basic concepts Diesel engine
Alternator
rectifier
Traction control
governor
Front traction motor bogie
Rear traction motor bogie
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.
The relation between speed and frequency is given by N = 120 f / P
where f is the frequency in Hz (cycles per second) P is the number of poles (2,4,6...) and
N is the rotational speed in revolutions per minute (RPM)
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.
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 .
Control unit features •
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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.
Actuator unit features •
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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.
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.
factors affecting tractive coefficient Traction between two surfaces depends on several factors including: 1. Material composition of each surface. 2. Macroscopic and microscopic shape . 3. Normal force pressing contact surfaces together. 4. Contaminants at the material boundary including lubricants and adhesives. 5. Relative motion of tractive surfaces
In the design of wheeled or tracked vehicles, high traction between wheel and ground is more desirable than low traction, as it allows for more energetic acceleration (including cornering and braking) without wheel slippage.
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, higherreliability AC induction motors. •
Usually, the traction motor is simply suspended between the truck (bogie) frame and the driven axle; this is referred to as a "nose-suspended traction motor".
The problem with such an arrangement is that a portion of the motor's weight is unsprung, increasing forces on the track.
By mounting the relatively heavy traction motor directly to the power unit rather than to the truck (bogie), better dynamics are obtained allowing muchimproved high-speed operation.
Rating : In diesel-electric the horsepower rating of the traction motors is usually 81% that of the prime mover. This assumes that the electrical generator converts 90% of the engine's output into electrical energy and the traction motors convert 90% of this electrical energy back into mechanical energy.
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
Classification of locomotives
The classification syntaxes: Locos, except the older steam ones, have classification codes that identify them. This code is of the form “ [ gauge ][ power ][load ][ series ][ sub type ][ suffix ] ”
The first letter (gauge) W- Indian broad gauge Y- meter gauge Z- narrow gauge(2.5 ft) N- narrow gauge (2 ft)
The second letter (motive power) D- Diesel C- DC electric (can run under DC traction only) A- AC electric (can run under AC traction only) CA- Both DC and AC (can run under both AC and DC tractions), 'CA' is considered a single letter B- Battery electric locomotive (rare) The third letter (load type)
G-goods P-passenger M-mixed traffic ; both goods and passenger S-Used for shunting U-Electric multiple units (E.M.U.) R-Railcars
THE fourth letter (series)
The series digit identifies the horsepower range of the locomotive. Example for the series letter ‘3’ means that the locomotive has power over 3000 hp but less than 4000 hp.
The fifth letter (subtype)
an optional letter or number that indicates some smaller variations in the basic model. For ex: ‘A’ for 100 hp, ‘B’ for 200 hp and so on……..
Electric maintenance shop Types of machines 1. Conventional machines 2. NC machine 3. CNC machines
1. Conventional machine: It is a simple machine which is now an old technique. 2. Numerical control machine: Numerical control is defined as a system in which the actions of the machines are controlled by the insertion of the numerical data. In other words number controls the action.
machines in area B Flame cutting
CNC Laser cutting
Steel plates are ultrasonically tested before being precision cut by numerically controlled flame cutting machines or by CNC LASER machine.
The laser beam is typically 0.2 mm (0.008 in) diameter at the cutting surface with a power of 1000 to 2000 watts. Lasers work best on materials such as carbon steel or stainless steels because these are difficult to cut due to their ability to reflect the light as well as absorb and conduct heat. This requires lasers that are more powerful.
Angular Boring Machine Fabrication of Engine Block
This special purpose machine has two high precision angular boring bars.
Boring bars are mounted on high precision bearings which provide control on size during angular boring.
Components after flame cutting and various machining operations are fit and tack welded before taking on rollovers. Heavy ArgonCO2 welding is done on these rollovers
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.
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.
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.
Basic features Diesel engine
Model 16 cylinder ALCO251C , DLW built Medium speed, 4 strokes Fuel efficient
Transmission system
Electrical AC-DC Electronic excitation control Traction alternator – BHEL TA10102DW Traction motor – BHEL TM4907 AZ – roller suspension bearings
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.
Thank you
