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