1
Industrial TRAINING
AT
COAL INDIA LIMITED
DANKUNI COAL COMPLEX
DANKUNI, HOOGHLY
WEST BENGAL
SOUTH EASTERN COALFIELDS LTD.

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TRAINEE NAME: - SOURISH BHATTACHARYYA
INSTITUTE: - HOOGHLY ENGINEERING AND
TECHNOLOGY COLLEGE
DEPARTMENT: - ELECTRICAL ENGINEERING
QUALIFICATION: - B.TECH, 6TH
SEMESTER, 3RD
YEAR
TRAINING PERIOD: - 16.06.2014 - 12.07.2014
Under The Guidance of
Mr. Sudipta Pal
S.E. (Chem.), I/C-Training
DANKUNI COAL COMPLEX

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ACKNOWLEDGEMENT
I am fortunate to receive a hearty Co-Operation and
Support from “Dankuni Coal Complex” which is very
important in making the Vocational Training a Success.
I am glad to get a very homely atmosphere at DCC.
I am thankful to Mr. S. K. Neogi (G.M) for allowing me
to undergo the Industrial Training.
I express my sincere most gratitude to Mr. Sudipta Pal,
S.E. (Chem.), I/C-Training, Anirudha Chakraborty,
S.E. (EE) for constructive ideas and suggestions in
preparation of this Project. I acknowledge him once more
for extending me to the Infrastructural Facilities of this
Plant and for providing valuable Information regarding
completion of my Summer Industrial Training.
I am grateful to the whole staff of Dankuni Coal Complex.

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PREFACE
Practical knowledge means the visualization of the
knowledge, which we read in our books. For this, we
perform experiments and get observations. Practical
knowledge is very important in every field. One must be
familiar with the problems related to that field so that he
may solve them and become a successful person. After
achieving the proper goal in life, an engineer has to enter
in professional life.
As a student of B.Tech in Electrical Engineering, I was
sent to Dankuni Coal Complex, Hooghly to undergo my
Industrial Training during Summer Vacation. The 30 day
training was commenced from 16th
June – 12th
July.
In the following few pages, I have prepared a
Comprehensive Report on my observation and experience
in Dankuni Coal Complex.
Although the Training Period was not so long to cover up
the entire Industry and its various systems due to its
vastness, I have tried my best to absorb it in the outmost.

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COVER INDEX
CONTENT PAGE NO
 BRIEF HISTORY OF D.C.C.
 PROCESS DIAGRAM OF D.C.C.
07
08
 POWER DISTRIBUTION SYSTEM
 ONE LINE DIAGRAM OF SUBSTATION
09
11
 MATERIAL HANDELLING PLANT
 COAL HANDELLING SECTION
 MAIN COMPONENTS OF COAL
HANDELLING PLANT
 CRUSHING/SCREENING SECTION
 COKE HANDELLING SECTION
13
13
15
16
17
 PRODUCER GAS PLANT
 TYPES OF ELECTRICAL DRIVES IN
P.G.P.
17
18
 RETORT HOUSE
 BRIEF INFORMATION ABOUT THE
MAIN COMPONENT USED IN RETORT
HOUSE
18
20
 GAS CLEANING PLANT
 VARIOYS UNITS OF G.C.P.
 AUXILIARY DRIVES IN THE GAS
COMPRESSSOR SECTION
21
22
23

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 TAR DISTILLATION PLANT 23
 UTILITIES 24
 BRIEF IDEA ABOUT INDUCTION
MOTORS
 BASIC CONSTRUCTION AND
OPERATING PRINCIPAL
 TYPES OF INDUCTION MOTORS
 STARTING METHOD OF THREE PHASE
INDUCTION MOTORS
 COMPARISON OF THE MOTOR
STARTING METHOD
 PROTECTION
 TYPICAL NAME PLATE OF AN
INDUCTION MOTOR
 MOTOR DUTY CYCLE AS PER IEC
STANDARDS
25
26
26
28
29
29
31
32
 RATINGS OF MACHINES USED IN D.C.C. 33
 TROUBLESHOOTINGS 40
 CONCLUSION 41

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BRIEF HISTORY OF D.C.C.
Dankuni Coal Complex was set up by Coal India Ltd. under the recommendation
of the Fuel Policy Committee, to meet the growing needs of “Environmental
Friendly Fuel at requirements of domestics & industrial sectors. The foundation
stone of this plant was laid by the late Prime Minister Smt. Indira Gandhi way
back in 1981.
The factory of Dankuni Coal Complex under Coal India Limited was set up
in May, 1990 at Dankuni in the district of Hooghly (W.B.) in between Durgapur
Express Highway and Howrah-Bardhaman Chord Line adjacent to Janai Railway
Station (Eastern Railway). The Factory has a total area of 121 acres of land and is
engaged in carbonisation of coal and recovery of by-products.
COMPANY SET UP
Name & Address: Dankuni Coal Complex
South Eastern Coal Fields Ltd.
Coal India Ltd.
P.O: Dankuni, Dist: Hooghly, Pin:
712310(W.B)
Name & Address of Head Office: South Eastern Coal Fields Ltd.
Coal India Ltd.
Seepat Road, Bilaspore, Pin: 495001(C.G)
Products Manufactured: CIL Coke, Light Oil, Heavy Oil, CVR Oil,
Dehydrated Tar, Pitch, Coal Gas
Category of Industry: Red (Large Scale)
No. of Shifts: 3 Shifts per day in rotation & also General
Shift
Total Area: 120 acres
Nearest Railway Station: Janai Road

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PROCESS FLOW DIAGRAM OF D.C.C

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Power Distribution System
Power Supply to DCC comes from WBSEB Substation at Rishra via 33KV
Double Ckt. 3 Phase 3 Wire Feeders. 33 KV supply voltage is step down to 6.6 KV
to distribute throughout the Plant by 2 nos. of 33/6.6KV, 10/12.5MVA DY11
transformer. Power at 6.6 KV is received by 4 units Substations where it is Step
down to 415 A.C by two nos. of 6600/415V, 1600KVA (U/S 1),2000KVA (U/S 2, 3,
4) DY11 transformer for utilization to provide Power to Motors, Lightning, Air
Conditioning & other Loads. One line from the 33 KV substations directly goes to
the Gas Compressors where the TOSHIBA motors require an input of direct
6.6KV
Each Substation supplies Power to a no. of Motor Control Centre (MCC) which is
located near individual load centers.
To supply survival power to plant in case of power failure from WBSEB there are
4nos. of emergency Diesel Generators of rating 500KVA, 200KVA.
For purpose of correction each Substation is equipped with 125KVAR capacity 3
Phase Capacitor Bank.
All H.T circuit breakers used in 33KV & 6.6KV Ckt. Are MOCB (make BHEL,
SEIMENS, ASEA & TOSHIBA). All 415V L.T breakers are ACB (make EE &
L&T).
Each Motor Control Center is equipped with an incoming Ckt. Breaker, Bus Bar
System & Individual Motor Panels. Most of Drive Motors employ Direct Online
Starter (DOL Starter), however there are some Drives which use Star/Delta
Starting method.

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Each panel of MCC generally consists of:-
1. Fuse disconnector
2. Magnetic Contactor with suitable rating
3. Directly or CT operated Bimetal Thermal Overload Relay
4. Emergency Stop Push Button
5. Control & Power Ckt. wiring
6. Suitable terminal connectors for Control & Power Ckt
7. Ammeter
STATION BATTERIES:
The 33KV Substation & Gas Compressor MCC are provided with 110V D.C supply
for operation of Control & trip.
In 33KV Substation the Battery Bank consists of 30 nos. of 2V Lead Acid cells.
Four Unit Substations are provided with 24V DC battery.
For charging of these batteries individual battery charger are present at each
substation.

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ONE LINE DIAGRAM OF SUBSTATION

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The main plants/units of the factory engaged
in production process are:
1) Material handling Plant (MHP): This section has two
parts as follows.
(i) Coal Handling Section
(ii) Crushing Section
(iii) Coke Handling Section
2) Retort House (RH)
3) Producer Gas Plant (PGP)
4) Gas Cleaning Plant (GCP)
5) Tar Distillation Plant (TDP)
6) Utility (Boiler, Air Compressor, De-Mineralized Water,
Pump House, Effluent Treatment Plant)

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MATERIAL HANDELLING PLANT
Material Handling Section is designed for the receipt of Coal (400mm) in Railway
Wagons & other raw material (including stones, dust and coal fines) by tracks &
for dispatch coke & coal fines. Elaborate System of Belt Conveyors is provided for
the transport of Coal & Coke within the Plant.
The total MHP is divided into 3 sections:-
 COAL HANDELLING SECTION
 CRUSHING/SCREENING SECTION
 COKE HANDELLING SECTION
COAL HANDELLING SECTION
The purpose of the Coal Handling Section is to receive coal by broad gauge open
railway wagons and other raw materials and then dispatch of coke and coal fines.
Elaborate arrangements of belt conveyors are provided for the transport of coal
and coke within the plant.
The sections in this plant are unloading section and feeding section.
Unloading section:
The coal is unloaded by the Rotary Wagon Tippler, rotating the whole railway
wagon by an angle of 165º.The sized coal (-200 mm) unloaded from the wagon
tippler will be received in the hoppers having two openings each. The hopper
which is provided with rack and pinion gate feeds the coal to inclined belt
conveyor(C-2) through heavy duty vibratory feeder and discharge chute. Coal (-
200mm) from the conveyor C-2 will be fed either to the conveyer C-4 above coal
storage bunker or to the conveyor C-3 above coal stock area.
The conveyor C-3 above open coal stock is provided with mobile tripper for stock
piling the coal on the open ground. This open yard coal is loaded into tripper truck
with the help of pay loader which is unloaded in the manual bunker C-1 as and
when required. This operation generally occurs when there is no coal supply from
outside, by wagons. About 3000 tons of coal can be stacked in open coal stock pile.

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The conveyor C-4 above coal storage and out loading bunker has a mobile tripper
to fill up twenty stock bunkers. There is also one direct bunker which is filled up
with the spillage from belt. Capacity of each bunker is 500 tons. The storage
bunker feeds the coal to conveyor C-5 through discharge chutes.
Reclaim conveyer C-5 will feed the coal through inclined conveyer C-6 from the
coal storage bunker to crusher/screen house for crushing and screening. A belt
weigher is provided on this belt conveyer for recording the quantities of coal to
crusher/screen house.
The magnetic separator is suitably provided on this inclined conveyer to remove
iron impurities from coal and prevent the crusher from damage.
Besides these, a metal detector is also mounted over the conveyer for detecting any
metallic pieces are 40 mm sizes and stopping the conveyer in case of their
detection. Detection shall be indicated through a suitable hooter system.
Feeding section:
In this section different mesh size coal are fed to different plants of the industry as
required. Coal from above conveyer C-6 is fed from single deck vibratory screen via
discharge chutes over size coal+100to -200 are being separated in the screen is fed
to the double roll crusher for crushing below 100mm from single deck vibratory
screen through discharge chute. The coal fraction -25, +25 to-40 and +40to-100
mm are separated in double deck vibratory screen.
(a)-25 mm coal are called coal fines which are conveyed by conveyer C-9 this
rejected coal fines are then accumulated in the coal fine bunker from C-9
conveyer. The coal fine bunker has 170 tons capacity and it has 2 openings
with racks and pinion gates to load the cola fines into trucks. These are then
sold to the Customers (Thermal Power Plants).
(b) The Coal of size -25 to -40mm will be fed to the conveyer C-8 with belt
weigh for feeding Producer Gas Plant.
(c)The sized coal +40 to -100 mm is fed to conveyer C-7 with the belt weigher
for feeding the Retort via fixed tripper and discharge chute at the end. Belt
weighers are provided for recording the quantities of coal supplied to the
retort house and producer gas plant.

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Main components of Coal Handling Plant
Wagon Tippler: - It is used for unloading of Incoming Coal Wagons & it is one of the
most vital equipment. The Wagon Tippler has two nos. of Slip Ring Induction Motors of
capacity 53KW each. Each Motor has 5-step rotor resistance. Step 1-4 are used for
acceleration & Speed control of Tippler. Step 5 is permanently used in the Rotor Circuit.
Each Motor has D.C Electromagnetic Brake. The Magnet operates to Release &
Brake thereby allows Tippler to rotate. The cylindrical cage of the tippler consists of two
circular ring fitted with gear teeth and connected to a platform with travel rails, support
rollers, girders, counter weights, hydraulic clamping device for wagon, from top as well
as side during tippling. These are giant machines having gear boxes and motor assembly
and are used to unload the coal wagons into the coal hoppers in less time where it moves
down to the vibratory feeder to the discharge chute.
In hauler & Out hauler: -There is arrangement of shunting IN & OUT of individual
Wagon from the Tippler. These are called:
 INHAULER: Used to transport Wagon into the Tippler prior to unloading.
 OUTHAULER: Used to transport Wagon out of the Tippler after unloading.
Vibrating feeders:-These are electromagnetic vibrating feeders or sometimes in the
form of dragging chains which are provided below the coal hoppers. The equipment is
used for control and continuous removal of coal and coal hopper. Thus we can say that a
vibrating feeder is used to transfer the large size materials and granular materials from
the hopper to receiving device uniformly, periodically and continuously in the
production flow and to feed materials into the crusher continuously and uniformly.
Characteristics of vibratory feeder:-
Smooth vibration, reliable operation, long service life, low noise, low power
consumption, easy to adjust, simple structure, easy to install, light weight, small volume,
simple maintenance.
Belt conveyors: -These are synthetic rubber belts that moves on metallic rollers called
idlers and are used for shifting of coal from one place to other places, conveyers are seen
on virtually all in the Coal Handling Plant (CHP).

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The Main Conveyer Belt paths can be classified as:-
 COAL STORAGE ROUTE
 COAL CHARGING ROUTE
 COKE DISCHARGING ROUTE
The efficiency of the CHP depends on the availability and reliability of the conveyer
system. In this case of emergency sufficient measures have been taken to ensure safety.
For example – a pull cord switch is available at regular intervals throughout the belt
which helps in operating the belt at any position in order to prevent accident.
Mobile tripper: -It is the discharge outlet that helps in dropping the coal at a specified
point. When this tripper fills up a particular space it is shown by an indication of the
tippler shifts to next position.
The main Drive Mechanism of Mobile Tippler consists of:-
Main Drive Motor: This drives the moving carriage chain by Sprocket Mechanism.
Hydraulic Thruster Motor: Used for Braking the Carriage.
Cable Drum Drive Mechanism: It is used for Reeling of Power Cable.
CRUSHING/SCREENING SECTION
The coal received in Crusher House is first separated into above 100mm and below
100mm size with the help of a single deck vibratory screen and a discharge chute
with a flap gate. Coal of +100 sizes is then fed to the roll crusher for crushing to
below 100mm; this crushed coal is then screened by a double deck vibratory screen
with screens of sizes 40mm and 25mm in sequence. This screening provides us
with the following 3 fractions:
The size -25 to -40mm coal will be fed to the conveyer C-8 with belt weigh for
feeding Producer Gas Plant.
The sized coal +40 to -100 mm is fed to conveyer C-7 with the belt weigh for
feeding the Retort via fixed tripper and discharge chute at the end.
Sizes of-25 mm coals are called coal fines which are conveyed by conveyer C-9.
The coal fine bunker has 170 tons capacity. These are then sold to Thermal Power
Plants.

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 -25mm : coal fines (despatched to NTPC)
 -40 and +25: For feeding to Producer Gasifiers.
 +40 and -100: For feeding to Retorts.
COKE HANDELLING SECTION
Conveyers (C0-1, CO-2, CO-3 & CO-4) bellow the four rows of Retorts through
travelling Coke chute and transfer to conveyer (C0-5/6) in front of Retort House
through Discharge Chute with Flap Gate. Through Discharge Chute Coke is
carried out to Connecting Conveyers (C0-7, CO-8) to Coke Screening House
where it is lead to Single Storage Bunkers by Conveyers (CO-9, CO-10). The Coke
Storage Conveyers (CO-9, CO-10) are provided with Mobile Tippler to feed Coke.
PRODUCER GAS PLANT
Objective:
The main aim of this plant is burning of coal in presence of air and steam to
produce clean and low Calorific value fuel gas to heat 5 benches of Continuous
Vertical Retort (CVR) located in the Retort House.
PGP unit‟s main responsibility is providing fuel (flue gas) to Retort House.
PGP generates the Flue Gas required as a fuel in the Retort House by Fischer
Process, burning -40 and +25 sized coal in limited supply of air (i.e. oxygen,
incomplete combustion). This unit consists of 5 Double Stage Gasifiers with Lock
Hopper system.
The top gas (120‟C) obtained from the distillation zone contains large
amount of volatile materials and tar which is separated by passing it through Tar
Knock-Out pots and Electrostatic Precipitator (ESP).The bottom gas obtained
from the gasification zone is at comparatively higher temperature (650‟C) is dust
and ash prone and hence passed through dust cyclone separator.
The cleaned top and bottom gases are then mixed and this Mixed Producer
Gas (>200‟C) is sent to the Retort House for internal plant consumption as fuel
through PG main.
.

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TYPES OF ELECTRICAL DRIVES /EQUIPMENTS in P.G.P
Hydraulic Pump for Gasifiers: This Motor driven pumps are used to supply high
pressure Hydraulic fluid to a set of reciprocating cylinders which moves the Gasifiers
Grate in a Circular motion thereby providing automatic removal of ash & Char from the
Gasifier.
The reciprocating motion of the Hydraulic cylinder is achieved through a no. of
electrically operated Solenoid Valves & Limit Switches.
Vibrating Screens: These Motors driven screens are used to feed properly sized coal
from individual Coal Bunkers into the Lock Hopper of the Gasifiers.
Coal Fines Conveyers: Down sized Coal from the vibrating Screens are carried by this
Chain Conveyer for Storage in Storage Bunker.
Air Blower: The process of manufacture of producer Gas, air & Steam is required to be
blown over bed of Red Hot Coal. Air Blower serves purpose of maintaining this Air flow.
This in turn helps to maintain positive Draft at the Inlet Header of the Gas Pipe of the
Retort.
Electrostatic Precipitators (ESP): Two nos. of ESP are used to separate Tar particles
from Top Gas. This is achieved by passing the gas in between a Discharge Electrode and
a Collecting Pipe maintained at very high Potential Difference (60 KV DC). At such a
high Potential difference ionized air particles is achieved by the effect of negative
Corona. The negatively charged particles are attracted to positive Collecting pipes
(positive is earthen) and hence separated from the Top Gas.
RETORT HOUSE
Here Coal is carbonized in Continuous Vertical Retorts while continuously
moving downward through the Carbonizing Zone. Destructive distillation of coal
is the process of pyrolysis conducted in a distillation apparatus retort in absence of
air to form the volatile products, which are collected from the top and solid
residue from the bottom. This application relates to a method and apparatus in
which coal is converted to gas, liquid and solid products by an integral
combination of pyrolysis, gasification and possibly Fischer- Tropsch synthesis.
Destruction distillation is not a unit operation like distillation, but a set of
chemical reactions. The process entails the “cracking” (breaking up of

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macromolecules into smaller, more volatile, components and this remains a viable
route to many compounds).
Low Temperature Carbonization (LTC) of Coal is carried out in the Continuous
Vertical Retorts (CVR) producing Coal Gas and increasing the Fixed Carbon
Content from 45% (Coal) to 60% (Coke).
Objective:
Here in this part of D.C.C the non- coking coal of sizes +40 mm to-100 mm, having
moisture content of 3-5%, is fed into a continuous vertical retort from the top and
is carbonized while moving down wards through the retort. Due to the
carbonization of coal, the products formed are:
(a) Solid: Carbonized Coke.
(b) Liquid: Tar
(c) Gaseous: Coal Gas
Thus the objective of this process is the production of coke, tar and gases.
Gas consisting of:
 CO2,CO,CH4,N2,O2,H2, Unsaturated Hydrocarbons[Pure Coal Gas
components];
 Ammonia, H2S, Naphthalene, Tar [Impurities to be removed in GCP]
Production:-
About 800 tons per day of solid smokeless coal branded as CILCOKE is
manufactured from low ash, low Phosphorous, low Sulphur Coal source.
Fixed Carbon content: 62-67%
Gas: 23%
Volatile Matter: 3-5%
Phosphorous: 0.03-0.04%
Calorific Value: 5000-5500 Kcal/kg

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Brief Information about the Main
Components used in Retort House
Hydraulic Pump Motors: This Motor provides pressurized Oil needed to work
Hydraulic circuits in the Coke Discharge of the Retort.
Flushing Liquor Pump Motor: It circulates Ammoniacal Liquor for spraying at the
gas off-take of individual Retort in order to cool the gas, temperature to 80̊C for
condensation of Tar & Ammonia which are collected in suitable time, otherwise this Tar
would clog the Steam gas pipe & equipment.
ID Fan Motors: These fans are used to circulate the flue gasses coming out of the
Combustion Zone of CVR, through Fire Tubes of the Waste Heat Boilers.
Askania: It is a Pressure Controlling Device. The Butterfly valve of Askania is kept
within the Coal gas line in between the Gas Tank Pipe & Main pipe to GCP. It maintains
a positive pressure of 3.5 mm H2O Gauge inside the Retort so that infiltration is avoided.
It consists of metallic diaphragm& Hydraulic system , similar to that of Retort . When
the Pressure inside the Retort increases the Butterfly Valve opens to reduce the Pressure
in Collecting Main & vice versa. A Bypass line is also present in the Coal Gas Line, before
Askania Butterfly Valve System, which is operated manually to maintain positive
pressure in case when the Askania fails. When Exhauster Gas Pressure is increased the
Gas is vented from the Retort House through Vent Valve to the Atmosphere.
Goose neck: From the top each retort a goose neck comes out which is connected to the
collecting main. As coal gas+ tar comes out in vaporized form through the neck of the
retort, arrangement is made within the goose neck to cool it down from 200 deg C to 75
deg C by spraying NH3 Liquor.
Coke Trolley: These are basically discharge Chutes mounted on Motor driven Trolley
cars & facilitates the discharge of Coke on the Coke belts.
Coke Quenching Water Pumps: These Motor driven pumps are used to supply
water for Quenching of Red hot Coke discharged from the Retort onto the belt.
Sump Pump Motors: Discharge system in the Retort as well as in other parts of the
plants are designed so that Rain Water may be collected at some pits from where this
water is collected & discharged into the drainage system of the plant with the help of
Sump Pumps.

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GAS CLEANING PLANT
Objective:
The Gas Cleaning Plant helps in the removal of impurities (tar, NH3, H2S) from
the coal gas from retort.
Process description:
The coal gas together with (tar, NH3, H2S) enters the GCP section from retort
house. A negative pressure in GCP is maintained by 2 exhausters: one is driven by
motors and the other is driven by steam. The gas first enters the primary cooler
where the gas is cooled from 75-35°C. There are 3 vertical primary coolers in GCP.
Here 75-80% tar together with ammoniacal liquor is separated from the coal gas
and is collected from the bottom of each collector.
The gas from the cooler then passes through the exhauster and enters the detarrer.
Here the rest of tar is completely separated from the gas. There are 3 detarrers in
GCP. The tar from the detarrer and from the primary cooler is cooled in the
decanter. The mixture of ammoniacal liquor and tar is collected in the liquor pit
and pumped to the decanter by gravity settling tank resp.
From the detarrer the gas enters the NH3 absorber section where NH3 is absorbed
by 5-6% H2SO4 pre heated at 60°C .The slurry is collected at the bottom of the
absorber, then passed at the centrifuge from where solid (NH4)2 SO4 is obtained
as a fertilizer.
After NH3 absorber the gas enters the naphthalene washer, where naphthalene is
removed by wash oil. The H2S is removed from the coal gas by absorption. STRED
FORD LIQUOR consists of soda ash, anthraquinone disulphonic acid and Sodium
Ammonium Vanadate (SAV) gas enters from the lower section of H2S washer. Gas
is contacted with STRED FORD LIQUOR in the special wooden packing.
The base of the washer allows sufficient delay time for the Oxidant of the H2S ions
to freed Sulphur by Pentavalent Vanadium in the STRED FORD LIQUOR. In this
way H2S is removed.

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Production:
About 18 million cft of coal gas per day for supply in and around Kolkata and
Howrah. Gases fuels being very clean in nature, would subsequently contribute to
the reduction of pollution level of Howrah and Kolkata. D.C.C serves as gas
supplier for GCGSC (Greater Calcutta Gas Supply Commission).
VARIOUS UNITS OF G.C.P
Primary Coolers: - 3nos. of Primary Cooling Tower Pumps are used to circulate water
to Primary Cooling Towers for cooling of incoming Coal gas from Retort House. They
also supply Cooling water to interstate Coolers of the Gas Compressors. The action is
facilitated by the use of 4nos. of Cooling Fans.
Exhauster:- The Electrical Motor driven unit consists of a variable speed Squirrel Cage
Induction Motor which drives as a Gas Compressor used to transport the gas from
Retort House through other sections of P.G.P. & finally into the Gas Holder.
Detarrer: - 3nos. of Detarrer are available in D.C.C. to separate Tar fog from the Coal
Gas being produced at the Retort. This is achieved by passing the gas in Potential
Difference (30KV DC). At such a high Potential Difference, ionization of Tar particles is
achieved by the effect of negative Corona.
Ammonia Absorber: - Here Ammonia (NH3) is reacted with dil.H2SO4 to form
Ammonium Sulphate. Motor Coupled to the Pump, Slurry Pump & other Liquor Pump is
main Drive in the Section.
Gas Holder: - The capacity of the Gas Holder is 30000 m3. It contains clean Coal gas
from GCP before being drawn by Gas Compressors. The Gas Holder being a Water Seal
type has a built arrangement for Pressure Release. It has 3 Zones to avoid excessive
Pressure inside the Holder or when the gas has higher content of Impurities.
Gas Compressor: - There are 3 Gas Compressors. These are mainly reciprocating type,
3 Stages & used for Compressing the Gas to 19.5 kg/cm2. These are driven by 1500KW
Synchronous Motors & are used to extract gas from the Gas Holder. These Synchronous
Motors are used for Power Factor correction of the Plant as whole.

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There are many interstate Coolers & Separators present. Water flows in the Shell side
& Gas in the tube Side. Coolers are used to increase the Differential Pressure of the Gas
& reduce the temperature rise due to High Pressure.
Gas Chilling & Dehydration Unit: - In Dehydration unit Gas is 1st
Dehydrated to
Prevent the condensation of L.O. & Moisture. Then it goes to the Chilling unit where it
is chilled with Refrigerator Freon. This condenses the Moisture & L.O present in the Gas
which is knocked off in a Separator. The gas is chilled from 40°C - 10°C & put in Gas grid
Line.
Auxiliary Drives in the Gas Compressor Section
Blower: - It develops positive pressure to stop Combustible gasses from entering
the Compressor.
Oil Pump Motor/Lubrication Pump: - This is used to provide Lubricating oil
to different parts of the Gas Compressor.
Solvent Injection Pump: - This Motor driven Pump is used to spray the Tar
dissolving chemicals in to the Common Section header of the 1st
Stage of the
Compressor.
Baring Gear Motor: - After the Auxiliaries are started the Synchronous Motor is
started by the help of Baring Gear at a very low speed prior to actual Start up.
TAR DISTILLATION PLANT
Coal tar is a black, viscous and sometimes semisolid fluid possessing an odor. The
tar collected in all the gas separators located in PGP, Retort and GCP are all
collected in 2 intermediate storage tanks, where ammonia liquor is separated from
which the tar ultimately reaches Tar Storage Tank. The tar is sent to the
dehydration unit after being heated to 120„C using steam which results in tar
moisture converting to steam.

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Objective:
The primary objective of this plant is:
(a) Dehydration of crude tar in the dehydrator column.
(b) Removal of pitch from the dehydrated tar in the pitch column.
(c) Separation of tar oils into light, medium and heavy fraction.
The Various Sections of this Plant are:
(a) Tar Distillation Section
(b) Caustic Washing section.
(c) De-Oiling & Springing Section.
(d) De-Hydration & De-Pitching Section.
(e) Primary Distillation Section.
(f) Batch Distillation Section.
(g) Solvent Recovery and BOD plant.
(h) Tank Farm.
UTILITIES
Utility is very important part of an Industry. So every Industry whatever it may be
must have a Utility Section. In D.C.C the Utility Section can be divided into:
De-Mineralized Water Plant: In D.C.C main water source is underground
water. This water is obtained by deep tube well. As the water contains minerals it
is highly corrosive in nature which may be harmful to the equipments used in
D.C.C so the water needs to de-mineralized.
Pump House: Process/Service water, Fire Water & Drinking water required for
the operation of the plant is supplied from the Pump House. To meet the
requirement of Service Water there are two nos. of Motor driven Vertical Shaft

25
Pumps. Similarly for the Fire Water there are two nos. of Motor driven Vertical
Shaft Pumps and 1 Pump is Diesel Engine driven used for Emergency Section.
Effluent Treatment Plant: Here the wastes from different sections of the Plants
such as Solvent Recovery, Domestic Sewage, Effluent from GCP, TDP and Retort
House is treated and discharged.
Central Laboratory: The laboratory holds the key for the formation of product
by testing the raw cola or the source coal and then limiting the operating
temperature and pressure etc.
Generally two types of analysis are done:
1. Proximate analysis
2. Ultimate analysis
Fire and Safety: Safety is the most Important Criteria of any plant. In D.C.C it
has been given a main importance. Activities that seek to minimize or to eliminate
Hazardous Conditions that can cause bodily injury. Hazards and following major
emergencies are covered by this plan:
1 Fire in plant
2 Release of toxic gasses
3 Explosion
4 Collapse of structure
BRIEF IDEA ABOUT INDUCTION MOTORS
INTRODUCTION
AC Induction Motors are the most common motors used in Industrial Motion
Control Systems, as well as in main powered home appliances. Simple and rugged
design, low-cost, low maintenance and direct connection to an AC power source
are the main advantages of AC induction motors.
Various types of AC induction motors are used in different sections of Dankuni
Coal Complex. Different motors are suitable for different applications. Although

26
AC induction motors are easier to design than DC motors, the speed and the
torque control in various types of AC induction motors require greater
understanding of the design and the characteristics of these motors.
This application note discusses the basics of an AC induction motor; the different
types, their characteristics, the selection criteria for different applications and
basic control techniques.
BASIC CONSTRUCTION AND OPERATING PRINCIPLE
Like most motors, an 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.
Stator
The stator is made up of several thin laminations of aluminum or cast iron. They
are punched and clamped together to form a hollow cylinder (stator core) with
slots. Coils of insulated wires are inserted into these slots. Each grouping of coils,
together with the core it surrounds, forms an electromagnet (a pair of poles) 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
The rotor is made up of several thin steel laminations with evenly spaced bars,
which are made up of aluminum or copper, along the periphery. In the most
popular type of rotor (squirrel cage rotor), these bars are connected at ends
mechanically and electrically by the use of rings.
The rotor is mounted on the shaft using bearings on each end; one end of the shaft
is normally kept longer than the other for driving the load.
TYPES OF INDUCTION MOTORS
Generally, induction motors are categorized based on the number of stator
windings. They are:
• Single-phase induction motor
• Three-phase induction motor

27
Single-Phase Induction Motor
There are probably more single-phase AC induction motors in use today than the
total of all the other types put together. It is logical that the least expensive, lowest
maintenance type motor should be used most often. The single-phase AC
induction motor best fits this description. As the name suggests, this type of motor
has only one stator winding (main winding) and operates with a single-phase
power supply. In all single-phase induction motors, the rotor is the squirrel cage
type.
The single-phase induction motor is not self-starting. When the motor is
connected to a single-phase power supply, the main winding carries an alternating
current. This current produces a Pulsating Magnetic Field. Due to induction, the
rotor is energized. As the main magnetic field is pulsating, the torque necessary for
the motor rotation is not generated. This will cause the rotor to vibrate, but not to
rotate. Hence, the single-phase induction motor is required to have a starting
mechanism that can provide the starting kick for the motor to rotate.
The starting mechanism of the single-phase induction motor is mainly an
additional stator winding (start/ auxiliary winding). The start winding can have a
series Capacitor and/or a Centrifugal switch. When the supply voltage is applied,
current in the main winding lags the supply voltage due to the main 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. The motor starts
rotating in the direction of the resultant magnetic field.
Once the motor reaches about 75% of its rated speed, a centrifugal switch
disconnects the start winding. From this point on, the single-phase motor can
maintain sufficient torque to operate on its own.
Three-Phase Induction Motor
Three-phase AC induction motors are widely used in industrial and commercial
applications. They are classified either as Squirrel Cage or Wound-Rotor
motors.
Another class of Induction Motor is Synchronous Motor.
These motors are self-starting and use no capacitor, start winding, centrifugal
switch or other starting device.
They produce medium to high degrees of starting torque. The power capabilities
and efficiency in these motors range from medium to high compared to their
single-phase counterparts. Popular applications include grinders, lathes, drill
presses, pumps, compressors, conveyors, also printing equipment, farm
equipment, electronic cooling and other mechanical duty applications.

28
STARTING METHODS of THREE PHASE
INDUCTION MOTORS
Once a supply is connected to a Three Phase Induction Motor a Rotating
Magnetic Field will be set up in the Stator; this will link and cut the Rotor bars
which in turn will induce Rotor currents and create a Rotor field which will
interact with the Stator field and produce rotation. Of course this means that the
three phase induction motor is entirely capable of self starting.
The need for a starter therefore is not, conversely enough, to provide starting but
to reduce heavy Starting Currents and provide Overload and Under-Voltage
Protection.
The most commonly used Starters in D.C.C are:-
1. DOL ( Direct On Line ) Starter
2. Star/Delta Starter
Direct On Line (DOL) Starter
This is the most common and simple Starting Method. The components consist of
only a main Contactor and Thermal or Electronic Overload Relay. The
disadvantage with this method is that it gives the highest possible starting
current. A normal value is between 6 to 7 times the rated motor current but values
of up to 9 or 10 times the rated current exist. During a Direct-on-Line start, the
starting torque is also very high, and is usually higher than required for most
applications.
The main components in DOL Starter Panel of a Motor are:
i. Fuse-Disconnector-Switch unit commonly called Fuse Switch unit.
ii. The Magnetic Capacitor of suitable Capacity.
iii. Direct or CT operated Bimetal Thermal Overload Relays.
iv. Control Circuit for Starting and Stopping the Motor.
Star/Delta Starter
It achieves an effective reduction of starting current by initially connecting the
stator windings in star configuration which effectively places any two phases in
series across the supply. Starting in star not only has the effect of reducing the
motor‟s start current but also the starting torque. Once up to a particular running
speed a Triple Pole Double Throw Switch changes the winding arrangements from
star to delta whereupon full running torque is achieved. Such an arrangement
means that the ends of all stator windings must be brought to terminations
outside the casing of the motor.

29
This starting method only works when the application is light loaded during the
start. If the motor is too heavily loaded, there will not be enough torque to
accelerate the motor up to speed before switching over to the delta position.
When starting up, the load torque is low at the beginning of the start and
increases with the square of the speed. When reaching approximately 80-85% of
the motor rated speed the load torque is equal to the motor torque and the
acceleration ceases. To reach the rated speed, a switch over to delta position is
necessary, and this will very often result in high transmission and current peaks.
In some cases the current peak can reach a value that is even bigger than for a
D.O.L start. Applications with a load torque higher than 50% of the motor rated
torque will not be able to start using the star-delta starter.
The main components in Star/Delta Starter Panel of a Motor are:
i. Fuse Switch unit for Isolation or Backup Protection.
ii. Three nos. of Magnetic Capacitor:- Main, Star & Delta.
iii. Direct or CT operated Bimetal Thermal Overload Relays.
iv. Control Circuit for Starting and Stopping the Motor.
COMPARISON OF THE MOTOR STARTING METHOD
Criteria Direct-On-Line Star-Delta
Inrush
Current
High Low
Voltage
Sags
Severe
> 0.5 p.u.
Less Severe
< 0.2 p.u.
Harmonics More Less
Transients Severe Less Severe
PROTECTION
The main Electrical Faults occurring in Motor can be classified as follows:-
i. Motor Overloading
ii. Single Phasing
iii. Stalled or Locked Rotor
iv. Short Circuit
v. Restricted Ventilation
vi. Excessive Temperature rise of Motor

30
vii. Faults in Relays
viii. Combined Overload or Earth Leakage Fault
The main Protective Devices used in D.C.C are:-
i. Back Up HRC Fuses ( used in all MCC Panels )
ii. Thermal Overload Relays
iii. Magnetic Overload Relays
iv. Winding Temperature Detectors
v. Combined Overload & Earth Leakage Protection
vi. MCCB ( Molded Case Circuit Breaker )
vii. Oil Circuit Breaker
viii. Vacuum Circuit Breaker
Maintenance in D.C.C can be broadly classified as
Corrective Maintenance/Breakdown Maintenance
This type of maintenance is actively carried out whenever there is case of
Discontinuation or Disruption in Service of particular running Machines.
Common Break Down maintenance jobs are carried out by Shift Personals; include
Basic Trouble Shooting, Diagnostic & appropriate Corrective actions. Problems
related to Motor such as Bearing Damages, Damage/Burning terminal leads,
Terminal box, Cooling fans, Fan Cover are undertaken at Site Workshop of
Electrical Department.
Preventive Maintenance
Preventive Maintenance or time based maintenance is carried out in order to
maintain the health of Equipments and reduce the chances of failure during
operation.
These Maintenance Schedules include:
 Daily Maintenance
 Weekly Maintenance
 Monthly Maintenance
 Half Yearly Maintenance

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TYPICAL NAME PLATE OF AN AC INDUCTION MOTOR
A typical name plate on an AC induction motor has:
Term Description
Volts Rated terminal supply voltage.
Amps Rated full-load supply current.
H.P. Rated motor output.
R.P.M Rated full-load speed of the motor.
Hertz Rated supply frequency.
Frame External physical dimension of the motor based on the NEMA
standards.
Duty Motor load condition, whether it is continuous load, short
time, periodic, etc.
Date Date of manufacturing.
NEMA Design This specifies to which NEMA design class the motor belongs
to.
Service Factor Factor by which the motor can be overloaded beyond the full
load.
Efficiency Motor operating efficiency at full load.
PH Specifies number of stator phases of the motor.
Pole Specifies number of poles of the motor.
Specifies the motor safety standard

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MOTOR DUTY CYCLE TYPES AS PER IEC STANDARDS
No. Ref. Duty Cycle Type Description
1. S1. Continuous running Operation at constant load of sufficient
duration to reach the thermal
Equilibrium.
2. S2. Short-time duty Operation at constant load during a given
time less than required to reach
the thermal equilibrium followed by a
rest.
3. S3. Intermittent periodic
duty
A sequence of identical duty cycles, each
including a period of operation at
constant load and a rest (without
connection to the mains).
4. S4. Intermittent periodic
duty
with starting
A sequence of identical duty cycles, each
consisting of a significant period of
starting, a period under constant load and
a rest period.
5. S5. Intermittent periodic
duty
with electric braking
A sequence of identical cycles, each
consisting of a period of starting, a
period of operation at constant load,
followed by rapid electric braking and a
rest period.
6. S6. Continuous operation
periodic duty
A sequence of identical duty cycles, each
consisting of a period of operation
at constant load and a period of
operation at no-load.
7. S7. Continuous operation
periodic duty with
electric
braking
A sequence of identical duty cycles, each
consisting of a period of starting, a
period of operation at constant load,
followed by an electric braking.
8. S8. Continuous operation
periodic duty with
related
load and speed
changes
A sequence of identical duty cycles, each
consisting of a period of operation
at constant load corresponding to a
predetermined speed of rotation,
followed by one or more periods of
operation at another constant load
corresponding to the different speeds of
rotation.
9. S9. Duty with non-
periodic
load and speed
variations
Duty in which, generally, the load and
the speed vary non-periodically within
the permissible range. This duty includes
frequent overloads that may
exceed the full loads.

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RATINGS OF MACHINES USED IN D.C.C
SECTION: MATERIAL HANDELLING PLANT
RATING OF MOTORS
NAME RATING SPEED VOLTAGE CURRENT DUTY
C1 22 1500 415 40 S1
C2 125 1485 415 216.5 S1
C3 75 1480 415 133 S1
C4 125 1485 415 216.5 S1
C5 55/75 1465 415 96 S1
C6 75 1482 415 127 S1
C7 75 1480 415 133 S1
C8 15 1460 400/440 29.5 S1
C9 12 1460 415 40 S1
C10 22/30 1460 415 38 S1
C11 9.3 1450 415 17 S1
C12 9.3 1450 415 17 S1
CO1 7.5 1450 415 13 S1
CO2 7.5 1450 415 13 S1
CO5 11 1450 415 20.5 S1
CO6 11 1450 415 20.5 S1
CO7 30 1470 415 52 S1
CO8 30 1470 415 52 S1
CO9 18.5 1470 415 32 S1
CO10 18.5 1470 415 32 S1
CO11 18.5 1470 415 32 S1
CO12 18.5 1470 415 32 S1
WAGON
TIPPLER
55/75 741 415Y 104 S3-40%
INHAULER 75 1520 415 127 S1
OUT
HAULER
55 1500 415 96 S1
VS 1 18.5 1500 415 32 S1
VDS 1 22 1500 415 40 S1

34
SECTION: PRODUCER GAS PLANT (PGP)
RATING OF MOTORS
NAME RATING
(KW/HP)
VOLTAGE
(V)
CURRENT
(I)
SPEED
(R.P.M)
DUTY
HYDRAULIC
PUMP FOR
GASIFIER(5+1)
22/33 415 40 1460 S1
AIR BLOWER 30/40 400/400 53 1465 S1
VIBRATING
SCREEN(5)
5.5 9.6 1500 S1
CHAIN
CONVEYOR
MOTOR
2.2/2.5 415 4 1500 S1
TAR TRANSFER
PUMP
4.5/5.5 415 8 1500 S1
SECTION: RETORT HOUSE
RATING OF MOTORS
NAME RATING
(K.W/H.P)
VOLTAGE
(V)
CURRENT
(I)
SPEED
(R.P.M)
DUTY
HYDRAULIC
POWERUNIT
MOTOR
3.7 415 7.9 1500 CR
FLUSH 11 415 20 1500 S1

35
LIQOUR
PUMP
ID FAN
MOTOR
30HP 415 43 1500 S1
ASCANIA
VALVE
1.5/2 415 43 1500 S1
COKE
TROLLEY
0.75 415 3.4 1500 S1
COKE
QUENCHING
18.5,15,22 415 32,29,40 1500 S1
SECTION: GAS CLEANING PLANT
RATING OF MOTORS
NAME RATING
(K.W/H.P)
VOLTAGE
(V)
CURRENT
(I)
SPEED
(R.P.M)
DUTY
GAS COMPRESSOR 1500 375 6600 136 CONTINIOUS
SOLVENT
INJECTOR PUMP
0.25 1395 220 1.36 CONTINIOUS
LUB.OIL PUMP 0.37 1400 415 1.17 CR
AUX.OIL PUMP 5.5 1445 415 11.4 CR
BEARING GEAR 11 1450 415 21 CONTINIOUS
EXHAUSTER 290 1492 500 400 S1
INSTRUMENT AIR
COMPRESSOR
110 1475 415 189 CMR
PROCESSOR AIR
COMPRESSOR
55/75 1475 415 102 S1
GAS COMPRESSOR
AIR
2.2 2860 415 4.3 CONTINIOUS
PRESSURIZATION
BLOWER MOTOR
2.2 2860 415 4.3 CONTINIOUS
OIL COOLER
PUMP
75 2950 415+6% 124 S1
SUMP PIT PUMP 1.5 1405 415 3.4 S1
SUMP PIT PUMP 0.75 1400 415 2.1 S1
H2S WASHER 75 2980 415 130 CONTINIOUS

36
SULPHUR FILTER
DRIVER
0.75/1 1395 415 1.84 CR
SECTION: TAR DISTILATION PLANT
RATING OF MOTORS
NAME RATING
(K.W/H.P)
VOLTAGE
(V)
CURRENT
(I)
SPEED
(R.P.M)
DUTY
CRUDE TAR
PUMP
7.5/10 2865 415 14 S1
CAUSTIC
DOZING
PUMP
0.37 1410 415 0.9 S1
PITCH
CIRCULATION
PUMP
5.5 2865 415 10 S1
PITCH
PRODUCT
PUMP
1.5/2 2850 415 4 S1
PITCH
PRODUCT
PUMP(NEW)
2.5/3 2850 415 4.6 S1
FUEL OIL
PUMP
1.1/1.5 1450 415 2.7 S1
CIRCULATION
PUMP
3.7 1430 415+6% 8 S1
CRUDE ACID
PUMP
2.2/3 2840 415 4.7 S1
PURE TAR
ACID PUMP
1.0/5.5 2850 415 8 S1
PITCH PUMP 3 2850 415 6 S1
TAR ACID
PUMP
2.2 2850 415 4.6 S1
FIRE WATER
PUMP
45/60 1470 415 81 S1
FEED PUMP 11/16 2900 415 21 S1
BLOWER 15/20 2900 415 28 S1

37
OIL PUMP 2.2 1400 415 4.6 S1
EFFLUENT
PUMP
5.5/7.5 1440 415 11.9 S1
RATING OF RECTIFIER TRANSFORMER (DETARER)
SECTION: GAS CLEANING PLANT (GCP)
MAKE: ADVANI OVERLIKON LTD.
TRANFORMER
KVA : 21.2
AC INPUT : 415V, 51A
FREQUENCY : 50Hz
PHASE : Single
TYPE OF COOLING : ON
PEAK VOLTAGE : 33000V, 350MA
OPERATION VOLTAGE : 25000V, 250MA
LINEAR REACTOR
KVAR : 7.6
VOLTAGE : 149V
AMPS : 51A
PHASE : Single
ELECTRONIC CONTROLLER FOR HV RECTIFIER
RATED INPUT VOLTAGE : 415V AC 50Hz
RATED INPUT CURRENT : 51A
RATED OUTPUT : 33000V, DC
RATED OUTPUT CURRENT : 350MA, DC
No of Electrodes : 145

38
HIGH VOLTAGE TRANSFORMER
RECTIFIER UNIT AT E.S.P (P.G.P)
MAKE: HIND RECTIFIERS LTD.
TYPE : OHTA/43/100
AC INPUT : 360 V, 19.71A
AC OUTPUT : 19450V, 0.1435A
KVA : 7.096
FREQUENCY : 50Hz
PHASE : SINGLE
DC VOLTAGE : 70KV/100MA
MAX.TEMP : 50degree centigrade
ACTIVE WEIGHT : 350kg
TANK : 160kg
OIL : 440kg

39
RATING OF CIRCUIT BREAKER USED
IN SUBSTATIONS
MAKE ASEA : MINIMUM OIL CIRCUIT BREAKER
TYPE : 12/240
VOLTAGE : 12KV
INSULATION LEVEL : 75/35KV
FREQUENCY : 50Hz
NORMAL CURRENT : SYM/ASYM
40/44KA
STANDARD : IEC 56
OIL : 8kg
WITH BUILT IN FUSE : 6600/1100V

40
TROUBLESHOOTINGS
PROBLEM SOLUTION
Motor Overloading Reduce Load or try to Start
Uncoupled from Load
Control Gear Defective Examine each steps of
Control Gear for Bad
contact or Open Circuit
Rotor Defective Look for Broken Rings
Poor Stator Coil
Connections
Remove End Shields
Mechanical Locking in
Bearing or Air Gap
Dismantle and Repair
Wrong Rotation Reverse connections at
switch board or at Motor
Motor`s one Phase Open Check to make sure all leads
are connected properly
Grounded Coil Locate and Repair
Unequal Terminal Voltage Check Leads and
Connections
Single Phase Operation Check for Open Contacts
Brushes are not in Proper
Position
See that the Brushes are
Properly seated.

41
CONCLUSION
During the last 30 days, I have been on Summer Industrial Training in
Dankuni Coal Complex. I have gained Basic knowledge about Practical
Applications of Engineering Theory into Practice.
I am very much hopeful that in the coming years of my career, this
Experience will help me integrate Theory and Practical and develop myself into
through bred professional. As a student of Technical Education it is very fortunate
to me that to me that all types of Live Problems and their Remedies are seen by me.
I have gathered in these days is about Precautions and Safety measures. I
once again like to thank sincerely all those who have extended their co-operation
to make my Training Days in Dankuni Coal Complex a success.
I am thankful to all the Employs and Managements for giving me their
Valuable Time in their occupational Busy Schedules.