training report on diesel locomotives

SUMMER TRAINING REPORT ON DIESEL ELECTRIC LOCOMOTIVE

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COMPANY PROFILE:

BASIC INFORMATION: General Manager

: Shri B.P. Khare

Establishment

: August, 1961

Website

: http://dlw.indianrailways.gov.in

Annual Production Capacity : 300 locomotives Annual Turnover (Rs.)

: 2124 crore

Total number of staff

: 5974

Workshop Land

: 89 Hectares

Township area

: 211 Hectares

Electrical power requirement requirement : 3468 KVA (Average maximum demand) Electrical energy consumption: 19.8 million (Units/Year) Standby power generation

: 3000 KW

Capacity

PRODUCTS: 1. DIESEL ELECTRIC LOCOMOTIVES (DEL) 2. DIESEL GENERATOR SET (DG SET) – SET) – 0.85 0.85 to 2.4 MW 3. SPARES

CUSTOMERS: Domestic

: Indian Railways, NTPC, VEDANTA, SAIL, VSP, Electricity Boards JSW, JAYPEE, MPSEZ

International : Tanzania, Tanzania, Vietnam, Vietnam, Bangladesh, Bangladesh, Sri Lanka, Malaysia, Sudan, Sudan, Angola, Angola, Myanmar, Senegal, Mozambique

TECHNOLOGY EDUCATION AND RESEARCH INTEGRATED INSTITUTIONS

SUMMER TRAINING REPORT ON DIESEL ELECTRIC L OCOMOTIVE

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DLW's vision "To be a world class Diesel Electric Locomotive Manufacturer"

DLW's Mission

To achieve the vision through Continuous Improvement in the areas of Human Resource Development, Product Quality and Development of Buyer-Supplier Partnership and teamwork with emphasis on Core Competence leading to Customer Satisfaction and Business Excellence. Objectives of DLW

Provide an equal opportunity, congenial and professional work environment to its employees with greater emphasis on teamwork and be the world‘s premier diesel loco manufacturer.



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INTRODUCTION

Diesel electric locomotives were introduced on Indian Railways in 1950's to exploit their versatility, better hauling capabilities, low m aintenance requirements requirements and overall cost advantage as compared to steam locomotives. Diesel Locomotive Works (DLW) was established in 1961 in collaboration with M/s ALCO, USA in the ancient City of Varanasi to undertake indigenous manufacture of diesel electric locomotives for meeting increasing transportation needs of Indian Railways. Over the years, DLW's production has progressively increased and it produced 257 locomotives, in the year 2008-09 and 258 locomotives, in the year 2009-10 as against 4 locomotives in the first year of its production in 1963-64. The locomotive out turn of 2009-10 has surpassed all past records. ALCO locomotives are now almost fully indigenous. Through in house development efforts, the original imported design has been made 7% more fuel-efficient and has also been successfully uprated to deliver about 30% more power, increasing it from 2600 HP to 3300 HP. In order to upgrade the technology and keep pace with the latest, Indian Railways entered into an agreement in year 1995, with M/s General Motors, USA for Transfer of Technology for the manufacture of 4000 HP state-of-the-art, AC-AC, microprocessor controlled, fuel efficient WDG4 / WDP4 locomotives at DLW. Series production of WDG4 class heavy duty freight locomotives and WDG4 class high speed passenger passenger locomotives (with speed potential of 160 Kmph) has started at DLW. These locomotives are now being manufactured at DLW in increasing numbers. The first indigenous, WDG4 freight loco, was manufactured in March 2002 and the first passenger version, WDP4, in March 2003. 380 such locomotives have been manufactured till March 2010. DLW has successfully absorbed the new technology and current indigenous content in WDG4/WDP4 loco is about 60%. st

Till 31 March 2010, DLW has manufactured 5774 locomotives (including 380 high horse power EMD locomotives) and 53 high capacity diesel-generating sets.



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BRIEF HISTORY:

The Diesel Locomotive Works (DLW) is a production unit owned by Indian Railways that manufactures Diesel-Electric Locomotives and its spare parts. It is the only Diesel Electric Locomotive Manufacturer in India. Established in August 1961, in Technical Collaboration with ALCO, USA for the manufacture of Diesel Electric Locomotive, it rolled out its first locomotive l ocomotive in 1964.

LOCOMOTIVES INTRODUCED: (In India) ● STEAM LOCOMOTIVE - 1853 ● ELECTRIC LOCOMOTIVE - 1925 ● DIESEL LOCOMOTIVE - 1957

MILESTONES

Transfer of Technology Agreement ●

DLW entered in an agreement with General Motors of USA (now EMD) in 1995, for technology of transfer to manufacture high horse-power 4000 HP AC-AC GT46MAC and GT46PAC locomotives in India making India the only country outside NorthAmerica to have this leading edge technology. Returns from Transfer of Technology

●

Got its first ISO certification ISO-9001 in 1997.

●

First PKD WDG-4 locomotive turned out in August 1999.

●

First DLW built 4000 HP WDP-4 loco l oco turned out in April 2002.

●

First indigenous passenger version of EMD loco WDP4 manufactured

●

Development of 16 cylinders 3300 HP Power upgraded DLW engine, WDM3D locomotive in

September 2003.

Locomotive design projects

●

WDG4 locomotive with IGBT base TCC (Siemens & EMD) turned out.

●

Indigenous AC-AC control for WDG4 (with distributed power controls)

●

Indigenous AC-AC control for WDP4 (with hotel load capability)

●

WDP4 locomotive with IGBT base TCC & Hotel load capability



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TYPES OF LOCOMOTIVES: The steam-powered locomotive played a key role during the development and golden age of railroading, but, despite its long and picturesque history, it has been superseded in developed nations by electric and diesel-electric locomotives for economic and environmental reasons. The few steam locomotives that remain in operation in developed nations are mostly nostalgic relics used chiefly to pull tourist trains.

STEAM LOCOMOTIVES: The reciprocating steam locomotive is a self-contained power unit consisting essentially of a steam engine and a boiler with fuel and water supplies. Superheated steam, controlled by a throttle, is admitted to the cylinders by a suitable valve arrangement, the pressure on the pistons being transmitted through the main rod to the driving wheels. The driving wheels, which vary in number, are connected by side rods. Steam locomotives are usually classified under the Whyte system, that is, by the number and arrangement of the wheels; for example, an engine classified as 2 – 2 – 6 – 0 has one pair of wheels under the front truck, three pairs of coupled or driving wheels, and no wheels under the trailing truck. In some cases the truck wheels of the tender (fuel carrier) are added.

ELECTRIC LOCOMOTIVES: Electric locomotives range from the small type used in factories and coal mines for local hauling to the large engines used on railroads. Electric locomotives generally have two or more motors. Power is collected from an electric trolley, or pantograph, running on an overhead wire or from a third rail at one side of the track. Battery locomotives, used only for local haulage, carry electric storage batteries that act as their primary source of power. Electric railroad locomotives are used chiefly on steep grades and on runs of high traffic density; although highly efficient they are not more widely used because of the cost of electric substations and overhead wires or third rails.



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DIESEL LOCOMOTIVES: Diesel-electric locomotives were introduced in the United States in 1924, and have become the most widely used type of locomotive. The modern diesel-electric locomotive is a self-contained, electrically propelled unit. Like the electric locomotive, it has electric drive, in the form of traction motors driving the axles and controlled with electronic controls. It also has many of the same auxiliary systems for cooling, lighting, heating, and braking. It differs principally in that it has its own generating station instead of being connected to a remote generating station through overhead wires or a third rail. These motors drive the driving wheels by means of spur gears. The ratio of the gearing regulates the hauling power and maximum speed of the locomotive. A modern diesel-electric locomotive produces about about 35% of the t he power of an electric locomotive of similar weight.

Diesel-mechanical locomotives have a direct mechanical link consisting of a clutch and a series of gears and shafts between the engine and the wheels, similar to the transmission in an automobile. Because mechanical drives deliver less power to the wheels than electric and diesel-electric systems, they are only used with the smallest locomotives.

In diesel-hydraulic locomotives the engine drives a torque converter, which uses fluids under pressure to transmit and regulate power to the wheels. Hydraulic drives are little used in the United States but are widely used in some countries, such as Germany.



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The factory of DLW is primarily divided in 3 parts according to the operations done at the respective shops:

1. ENGINE DIVISION 2. LOCO DIVISION 3. BLOCK DIVISION

1. ENGINE DIVISION: COMPONENT MACHINING:

Over 2000 components are manufactured in-house at DLW. These include ALCO turbo superchargers, lubricating oil pumps, cam shafts, cylinder heads, laser hardened cylinder liners, connecting rods and various gears. Our well-equipped Machine Shops have dedicated lines for operations like turning, milling, gear hobbing, drilling, grinding and planning etc.

In addition, DLW is equipped with a variety of special purpose machines and a large number of state-of-the-art CNC machines to ensure quality and precision. Associated manufacturing process like heat treatment and induction hardening are also carried out in-house. A new eco friendly laser hardening machine has been setup which is designed to laser harden the inner bore of engine cylinder liner and this feature advantages such as low running cost, state of the art controls to provide reliable and versatile laser power for ultimate quality requirements.



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ENGINE ASSEMBLY & TESTING: Pre-inspected engine block, crankshaft, cylinder liners, pistons, connecting rods, cylinder heads, exhaust manifold, turbo supercharger supercharger and all related piping are used in assembly of engine.

Electrical machines like traction alternator, auxiliary generator and exiter are thereafter coupled on the engine. The complete power pack with electrics are tested on computerized Engine Test Bed to verify prescribed horsepower output. Vital parameters of engine health are checked to assure the quality of product. Only after the engine parameters are found perfect the power pack are cleared for application on locomotives.



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2.LOCO DIVISION COMPONENT FABRICATION: Precision cutting and forming of sheet metal is

utilized

for

manufacture

of

superstructures superstructures including drivers cab engine hoods, and compartments for housing electrical

equipment.

All

activities

connected with pipes like pickling, bending, cutting, forming and threading of pipes of various sizes are undertaken in another well-equipped work area.

All electrical equipment is assembled in the fabricated control compartments and driver's control stands are done in another work area.

UNDERFRAME FABRICATION Underframes are fabricated with due care to ensure designed weld strength. Requisite camber to the underframe is provided during fabrication itself. Critical welds are tested radio-graphically.



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Welder training and their technical competence are periodically reviewed. High Horse Power (HHP) underframe is fabricated using heavy fixtures, positioners to ensure down hand welding. Fixtures are used to ensure proper fitting of components and quality welding in subsequent stages. BOGIE MANUFACTURING Special purpose machines are utilized for machining cast and fabricated bogie frames. Axle and wheel disc machining is undertaken on sophisticated CNC machines. Inner diameter of wheel discs are matched with the outer diameter of axles and assembled on wheel press. The complete truck (bogie), including i ncluding bogie frames, wheels and axles, brake rigging and traction motors are assembled which is ready for application to locomotive.



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LOCOMOTIVE ASSEMBLY: Tested engines are received from Engine Division. Similarly underframes are received from Loco frame shop and assembled trucks from Truck machine shop. Superstructure compartments and contractor compartment are received from respective manufacturing and assembly shops of Vehicle Division. Important alignments like crank shaft deflection; compressor alignment and Eddy Current clutch/radiator fan alignment are done during assembly stage.

Electrical control equipments are fitted and control cable harnessing is undertaken. The complete locomotive is thus assembled before being sent onwards for final testing and spray painting. All locomotive are rigorous tested as per laid down test procedures before the locomotive is taken up for final painting and dispatch for service.



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3.BLOCK DIVISION:

Flame Cutting of Components Steel plates of sizes up to 80 mm thickness are ultrasonically tested before being precision cut by numerically controlled flame cutting machines, Plasma Cutting Machine.

Components are straightened and machined prior to fitting & tacking on fixture designed especially for engine block fabrication to ensure close tolerance on engine block.

Fabrication of Engine Block/ Crankcase Components after flame cutting and various machining operations are fit and tack welded before taking on rollovers. Heavy Argon-CO2 welding is done on these rollovers. High quality of welding is done by qualified welders. Weld joints are subjected to various tests like ultrasonic, ultr asonic, X-rays, Visual etc.

Down-hand welding is ensured using specially designed positioners. Fabrication of engine block is completed by submerged arc welding using semiautomatic welding machines.



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Special fixtures are used for making down-hand welding possible in inaccessible areas. Critical welds are subjected to radiographic examination. All welders are periodically tested and re-qualified for the assigned. After complete welding weldment is stress relieved and marking is done for subsequent subsequent machining.

Portal Milling Machine Engine block machining is done on Portal Milling Machine which is a 5 axis CNC machine with SIEMENs 840-D state of art system

control

management

with

system.

dedicated This

tool

machine

performs milling, drilling, tapping and boring operations in single setting.

The machine accuracy of 10m enables adhering to the tolerance required on engine block.



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Angular Boring Machine Angular boring "V" boring is done of special purpose machine which is a special purpose machine, which has two high precision angular boring bars on which different boring inserts are mounted.

The cutting inserts on boring bars to achieve evenly distributed cutting load during boring operation. This contributes to t o accuracy while machining.

Boring

bars

are

mounted

on

high

precision bearings which provide control on size during angular boring.

The machine is capable of boring and drilling to different sizes.



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DIESEL-ELECTRIC LOCOMOTIVES: NOMENCLATURE OF LOCOMOTIVES: (What do the designations such as ‗WDG‗WDG -4‘ mean?) Locos, except for the older steam ones, have classification codes that identify them. This code is of the form: ―(Gauge) (Power) (Load) (Series) (Subtype) (Suffix)‖ The first letter (gauge): W- Indian broad gauge Y- Meter gauge Z- Narrow gauge (2.5 ft) N- Narrow gauge (2 ft) — The 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 The fourth letter (series): x→ Any numbers in the name represent the horsepower (hp=x×1000) A→ 100 hp B→ 200 hp C→ 300 hp; and so on... Hence WDG-3A stands for Wide Diesel Goods- 3100 hp engine & WDP-4 represents r epresents Wide Diesel Passenger- 4000hp



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LOCOMOTIVE DEVELOPMENT:

Loco-Type-> YDM4 WDS6/ WDM2 WDP 1 WDG2/ WDP2 WDG4 AD Year

68-69 74-75

C

WDP 4 /4B WDM3

3A

D

94-95

95-96

95-96

9898- 99 99-2000

02-03

03-04

91

236

Introduced No. Produced 609

564

142

69

1183

44

308

Power (HP)

1350

3100

2300

3100

3100

4000/ 4500 4000/ 4500 3300

Axle Load(T) 12

20/21

18.8

20

20.5

19.5

21

19.5 / 20.2 19.5

Gauge(mm)

1000

1676

1676

1676

1676

1676

1676

1676

Wheel

Co-Co Co- Co Co-Co Bo-Bo

1350

Co-Co Co-Co Co-Co

A-A-I

Arrangement

1676 I-A- Co-Co

A / CO-CO

Wheel Dia.

965

1092

1092

1092

1097

1092

1092

1092

1097

Height

3407

4027

4115

4088

4162

4081

4201

4201

4162

Width

2730

3022

2864

2864

3016

3000

3127

3127 / 3250 3016

15863

14810

17840

17900 19964

19964

17350

117.0 126

117/121.2

117

27/38

38.6

Length (mm) 13515 16150 Weight (T)

72

120/26 112.8

80

123

T.E. Max

18.94 34/35.7 30.45

20

40.6

/ 29.25 54

37.9 Speed(km/h) Speed(km/h ) 96

65

120

120

100

160

100

160/130

120

Fuel

5000

5000

3000

6000

6000

6000

4000

5000

E-

EM

Type

with/

with/

process

µ-

without

without

or

process

SIBAS-16

SIBAS-16

or

/MAS 696

/MAS 696

tank 3000

capacity(Lts) Locomotive 3Control

Field

E- Type E- Type E- Type EType/

2000 EM 2000 µ -



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1. COMPONENTS

The Diesel Electric Electric Locomotive has has the following main components: 1. CP (Control Panel) 2. 16 cylinder Diesel Engine 3. Alternator 4. Auxiliary Generator & Exciter 5. Traction Motors 6. Radiator Control Fan & Blower Motor 7. Control Systems Systems and Governor 8. Master Control 9. Cab 10. Crank Case Exhauster 11. Mechanical Assembly

1. CONTROL PANEL: The CP or the Control Panel (wrt WG3A loco) consists of: 

Control Switch



Display Unit



LED Panel



Microprocessor Microprocessor based Control Unit



Reverser



BKT



Valves



Hooter



CK1/CK2/CK3



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The top portion of CP has sensors and relays connected to the microprocessor unit. The display unit of microprocessor shows working condition of items in engine (electrical equipments apart from engine). 

The LED Panel displays the overload, auxiliary generator failure, hot engine, rectilinear fuse blown, etc. The battery ammeter shows the charging state of the batteries.



REV: Field wiring goes to reverser (REV) and hence it is used to control the polarity of the field which in turn controls the direction of train.



BKT: It is a switch which in one direction is used used to motor the loco loco while in other it is used for dynamic braking.



Microprocessor based Control Unit: On-board microprocessors control engine speed, fuel injection, and excitation of the alternator. These computers also interconnect with improved systems to detect slipping or sliding of the driving wheels, producing faster correction and improved adhesion. An additional function of the microprocessor is to monitor performance of all locomotive systems, thereby increasing their reliability and making the correction of problems easier.



Hooter : It is a vigilance control device (VCD) to keep the driver alert. If the driver isn‘t doing anything with the controls for over a minute, the hooter ‗hoots‘ and brings the engine speed to the normal speed (low) without asking the driver. It can only be reset after 2 minutes and hence the driver will be held responsible for delay in reaching the next station.



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2. CYLINDER DIESEL ENGINE:

It is an internal-combustion engine in which heat caused by air compression ignites the fuel. At the instant fuel is injected into a diesel engine‘s combustion chambers, the air inside is hot enough to ignite the fuel on contact. Diesel engines, therefore, do not need spark plugs, which are required to ignite the air-fuel mixture in gasoline engines. engines. The Diesel engine has 16 cylinders. Pistons inside i nside the cylinders are connected by rods to a crankshaft. As the pistons move up and down in their cylinders, they cause the crankshaft to rotate. The crankshaft‘s rotational force is carried by a transmission to a drive shaft, which turns axles, causing mechanical output. Eight 8V and four 2V Batteries are used in series to run a more powerful starter motor, which turns the crankshaft

to

initiate

ignition

in

a

diesel

engine

for

the

first

time.

The diesel engine is the prime source of locomotive power. When the engine is running, it directly drives three electrical generators with associated cooling fans, a multi-cylinder air compressor, a traction motor blower, and the water and lube oil pumps. The engine-driven components in the locomotive convert the engine mechanical power power to other forms to t o perform their individual functions:

710 Engine Specifications 

11.63 L (710 in3) per cyl.



Bore: 230.2 mm



Stroke:279.4 mm



BMEP:11.2 bar



Dry weight: 17,960 kg (16-710)



Ratings:1640 kW (8-710)



4100 kW (20-710)



Two-stroke, uni-flow scavenging



45°Vee



High-efficiency turbocharger


SUMMER TRAINING REPORT ON DIESEL ELECTRIC LOCOMOTIVE

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3. ALTERNATOR: An alternator converts kinetic energy into electrical energy. All recently manufactured automobiles rely on alternators to charge the battery in the ignition system and supply power to other electrical equipment. Alternators are sometimes called AC generators because they generate alternating current (AC). Electric current can be generated in two ways: The magnet may rotate inside the coil, or the coil may rotate in a magnetic field created by a magnet. The component that remains stationary is called the stator, and the component that moves is called the rotor. In alternators, the coil is the stator and the magnet is the rotor. A source of mechanical power, i.e. the diesel engine turns the rotor.

The traction alternator rotates at engine speed, generating alternating current AC power. The AC power is converted to DC power by rectifier banks within the generator assembly. The DC power is applied to the DC link. Switchgear and contactors apply DC link voltage to traction inverter circuits. The traction inverters convert DC link voltage to 3-phase AC power for the traction motors.

NOMINAL

ELECTRICAL

RATING 

TA204000 kVA / kW



900 RPM, 75 Hz



50°C Ambient



2450 VDC



1633 IDC



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4. AUXILIARY GENERATOR AND EXCITER Introduction: The Alternator has these two components. The exciter and the auxiliary generator consist of two armatures on a single shaft.

Auxiliary generator is an electrical machine which converter mechanical power of engine to low voltage power for the purpose of lighting, battery charging and control circuits. It supplies a constant voltage of around 72V for supplying power to charge the battery for the control equipment and to power the locomotive lights.

The Exciter supplies excitation for the main generator. Starting of Engine The supply from the batteries is given to the exciter. The exciter has armature and field windings. Hence it starts rotating as it receives the supply voltage. The Exciter is coupled with the rotor of the alternator which in turn is connected with the propeller shaft. When the propeller rotates at a particular rpm, the engine gets started. It‘s just like starting a bike. The ‗kick‘ must be powerful enough to start st art its engine. Later the engine runs on diesel oil (fuel). As soon as the engine starts, the auxiliary generator also coupled with the alternator starts charging the batteries. Its potential is maintained at ~72V

EEE Department, Technology Education and Research Integrated Institutions


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Construction: 

ALCO AG: The rotor of this machine is armature and stator is field. The stator consists shunt and series field. The series field is used during cranking of diesel engine and acts as DC series motor during cranking. The shunt field is controlled through microprocessor or through VRP for output voltage control.



EMD AG: The rotor having main generator field, pilot exciter armature and full wave bridge rectifier mounted on same shaft and Stator having main generator armature and pilot excited field. The pilot exciter field is controlled to control the exciter armature output that after rectification to DC is fed to main generator field thus controlled 3 phase-55Vac output is obtained from EMD AG.

Similarities and dissimilarities between ALCO and EMD AG: 

Primary function of both the machines is same i.e. generating power for battery charging and lighting and control circuit.



Power rating ALCO AG is 12KW whereas EMD AG is 18 KW,



Nominal output voltage is 72±1Vdc in ALCO and 74±1Vdc (rectified) in EMD.



AG in ALCO is basically DC shunt generator whereas in EMD it is 3 phase AC generator with built in exciter.



AG in ALCO locomotive is mounted on Alternator is driven by Alternator gear train whereas in EMD, mounted on and driven by engine shaft through gear train.



Both the machine are driven by engine whose speed are varying and hence voltage regulator are used. 

E-type : VRP (electronic device)



Micro : AG control card



EMD : DVR



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5. TRACTION MOTORS:

It‘s an electric motor providing the primary rotational tor que que of the engine, usually for conversion into linear motion (traction). Traction motors are used in electrically powered rail vehicles such as electric multiple units and electric locomotives, other electric vehicles such as electric milk floats, elevators and conveyors as well as vehicles with electrical transmission systems such as diesel-electric and electric hybrid vehicles. Traditionally, these are DC serieswound motors (in ALCO locomotives), usually running on approximately 600 volts. For AC-AC traction 3-phase induction motor is used.



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6. RADIATOR COOLING FAN AND MOTOR : Introduction: During operation of engine, heat is generated that is required to be extracted from engine for preventing the engine from major damage and for maintaining the normal operating temperature of the engine. The heat extracted from engine is carried to the radiator by engine cooling water, where it is cooled by cooling fan known as Radiator fan. Construction: 

ECC (In ALCO): ECC having outer rotor of copper lining and inner rotor with exciting coil. Outer rotor is coupled to diesel engine shaft and inner rotor to the horizontal shaft of gear box. The gear is right angle type. The other end of the gear is connected to the radiator fan shaft. The inner rotor having exciting coil connected to the two slip rings. The 72 V power is supplied to the exciting coil through 4 radial brushes mounted on slip rings.



Radiator Motor (In (In EMD): The Radiator Radiator blower motor is of inverted squirrel squirrel cage induction type i.e. rotor is out side the stator. The stator is wound for 3 phase connected in star for with two sets of input leads i.e. 6 connection terminal. One set is for 8 pole arrangement and other is for 16 pole. For slow speed 16 pole arrangement is taken and for fast speed 8 pole arrangement is taken.



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Working: The two Radiator fan in EMD loco is controlled in sequence by EM2000 at the interval of 20 st

sec from slow to fast 1 radiator than slow to fast of 2

nd

radiator and tries to maintain engine

temperature between 79ºC to 85ºC. The function of switching from off to slow and then slow to fast of two radiators is accomplished by two sets of contactors.

Similarities and dissimilarities between ALCO and EMD Cooling fan and motor: 

In ALCO locomotive radiator cooling arrangement is of exhaust type whereas in EMD locomotive it is forced cooling type.



In ALCO locomotive radiator is driven by engine shaft through Eddy current clutch (ECC), whereas in EMD it is driven by a 3-phase motor powered from Companion Alternator.



The radiator in ALCO locomotive operates on two speeds Half/Full to the current engine speed due to mechanical coupling. In EMD locomotive also, radiator operates on two speed Half/Full but the control is deferent.



In ALCO, the Half/Full speed is controlled by inserting or removing resistance to the ECC exciting coil. In EMD locomotive, speed is controlled by pole changing mechanism.



In ALCO, one nos. radiator fan and ECC is fitted in EMD locomotive. Two nos. per locomotive fan and motor is used.



Rating:

ALCO: 60KW, 1000rpm EMD: 60HP, at 120 Hz



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Radiator Cooling blower Motor: Two 8 blade 52‖ cooling fans, which operate independently, are located under the radiators in the long hood carbody structure. They are numbered 1, and 2, with the No. 1 fan being closest to the cab. For fuel efficiency, each cooling fan is driven by a two-speed AC motor, which in turn is powered by the companion alternator. As the engine coolant temperature rises, the fans are energized in sequence by the control computer (slow speed). As additional cooling is required, the fans switch to full speed in progression as coolant temperature rises. As coolant temperature drops, the fans switch off one at a time. The cooling fans are controlled by the computer which acts on the contactors. The computer also controls the fan sequencing duty cycle and speed (low or high) to ensure even fan and contactor wear. The two-speed cooling fan system consists of two full speed contactors (FCFA and FCFB) and one slow speed contactor (FCS) per cooling fan motor. The system maintains the coolant coolant temperature within a predetermined range range of 79º C to 85º C (175º F to 185º F).

7. CONTROL SYSTEMS AND GOVERNER: EEE Department, Technology Education and Research Integrated Institutions


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A major part of locomotive control system operation involves the interrelated functions of the throttle, engine speed (governor) control, and load (regulator) control. These functions are: 

By controlling the amount of fuel injected into the engine cylinders, the engine governor holds engine speed constant at the speed appropriate for the throttle setting.



Changing operating conditions create change in the diesel engine loading level. When engine load changes or engine output power level changes, engine speed temporarily changes. The load regulator acts to balance engine loading with available engine power.



As the driver advances the throttle, the electrical control system causes more current to flow through the traction alternator field. Increasing excitation current results in increasing power supplied to the t he traction motors.



Woodward UG-25+ Electronic-Hydraulic Governor



Therefore, locomotive power and engine speed increases progressively as the throttle advances from one notch to the next.



Most control and protective functions are programmed into EM2000, which monitors critical functions in the locomotive power system and displays a message if a fault occurs. For serious faults the EM2000 also sounds the alarm bell and takes corrective action.



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8. MASTER CONTROL: It‘s the unit that has the handles to regulate the speed of the loco as well as the direction of motion. It has numbering from 0-9 and each increment causes rise in speed in forward direction. It can also be used to reverse the direction of motion by pushing the handle in the opposite sense. It is present on the control desk of the cab.

9. CAB: It‘s the driver‘s cabin with 2 control desks, the Control Panel (CP) and chairs for the driver. The Cab is at one end of the locomotive with limited visibility if the locomotive is not operated cab forward. Each control desk has the Independent SA9 brake for braking of the engine alone and Auto Brake A9 for the braking of the entire loco.

It has the following components: EEE Department, Technology Education and Research Integrated Institutions


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inclined tracks)

ce nearly equal to the length of the train, to be used only during an emergency) emergency)

The various parts of the control console are shown in the figure above.

10. Crank case exhauster: It is the device used to evacuate the diesel engine

chamber.

11. MECHANICAL ASSEMBLY: All mechanical parts on the engine apart from the above mentioned units may be grouped in this category. It essentially consists of: 

Base frame



Wheels



Air Brakes



Batteries



Sand Box



Vacuum brakes



Fuel tank (Loco fuel oil tank capacity is 3000-6000L) etc



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WORKING OF A DIESEL ELECTRIC LOCOMOTIVE:

In a diesel-electric locomotive, the diesel engine drives an electrical generator or alternator. (The traction alternator is the most important component of the main generator assembly.) The traction alternator converts diesel engine mechanical power into alternating current electrical power. Internal rectifier banks in the main generator assembly convert traction alternator output alternating current to direct current.

Rectified DC power produced by the traction alternator is distributed through the DC link to DC/AC inverters in the Traction Control (TC) cabinet. Based on inputs from the locomotive computer (EM2000), traction inverters supply 3-phase AC power to six traction motors. The EM2000 responds to input signals from operating controls and feedback signals from the power equipment.

The term traction control converter (TCC) refers to an electrical device that can convert AC to DC and invert DC into AC (traction power). The terms converter and inverter are used interchangeably in this manual. Each traction motor is geared directly, with a single pinion, to a pair of driving wheels. The maximum speed of the locomotive is set by locomotive gear ratio (ratio of traction motor revolutions to wheel revolutions) and wheel size. EEE Department, Technology Education and Research Integrated Institutions


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TRACTION MECHANISM IN LOCOMOTIVES:

TRACTION: It refers to the maximum frictional force that can be produced between surfaces without slipping. Three types of mechanism are possible in traction: tr action:

1. DC TRACTION: Used earlier in low power locomotives

2. AC-DC TRACTION: In ALCO A LCO locomotives

● In WDM-3D and WDM-3A WDM-3A locos, the diesel engine‘s mechanical output is used to run the shaft of the Alternator. The alternating output of the Alternator is then rectified to DC via solid-state rectifiers and is fed to traction motors (DC) that run the loco wheels. Thus they operate on AC-DC Traction mechanism

3. AC-AC TRACTION: TRACTION: In EMD locomotives

● . WDG4 and WDP4 locos have AC-AC traction with microprocessor control, i.e. AC Traction motors are used thus eliminating the motor commutator and brushes The result is a more efficient and reliable drive that requires relatively little maintenance and is better able to cope with overload conditions.



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BRAKING MECHANISM: 1. Air Pressure Braking: On a train, the brake shoes are pressed directly against the wheel rim. A compressor generates air pressure that is stored in air tanks. Air hoses connect the brakes on all the train cars into one system. Applying air pressure into the system releases the brakes, and releasing air pressure from the system applies the brakes.

2. Dynamic Braking:

It is the use of the electric traction motors of a railroad vehicle as generators when slowing the vehicle. It is termed rheostatic if the generated electrical power is dissipated as heat in brake grid resistors, and regenerative if the power is returned to the supply line. Dynamic braking lowers the wear of friction-based braking components, and additionally regeneration can also lower energy consumption.

During braking, the motor fields are connected across either the main traction generator (diesel-electric loco) or the supply (electric locomotive) and the motor armatures are connected across either the brake grids or supply line. The rolling locomotive wheels turn the motor armatures, and if the motor fields are now excited, the motors will act as generators.

For a given direction of travel, current flow through the motor armatures during braking will be opposite to that during motoring. Therefore, the motor exerts torque in a direction that is opposite from the rolling direction. Braking effort is proportional to the product of the magnetic strength of the field windings, times that of the armature windings.

In DLW Locomotives the braking method used is rheostatic, i.e. the traction motors behave as generators (separately excited) and their electrical power is dissipated in



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brake grid resistors. This method is used for minimizing speed of the loco. The loco actually comes to a halt due to factors like air resistance, friction with the rail, etc.

BIBILIOGRAPHY:



Documents Provided By DLW



www.scribd.com



www.indianrailways.gov.in



www.railway-technical.com/



Wikipedia


training report on diesel locomotives

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