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Transcript of Apoorva Report
A
TRAINING REPORT
ON
BHARAT HEAVY ELECTRICALS LIMITED
Submitted in partial fulfillment of the requirement for the award of degree of
BACHELOR OF TECHNOLOGY
In
ELECTRICAL ENGINEERING
Submitted by : Submitted to:
APOORVA CHHABRA Mr. ABHISHEK SHARMA
(08EBNEE008) Head Of Department
Electrical Engineering
DEPARTMENT OF ELECTRICAL ENGINEERING
BANSAL SCHOOL OF ENGINEERING AND TECHNOLOGY,JAIPUR
JUNE, 2011
1
ABSTRACT
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. According to this life, he has to serve an industry, may be public or private
sector or self-own. For the efficient work in the field, he must be well aware of the
practical knowledge as well as theoretical knowledge.
To be a good engineer, one must be aware of the industrial environment and must
know about management, working in such a industry, labor problems etc., so that he can
tackle them successfully.
Due to all the above reasons and to bridge the gap between theory and practical, our
engineering curriculum provides a practical training of 30 days. During this period, a
student works in the industry and gets all type of experience and knowledge about
the working and maintenance of various types of machinery.
I have undergone my 30 days training (after VI Semester) at BHARAT
HEAVY ELECTRICALS LIMITED. This report is based on the knowledge, which
I acquired during my 30 days training period at the plant.
2
ACKNOWLEDGEMENT
It gives me immense pleasure to present my Project Report before you. I have taken
efforts in this project. However, it would not have been possible without the kind support
and help of many individuals and organizations. I would like to extend my sincere thanks to
all of them.
I am highly indebted to Mr.Abhishek Sharma for their guidance and constant
supervision as well as for providing necessary information regarding the project & also for
their support in completing the project..
I would like to express my special gratitude and thanks to industry persons for
giving me such attention and time.
My thanks and appreciations also go to my colleague in developing the project and
people who have willingly helped me out with their abilities.
APOORVA CHHABRA
3
CONTENTS
CERTIFICATE...................................................................................................................
iii
ABSTRACT.........................................................................................................................
.iv
ACKNOWLEDGEMENT.................................................................................................
...v
CONTENTS........................................................................................................................
.vi
LIST OF
FIGURES.............................................................................................................ix
LIST OF
TABLES................................................................................................................x
4
Chapter 1
INTRODUCTION...............................................................................................................10
1.1 BHEL-A brief profile.....................................................................................................10
1.2 BHEL- An overview......................................................................................................11
1.2.1 Background of BHEL
1.2.2 Present position of BHEL
1.3 Manufacturing units & product profile..........................................................................16
1.4 Technical collaborators..................................................................................................19
Chapter 2 BHEL (Haridwar)-A profile.............................................................................21
2.1 Profile of HEEP.............................................................................................................21
2.2 HEEP product profile.....................................................................................................22
2.3 Brief description of manufacturing blocks at BHEL (Haridwar)..................................23
2.2.1 Block-1 Electrical machine block
2.2.2 Block-2 Fabrication Block
2.2.3 Block-3 Turbine Block
2.2.4 Block-4 CIM & ACM Block
2.2.5 Block-5 Forging Block
2.2.6 Block-6 Stamping Block
2.2.7 Block-7 Wood Working Section
2.2.8 Block-8 Heat Exchanger Block
Chapter 3 COIL AND INSULATION MANUFACTURING SHOP
(BLOCK-IV).........................................................................................................................28
3.1 Brief summary about bar shop.......................................................................................28
3.2 Manufacturing process of bars.......................................................................................29
5
Chapter 4 ELECTRICAL MACHINE BLOCK(BLOCK-I)...........................................41
4.1Manufacturing process of turbo generators....................................................................44
References.............................................................................................................................55
Appendix-A...........................................................................................................................56
Appendix-B...........................................................................................................................57
6
LIST OF FIGURES
Figure No. Figure Name Page No.
2.1 Rotor winding 25
2.2 Generator testing 26
4.1 Stator frame 44
7
LIST OF TABLES
Table no. Table name Page no.
1.3 Manufacturing units and
product profile
16
1.4 Technical collaboration 19
8
Chapter 1- INTRODUCTION
1.1 BHEL-A Brief Profile
The “Navratanas” declared by Indian government are NTPC,
VSNL, ONGC, IOC, HPCL, SAIL, BHEL, IPCL, BPCL, etc. Therefore, B.H.E.L. is one of
the Navratanas and is the largest engineering enterprise of its kind in India with an excellent
track record of performance. The company is engaged in engineering development and
manufacturing of a wide variety of mechanical and electrical equipment for generation,
Transmission, and electricity. The company today enjoys National and International
presence featuring in the “Fortunes Internationals 500” and is ranked among the top 12
companies in the world.
A widespread network comprising of 14 manufacturing companies, which have
international recognition for its commitment towards quality. With an export presence in
more than 60 countries, BHEL is truly India’s ambassador to the world. BHEL’s vision is
to become world class engineering enterprise, committed to enhancing stakeholder value.
BHEL has:-
Installed equipment for over 90,000MW of power generation for Utilities,
captive and Industrial users.
Supplied over 25000 Motors with Drive Control System to power projects,
Petrochemicals Refineries, Steel, Aluminum, Fertilizer, Cement plant, etc.
Supplied Traction electrics and AC/DC locos over 12000 kms Railway
network.
Supplied over one million Values to Power Plants and other Industries
9
1.2 BHEL - AN OVERVIEW
The first plant of what is today known as BHEL was established nearly 40 years ago
at Bhopal & was the genesis of the Heavy Electrical Equipment industry in India.
BHEL is today the largest Engineering Enterprise of its kind in India with
excellent track record of performance, making profits continuously since 1971-72.
BHEL business operations cater to core sectors of the Indian Economy like.
Power
Industry
Transportation
Transmission
Defenses etc.
Today BHEL has
14 Manufacturing Divisions
9 Service Centers
4 Power Sector Regional Centers
10
150 Project sites
BHEL’s vision is to become world -class engineering enterprise, committed to
enhancing stakeholder value. The greatest strength of BHEL is its highly skilled and
committed 44,000 employees.
POWER SECTOR
Power sector comprises of thermal, nuclear, gas and hydro business. Today BHEL
supplied sets account for nearly 65% of the total installed capacity in the country as
against nil till 1969-70.
BHEL has proven turnkey capabilities for executing power projects from concept to
commissioning and manufactures boilers, thermal turbine generator set and
auxiliaries up to 500MW.
It possesses the technology and capability to procure thermal power
generation equipment up to 1000MW.
Co-generation and combined cycle plants have also been introduced.
For efficient use of the high ash content coal-BHEL supplies circulating fluidized
boiler.
BHEL manufactures 235MW nuclear sets and has also commenced production of
500MW nuclear set.
Custom-made huge hydro sets of Francis, Elton and Kaplan types for different head-
discharge combinations are also engineered and manufactured by BHEL.
INDUSTRY SECTOR
11
BHEL is a major contributor of equipment and system to important industries like
Cement
Petrochemicals
Fertilizers
Steel paper
Refineries
Mining and Telecommunication
The range of system and equipment supplied including captive power stations
High speed industrial drive turbines
Industrial boilers and auxiliaries
Waste heat recovery boilers
Gas turbines pump, valves, seamless steel tubes
Heat exchangers
Process control etc.
TRANSPORATION:-
BHEL supplies a wide equipment and system to Indian Railways.
1. Electric locomotive
12
2. Traction electric and traction control equipment
1.2.1 BACKGROUND OF THE B.H.E.L
Heavy Electrical (India) ltd. [HE (I) L] was set up in Bhopal in 1956 with a view to
reach self-sufficiency in power equipment’s vital for industrialization of the country, and
then B.H.E.L. came into existence in 1964. Three plants were stabilized under B.H.E.L. are
as follows:
High Pressure Boiler Plant – Tiruchy (T.N.) (MAY 1965)
Heavy Power Equipment Plant – Hyderabad (A.P.) (DEC 1965).
Heavy Electrical Equipment Plant – Haridwar (Utarakhand) (JAN 1967).
As there was need for development of power equipment manufacturing in India and also
with a view to optimally utilize the resources HE (I) L. was merged in B.H.E.L.
1.2.2 PRESENT POSITION OF B.H.E.L.
At present B.H.E.L. have 14 manufacturing units. The major units are B.H.E.L. –
Bhopal, B.H.E.L. – Hyderabad, B.H.E.L. –Tiruchy, and B.H.E.L. – Hardwar. The corporate
office is situated in New –Delhi and provides necessary top management leadership,
direction, strategic-planning and operational and management support Services. It also
coordinates the activities, function of various manufacturing, service divisions and
numerous other functional and product groups. It also looks after the long – term planning
in regards to resource and marketing and also planning for marshalling of human, physical
and financial resources.
13
COMPANY OBJECTIVES
BUSINESS MISSION :
To maintain a leading position as suppliers of quality equipment, system and
services in the field of conversion, transmission utilization and conversation of energy for
application in the areas of electric power transportation, oil and gas exploitation industries
utilize company’s capabilities and resources to expand business into allied areas and other
sectors of the economy like defiance, communication and electronics.
GROWTH :
To ensure a steady growth by enhancing the competitive edge of B.H.E.L. in
existing business in new areas and international operators.
PEOPLE ORIENTATION:
To enable each employee to achieve his potential, improve is potential, improve his
capabilities perceive his role and responsibilities and success of the company. To invest in
human resources continuously and be alive to their needs.
TECHNOLOGY :
To achieve technological excellence in operations by development of indigenous
technology and efficient absorption and adoption of imported technologies to suit business
needs and priorities and provide a competitive advantage to the company.
14
IMAGE :
To fulfill the expectation which stakeholders like government as owner,
employees, customers and the country at large house from B.H.E.L.
15
1.3 MANUFACTURING UNITS AND
PRODUCT PROFILE:
NAME OF
PLANT
PLACEPRODUCT
Steam less plant. Tiruchirappali(Tiruchy).
Steam less steel tubes,Spiral fin welded tubes.
Boiler auxiliaries.Ranipet. Electrostatic precipitation, Air pre-heater,
Fans, Wind electric generators, Desalination plants.
Industrial valves plant.
Govindwal. Industrial valves and Fabrication.
Heavy electrical equipment plant.
Haridwar. Steam – turbines, Hydro – turbines, Gas – turbine, Turbo generators, Control panels, Light aircrafts, Electrical machines.
Central foundry forge plant.
Haridwar. Heavy casting and forging.
Heavy electrical plant.
Bhopal. Steam turbines ,Turbo generators ,Hydro sets ,Switch gear controllers,
Transformer plantJhansi.
Transformers ,Diesel shunt less ,AC locos ,AC EMU.
16
Heavy power equipment plant
Hyderabad Power generating set ,Industrial turbo – sets,Compressors ,Pumps and heaters ,Bow – mills ,Heat exchangers oil rings ,Gas turbines ,Switch gears
Electronic division
Bangalore Energy meters, Water meters, Control equipment, Capacitors, Photovoltaic panels and Electronic private automatic branch exchange.
Insulator plant Jagdishpur Insulators and bushing
Electronic system division, electronic city.
Bangalore Simulator,Telecommunication system ,Other advanced micro –processor based control system
Electro–porcelain division.
Bangalore Insulator and bushing ,Ceramic liners
Component fabrication plant.
Rudrapur Windmill ,Solar water heating system
Amerphass silicon solar cell plant.
Guragaon Solar cells ,Solar lanterns chargers ,Solar clocks.
Heavy electrical equipment repair plant.
Varanasi. Repair shop for power generating equipment.
Electrical machine repair shop.
Mumbai. Repair of electrical machines
Table 1.3-manufacturing units & product profile of BHEL
17
1.4 TECHNICAL COLLABORATORS:
NAMES OF COLLABORATOR COUNTRY PRODUCT
Siemens. Germany.Steam turbines ,Generators ,Lateral / Arial condensers.
National oil well.U.S.A. Christmas tree and
Well head assembled.
General electrical company. U.S.A. Gas turbines.
Asian brown boveri. Switzerland.High voltage directs current system (HVDC).
May & christe gumbh.Germany.
Dry type transformer.
Siemens AG. Germany. Large size gas turbines.
18
National oil well. U.S.A. Composite block valves,Sub – sea well ,Head assembly ,Caring support machine suspension equipment.
Nordex A/S . Denmark. Wind electric–generators.
Energy techniques. Germany. Bed combustion boiler.
Siemens AG. Germany. Electrical machines
Melara SPA. Italy. Super rapid.
Table 1.4- Technical collaboration
19
CHAPTER-2
B.H.E.L. (HARIDWAR): A PROFILE
B.H.E.L. Haridwar, one of the keys manufacturing units of B.H.E.L. is located
between Shivalik Mountains and Holy River GANGA. Its manufacturing plant includes two
factories at Hardwar.
On the northern side is heavy electrical equipment plant (H.E.E.P.), which
commenced production in 1967 with know–how from M/S Kraft-work union, AG of
Germany. Now H.E.E.P. has a technical collaboration with M/S Siemens’ Germany. For
manufacturing of large size gas turbine.
Located immediately to the south of H.E.E.P. is the central foundry forge plant
(C.F.F.P.) which was primarily set up for manufacture of alloy steel casting and forging
required for industry and power generation equipment. It was established in technical
collaboration with M/S Crensot – Loire of France.
2.1 PROFILE OF HEEP
ESTABLISHMENT AND DEVELOPMENT STAGES:
DRP prepared in 1963 – 64 , construction started from Oct 1963.
Initial product of electric motors started from Jan 1967.
Major contribution /election /commissioning completed by 1971 –72 as per original
DRP scope.
Establishing in 1960’s under the Indo- soviet agreement of 1959 and 1960 in the area of
scientific, technical and industrial co-operation.
Motor manufacturing technology up dated within siemen’s collaboration during
1984 –87 .
20
Facilities being modernized continually through Replacement, reconditing,
retrofitting, technological, operational balancing
2.2 HEEP PRODUCT PROFILE
1. THERMAL SETS:
Steam turbines and generator up to 500MW capacity for utility and combined cycle
applications; capability to manufacture up to 1000MW unit cycle.
2. GAS TURBINES:
Gas turbines for industry and utility application; range-3 to 200 MW (ISO).
Gas turbines based co-generation and combined cycle system.
3. HYDRO – SETS:
Custom– built conventional hydro turbine of Kaplan,
Francis and Pelton with matching generators up to 250 MW unit size.
Pump turbines with matching motor-generators
Mini / micro hydro sets.
Spherical butterfly and rotary valves and auxiliaries for hydro station.
4. EQUIPMENT FOR NUCLEAR POWER PLANTS:
Turbines and generators up to 500MW unit size.
Steam generator up to 500MW unit size.
Reheaters / separators.
Heat exchangers and pressure vessels.
21
5. CASTING AND FORGINGS:
Sophisticated heavy casting and forging of creep resistant alloy steels, stainless steel
and other grades of alloy meeting stringent international specifications.
6. DEFENCE PROCEDURE:
Naval guns with collaboration of Italy.
2.3 BRIEF DESCRIPTION OF MANUFACTURING BLOCKS AT
BHEL (HARIDWAR):
The various blocks in HEEP are as follows:
Block-1: Turbo generator Shop
Block-2: Fabrication Shop
Block-3: Turbine Shop
Block-4: Insulation Block
Block-5: Forging Shop
Block-6: Stamping Shop
Block-7: Packing and Wood Working Shop
Block-8: Heat exchanger block
2.3.1 Block- I
Block-I, also known as Electrical Machines Block, is designed to manufacture Hydro
generators, Turbo generators and Testing facilities for Turbo generators. There is also a
special Test Bed for testing of turbo generators of capacity of 500 MW and above. Apart
from facilities and equipment for manufacture of turbo generators, the Block also has a
“Bebitting Section”.Bebitting of bearing liners for Turbo generators, Turbines, Hydro
22
generators, is carried out in this section. The Block has its own over speed balancing
installation; where the dynamic balancing of Turbo generator-rotors of less than 500 MW
rating is done. Rotors having higher rating are balanced in OSBT of Block-III.
Fabricated components are received from fabrication blocks (Block-II, IV, VI, VIII), while
other castings, forgings are received from CFFP and other sources for Turbo generators,
Hydro generators and Electrical motors. Stampings are received from Stampings
manufacture section; Block-VI and coils, bars, insulating details and sheet metal
components are received from Block-IV. These are then machined, assembled, tested and
dispatched.
Fig 2.1- Rotor Winding
23
Fig 2.2-Generator Testing
2.3.2 Block –II
Block-II, also known as Fabrication Block, is a feeder block for various
products- Steam Turbines, Hydro Turbines, Turbo generators, Hydro generators, Electrical
Machines, Apparatus and Control Gear, Aircraft and SRGM (Smooth Recoil Gun
Mounting). The main processes in this Block are cutting, bending and welding of metal
sheets etc. to form fabricated structures.
The Block also has useful equipments like Hydraulic Bending Presses and
Straightening Rollers. Other notable facilities include a CNC six-spindle drilling machine, a 24
plasma-flame cutting machine, shot-blasting apparatus and various furnaces. The Block
also has facilities for NDT (Non Destructive Testing) of various components. The following
Non-Destructive tests can be conducted – DP Test (Die Penetration Test), MPI (Magnetic
Particle Inspection), UT (Ultrasonic Testing) and Radiography which includes X-ray and -
ray testing.
2.3.3 Block – III
It is known as the TURBINE BLOCK, this is the major block for
manufacturing turbines. All types of Hydro, Steam, Gas and nuclear Turbines are
manufactured and dispatched from this block. Blades of different stages are also
manufactured here in this block.
2.3.4 Block- IV
Block-IV, also called as CIM&ACM (Coil and Insulation Manufacturing
& Apparatus and Control Gear Manufacturing), is a feeder block to Block-I. It is a feeder
block for Class ‘F’ windings for Turbo generators, Hydro generators and Class ‘F’ and ‘H’
insulation for AC and DC motors. It also supplies all insulation components for Turbo
generators, Hydro generators, and motors. Control panels for Turbo generators, Hydro
generators, Industrial drives for motors, and Turbo generators auxiliaries, contactor relays
and master controllers are also manufactured in this Block.
2.3.5 Block -V
Block-V, also called as Fabrication and Forge Block is again a feeder
block. Fabrication work being done in this block is of Steam Turbine parts like Condenser,
Water Box (Front and Rear), assemblies of LP cylinder, Storage Tanks etc.; Hydro Turbine
parts, Hydro generator and motor assemblies and components. Forging of carbon, alloy and
stainless steels are manufactured in this block. It is equipped with pneumatic hammers, gas-
fired furnaces and hydraulic manipulators.
25
2.3.6 Block -VI
Block-VI, also called as Fabrication Block, is also a feeder block.
Manufacturing of all types of dies, including stamping dies and press forms is carried out in
one bay, while stamping for Turbo generators, Hydro generators and motors are
manufactured in other bay. The Block is equipped with Welding, Drilling, Shot Blasting
and CNC Flame cutting facilities. The tems manufactured in this block are Condensers,
Steam Turbine components (Oil Tanks and Hollow Guide Blades), Hydro Turbine
components (Stay Rings), Hydro generator and motors
(Stator Frames) etc.
2.3.7 Block -VII
Block-VII, also called as Woodworking section, is also a feeder block.
Bay-I, known as Packaging section manufactures packages for packaging and dispatch of
various products.
2.3.8 Block- VIII
Block-VIII, also called as Heat Exchanger Block, is designed to
manufacture Heat Exchanger Units for Steam Turbines, Hydro Turbines, Turbo generators,
Hydro generators etc. Blanks cut to size and shape are received from Block-II and Block-
VI. These are assembled, welded and machined. The items manufactured here are – LP
Heater, Ejectors, Gland Steam Coolers, Oil Coolers, Oil Tanks, Bearing Covers, Turbine
shaft Covers, Oil Bath and Thrust Bearings.
26
CHAPTER -3
COIL & INSULATION MANUFACTURING SHOP
(BLOCK-IV)
BAY-I:
Bar winding shop manufacturing of stator winding bars of generator.
BAY-II:
Manufacturing of heavy duty generator stator bars with New CNC M/c No. 3-464 i.e.
Robol bar centre.
BAY-III-
Insulation detail shop. Manufacturing of hard insulation &machining of hard
insulation part (Glass textolite) such as packing, washer, insulation box, wedges etc.
3.1 BRIEF SUMMARY: ABOUT THE BAR SHOP
Bar Shop:
This shop is meant for manufacturing of stator winding coils of turbo-
generator
Why do we call it bar:
It is quite difficult to manufacture, handle and wind in the stator slot of
generator of higher generation capacity because of its bigger size and heavy weight. That is
why we make coil in two parts. One part its bottom part of coil called bottom or lower bar
another part of coil is called top bar or upper bar.
27
TURBO GENERATOR BAR
For the turbo generator the manufacturing of bars of standard capacity such as
100 MW, 130MW, 150MW, 210/235MW, 210/250MW. This plant has capacity
and technology to manufacturing 800 MW generators.
TYPE OF GENERATORS
The generator may be classified based upon the cooling system used in the
generators such as;
THRI, TARI, THDI, THDD, THDF, THFF, THW
T = First alphabet signifies the type of generator i.e. Turbo Generator
or Hydro Generator.
H/A = Second alphabet stands for the cooling media used for the cooling
of rotor i.e. Hydrogen Gas or Air.
R/D/F/I = Third alphabet signifies the type of cooling of rotor i.e. Radial,
indirect, forced, direct etc.
I/D/F = Last alphabet stands for the type of cooling of stator i.e. Indirect
cooling, direct cooling, forced cooling.
W = cooling media used for cooling of stator coil e.g. water.
28
3.2 Manufacturing process of Bars:
1. MATERIAL CHECKING
First we check the material of the conductor. And the total insulation upon the
conductor. The width of the copper conductor should be:
a. For Lower bar = 8 x 2.8mm (Solid)
b. For Upper bar = 8 x 1.3mm (Solid)
c. For Hollow conductor= 8 x 4.6 x 1.5mm (Solid)
2. CONDUCTOR CUTTING AND END CLEANING
This process is done by the automatic CNC machine, in this process the length
of lower bar & upper bar is decided as following as per drawing-
Lower Bar
a. Solid conductor length = 10,200mm (10 Plates)
b. Hollow conductor length = 10,200mm (10 Plates)
Upper Bar
a. Solid conductor length = 10,050mm (10 Plates)
b. Hollow conductor length = 10,050mm (10 Plates)
This insulation is removed from both ends after the cutting of conductor i.e. 500mm for
both lower & upper bar.
3. TRANSPOSITION OF CONDUCTOR
Transposition means changing or shifting of position of each conductor in active
care (slot) part. After cutting the required number of conductors are arranged on
the comb in staggered manner and then bands are given to the conductor with the
help of bending die at required distance. Then the conductors are taken out from
29
the comb and die and placed with their ends in a line and transposition is carried
out. This process is repeated for making another half of the bar which would be
mirror image of the first half. The two halves of the bar are overlapped over each
other and a spacer is placed between the two halves
Setting of die
a. Comb of setting for lower bar’s
Die 1st Die 2nd Die 3rd
2200.2mm 3735.3mm 6586.2mm
b. Comb of setting for Upper bar’s
Die 1st Die 2nd Die 3rd
2109mm 3620.2mm 6496.2mm
This process is repeated to making another half of the bar.
4. CROSS OVER INSULATION
Cross over insulation is giving to the conductor for the protection in which the
insulating spacers are provided at the cross over portion. In this insulation the No-
max paper is used.
Here the filter material (insulating putty of molding micanite) spacer is
provided along the high of bar to maintain the rectangular shape. The size of spacer
should be –
1st Band = 146mm
2nd Band = 219mm
3rd Band = 292mm
5. STACK CONSOLIDATION OR PRESSING
The core part of the bar stack is pressed in press under the pressure between 70kg to
80kg (various from product to product) and the temperature between 90 Deg.C to
160 Deg.C for a given period. Here four bars is pressed in one time and six to eight
plates are used for pressing. After that the consolidated stack is withdrawn from the
press.
30
6. INTER STAND SHORT TEST (I.S.S.Test)
In this test first we make the distance to the non insulating portion of the bar. Here
we check the short between any two conductor. After this test the bars are again go
for the second pressing. In which attached full slot separator between two half bar
no-max paper and tapped with transparent film. In this test if any error is found then
it has to be rectified.
7. FORMING OF BAR
In this operation the straight bar stack is formed as per overhang profile. In this
process bars should be formed on universal former and marked for the thermal
space. After it they are moved for cutting of extra conductor.
8. PICKLING OF BAR END
Pickling is the process of the cleaning of components by the chemicals. The pickling
solutions are:
a. Water = 100 parts by weight
b. Sulphuric Acid = 10 parts by weight
c. Phosphoric Acid = 5 parts by weight
d. Hydrogen per Oxide = 5 parts by weight
The temperature should be maintain 50 Deg.C to 60 Deg.C. The end portion of bar
is dipping in this solution upto 10 to 15 min.
During this pickling process some aciditic properties are effected to the end portion
of bar. So to neutralization of it dipped the bars again in the ammonia solution. For the
shining of end part the bars are dipped in ethyal alcohol solution and dry with nitrogen
Pressure.
9. COIL LUG MOUNTING
31
In this process contact sleeve and the bottom part of the water box are adjust at the
give dimensions. The operation of mounting of contact sleeve and bottom part of
water box is complete in following steps-
a. Check the dimension of contact sleeve and water box bottom part.
b. Stand by bar for setting of lug.
c. Setup to the solid conductor in each row as per drawing.
d. Then insert the contact sleeve upon the solid and hollow conductor and temporally
installed to it. And also installed the bottom part of water box.
e. Maintain the gap between contact sleeve and bottom part of water box approx
20mm.
After the lug mounting cutting of extra solid conductor.
10.MAIN BRAZING
There are the following steps to brazed the lug.
a. Stand by bar of setting for brazing.
b. Then heated the lug point through the two indictor at the temperature of 700 Deg.C .
c. For brazing use brazing alloy L-Ag-15P by four person. This is the silver platinum
alloy wire of melting point 700 Deg.C to 750 Deg.C.
d. This Temperature is give through the laser rays.
11.CONDUCTOR CUTTING, FACE MILLING AND DEBBERING
After the main brazing bars is moved for cutting of extra part of conductors as per
drawing. Here cut the end part of the bottom part of water box and taken for face
milling.
In this process the conductor is given the accurate shaped as per the measurement
and it is taken in account that any part of the surface is not left uneven and dull.
Then in Debbering, the bars edges are many a time left with twigs and sharp needle
type mettle cutting known as bar and this process of removing is known as
Debbering.
32
12.FIRST PICKLING
This is the same process of pickling which is done before the lug mounting or zero
pickling. After this pickling process the bar is moved the brazing of top part of water
box in both side.
13.BRAZING OF TOP PART
Thought the induction process the top part of water box is brazed in both side.
As per the previous main brazing first we stand by bars of setting for brazing then
we attached the top part from the bottom part of water box. Then healed the top part by
top inductors at the temperature of 400Deg.c.
For this type of brazing use L-Ag-40Cd. This is the alloy silver academy which have
40% cadmium and the melting point is 400 Deg.C to 500 Deg.C. This brazing is done
for both end.
After the brazing the bars is go for second pickling which is the same process as
previously explain.
14.WATER FLOW TEST
Thought this test check the flow water equivalently in the hollow conductor of the
bar. There is the following steps of checking-
a. Water should be exit all the total hollow conductor.
b. If some burrs are jammed it should be removed to give very high pressure of water
and clean with the help of solid wire.
c. The main point of testing is that the water flow into the bar and exit from the water
box fall down approximately to cover 1 Mtr. From each conductor.
33
15.NITROGEN LEAK TEST
In this test the bar is tested for leakage into the components of bar. In this test flow
of nitrogen gas with pressure of 10kg/Cm2 to check the leakage in to the hollow
conductor. If leakage found the bar is rejected.
16.THERMAL SHOCK TEST
The cycles of hot (80 Deg.C) and cold (30 Deg.C) water are flew thought the bar to
ensure the thermal expansion and contraction of the joints. The time of low of hot &
cold water should be approx 32 to 40min and give the time between to flow of hot &
cold water is 5 min. this process is applied at least 8 hours.
17.HELIUM LEAKAGE TEST
In this test the bar’s end is tested to flow of helium gas with the given pressure if the
end part of the bar is leakage then the helium gas is covered the surface of water box
and indicator indicate the point of leakage.
18.INSULATION
For the insulation sunmika therm tape or sunmika pleese tape is used which is the
combination of mica + glass + varnish. It is used for corona protection. In this
insulation to layer of pleese tape + to layer of therm tape and after them again to
mica pleese tape is used.
Process of Insulation
a. Clean the bar.
b. Clean with chemical or thinner.
c. Taping
d. Realizing film from the mica plastic section.34
Fig 3.2.1- mica taping machine
In insulation the wall thickness of insulation is subjected to the generating voltage of the
machine.
19.IMPREGNATION AND BAKING
1. Thermoreactive system: In case of rich resin insulation the bar is pressed in closed
box in heated condition and baked under pressure and temperature as per
requirement for a given period.
2. Micalastic system: In case of poor resin system the insulated bars are heated under
vacuum and impregnated (dipped) in heated resin so that all the air gaps are filled,
layer by layer with resin then extra resin is drained out and bars are heated and
baked under pressed condition in closed box fixture.
VPI Micalastic System
The bars already laid in closed fixture and full fixture is impregnated in resin and then
fixture with box is baked under given temperature for the given duration.
35
Automatic Vacuum Pressure Impregnation Plant will be used for vacuum pressure
impregnation of Stator Winding Bar of large size Turbo generator - capacity up to 1000
MW.
VIP Micalastic System
The individual bar is heated in vacuum and impregnated in resin. Then bar is taken out
and pressed in closed box fixture and then baked at given temperature for given
duration.
Impregnation Tank
Internal Diameter: 2200.00 mm;
Cylindrical Length: 14000.00 mm;
Operating Vacuum: < 0.1 mbar;
Operating Pressure: 7 bar;
Operating Temperature: 90 Degree Centigrade
Impregnation Tank shall be welded structure complete with Rear
Dished End with suitable electrical / brine solution heating arrangement; Internal Rails for
trolley movement; Electrical / Brine Solution Heating arrangement for heating the
cylindrical portion of Impregnation Tank; Front Cover with bayonet locking arrangement
with automatic closing and opening system, highly effective sealing system and electrical
heating arrangement; all sealing parts; all mountings on the Impregnation Tank for the
measurement of temperature and vacuum; effective Ventilator unit for the fume extraction
at the mouth of Impregnation Tank; resin mixture inlet / outlet connection; Vacuum pipe
connection; Nitrogen gas inlet connection, viewing glass with provision of illumination etc.
36
Trolley Movement:
Trolley DRIVE-IN and DRIVE-OUT arrangement shall be motorized.
The trolley shall move with the help of chain and gear. The motor is to be kept outside the
impregnation tank. Switch ON and OFF control is NOT TO BE INTEGRATED WITH
AUTOMATIC CONTROL OF THE IMPREGNATION PLANT. Stopper is to welded on
the end portion of rails for the termination of the trolley movement inside the impregnation
tank.
Impregnation Tub:
Impregnation tub suitable for impregnation of stator winding bar of 1000
MW TG set, shall be supplied by the vendor. Impregnation tub will be fabricated structure
for static operating load of total 13500.00 KG (1500.0 KG of the job + 12000.0 KG of resin
mixture). Small inclination is to be provided at the bottom base of the impregnation tub so
that resin mixture is completely drained out during back transferring of resin mixture from
impregnation tub to storage tanks. Height of impregnation tub is to be designed so that the
job kept inside the impregnation tub, is visible through the viewing glass provided along the
length of cylindrical portion of impregnation tank.
Resin mixture storage tanks
Resin mixture storage tanks shall be complete with motorized
agitator; heating arrangement either by electrical heating or brine solution to heat up the
resin mixture; cooling by forced water cooling in two stages :
First Stage - by water cooling and Second Stage - by chilled water through refrigeneration
unit -; connection for evacuation in the storage tanks; connection of pressurization of resin
mixture with Nitrogen gas, mounting for the measurement of the temperature of resin
mixture and vacuum, viewing glass with illumination arrangement at the top of the storage
tanks, reliable and effective level switch for the indication of resin mixture level etc.
37
Temperature for heating the resin mixture in Resin Storage Tanks:
75 Degree Centigrade; Temperature for storing the resin mixture
= 10 + /- 2 Degree Centigrade; Regulation of Temperature during heating and cooling mode
= + / - 2 Degree Centigrade; Heating up time for resin mixture from 10 + /- 2 Degree
Centigrade to 75 Degree Centigrade in approx. 2 hours; Total cooling down time of resin
mixture for each storage tank to 10 + / 2 Degree Centigrade from 75 Degree Centigrade
should be in approx. 2 hours. Very fast heating and cooling system should be provided.
VACUUM SYSTEMS for the Impregnation Plant:
To achieve ultimate vacuum less than 0.1 mbar, reliable and highly
effective vacuum pumps and its system shall be supplied. At the start, rough vacuum pump
shall be SWITCH ON and the fine vacuum pump shall be SWITCH ON attaining the
vacuum 0.5 mbar in impregnation tank. The fine vacuum pump will be under operation till
transferring of resin mixture in impregnation tub.
NOTE:
a) 1 no. additional rough vacuum pump shall also be supplied and connected in the system,
ready for use as and when required.
b) One no. fine vacuum pump shall be included in the list of Spares.
Vacuum systems shall be supplied with condensate separator, drainage valve, aeration
valve, accessories for cooling circuit, vacuum measuring device, other essential instruments
etc, and automatic SWITCH ON of the stand by rough vacuum pump in case any problem
and SWITCH ON the fine vacuum pump at set value.
BRINE SOLUTION TANK:
38
Suitable capacity of brine solution tank to heat up simultaneously
impregnation tank and storage tanks if not heated electrically, complete with necessary
valves, level switch indicator, provision for makeup water etc. are to be provided.
Impregnation Process -
1. VACUUM DRYING OF JOB:
1.0) Placement of stator winding bar in the impregnation tub kept on the trolley of
Impregnation Tank
2.0) Drive in the trolley inside the Impregnation Tank. Closing of the front cover of
Impregnation Tank.
3.0) Commencement of heating the job
4.0) Commencement of evacuation of the job
5.0) Drying of job under vacuum < / = 0.1 mbar at temperature 75 + / 5 Degree Centigrade
for minimum 10 hours
6.0) Drying of job under vacuum will be stopped if the pressure rise in impregnation tank in
10 minutes after closing of vacuum valve is less than 0.05 mbar
2. IMPREGNATION CYCLE:
1.0) While job is under vacuum drying, resin mixture is heated in storage tank at
temperature 70 + 3 Degree Centigrade and the vapours are sucked under vacuum < / = 5
mbar at temperature > / = 60 Degree Centigrade
39
2.0) Transferring resin mixture from storage tank to impregnation tub, on certification
proper drying under vacuum.
3.0) Maintaining resin mixture level 100.00 mm above than the highest part of the job
4.0) Pressurization of resin mixture with Nitrogen gas after 10 minutes of resin stabilization
5.0) Increase in Nitrogen pressure to 5 bar within 80 minutes in uniform stages
6.0) Holding the 5 bar pressure for 120 minutes
3. BACK TRANSFERING OF RESIN MIXTURE:
1.0) On completion of Impregnation Cycle Quick Back Transferring of resin mixture from
impregnation tub to storage tank through filter, by pressure difference in 2
2.0) Quick cooling of resin mixture in storage tank at temperature at 10 + / - 2 Degree
Centigrade but not less than 8 Degree Centigrade, in 2 hours
3.0) Opening of front cover after dripping of resin mixture from job for 10 minutes in
impregnation tub
4.0) Extraction of fumes of resin mixture at the mouth of impregnation tank for 10 minutes
5.0) Driving out the trolley from impregnation tank
6.0) Removal of impregnated job from impregnation tub for next operation
20. FINISHING
The baked and dimensionally correct bars are sanded-off to smoothen the edges and
surface calibrated if required for the dimension.40
21. CONDUCTING VARNISH COATING
OCP (Outer Corona Protection) Coating: The black semi-conducting varnish coating
is applied on the bar surface on the core length.
ECP (End Corona Protection) Coating: The grey semi-conducting varnish is applied
at the bend outside core end of bars in gradient to prevent from discharge and minimize
the end corona.
22. TESTING
1. Tan Test: This test is carried out to ensure the healthiness of dielectric (insulation)
i.e. dense or rare and measured the capacitance loss.
2. H.V. Test: The each bar is tested momentarily at high voltage increased gradually
to three times higher than rated voltage.
23.DISPATCHED FOR WINDING
If the bar is passed in all the operation and testing after completing then the bar is send
for stator winding.
41
CHAPTER-4
Electrical Machine Block
(Block-1)
Block-I, also known as Electrical Machines Block, is designed to
manufacture Hydro generators, Turbo generators and Testing facilities for Turbo generators.
There is also a special Test Bed for testing of turbo generators of capacity of 500 MW and
above. Apart from facilities and equipment for manufacture of turbo generators, the Block
also has a “Bebitting Section”. Bebitting of bearing liners for Turbo generators, Turbines,
Hydro generators, is carried out in this section. The Block has its own over speed balancing
installation; where the dynamic balancing of Turbo generator-rotors of less than 500 MW
rating is done. Rotors having higher rating are balanced in OSBT of Block-III.
Fabricated components are received from fabrication blocks (Block-II, IV, VI, VIII),
while other castings, forgings are received from CFFP and other sources for Turbo
generators, Hydro generators and Electrical motors. Stampings are received from Stampings
manufacture section; Block-VI and coils, bars, insulating details and sheet metal
components are received from Block-IV. These are then machined, assembled, tested and
dispatched.
4.1 Manufacturing process:-
TURBO GENERATOR
a) Making of blanks is done for checking the availability of machining allowances.
b) Machining of the major components is carried out in Bay - I & Bay- II and other small
components in Bay - III and Bay - IV. The boring and facing of stators are done on CNC
horizontal boring machine using a rotary table. The shaft is turned on lathe having swift
2500 mm and the rotor slots are milled on a special rotor slot milling machines
42
c) In case of large size Turbo Generators core bars are welded to stator frame with the help
of telescopic centring device. The entering of core bar is done very precisely. Punching are
assembled manually and cores are heated and pressed in number of stages depending on the
core length.
d) Stator winding is done by placing stator on rotating installation. After laying of lower
and upper bars, these are connected at the ends, with the help of ferrule and then soldered
by resistance soldering.
e) Rotor winding assembly is carried out on special installation where coils are assembled in
rotor slots. The pressing of overhang portions carried out on special ring type hydraulic
press, whereas slot portion is pressed manually with the help of rotor wedges. Coils are
wedged with special press after laying and curing. The dynamic balancing of rotors is
carried out on the over speed balancing installation. 500 MW Turbo Generators are
balanced in vacuum balancing tunnel.
f) General assembly of Turbo Generators is done in the test bed. Rotor is inserted in the
stator and assembly of end shields; bearings etc. are carried out to make generators ready
for testing. Prior to test run the complete generator is hydraulically tested for leakages.
g) Turbo Generators are tested as per standard practices and customer requirements.
500 MW Turbo generators at a glance -
2-Pole machine with the following features:-
•Direct cooling of stator winding with water.
•Direct hydrogen cooling for rotor.
•Micalastic insulation system
•Spring mounted core housing for effective transmission of vibrations.
•Brushless Excitation system.
•Vertical hydrogen coolers
43
Salient technical data–
•Rated output: 588 MVA, 500 MW
•Terminal voltage: 21 KV
•Rated stator current: 16 KA
•Rated frequency: 50 Hz
•Rated power factor: 0.85 Lag
•Efficiency: 98.55%
Important dimensions & weights –
Heaviest lift of generator stator: 255 Tons
Rotor weight: 68 Tons
Overall stator dimensions [LxBxH]: 8.83Mx4.lMx4.02M
Rotor dimensions: 1.15M dia x 12.11 M length
Total weight of turbo generator: 428 Tons
Unique installations–
Heavy Electrical Equipment Plant, Haridwar is one of the best equipped and most modern
plants of its kind in the world today. Some of the unique manufacturing and testing facilities
in the plant are:
TG Test Bed–
New LSTG [Large Scale Turbo Generator] Test Bed has been put up with indigenous
know- how in record time for testing Turbo generators of ratings 500 MW and above up to
44
1000 MW. It caters to the most advanced requirement of testing by employing on-line
computer for data-analysis.
Other major facilities are as follows –
•Major facilities like stator core pit equipped with telescopic hydraulic lift, micalastic plant
for the manufacture of stator bars, thermal shock test equipment, rotor slot milling machine
etc. have been specially developed by BHEL.
•12 MW/10.8 MW, 6.6 KV, 3000 RPM AC non salient pole, synchronous motor has been
used for driving the 500 MW Turbo-generator at the TEST Bed. The motor has special
features to suit the requirement of TG testing (500 MW and above). This is the largest
2- pole (3000 rpm).
Over speed Balancing vacuum tunnel –
For balancing and over speeding large flexible Turbo generators rotors in vacuum for
ratings up to 1,000 MW, an over speed and balancing tunnel has been constructed
indigenously. This facility is suitable for all types of rigid and flexible rotors and also high
speed rotors for low and high speed balancing, testing at operational speed and for over
speeding.
Generator transportation –
•Transport through300 Tons 24-Axle carrier beam railway wagon specially designed
indigenously and manufactured at Haridwar.
•The wagon has been used successfully for transporting one generator -from Calcutta Port
to Singrauli STPP
45
4.2 Stator :-
4.2.1. Stator frame fabrication:-
Firstly the cutting, bending, welding and N.D.T testing of stator frame
and End Shield is done in block 2.Material used for stator frame and End Shield is Carbon
Steel.
Figure 4.2.1- Stator Frame
46
CUTTING:-
CNC Gas and CNC Plasma is used for cutting at 6000 Deg.C.Gas used for Gas cutting is
Oxygen and Acetylene and for Plasma cutting it is Argon, Hydrogen and Nitrogen.
DRILLING:-
After cutting drilling of material is done.
BENDING:-
Three Roll Bending is used for bending the sheets.
WELDING:-
Arc welding is used to weld the parts and bend material and for some parts gas welding is
also used.
N.D.T:-
After the welding NON DESTRUCTIVE TESTING (N.D.T) of the material is done.
4.2.2 Stator Frame Machined:-
HOLES:-
Holes are formed of dia 36 where End Shield Is to be Bolted.
INTERNAL DIA.:-
Internal dia is formed according to the drawing.
COOLING WINDOW:-
Cooling windows are also formed during machining.
47
3. Hydraulic Testing:-
After the drilling hydraulic testing of frame is done at high pressure of 2, 5,
8,10kg/cm2.
4. Core Building:-
Than frame send to the core department in block-1.
Process of Core Department:-
1. Elastic Property of Body is checked.
2. Baskets are formed:-
Total 7 Baskets in one stator body and in one Basket 3 Spring 2 vertical and 1
horizontal.
Vertical springs are to bear the load
Horizontal spring is to control the vibration.
3. Stator body placed in Core pit vertically.
5. Stator Winding: -
During this process Electrical winding of the stator like bars are Inserted
with insulation and total 24 core bars are inserted which are formed of stainless steel at the
Turbine end and core bar of Mild Steel at the Exciter end and one core bar is of 6 mt.
Headers are also inserted during winding which are used for the entry of cold water and exit
of the hot water.
Stamping are inserted in the stator which are Formed of Silicon Steel. It is of .5mm
in width and 70mm Stamping used in one package and after each package
Ventilation is used for the flow of Hydrogen as a coolant and total 87 Packages are
used.
Dove Tails Bars are inserted and then pressing of packages is done.
At the ends of packages End Stampings are used for the external Support.
48
A Core building of stamping is formed and coils are inserted during winding and
then this core building is transfer to impregnation plant.
6. End Shield Fabrication:-
End shield fabrication is done in block 2 as per Requirements.
7. End Shield Machined:-
After fabrication End shield machined is done in Block 1.
Process of End Shield machining:-
1. Stator joining Holes are drilled.
2. End to End shield Holes.
3. Surface Machining.
4. Cooler windows.
5. Blue Matching.
8. Pneumatic Testing:-
After the End Shield is machined Pneumatic testing (air leakage testing) is
done at 6 kg/cm2 for max 4 hrs.
9. Rotor Forging:-
Forging of the Rotor shaft is done in Foundry plant.
10. Rotor Machined:-
After the forging Rotor shaft is machined.
Process of Rotor Machining:-
49
1. Final dia of shaft is checked.
2. Slot milling is done for the insertion of Coils.
3. Coupling Holes for coupling at Turbine and Exciter end are formed.
11. Rotor Winding:-
In this process Electrical winding of 250 MW, 500MW AND 600 MW
of the Rotor is done.
Process of Rotor Winding:-
1. Insertion of coil is done in two parts i.e. two poles are there and in each pole 7 coil in
each pole and total 14 coils in two pole and one coil is formed by the 11 long strips and they
are joined by the insulating material called as Texolite.
2. Than four pins are formed at the exciter side end for the current supply.
3. Now heating is done at 130 C for insulation and again heating is done at 160 C.
4. Than Ritter ring is used to cover the winding.
5. At last Rotor balancing is done at 3600 rpm in Balancing Tunnel.
12. Final Assembly:-
Now final assembly of generator is done.
Process of Final assembly:-
1. Wound Stator and Wound Rotor are assembled at testing bed.
2. Wound Rotor is inserted in the wound Stator with the help of high capacity cranes.
50
3. After the insertion of Rotor following products are inserted for the smooth and safe
running of Generator.
Primary water tank at the top of the Generators.
Bearings in the End Shield.
Inner oil catchers.
Outer oil catchers.
Air gap seal rings.
Seal body +Seal rings.
Baffels rings for circulation of Hydrogen.
Terminal box.
Terminal bushings.
Hydrogen coolers in End shield.
Support ring used at the Exciter End.
Magnetic shunt used at Exciter and Turbine End to reduce the leakage of
flux.
Support Ring for the overhang winding of wound Stator.
At last End Shields are fitted.
Now the Generator’s Testing is done.
51
REFERENCES
INTERNET
1. http://www.bhelhwr.co.in/bhelweb/index.isp
2. http://www.bhel.com/about.php
3. http://en.wikipedia.org/wiki/Bharat Heavy Electricals Limited
BOOKS
[1]. B.L. Theraja, A.K. Theraja, A Textbook of Electrical Technology, Volume II, S.Chand
[2]. J.B. Gupta, Theory & Performance of Electrical Machines, S.K. kataria & sons
[3]. P.S. Bhimbra, Electrical Machines
52
APPENDIX-A
ENGINEERING CAPABILITIES
-EXTENDING LIMITS WITH LATEST TECHNIQUES
BHEL possesses very strong engineering base, R&D infrastructure, very precise CNC &
conventional machine tools, sophisticated technologies and capabilities to produce
hydro-generators of capacity up to 300 MW based on customer’s requirements as per
national /international standards.
BHEL has the latest hardware and computer software for design development of large
capacity (> 250 MW) and large size hydro-generators.
Latest computational techniques for design analysis and integrated manufacturing like
CAD, FEM, and CAM etc. are used.
Use of solid modelling, finite element modelling and further downstream applications
for solution of design structure, heat transfer, electro-magnetic applications etc. for
optimisation.
The computer software is also used for thermal network solutions and ventilation
system, which are vital parameters for large capacity machines
53
APPENDIX-B
1. HYDROGEN AND WATER COOLED TURBO GENERATORS OF
500 MW RANGE (TYPE: THDF)
SALIENT DESIGN FEATURES
1• Stator winding directly water- cooled
2• Rotor winding directly hydrogen cooled (axial)
3• Leaf spring suspension of stator core
4• Micalastic insulation system
5• End shield mounted bearings
6• Support ring for stator over hang
7• Magnetic shunt to trap end leakage flux
8• Ring type shaft seals with double flow
9• Multistage compressor and vertical coolers on turbine end
10• Brushless/static excitation
11• Integral coupling of rotor
54
2-HYDROGEN COOLED TURBOGENERATOR OF 140-260 MW
RANGE (TYPE: THRI)
SALIENT DESIGN FEATURES
1. Stator core and rotor winding directly hydrogen cooled
2. Indirect cooling of stator winding
3. Micalastic insulation system
4. End shield mounted bearings
5. Ring type shaft seals
6. Symmetrical ventilation.
7. Brushless/static excitation
8. Integral coupling of rotor
55
3.-HYDROGEN AND WATER COOLED
TURBOGENERATORS OF 500 MW RANGE (TYPE: THDF-115/59)
SALIENT DESIGN FEATURES
•Stator winding directly water-cooled
•Rotor winding directly hydrogen cooled (axial)
•Leaf spring suspension of stator core
•Micalastic insulation system
•End shield mounted bearings
•Support ring for stator over hang
•Magnetic shunt to trap end leakage flux
•Ring type shaft seals with double flow
•Multistage compressor and vertical coolers on turbine end
•Brushless/static excitation
•Integral coupling of rotor
56
4 -HYDROGEN AND WATER COOLED TURBOGENERATORS
OF 200-235 MW RANGE (TYPE: THW)
SALIENT DESIGN FEATURES
•Stator winding directly water- cooled
•Rotor winding directly hydrogen cooled by gap pickup method
•Resiliently mounted stator core on flexible core bars
•Thermo reactive resin rich insulation for stator winding
•Top ripple springs in stator slots
•Enclosed type slip rings with forced ventilation
•Ring/thrust type shaft seals
•Two axial fans for systematic ventilation and four Hydrogen Coolers
•Static excitation
57
58