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 M\s 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.

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’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.

PRINCIPLE OF DIESEL ENGINE

When the piston is at the top of its travel, the cylinder contains a charge of highly compressed air.

Diesel fuel is sprayed into the cylinder by the injector and immediately ignites because of the heat and pressure inside the cylinder.

The air in the cylinder is raised to about 500-600 psi which raises the temperature inside to about 1000 0 F.

The pressure created by the combustion of the fuel drives the piston downward. This is the “power stroke”.

.

As the piston nears the bottom of its stroke, all of the exhaust valves open. Exhaust gases rush out of the cylinder, relieving the pressure

As the piston bottoms out, it uncovers the air intake ports. Pressurized air fills the cylinder, forcing out the remainder of the exhaust gases.

The exhaust valves close and the piston starts travelling back upward, re-covering the intake ports and compressing the fresh charge of air. This is the ”compression stroke”.

components in diesel engine 1. Valves : For a two-stroke engine, there may simply be an exhaust

outlet and fuel inlet instead of a valve system.

2. Exhaust systems: The exhaust system frequently contains devices to control pollution, both chemical and noise pollution.

3. cooling systems: Combustion generates a great deal of heat, and some of this transfers to the walls of the engine. Cooling systems usually employ air or liquid (usually water) cooling.

4. Piston: It is located in a cylinder and is made gas-tight by piston rings. Its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In two-stroke engines the piston also acts as a valve by covering and uncovering ports in the cylinder wall.

5. Crank shaft: Most reciprocating internal combustion engines end up turning a shaft. This means that the linear motion of a piston must be converted into rotation. This is typically achieved by a crankshaft.

6. Starter systems : All internal combustion engines require some form of system to get them into operation. Most piston engines use a starter motor powered by the same battery as runs the rest of the electric systems.

7. Lubrication Systems: Internal combustions engines require lubrication in operation that moving parts slide smoothly over each other. Insufficient lubrication subjects the parts of the engine to metal-to-metal contact, friction, heat build-up 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 governorElectrical or electronic component to control or modify the electrical supply

to the traction motions Inverters

basic concepts

Diesel engine

Alternator rectifier

governorTraction control

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.

Typically, a rotating magnet called the rotor turns within a stationary set of conductors wound in coils on an iron core, called the stator. The field cuts across the conductors, generating an electrical current, as the mechanical input causes the rotor to turn.

Alternating voltage may be generated by rotating a coil in the magnetic field or by rotating a magnetic field within a stationary coil. The value of the voltage generated depends on -

the number of turns in the coil. strength of the field. the speed at which the coil or magnetic field rotates.

Synchronous speedThe 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

The relation between speed and frequency is given by

N = 120f / 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.

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 .

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.

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.

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.

THROTTLE It is the mechanism by which the flow of a fluid is managed by constriction or

obstruction.

An engine's power can be increased or decreased by the restriction of inlet gases.

A throttle position sensor (TPS) is a sensor used to monitor the position of the throttle in an internal combustion engine.

The sensor signal is used by the engine control unit (ECU) as an input to its control system. The ignition timing and fuel injection timing are altered depending upon the position of the throttle, and also depending on the rate of change of that position.

Engine control units control engines by determining the amount of fuel, ignition timing and other parameters, by monitoring an engine through sensors, and reading values from multidimensional maps.

Throttle handle position Idle position :

1. The prime mover will be receiving minimal fuel, causing it to idle at low RPM.

2. The traction motors will not be connected to the main generator and the generator's field windings will not be excited . the generator will not produce electricity with no excitation. Therefore, the locomotive will be in "neutral".

To set the locomotive in motion, the reverser control handle is placed into the correct position (forward or reverse), the brake is released and the throttle is moved to the run 1 position (the first power notch).

The first power position :

1. this cause the traction motors to be connected to the main generator and the latter's field coils to be excited.

2. It will not, however, increase engine RPM.

3.With excitation applied, the main generator will deliver electricity to the traction motors, resulting in motion. Thus the locomotive will easily accelerate.

As the throttle is moved to higher power notches, the fuel rate to the prime mover will increase, resulting in a corresponding increase in RPM and horsepower output.

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 control systemA traction control system (TCS), also known as Anti-Slip Regulation (ASR),

is designed to prevent loss of traction of the driven road wheels, and therefore the control of the vehicle, when excessive throttle is applied by the driver.

The intervention can consist of one or more of the following:

1. Retard or suppress the spark to one or more cylinders

2. Reduce fuel supply to one or more cylinders

3. Brake one or more wheels

4. Close the throttle, if the vehicle is fitted with drive by wire throttle.

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.

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 much-improved 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.

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.

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.

For railroad traction the AC motor is preferable to a DC machine on several counts. It is an induction motor with a squirrel-cage rotor , and it has no commutator or brushes and no mechanically contacting parts except bearings, so that it is much simpler to maintain and more reliable.

3. Multi system: Because of the variety of railway electrification systems, which can vary even within a country, trains often have to pass from one system to another. One way this is accomplished is by changing locomotives at the switching stations.

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.

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.

Key components of a bogie include:

1. The bogie frame itself.

2. Suspension to absorb shocks between the bogie frame and the rail vehicle body. Common types are coil springs, or rubber airbags.

3. At least one wheel set, composed of an axle with a bearings and wheel at each end.

4. Axle box suspension to absorb shocks between the axle bearings and the bogie frame.

5. Brake equipment. Two main types are used: brake shoes that are pressed against the tread of the wheel, and disc brakes and pads.

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

Half-wave rectification

Either the positive or negative half of the AC wave is passed, while the other half is blocked. Because only one half of the input waveform reaches the output, it is very inefficient if used for power transfer. Half-wave rectification can be achieved with a single diode in a one-phase supply, or with three diodes in a three-phase supply.

Full-wave rectification

A full-wave rectifier converts the whole of the input waveform to one of constant polarity (positive or negative) at its output. Full-wave rectification converts both polarities of the input waveform to DC (direct current), and is more efficient. However, in a circuit with a non- centre tapped transformer, four diodes are required instead of the one needed for half-wave rectification. Four rectifiers arranged this way are called a diode bridge or bridge 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……..

Telephone exchange Provides telephone connections to the D.L.W. administrative blocks and D.L.W.

colony area.

The exchange is also provided with rack type Main Distribution Frame (M.D.F.). This has capacity to mount fuse mounting with fuses and test jacks.

The exchange is designed to perform satisfactorily for a line loop resistance of 1000 ohm for each subscriber.

The local loop is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the  telecommunications service provider's network.

The exchange works on D.C. supply of 50 volts obtained from battery set which is connected in parallel to the charger which is operating on 230 volts A.C.

The voltage required when two subscriber talks is 12 volts.

Important parts in exchange 1. Battery charger : Charger operates on 230volts A.C.

supplied to it and provides 48-50 V D.C. to the exchange. Charger is attached with a battery in parallel. Whenever electricity goes off the charger is attached to the battery and it starts working on battery.

2. Battery: In the exchange batteries are used to operate it. Batteries are

connected in parallel as soon as electricity goes off the exchange gets connected to the battery.

Lead acid battery: Invented in 1859 , are the oldest type of rechargeable battery.

Construction : In a complete battery there is a negative and positive plate. All negative plates are joined with the help of solder at the terminal post, which is called negative terminal and vice-versa for the positive terminal.

The negative and positive plates are kept in such a manner that every positive plate is in between two negative plates. In this way the number of negative plates is more than the positive plates. Positive plate and negative plate are very close to one other.

There is a doubt of mixing of the plates that’s why separator is used between them of wood rubber, glass, ebonite to keep them at a distance.

There are 4 batteries 12 V each; total 50 V is required for exchange. Each battery has 6 cells each of 2.15 V each.

Electrochemistry: When load is given , current flows the highest side of H2SO4 burst and by this action H+ ions goes to the positive plate (PbO2) and SO4- - ions goes to the negative plate (Pb). Then the equation formed at

 Positive plate:

PbO2 + H2 +H2SO4 PbSO4 + H2O

(Lead sulphate)Negative plate:

Pb + SO4 PbSO4 (Lead sulphate)

Intermediate distribution frame

A frame that

(a) cross-connects the user cable media to individual user line circuits and

(b) may serve as a distribution point for multi pair cables from the main distribution frame (MDF) to individual cables connected to equipment in areas remote from these frames.

The cables that come out of the exchange line cards are installed in the crown type on the wall are called I.D.F.

Main distribution frame

It is a signal distribution frame for connecting equipment to cables and subscriber carrier equipment.

termination point within the local exchange .

exchange equipment and terminations of local loops are connected by jumper wires at the MDF.

The fuse is attached on the back side of the tag block for the safety. As when thundering or vibrations occurs the fuse gets blow off making the circuit break and thus we can prevent further damage.

Jumper wire

Each jumper is a twisted pair.

Twisted pair cabling is a form of wiring in which two conductors are twisted together for the purposes of cancelling out electromagnetic interference (EMI) from external sources.

Electromagnetic interference : It is a disturbance that affects an electrical circuit due to either

electromagnetic radiation emitted from an external source.   The disturbance may interrupt, obstruct, or otherwise degrade or limit the

effective performance of the circuit.

In balanced pair operation, the two wires carry equal and opposite signals and the destination detects the difference between the two.

Distribution pole

DP is much nearer to the consumer where it is easier to take cable from the consumer.

Distribution board In telecommunications, a distribution

frame is a passive device which terminates cables, allowing arbitrary interconnections to be made.

It is a box type board in which cable pads are distributed according to the number which are to be provided near the distribution.

D.B. is installed after a certain interval of the distance make the proper distribution of the cable easier to reach the consumer.

faults

Line contact: It means that the drop wire has connected either with pole

or a tree and a busy tone is obtained when we ring the number.

Line earth: It means that the wire which is broken is in

touch with a pole or earth and there is a soft humid sound is coming when we dial the number.

 Line disc: The wire has been broken down.

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.

elements of numeric control

1. Control unit 2. Machine 3. Axis drive unit 4. Operators control unit 5.Tape reader unit

The manufacturing information on the drawing is converted into punched holes on a paper tape. The preparation of the tape can be on manual fluxo writer or by a post processor. The tape thus prepared is fed through the control unit tape reader. For the control units with memory, the tape information is preserved in the memory. The tape serves like a guide for the machine movement and other machines related functions.

Classification of numeric control 1. Point to point system: This feature is only useful for drilling and boring

operations. The machine operations are possible at specified positions.

2. Straight line system: In this system the control can command a path operation

in a single axis at a time.

3. Continuous path system: In this system the control instructs the machine to

make movements like 2 or 3 axis at a time. The machine may be directed to make helical or circular path.

Computerized numerically controlled machine In CNC the control system further energized with a mini computer or a post

processor.

The control unit stores the programmed information of the work piece, the travel limits, collisions zones and the diagnostic information etc. it also gives a feedback to the operator about the current position and distance to be travelled etc.

CNC machines have the ability to edit or alter the existing program in no time.

Comparison between machine conventional, NC and CNC machines

NO. CONVENTIONAL NUMERICAL CONTROLLED

CNC

1. Occupies more space Depends upon design

Occupies less space

2. Run by operator Run by paper tape Run by paper tape or memory

3. Cycle time is more Cycle time is less Cycle time is less

4. Operator has to clamp tools manually

Partially automatic clamping

Fully automatic tool changing, indexing

NO. CONVENTIONAL NC CNC

6. Prone to human errors, design modification is difficult

Flexibility to some extent High degree of flexibility in design, modification and editing

7. No facility of program storage and diagnostics

Some NCs have backup memory with limited input storage

Program storage, editing and fault diagnostic are possible

8. Repeatability depends upon operator

Partially depends on operator

High repeatability

9. Limitations in selecting specific cutting parameters

Selection of optimum speed is possible to some extent

Selection of any specific cutting parameters is possible

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 Argon-CO2 welding is done on these rollovers

CNC milling machines

CNC mills can perform the functions of drilling and often turning.

CNC Mills are classified according to the number of axes that they possess.

A standard manual light-duty mill is typically assumed to have four axes:

Table x.

Table y.

Table z.

Milling Head z.

Breakdown maintenance Break down of machine can occur due to the following two reasons:  Due to unpredictable failure of component which cannot be prevented. Due to gradual wear and tear of the parts of the machine which can be prevented

by regular inspection known as preventive maintenance.

Preventive maintenance

Also termed as “planned maintenance” or “systematic maintenance” .

An extremely important function for the reduction of the maintenance cost and to keep the good operational condition of equipment.

objective of preventive maintenance

To obtain maximum availability of the plant by avoiding break down and by reducing shut down period to a maximum.

To keep the machine in proper condition so as to maintain the quality of the product.

To ensure the safety of the workers.

To keep the plant at the maximum production efficiency.

To achieve the above objectives with most economical combination.

Electric repair shop

Meter section

Calibration of meter is done and the fault in the meter is detected.

Calibration Calibration is a comparison between measurements-one of known

magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device. The device with the known or assigned correctness is called the standard. The second device is the unit under test (UUT), test instrument (TI).

Overhauling section

Induction motor

The most common motors used in industrial motion control systems, as well as in main powered home appliances.

Advantage of AC induction motor:

1. Simple and rugged design,

2. low-cost,

3. low maintenance and

4. direct connection to an AC power source.

BASIC CONSTRUCTION AND OPERATING PRINCIPLEAn AC induction motor has a fixed outer portion, called the stator and a

rotor that spins inside with a carefully engineered air gap between the

two.The rotating magnetic field is created naturally in the stator because of the

nature of the supply.

formula : the relation between supply frequency f, the no of poles p, and the synchronous speed is Ns = 120f /p.

Rotor speed: Nr = Ns(1 – s) , where s is the slip.

A synchronous motor always runs at synchronous speed with 0% slip.

stator• Made up of several thin laminations of aluminium.

• Punched and clamped together to form a hollow cylinder with slots . • Coils of insulated wires are inserted into these slots.

• Each grouping of coils, together with the core it surrounds, forms an electromagnet on the application of AC supply.

• The number of poles of an AC induction motor depends on the internal connection of the stator windings.

• The stator windings are connected directly to the power source. Internally they are connected in such a way, that on applying AC supply, a rotating magnetic field is created.

rotor• Made up of several thin steel laminations with evenly spaced bars, of aluminium or copper.

• In the squirrel cage rotor, these bars are connected at ends mechanically and electrically by the use of rings. • Squirrel cage rotor has a simple and rugged construction.

• The rotor consists of a cylindrical laminated core with axially placed parallel slots for carrying the conductors.

• Each slot carries a copper, aluminium, or alloy bar. These rotor bars are permanently short-circuited at both ends by means of the end rings.

Single-Phase Induction Motoronly one stator winding and operates with a single-phase power supply, the

rotor is the squirrel cage type.

It is not self-starting.

When the motor is connected to a 1-ф supply, the main winding carries an AC and produces a pulsating magnetic field.

Due to induction, the rotor is energized but the torque necessary for the motor rotation is not generated and s will cause the rotor to vibrate, but not to rotate.

The start winding can have a series capacitor and a centrifugal switch.

When the voltage is applied, current inthe main winding lags the supply voltage

due to themain winding impedance.

At the same time, current in the start winding leads/lags the supply voltage depending on the starting mechanism impedance.

Interaction between magnetic fields generated by the main winding and the starting mechanism generates a resultant magnetic field rotating in one direction.

At 75% of its rated speed the centrifugal switch disconnects the start winding and the 1-ф motor can maintain sufficient torque to operate on its own.

Capacitor Start AC Induction Motor• The capacitor start motor also has a centrifugal switch which disconnects the start winding and the capacitor when the motor reaches about 75% of the rated speed.

• Capacitor is in series with the start circuit, creates more starting torque, typically 200% to 400% of the rated torque.

• And the starting current, usually 450% to 575% of the rated current.

• They are used in applications like small conveyors, large blowers and pumps.

Capacitor Start/Capacitor Run ACInduction Motor

This motor has a start type capacitor in series with the auxiliary winding like the capacitor start motor for high starting torque.

it also has a run type capacitor that is in series with the auxiliary winding after the start capacitor is switched out of the circuit. This allows high overload torque.

costly due to start and run capacitors and centrifugal switch.

Can be used for woodworking machinery, air compressors, high-pressure water pumps, vacuum pumps and other high torque applications requiring 1 to 10 hp.

TORQUE-SPEED CURVES OF DIFFERENT TYPES OF SINGLE-PHASE INDUCTION MOTORS

THREE-PHASE AC INDUCTION MOTORwidely used in industrial and commercial applications.

classified either as squirrel cage or wound-rotor motors.

These motors are self-starting.

They produce medium to high degrees of starting torque.

applications include grinders, lathes, drill presses, pumps, compressors, conveyors, also printing equipment, farm equipment etc.

Starting of motor

Variable-frequency drives

A VFD can easily start a motor at a lower frequency than the AC line, as well as a lower voltage, so that the motor starts with full rated torque and with no inrush of current. The rotor circuit's impedance increases with slip frequency, which is equal to supply frequency for a stationary rotor, so running at a lower frequency actually increases torque.

TORQUE-SPEED CURVE OF 3-PHASE AC INDUCTION MOTOR

Transport section

In transport section there are basically two types of machine are used for transportation purpose of the different jobs from one shop to other.

Different machines used are 1. fork lift truck 2. cranes

Fork lift truck

forklift  is a powered industrial truck used to lift and transport materials.

Counterbalanced forklift components

  Truck Frame - is the base of the machine to which the mast, axles, wheels, counterweight, overhead guard and power source are attached.

Cab - is the area that contains a seat for the operator along with the control pedals, steering wheel, levers, switches and a dashboard containing operator readouts.

Overhead Guard - is a metal roof supported by posts at each corner of the cab that helps protect the operator from any falling objects. 

Power Source - may consist of an internal combustion engine or battery.

cranesA crane is a lifting machine, generally equipped with a winder (also called a wire rope drum), wire ropes or chains and sheaves, that can be used both to lift and lower materials and to move them horizontally.

General characteristicsUsed 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

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.

General characteristics

Installed 3100 hpPower input to traction under site condition 2750 hpGauge 1676 mm

Principle dimensionLocomotive weight 123000 kgNominal axel load 20500 kgWheel diameter 1092 mm Maximum starting tractive effort 37884 kgFuel tank capacity 6000 litersMax speed 100 km/hr

Basic features 

Diesel engine

Model 16 cylinder ALCO251C , DLW builtMedium speed, 4 strokesFuel 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