Internship Report

M S Ramaiah Institute of Technology
Bangalore
Report on Industrial Training
received at
Larsen & Toubro Construction Equipment Ltd.
Byatarayanapura, Bellary Road, Bangalore.
Submitted in partial fulfillment of the requirement
for the award of the degree of
Bachelor of Engineering
in
Mechanical Engineering
Submitted by
Bharat Joshi
1MS12ME041
Under the guidance of
Mr. Venkateshwara Rao
Senior Manager
L&T Construction Equipment Ltd.
Year: 2015

Bharat Joshi: 1MS12ME041 L&T Construction Equipment Ltd.
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Acknowledgement
The satisfaction of completion of any task is incomplete without the mention of
those people whose constant guidance and encouragement crown all the efforts
with success.
Our sincere thanks to the Department of MechanicalEngineering, M S Ramaiah
Istitute of Technology, for allowing us to indulge in this training program, which
has greatly educated us on the realities of engineering.
Our respectful gratitude to Mr. Venkateshwara Rao, Senior Manager, L&T
Construction Equipment Ltd., for sharing with us his vast knowledge base on the
functioning of the entire manufacturing plant.
We are grateful to Mr. Samuel Prashanth Kumar, HR Department, for guiding
us through the internship period.
We thank Mr. Rajiv Kamath for his patience and for helping us better understand
the technical aspects ofthe manufacturing unit.
Bharat Joshi
1MS12ME041
25th
April, 2015.

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Contents
About LTCE 5
Industry 5
Classification of Industry 5
Department Organization at LTCE 7
Productivity 9
Quality 10
Cranes 10
Types of Cranes 11
Fabrication Processesat LTCE 11
Welding Torch 15
Wire Feeder 17
Laser Vision Tracking 17
Through Arc Seam Welding 18
Gas Nozzle Sensing 18
TorchCleaner 18
Gas Storage 19
Compressor 19
CNC Machines 22
CNC Processes 22
CNC Coordinate System 23
Types of CNC Coordinate System 23
Robots 24
CLOOS Robot 25
IGM Robot 26
Uranami Welding Robot 27
Uninterrupted Power Supply 28
Power Generation 28
SkodaGenerator 29
Power Receiving Station 31
Metering Kiosk 32
Circuit Breakers 33
Isolator Room 34
Substation 35
Transformers 36
Bucholz Relay 37
Power Tariff 38
Energy Conservation 39

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Safety 40

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About LTCE:
 Larsen & Toubro was started by a pair of Danish refugees in India, in 1938.
 It is an example of opportunistic start-up. It was started as the founders
could not return to Europe due to World War II.
 It is India’s largest engineering and construction company.
 Was awarded the “Company of the Year” at the Economic Times Awards
2010.
 LTCE is a manufacturer of earth-movers and excavators of various loads and
sizes.
 It was earlier tied up with the Japanese company Komatsu, but split up in
2008.
Industry:
Industry is an entity aimed at producing goods or providing services within a
socio-economic space. It employs specific techniques to collect and process
resources to obtain finished products aimed at satisfying customer needs.
Classificationof industry:
1. Basedon utility:
 Professional, Scientific and Technical services.
 Health care.
Excavator

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 Public administration.
 Telecommunication services
 Agriculture, forestry, fishing and hunting.
 Transportation.
 Finance and insurance.
 Mining, quarrying, oil and gas extraction.
 Construction.
 Manufacturing.
 Wholesale trade.
 Retail trade.
2. Basedon ownership:
 Private sector- The private sectoris usually composed of
organizations that are privately owned and not part of the government.
These usually include corporations and partnerships. The private
sectoris that part of the economy, sometimes referred to as the citizen
sector, which is run by private individuals or groups, usually as a
means of enterprise for profit, and is not controlled by the state (areas
of the economy controlled by the state being referred to as the public
sector).
 Public Sector- The public sectoris usually composed of
organizations that are owned and operated by the government. This
includes federal, provincial, state, or municipal governments,
depending on where you live. Privacy legislation usually calls
organizations in the public sector a public bodyor a public authority.
The main motive is to provide employment to the public mass.
 Joint sector- Joint sector industries are owned jointly by the
government and private individuals who have contributed to the
capital, but the day-to-day management is in private hands.
 Co-operative sector - The cooperative sectorcan be defined as that
sectorof the economy carried out by cooperatives, defined by the
International Cooperative Alliance as “autonomous association of

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persons united voluntarily to meet their common economic, social,
and cultural needs and aspirations through a jointly-owned and
democratically-controlled enterprise.” The cooperative sector is
distinguished from the state or public sector, which is carried out by
the State and its instrumentalities including public corporations, and to
the so-called private sector, which is carried out by private individuals
and organizations.
 MNC - A multinational corporationis usually a large corporation
which produces or sells goods or services in various countries. The
problem of moral and legal constraints upon the behavior of
multinational corporations, given that they are effectively "stateless"
actors, is one of several urgent global socioeconomic problems that
emerged during the late twentieth century.
Departmentorganizationat LTCE:
 Production department – It is responsible for converting raw material into
finished goods. It is necessary to ensure that the process is smoothand
efficient for maximum productivity and quality.
 Production and planning department – This department decides the
sequence of tasks in the production process.They also set the standards and
targets for each stage of the process.
 Purchasing department – It acquires the materials, components and
equipment from various sources. Thus, it must interact with various
suppliers from whom they outsource materials. It also has to ensure that the
materials received are of good quality and arrive on time.
 Stores department – Stores is where the raw materials, equipment and tools
are kept for the manufacturing process.Any worker who wishes have access
to these materials, must first obtain permission to do so. The store keeps
track of each of its materials.
 Designand technical support department – They are responsible for the
design and testing of new productprocessand prototypes, and hence
qualifying them for mass production.

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 Works department – it is concerned with the manufacture of products. It
ensures the smooth functioning of the production line and conducts any
necessary repair.
 Quality control – They conductinspection on the final finished products by
picking out samples from a given batch. They must identify any
discrepancies or inaccuracies and point them out to the production unit.
 Manpowerplanning department – They basically predict the number of
workers required for a particular task and hence assign each worker with a
specific activity.
 Retrenchment department – Dismissal is when a worker is told to leave
his work due to unsatisfactory performance or poorbehavior. Redundancy is
when the factory no longer requires certain number of worker either because
the unit is being shut down or there is a need to cut costs. It may also be due
to the substitution of manual labour by automation. This department looks
into these issues.
 Marketing department – It is responsible for taking the productout into
the market and selling it.
 Sales department – It is concerned with the logistics of the products in
different regions.
 R&D department – This department comes up with new innovative
products orprocesses and tests them, to find out if they can be produced in
mass quantity.
 Promotion department – It decides on the type of promotion technique to
be used for the product, arranges advertisements and the advertising media
to be used.
 Distribution department – Concerned with the transportation of the
productto the market place.
 Finance department – They keep records of the purchases and sales made
by the business and the capitol spending. They also prepare the profit and
loss accounts and the final balance sheets. Finance department provides
other departments with the necessary information regarding money and
funds. The wages section of the finance department will be responsible for
calculating the wages of the employees and organizing the collection of
income tax and national insurance for Inland Revenue. It will also be

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concerned with how a business will raise finance, taking loans and repaying
interest. It will also arrange the payment of dividends to shareholders.
 Human resource department – The role of this department is to recruit,
train and dismiss employees from the organization. Training is mainly done
to enhance employee skills and to motivate them. The training may be of the
following types:
 Induction training
 On-the-job training
 Off-the-job training
Productivity:
It is the average measure of the efficiency of production. It is indicated by the ratio
of output to input. The company constantly tries to increase productivity by
employing new methods, avoiding wastage, minimizing losses or optimizing
processes.The following are some factors that LTCE considers to be of importance
to productivity:
 Location– Proximity to market and raw materials, rules and regulations of
the region, workforce available.
 Government – Laws and regulations, freedom of transportation of goods.
 Management – Efficiency of management, speed of decision making,
communication between higher authorities and workers.
 Personnel – Skill of workers, suitability of the worker for specific tasks.
 Finance – Model of funding, capitol flow.
 Organization– Should be simple and clear, well laid-out responsibilities.
 Technology– Automation, process layout, simultaneous operations.

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Quality:
Quality in business, engineering and manufacturing is defined as the fitness for
purposeof any product.
There are five aspects of quality in a business context:
 Producing – providing something.
 Checking – confirming that something has been done correctly.
 Quality Control – controlling a process to ensure that the outcomes are
predictable.
 Quality Management – directing an organization so that it optimizes its
performance through analysis and improvement.
 Quality Assurance – obtaining confidence that a productor service will be
satisfactory (normally performed by a purchaser).
Cranes:
 A crane is used to transport objects from one part of the shop floor to
another.
 It has a teach pendant with buttons to control its movement in up-down
direction by hoist, right-left direction by trolley, back- forward direction by
bridge.
 3-P Input supply (RYB) is given to contactorcoil which moves the motor in
1 specific direction and input supply (YBR) reverses its direction for same
axis.
 Self braking system is provided so that when power is given, brake springs
open to move the crane.
 Gear box is used to increase or decrease the motor speed.
 Ropedrum for storing the hard metal rope.
 Hooks for carrying the metal parts.
 Hook block with pulleys is used to move the hooks up-down.

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Types of cranes:
 EOT (Electric Overhead Travelling) cranes - Moves on top rails and
covers complete 3-D spaceof shop. It is used for lifting heavy parts to very
long distances.
 SP (Semi-Portal) cranes – It has one side running on top rail while the side
runs on the bottomrail. It is used to carry objects nearby.
 JIB cranes – It is pivoted along an axis and can freely rotate 3600 in 3-D
space. It is used to carry weights in oppositedirections
 PoweredTrolleycranes – It moves on bottom rails and is used to transport
extreme heavy materials.
 Gantry Trolley cranes – They have limited 6- direction movement areas
and are used to carry parts of a particular process atthe same restricted
place.
Fabricationprocesses at LTCE:
The following are some of the manufacturing processesemployed at LTCE for the
manufacture of earth-movers and excavators:
 Shot Blasting - Shot blasting is a method used to clean, strengthen or polish
metal. Shot blasting is used in almost every industry that uses metal,
including aerospace, automotive, construction, foundry, shipbuilding, rail,
and many others. There are two technologies used: wheel blasting or air
blasting. Shot blasting consists of attacking the surface of a material with
one of many types of shots. Normally this is done to remove something on
the surface such as scale, but it is also done sometimes to impart a particular
surface to the object being shot blasted, such as the rolls used to make a 2D
finish. The shotcan be sand, small steel balls of various diameters, granules
of silicon carbide, etc.
 Gouging - Gouging is used in joint preparation and for the removal of
defective welds.
Gouging is similar to gas cutting. An oxyfuel gas flame heats up the piece to
be worked to ignition temperature, and the cutting oxygen jet combusts and

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carries away the molten metal. The equipment is the same as in gas cutting;
only the nozzle needs to be changed. In gas cutting, the cutting oxygen beam
is directed at the work piece at a ninety-degree angle, while in gouging the
oxygen beam is almost parallel with the surface of the piece to be worked.
An oxyfuel gas flame can also be used in flame cleaning, to clean surfaces of
rust, mill scale, paint, grease and dust. Examples of processes include the
treatment of steel and concrete surfaces, as well as of offshore constructions.
In gouging and flame cleaning, various fuel gases are used together with
oxygen. By using ODOROX® (odorized oxygen) you can minimize the risk
of fire and explosion always associated with fuel gases. The odourprovides
a timely warning of gas leaks.
 Drilling - Drilling is a cutting process that uses a drill bit to cut or enlarge a
hole of circular cross-sectionin solid materials. The drill bit is a rotary
cutting tool, often multipoint. The bit is pressed against the work piece and
rotated at rates from hundreds to thousands of revolutions per minute. This
forces the cutting edge against the work piece, cutting off chips from the
hole as it is drilled.
 Bending - Bending is a process bywhich metal can be deformed by
plastically deforming the material and changing its shape. The material is
stressed beyond the yield strength but below the ultimate tensile strength.
The surface area of the material does not change much. Bending usually
refers to deformation about one axis. Bending is a flexible process bywhich
many different shapes can be produced. Standard die sets are used to
producea wide variety of shapes. The material is placed on the die, and
positioned in place with stops and/orgages. It is held in place with hold-
downs. The upper part of the press, the ram with the appropriately shaped
punch descends and forms the v-shaped bend.
 Welding - Welding is a fabrication or sculptural process that joins materials,
usually metals or thermoplastics, by causing fusion, which is distinct from
lower temperature metal-joining techniques such as brazing and soldering,
which do not melt the basemetal. In addition to melting the base metal, a
filler material is often added to the joint to form a poolof molten material
(the weld pool) that cools to form a joint that can be as strong as the base

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material. Pressuremay also be used in conjunction with heat, or by itself, to
producea weld.
 Honing - Honing is an abrasive machining process that produces a precision
surface on a metal work piece by scrubbing an abrasive stone against it
along a controlled path. Honing is primarily used to improve the geometric
form of a surface, but may also improve the surface texture. Honing can be
done on a honing wheel which is quite similar to a grinding wheel apart
from the fact that the abrasive size is extensively small. Honing can also be
done by rubbing the work piece between the honing plate and abrasive
suspended fluid film.
 Centreless grinding - Centerless grinding is a machining process that
uses abrasive cutting to remove material from a work piece. Centerless
grinding differs from centred grinding operations in that no spindle or fixture
is used to locate and secure the work piece, the work piece is secured
between two rotary grinding wheels. The speed of their rotation relative to
Honing process setup

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each other determines the rate at which material is removed from the work
piece. Only cylindrical work pieces can be ground on a centre less grinding
machine.
 Induction hardening - Induction hardening is a form of heat treatment in
which a metal part is heated by induction heating and then quenched. The
quenched metal undergoes a Martensitic transformation, increasing
the hardness and brittleness of the part. Induction hardening is used to
selectively harden areas of a part or assembly without affecting the
properties of the part as a whole. Induction heating is a non contactheating
process which utilises the principle of electromagnetic induction to produce
heat inside the surface layer of a work-piece.
Principle of Centreless grinding

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 Korene Process -Pre-heating is done at 3500C for half an hour. Component
is immersed in treatment tank at 4500C for 30 minutes. Silicon removal
through ion exchange in the tank. Air cooled to room temperature. It is then
processed to the phosphating shop.
 Phosphating - Phosphate coatings are used on steel parts
for corrosion resistance, or as a foundation for subsequent coatings or
paintings. It serves as a conversion coating in which a dilute solution
of phosphoric acid and phosphate salts is applied via spraying or immersion
and chemically reacts with the surface of the part being coated to form a
layer of insoluble, crystalline phosphates. Phosphateconversion coatings can
also be used on Aluminium, Zinc, Cadmium, Silver and Tin.
Weldingtorch:
A welding torch is used for focusing the heat on the job. Welding current to the
electrode is delivered by the power sourceto the torch through suitable copper
Induction hardening

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cables. The weld zone is shielded by inert gases like CO2, Argon, a mix of CO2 +
Argon, He, Ne, etc.
There are mainly 2 types of welding torches used at LTCE:
 Single torch - One filler wire is used for welding. It is used for thin weld
joints.
 Tandem torch - Two electrode filler wires are used for welding. One for 1st
layer and other for final layer. Used for thick and very strong weld joints. It
is capable of higher travel speeds. It leaves behind lower hydrogen weld
deposit. Also, there is lower arc spatter level. It is capable of high deposition
welding for heavy plate fabrication. It is useful as it saves robottime and
gives high productivity
Single torch
Tandem torch

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Wirefeeder:
 It adds filler material or welding wire to the joint during robotic welding.
 In LTCE,consumable elecrode is used for the welding process.
 In every robot, PUSH-PULL system is there, that is, wire feeder pushes the
welding wire to the robotarm and the welding torch pulls the welding wire.
 Internally, gear boxis there which rotates in such a way that the wire is fed
to the robot.
Laser VisionTracking:
This method provides weld for joint thickness less than 1 mm. Laser sensor is
attached 1 inch ahead of welding torch. Laser diode projects a line onto the part. A
camera detects the joint seam based on distortion line. Camera software provides
feedback to the robot, allowing robotto make necessary adjustments in torch
position, its travel speed, weave amplitude, and other weld parameters like welding
voltage and welding current. Its digital tech allows for sensorto have clearer
signal. It also reduces noise and unwanted feedback.
Wire feeder

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Through Arc Seam Welding
It uses welding current feedback to determine the vertical position of the torch.
Increase in distance of torch tip and work causes decrease in welding current and
vice-versa. Uses welding current feedback and weave amplitude of robotto
determine the lateral position of torch in weld joint. As the torch reaches the edge
of the weave cycle, arc current peaks. The current density is least at the weld joint
centre. If the value of peak current at the edge of weave cycle increases, then this
means that the torch is moving away from the weld joint and TAST, hence, it
makes the necessary corrections. Travel speed is about 35-50inch/min. Material
thickness is greater than 2mm. Quick change of current is not there, thus, causing
error.
Gas Nozzle Sensing:
This touch sensing works by making contact of electrode or nozzle with the part of
the welding metal. The nozzle touches a plate and comes back to its reference
point. It again touches another plate and again comes back to that reference point.
Hence, knowing their distances from refer point, the coordinates are recorded into
the memory. Knowing the coordinates, it automatically moves in a formed
diagonal direction of that rectangle formed. It allows adjustments in 1-D, 2-D and
3-D. But, large amount of time is consumed in performing the search routines.
Torch cleaner:
Torchcleaning is required for removing any metal waste present inside the torch.
The system sprays an anti-spatter agent into the nozzle. Some remain inside the
nozzle mouth to collect the anti-spatter agent. Cleaning system automatically
activated at requires intervals of time after a particular welding process time is
over.

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Gas Storage:
 Acetylene is a primary fuel used in gas welding operations along with
oxygen.
 It is stored in pressurised, thick walled cylinders.
 The compressed air in the air receiver is at a pressure of 7bar (approx) which
is then streamlined with the acetylene channel and supplied to the welding
unit.
 A flashback arrester is used to prevent backfiring from fabrication shop to
storage cylinders.
 Oxygen acts as a catalyst in the combustion reactants for welding processes.
 Carbon Dioxide is used for welding.
 These are effectively traversed to the required components through the
compressed delivery system.
Compressor:
An air compressor is a device that converts power (usually from an electric motor,
a diesel engine or a gasoline engine) into kinetic energy by compressing and
pressurizing air, which, on command, can be released in quick bursts.
Torch cleaner

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A very highly compressed air used in torch cleaning, grinding, wire cutting,
polishing, etc. It saves a lot of electricity saved when used for high force works.
It possessa controlvalve which controls the amount of air to be compressed and
the range of pressure controlled by it depends on the extent of the demand of the
compressed air in the process shop.
LTCE employs 2 types of compressors:
1. Reciprocating aircompressor
 50A input DC motor drives a shaft.
 Air is sucked in through a suction valve.
 That shaft hence rotates which further causes a to-fro motion of a
connector.
 With connectorare 2 oppositely attached pistons themselves move in
to and fro direction
 Rotary motion hence converted to reciprocating action
 One side piston action compesses the air at a low pressure, which then
passes through a heat exchanger and is then compressed to more high
pressure.
 Due to another side piston force action this highly compressed air is
again cooled down and sent to supply lines and storage reserves.
 1bar water and 1.5 bar oil pressures are required to run the coolant
system and shaft respectively.
2. Screw Compressor
 A shaft rotates causing screw movement.
 Air is sucked through upper pump and oil is sucked through the lower
green pipe. Both are mixed and taken to very high pressure due to the
screw movement.
 Complete mix is passed through the green pipe. It reaches a tank
where air (green) and oil (yellow) are separated.
 Air is passed to cooler through blue line and sent to storage tank and
supply lines.

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 Oil passed through cooler, cooled down and sent back to the upper
screw compressor.
 It has PLC controlled automated standby mode.
Screw compressor
Layout of a screw compressor

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CNC Machines:
 It works and moves its parts with the help of predefined codes and
instructions.
 Has CNC controlunit (for program storage), electrical cabinet (for giving
supply to servo motor), servo drives, machine tool and feedback elements
(encoders)for comparing computed O/P with the required O/P
 Bending, drilling, boring, honing, grinding, induction hardening and various
such operations are carried out in a CNC machine.
CNC Processes:
1. Basedon movement
 Point-to-point - Machine performs machining operations at specified
position, like drilling.
 Straight line - Machines at a time in one direction only, like milling
4 axes CNC machine for turning operation

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 Continuous path - Interrelated motion of tool and the work piece
along different coordinate axis to machine contours and curves
continuously.
2. Basedon feedback
 Open loop - No check of obtained position with respectto the
command position. Forexample, giving a command for slide
movement does not ensure it actually moves.
 Closedloop - Encoder as feedback device keeps check to make sure
that obtained position is the command position and to make no error.
CNC CoordinateSystem:
 A locating system required as reference location of CNC tool whenever it is
switched on.
 Distance measured is in inches.
Types of CNC CoordinateSystems:
1. Absolute system
 Describes every tool movement in terms of the coordinates of tool
with respectto the reference point.
 Works normally in first quadrant (always +ve).
2. Incremental system
 Instruction given for the toolmovement in terms of moving –ve or
+ve along X & Y directions with respectto the present toolpoint.

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Robots:
Robotis a programmable machine capable of performing mechanical operations.
LTCE employs robots at different stages of its productionline.
The following are the reasons that LTCE considers while installing robots:
 For higher accuracy.
 For operations that can be dangerous for manual laborers.
 To perform actions in places that cannot be reached manually.
 To perform multiple actions at once.
 To change tools at a faster rate.
The robotselected for a task depends on the movement required. The following is
the robot classification based on movement:
 Limited sequence control – It performs simple tasks, like pick and place
operations. Mechanical stops are used to set limits
 Point-to-point control – The robotis made to move from one coordinate to
another and each coordinate is stored in the program. The movement can be
played back at another time.
 Continuous path control - Has greater storage capacity to record the large
number of closely spaced locations for smoothcontinuous motion. The
movement of arm and wrist controlled by it. Interpolation calculations help
in calculating the linear and circular path. Axes velocities are also
controlled.
 Intelligent movement – It has sensors that interact with the environment
and make decisions when an operation goes wrong. They make
computations during the cycle and give appropriate feedback.
The robots at LTCE can be programmed to perform various tasks. The following
are the ways in which programming is done:

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 Lead-through programming – The operator moves the robotmanually to
perform the task. Once this is done, the robotrecords the path movements at
specific intervals of time. Hence, the path can be played back and the
movement repeated. This is employed for spray painting.
 Online programming – The robotactions are controlled using a teach
pendant or a joystick. The robotrecords the movement for playback at a
later stage. The speed of the movements also can be controlled later. Using
these controls, the necessary actions can also be selected. This is used for
continuous arc welding.
 Offline programming – the programming is done in a robot cell using
coding and simulation tools. The program is then fed into the robot, which
reads the instructions and performs tasks accordingly. As no manual
movement is involved, this is a highly accurate method of programming. By
supplying a set of codes, we ensure that the robotis capable of performing
simultaneous actions. LTCE uses this method for touch probes.
CLOOS Robot:
 Manufactured in Germany.
 The robotis used for inert gas welding of the main frame and boom.
 It uses 92% argon and 8% CO2 is used as shielding gas.
 Thin metal wires are used for as filler.
 Robo-1has one single torch, one tandem 100 bent torch & 11 axes of
movement.
 Robo-2has only one tandem 450 bent torch & 12 axes of movement (here
one extra rotational axis of torch for centre frame full welding).
 Robo-1is used for only boom welding but Robo-2is used for both centre
frame and boomwelding.
 Robo-1is used for welding boom of PC- 200/210 models and Robo-2is used
for PC-300/130 models, also for centre frame welding.

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IGM Robot:
 This is an AC servomotor based robotfrom Austria.
 It is MIG welding type robotwith 11 axes.
 Argon is used as a shielding gas and water as a coolant.
 Tandem torch has 2 wires - one lead wire and the other a slave wire.
 Tachogenerator is used as feedback system.
 Laser camera sensing system to locate position of weld object.
 Mixture of air and oil is used for torch cleaning, as residue blocks the
opening of nozzle.
 Push pull wire sensing system is employed, that is, at the lower end wire is
pushed while at the upper end, wire is pulled by the robotarm.
Robo-1 welding the central frame.

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 Uses 30V and 300A current as power source.
 Uses CNC programming for welding dimensions & directions, hence it used
for different specification of boom.
 Advanced job holders and fixtures are used for depositing max amount of
metal.
Uranami WeldingRobot:
 Manufactured in Japan.
 It is a MIG welding robotwhich uses CO2 as shielding gas.
 Three plates are welded to form one side plate of the boom. The plates to be
welded are kept such that their edges are at 5mm distance gap from each
other.
 Wire sensing system - Centres of plate gaps at both ends of edge form a line.
The torch follows this line to feed the welding metal wire.
 For a butt joint, only one side of the plate is welded. The other side is auto-
welded becausethe molten metal reaches the lower end of the plate.
IGM robot welding a boom.

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 Two welding layers are used - one for thin welding (330A/33V) and the
second for thick welding (440V/44A).
 Cooling system provided to both - welding torch and job system through
coppertubes having cold water and a properheat exchanger.
 Ceramic plate is used at the ends of welding plate as these plates have
grooves which hold extra metal in them.
 Hydraulic clamping is used to hold the job.
UninterruptedPower Supply
ONLINE UPS OFFLINE UPS
The input AC supply is converted to DC
and then back to AC at set values
The input AC supply is going directly
to load and charging the battery bank
Due to double conversion, efficiency is
less
Due to single conversion efficiency is
high
There is no interruption of work due to
change over elimination.
Saves productivity and time
Costlier
There is interruption due to power
failure change over
Interrupts work
Less costly
Power Generation:
Power Generation is required to provide back up to all the machines running in the
industry. Various blocks have different power requirements and these are met
through the power generated by the three generators in the power plant.
A power generator needs 5 different systems. These are:

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 Fuel System
 Air supply System
 Lubrication oil System
 Water cooling System
 Electrical System
Skoda Generator:
 4 Stroke, 6 piston cylinders are arranged inline.
 The system is water cooled (soft water at a very low temperature is used to
coolthe engine).
 Compressed air (at 25 bar) is used for initial piston movement through
cylindrical head.
 Turbocharger filters and pre-heats the suction air by the hotness of exhaust
gases.
 Heat Exchanger (raw water and soft water flow in oppositedirection to
allow maximum heat transfer, similarly for oil heat exchanger).
 Fuel Pump sprays the diesel in cylinder.
Construction of a Skoda generator

30
 Air Bottle is used for storing the compressed air.
 Rocker arm for opening and closing the valves for passing the fuel through
it.
 Governor controls the flow of fuel into each cylinder.
 Fuel Injectors atomizes the fuel for better combustion.
 Flywheel makes the speed variations gradual, for almost constant RPM.
Because the engine speed is low, a bigger flywheel is required.
 Salient Pole Alternator. (Rated speed 375 rpm to generate 50Hz supply.)
 DC Exciter, a simple DC generator 110V, 100 A, is connected to the field of
alternator through slip rings.
 ProcessSuctionstrokecompressionstrokecombustionstrokepower
stroke.
Fuel System
Lubrication System

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 Engine converts thermal energy to mechanical energy. Mechanical linear
motion is converted into rotational motion by the crankshaft. This rotational
motion moves the fields of alternator which are charged by the DC exciter.
Hence, electrical energy is generated.
 AVR (Automatic Voltage Regulator) controls the field of exciter which
further maintains rotations, flux and hence, power supply. Exciter controls
the field of alternator. Hence AVR indirectly controls the output voltage.
Power ReceivingStation:
 It basically consists of 11KV incomer overhead lines, fed from
BESCOM Sahakaranagar Substation.
 11 KV, 3 core240 sq.mm XLPE cables are used.
 GOS (Group Operating Switch) 11 kV 400 Amp HT Fuses. It has a
3-phase supply (RYB).
 Metering Kiosk has CTs and PTs, Electronic TRI vector Meter.
 Lightning arrestor is provided for safety.
 A wireless link antenna is also installed.
 Outgoing to main OCB, that is, the 11 kV HT room.
Skoda generator in substation 1

32
 Underground HT cables are laid out.
 Route Markers are provided as guidance.
Metering kiosk:
 This is where the power usage is shown.
 It is a cable entry type.
 3 CT (Current transformers) and 2 PT (Potential transformers) are
provided in the kiosk.
 CT: 125/5 is the current step down ratio.
 PT: 11000/110 is the power step down factor.
 Multiplying factor : 2500
 Displays power (kVA, kWh, kVAr), Voltage and Current, Power
factor, Frequency, Time.
Receiving station

33
 It is tamper proofand fraud can be easily detected.
 The power triangle is sum of (kW, kVA) and the meter which
gives readings all of the above variables is called TRI vector meter.
CircuitBreakers:
A circuit breaker is an automatically operated electrical switch designed to protect
an electrical circuit from damage caused by overload or short circuit. Its basic
function is to detect a fault condition and interrupt current flow. Unlike a fuse,
which operates once and then must be replaced, a circuit breaker can be reset
(either manually or automatically) to resume normal operation. Circuit breakers are
made in varying sizes, from small devices that protect an individual household
appliance up to large switchgear designed to protect high voltage circuits feeding
an entire city.
LTCE employs 2 types of circuit breakers in its substations. They are explained as
follows:
 Oil Circuit Breaker- Mineral oil has better insulating property than air. In
oil circuit breaker the fixed contact and moving contactare immerged inside
the insulating oil. Whenever there is a separation of current carrying contacts
in the oil, the arc in circuit breaker is initialized at the moment of separation
of contacts, and due to this arc the oil is vaporized and decomposed in
mostly hydrogen gas and ultimately creates a hydrogen bubble around the
arc. This highly compressed gas bubble around the arc prevents re-striking
Metering kiosk with labels

34
of the arc after current reaches zero crossing of the cycle. The oil circuit
breaker is the one of the oldest type of circuit breakers.
 Vacuum Circuit Breaker - A vacuum circuit breaker is such kind of circuit
breaker where the arc quenching takes place in vacuum. The technology is
suitable for mainly medium voltage application. Forhigher voltage vacuum
technology has been developed but not commercially viable. The operation
of opening and closing of current carrying contacts and associated arc
interruption take place in a vacuum chamber in the breaker which is called
vacuum interrupter. The vacuum interrupter consists of a steel arc chamber
in the centre symmetrically arranged ceramic insulators. The vacuum
pressure inside a vacuum interrupter is normally maintained at 10 - 6 bar.
IsolatorRoom:
 This is where the input power is distributed to the various parts of the plant.
Oil circuit breaker

35
 The 11 kV input supply is received in this room.
 6 OCBs are present for safety purposes. They are 1 Incomer OCB and 5
Transformer OCB
 Bucholz Alarm (High temp alarm), Bucholz Trip (High temp trip) are also
provided.
 Voltage and Current are displayed on an analog meter.
 Flame-proof entrance dooris provided to this room.
Substations:
 It has the capacity for 11KV/440V.
 4 nos. 1000 KVA Transformers are present.
 2 nos. 860 KVA Diesel Generator Sets are also available.
 OCBs are kept in the Isolator Room.
 LT Panels, Capacitor Banks
 Smoke and Flame detectors have been installed.
 Transformer 1 and 2 feed MW and Transformer 3 and 4 feed HW.
Isolator room

36
Transformers:
 4 nos. 1000 KVA at Substation 1 (TR 1 to TR 4).
 Make: Kirloskar, 11000/433V, 52.5/1334.0 Amp, 50 Hz.
 1 no. 1000 KVA at Substation 3 (TR 5).
 Make: Universal Transformers, 11000/433V, 50 Hz.
 1 no. 2000 KVA at Substation 2.
 Make: Kirloskar, 11000/3300/6600V, 50 Hz. Having one primary winding
and 2 nos. of secondary winding. Used for testing of Excavators with
electric prime movers.
 All the transformers are oil immersed.
 The transformers are all of step down (11KV/430V) type.
 The coolant is oil.
 Cooling Fins are provided. The temperature is more at the top and lower
towards the bottom, becauseoil after heating rises up in plate and dissipates
heat.
 Transformer Oil tank (Capacity: around 950 lit. avg.) is used as conservator
also in case of oil scarcity or oil burns.
 Silica Gel air breather is attached to the conservator. It has small amount of
transformer oil at the bottomto purify the sucked in air. Silica granules
demoisturize the air as it passes through it, because moistured air mixing
with oil conducts strongly.

37
 Internal Temperature Meter (Yellow indicator at 40 C and Red indicator at
75 C)
 Earthing of Transformer body& Neutral is done using 2 distinct copper/GI
strips going into the earth.
 Placed in a coollocation under shade and covered all around with stones
(not with grass as it can catch fire due to underground heat).
 Electrically well protected by OCBs on primary side and ACBs on
secondaryside.
Bucholz Relay:
 Almost all large oil-filled transformers are equipped with a Buchholz relay.
 The gas and oil actuated Bucholz relay is designed to detect faults as well to
minimize the propagation of any damage which might occurwithin oil-filled
transformers.
 Installed in the pipework between the top of the transformer main tank and
the conservator.
Oil immersed transformer with fins

38
 Under normal conditions the relay is completely full of oil. Operation
occurs when floats are displaced by an accumulation of gas, or a flap is
moved by a surge of oil.
 A Buchholz relay will detect:
 Gas produced within the transformer
 An oil surge from the tank to the conservator
 A complete loss of oil from the conservator (very low oil level)
 Silica gel breather is used becauseair needs to be demoisturized else, when
absorbed into the oil, it degrades its dielectric strength and lowers its VBD –
Breakdown Voltage. (Normal VBD is 70 KV for new oil). So oil
decomposesat a lower temperature.
 OCB (for protection from surges in Voltage and Current).
Power Tariff:
 Power report is prepared on the 1st day f every month.
 Energy meter readings from all SDBs, receiving station, DG sets are
recorded.
 2200 KVA: Sanctioned Contract demand.
 Fixed Charges: 75% of the sanctioned max. Demand or actual whichever is
higher @Rs. 180/KVA.
 1st lakh units charged @Rs. 5.10.
 Next (balance) units charged @Rs. 5.50.

39
 Total Charges = Fixed charges + 1st slab + 2nd slab+Tax@5%.
 Depending upon the sanction maximum demand, BESCOM gives a
maximum number of units that we can consume for a month.
 3 MMD has to be deposited with BESCOM before servicing the feeder
(Mirror Money).
 Avg. costper unit for May 2015 is Rs. 6.30
 Per month electric bill in LTK is 42 lakh.
Energy Conservation:
LTCE understands the need for reducing power wastage. It reduces wastage by
minimizing losses and by optimizing processes. Following are the various ways in
which this done at the manufacturing unit:
 Solar powered street lights are used throughout the factory.
 Solar powered lights are used on the shop floor during non-production
hours.
 Programmable timers are used for fabrication and assembly shop lights and
also to run the air compressors.
 Mercury vapour lamps for strong white light, sodium vapour lamps for
strong yellow light and LED lights for long-running white light is used
during night shifts.
 Factory layout is such that cable length is minimum, hence, cable losses are
minimum.
 Air pressureunits are placed to ensure unnecessary air leakage.
 Solar powered heating units are used to preheat water up to a certain
temperature to reduce LPG consumption.
 Rain water harvesting is done to reduce water intake.
 Digitally controlled air management system is used to provide continuous
supply of air, hence, reducing loading period of air compressor.

40
Safety:
LTCE gives paramount importance to safety measures and equipment. While it
realizes than human health and safety is above manufacturing, it also understands
that a safe environment gives workers to perform tasks without hesitation.
The following are some of the safety measures employed LTCE in its
manufacturing unit:
 Personal Protective Equipment (PPE) is made compulsorybefore entering
the shop floor.
 Areas designated for walking, standing/observing, instructing etc. are
respectively indicated using paint, to ensure that a non-worker is not injured
by moving machine parts.
 Earthing is done for every building.
 Safety interlocking for electrical systems is done.
 All buildings have ducts on either side such that are is expelled from one
side while more air is sucked in from the other. This ventilation system
ensures that poisonous gases are not retained in the building.
 Generators are located in isolated areas, so that any breakout of fire does not
affect neighbhouring buildings.
 Painting is performed in a closed enclosure to ensure that toxic lead gases
are contained.
 Electrical safety devices such as MCB, Panel CB, Substation CB and OCB
are used.
 Exit routes are clearly marked for speedy evacuation during emergencies.
 X ray scanners are kept in isolated chambers below the ground, so that the
radiation does not affect others.
 Machines have safety precautions mentioned on them.
LTCE also lists a number of do’s and don’ts in its workers manual that is to be
followed by each employee mandatorily. Some of these are listed below:

41
 Do not start or shut down equipment or installations without standard written
operating procedures.
 Do not perform simultaneous operations without prior visit.
 Do not make any technical or organizational changes without prior
authorization.
 Do not work at high points without safety harness.
 Do not work in confined spaces without the atmosphere being checked.
 Do not perform excavation work without a map of all underground hazards.
 Do not walk under a load which is being lifted.
 Do not perform tasks or installations without personal protective equipment.
 Do not perform a task if you do not have the right tools for the job or the
environment.

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