BHEL

INDUSTRIAL TRAINING REPORT

ON BHEL

SUBMITTED BY: DERIL SIMON

ELECTRICAL ENGG. FINAL YEAR-2006 ROLL NO:-02EE48

P REFACE

It is matter of great happiness for me that within a short span of 45 days, I am presenting my vocational training report with the expertise in "production unit BL-1, Machine shop BL-1, Electrical maintenance”. Needless to say that the report covers most of the thing, which strictly speaking is, based on the experience what I get in BHEL. Hardwar, effort has been made to such a way as to give proper sequence & a very simple & a very simple & integrated structure for everybody to understand with ease. In order to make the treatment of certain application explicityl understand ably, through pictures, required samples, & needed circuitry are presenting to the report where are required to better construct.

In the first section of report you have to find the historical & gorgeous look of BHEL, Haridwar. The second section deals with overall information of production (Generators & Motors), Machine shop BL-1.

Apart this I have done my all celebrities & effort to give the concise & untreatable from to the report.

I shall fell grateful if readers by pointing out mistakes give suggestions & information in the report in the report extended his hand of participation.

SANJULI HARIDWAR (02EE43, 6th sem) 30, July, 2005

,

A CKNOWLEDGEMENT

I have a great pleasure in acknowledgement the hellos received from all those who favored me with it in giving shape to the present position of the report. I owe a deep intellectual dept to various authors, engineers & technicians who through their rich & varied contribution have greatly improve my training purpose. I am under a great depth of gratitude to our coordinator. Mr. D kayal, Additional General Manager for his valuable support& guidance at various steps of training. I am also sincerely thankful to the suggestions & hello rendered by Mr. D Pant.

C ONTENTS I NSIDE

BHEL - OVERVIEW

HEEP – OVERVIEW

MANUFACTURING FACILITIES

BLOCK-1 PRODUCTION UNIT

I. BAY-1II. BAY-2

III. BAY-3IV. BAY-4

REFRENCES

B HEL – A N O VERVIEW

The first plant what is today was an BHEL, was established nearly 39 year ago at Bhopal and was the genesis of the heavy electrical equipment industry in India BHEL is today, the largest engineering enterprise of its kind in India, with a well-recognized track record of performance, making profits continuously since 1971-72 it achieved a sales turnover of Rs. 6347cr. With a per- tax profit of Rs. 294cr. In 2000-2001.

B.H.E.L caters to core sectors of the Indian Economy viz. power, Industry, Transportation, transmission, Defense, etc.

The wide network of BHEL’s manufacturing division nine service centers and four Power Sector Regional Centers and about 150 project sites enables the company to be closer to its customers and provide them with suitable product, system and services and competitive prices. Having attained ISO 9000 certification, BHEL is now embarking upon the total quality management.

The company’s inherent potential coupled with its strong performance over the year, has resulted in it being chosen as one of the “Nirvana” poses, which are to be supported by the Government in their endeavor to become future global players.

BUSINESS SECTORS:-

To provide a strong market orientation, BHEL’s operation is organized around three business sectors, viz, Industry and International.

POWER SECTOR:-

Power sector comprises thermal, nuclear, gas and hydro power plant business. Today, BHEL supplied sets account for nearly 64737 or 65% of the total installed capacity of 86,636 M Win in the country as again nil till 1979-70.

BHEL has proven turnkey capabilities for executing power project form concept to commissioning; it possesses the technology and capability to produce thermal power plant equipment up to1000 MW rating and gas turbine generator sets up to a unit rating of 240MW. Cogeneration and combined cycle plant have been introduced to achieve higher plant efficiencies. To make efficient use to the high ash content coal available in India, BHEL supplies circulating fluidized bed boilers to both thermal and combined cycle power plants.

BHEL manufactures 235 MW nuclear turbine generator sets and commenced production of 500 MW nuclear turbines generators sets.

Custom made hydro sets of Francis; Pelton and Kaplan types for different head-discharge combinations are also engineered and manufactured by BHEL. In all, more than 700 utility sets of thermal, hydro, gas and nuclear have been given on contract to BHEL as on date. The power plant equipment manufactured by BHEL is based on contemporary technology comparable to the best in the world and is also internationality competitive.

INDUSTRY SECTOR:-

BHEL is major contributor of equipment and industries like cement, fertilizers, refineries, petrochemical, steel, paper and telecommunication. The range of system & equipment supplied include captive power plant, high speed industrial drive turbine industrial boilers and auxiliaries, waste heart recovery boilers, gas turbines, heart exchanges & pressure vessels, centrifugal compressors, electrical machines, pumps, valves, seamless steel tubes, process control, etc.

BHEL is a major producer of large size thyristor devices; it also supplies digital distributed control system for process industries and control & instrumentation for power plant and industrial application. BHEL is the only company in India with the capability to make simulators for power plants, defiance and other applications.

TRANSMISSION:- BHEL also supplies a wide range of transmission products systems up to 400 KV class. These include high voltage power & distribution transformers, instrument transformers, dry type transformers, SF6 switchgear, capacitors and

insulators etc. for economics transmission of bulk power over long distances; high voltage direct current (HVD) systems are supplied. Series and shunt compensation systems have also been developed and introduced to minimize transmission losses. TRANPORATATION:-

A high percentage of trains operated by Indian railways are equipped with BHEL’s traction control equipment including the metro at Calcutta. The company supplies broad gauge electric locomotives to Indian railways and diesel shunting locomotives to various industries. 5000/4600 hp AC/DC locomotives developed and manufactured by BHEL have been leased to Indian railway. Battery powered road vehicles are also manufactured by the company.

RENEWABLE ENERGAY:-

Technologies for exploiting non-conventional and renewable sources of energy include wind generators, solar-power based pumps, lighting and heating system. BHEL manufactures wind electrical generator of unit size up to 250 KW for wine farms to meet the growing demand for energy.

BHEL has commenced manufactures of large Desalination plant to help augment the supply of drinking water to people.

HUMEN RESOURCE DEVELOPMENT: -

The prized asset of BHEL is its 62.507 employees. The human Resources Development Institute and other training institute of the company help are not only keeping their skills updated and finely honed but also add new skills when required. Continuous training and retraining, a positive work culture and participative workforce style of management have led to the development of a committed and motivated workforce and enhanced productivity and quality levels.

H EEP : A N O VERVIEW

Over the years, BHEL as emerged as world-class engg. & Industrial giant, the best of its kind in entire south East Asia. Its business profile cuts across various sectors of engg/power utilities & industry. The company today enjoys national & international presence featuring in the "fortune international-500" & is rank among the top 12 companies in the world, manufacturing power generation equipment. BHEL has now 14 manufacturing divisions , 8 service centers & 4 power sectors regional centers besides a large nos. of projects site spread over India & abroad. The company is embarking upon an ambitious growth path though clear vision; mission & committed values to sustained & augment its image as a world class enterprise. VISION:-

A world class, innovative, competitive & profitable engg. Enterprise providing business solutions. MISSION:-

To be the leading Indian engg. Enterprise providing qualities products system& services in the field of energy, transportation, infrastructures & other potential areas. VALUES:-

* Meeting commitments made to external & internal customers.* Foster learning creativity & speed of response.* Respect for dignity & potential of individuals.* Loyalty & pride in the company.

* Team playing.* Zeal to excel.* Integrity &fairness in all matters.

HEAVY ELECTRICALS EQUIPMENTS PLANT (HEEP):- At hardwar, against the picturesque back ground of shivalik hills, 2 important manufacturing units of BHEL are located viz. HEEP& central foundry forge plant (cfpp).T he hum of the construction machinery woke up shivalik hills during early 60s & sowed the seeds of one of the greatest symbol of indo soviet collaboration - HEEP of BHEL.Following is the brief profile of HEEP:-

1. ESTABLISHMENT & DEVELOPMENT STAGES

* Established in 1960 under the indo soviet agreement of 1959 &1960 in the area of scientific, technical &industrial cooperation.*DPR-prepared in 1963-64 construction started from October 1963.* Initial production of electric motors started from January 1967.* Major cunstruction/erection/commisioning completed by 1971-72 as per original DPR scope * Stamping unit added later during 1968 -72.* Annual manufacturing capacity for thermal sets was expanded from 1500 MW to 3500MW under LSTG project during 1979-85(sets up to 500MW, extensible to 1000/1300MW unit size with marginal addition facilities with the collaboration of M/s KWU-SIEMENS, Germany.)* Motor manufacturing technology updated with siemens collaboration during 1984-87.* Facilities being modernized continually through replacment/reconditoning - retrofitting, technological/ operational balancing.

2. HEEP PRODUCT PROFILE

*THERMAL & NUCLEAR SETS(Turbines, generators, condensers & auxiliaries of unit capacity up to 1000 MW)*HYDRO SETS INCLUDING SPHERICAL & DISK VALUS(Kaplan, Francis, pelton, reversible turbines of all size & matching generators & auxiliaries maximum runner dia- 6600 mm.)*Electrical Machines (For various Industrial applications, pump drives & power station auxiliaries, Units capacity up to 20000 KW AC/DC)*CONTROL PANELS(For thermal/ Hydro sets & Industrial drives)*LARGE SIZE GASS TURBINES

(Unit rating 60-200 MW)*LIGHT AIRCRAFT*DEFENCE PRODUCTS

3. HEEP: FACILITIES & INFRASTRUCTURE

Modernization & regular updation/upgradation of facilities & other infrastructure is a continuous endeavourer at HEEP, BHEL. After initial setting up of the plants during the year 1964/72, in collaboration with the soviet union, the plants facilities & infrastructure have since been continuously upgraded under various investment project viz, stamping unit project, LSTG project, motor project, Governing component project, TG facilities Modernization, TG facilities augmentation, quality facilities augmentation, EDP project, gas turbine project. Facilities have also been added and establishments have been created for new products in defense & aviation projects. Additionally, R&D facilities have also been created under generators research institute, pollution control research institute, HLT modernization and other such schemes.

To day the plants has unique manufacturing and testing facilities, computerization Numerically controlled machines- tools, blades shop, heavy duty lathes, milling machines, boring machines, machining centers and many more. The over speed vacuum balancing tunnel created for rotors up to 1300 MW (320 T, 6.9 M- dia bladed rotor, 6 rpm. up to 4500 rpm) is one of the eight of its kind in the entire world.

The total spectrum of sophisticated, unit and other facilities at Heep, Haridwar are the state of the art in manufacturing processes and can be utilised for a verity of products manufactures.

M ANUFACTURING F ACILITIES

HEEP Haridwar plant is equipped with most modern and sophisticated machine tools, facilities and test equipment to manufacture and test generators up to 1000 MW rating, which include:

Most modern micalastic insulation plant for stator bars Overspeed and vacuum balancing tunnel Koellmann rotor slot milling machine upto maximum barrel length of

7000 mm, barrel dia. of 1800 mm and rotor weight of 225 tons Two computerised test beds to test large size generators upto 1000

MW Wotan CNC horizontal boring machine Center lathe machine up to max. length of 16 m and dia. of 3.15 m Insulation life endurance test assessment facility

Besides these, HEEP has also set up a Generator Research Institute with an objective to develop basic know-how and know-why through experimental studies for reliable, efficient and optimum design of generators and improve their performance in service.

F ORWARD

Business mission of BHEL is ---"To be the leading Indian engineering enterprise providing quality products, systems and services in the fields of energy, transportation, industry, infrastructure and other potential area". In line with this mission, HEEP _ one of the major manufacturing units of BHEL, strives to achieve Technological Excellence in all area of its operations. Manufacturing & Engineering facilities and infrastructure at HEEP are comparable to any World - class enterprise of its kind.

To be at par with advanced global competitors and to meet the changing needs of different products, the Modernization and Technological up gradation of facilities is a continuous endeavor at HEEP. Keeping pace with the the State - Of - The - art, manufacturing facilities have been augmented to include a host of CNC machine - tools, incorporating computer - aided manufacturing. Plans are in hand to introduce Computer Integrated Manufacting, Flexible Manufacturing Systems, Electro - chemical machining in near future. Also Computer - aided engineering and design has become a way of life for the Engineering professionals at HEEP.

This publication on "Directory of Manufacturing and Engineering Facilities" will serve the facility planners and users as a reference guide and present the vivid picture of Engineering and Manufacturing Potential & Capabilities of this unique plant.

(M. K. Mittal) Executive Director

BHEL, HARDWAR

B LOCK - 1 P RODUCTION U NIT

* BAY-1

INTRODUCTION, LSTG ROTOR WINDING & STATOR WINDING(T.G), OVERSPEED BALANCING TUNNEL.

* BAY-2

MOTOR IRON ASSEMBLY, HEAVY ROTOR ASY., STATOR WINDING AND IMPREGNATION PLANT.

* BAY-3

MEDIUM ROTOR IRON ASSEMBLY, COMMUTATOR SECTION,FIXTURE AND BUSBAR,TEST STAND.

* BAY-4

SMALL SIZE MOTOR, POLE SECTION, T.R.C. ROTOR COIL SECTION.

I NTRODUCTION

From the Electrical point of view the main stress is given on the manufacture and maintenance of turbo (large) generators and hydro generators as well as A.C & D.C motors in block-1 with the largest manufacturing techniques being employed for their production. This block is also significance its better production and quality control performanceblock-1 has the tremendous part of all block present in BHEL with accordance to manufacturing techniques. The largest machine shop of India is also available of this block. There are many achievements are established by this block.

Block-1 was established by BHEL HEEP (Heavy Electrical Equipment

Plant, Hardware). Inaugurated by sh. D. sanjivayya, Union Minister for

Industry, Smt. Suchetra Kripalani, 3rd

Jan. 1967, Chief Minister, Uttar Parades, Presided 13 Paush-Saka 1888.

ELECTRICAL MACHINES BLOCK (BLOCK-1)

Block-1 is designed to manufacture Hydro generators, Turbo generator & large & medium size AC & DC electrical M/Cs. Equipment layout plan is as per drawing no. 003 appended in section-3. The block consist of 4-bays: Bay-1(36*482 meters), Bay-2(36*360 meters) & Bay -3&4 of size 24*360 meters each. For handling & transporting the various components overhead crane facilities are available, depending upon the products manufactured in each Bay. These are also a number of self propelled electrically-driven transfer trolleys for the inter bay movement of components/assemblies.

Convention bay wise brood distribution of products is as follows:--

LSTG Area Large size turbo generators.

Bay-1 Hydro generators their exciter; PMG & large size turbo generator. Bay-2 Turbo generator, their exciter & heavy electrical motors Bay-3 Medium size electrical motors Bay-4 Small & miscellaneous components for all electrical M/Cs. Testing facility for turbo generator & heavy motors are available in Bay-2 & for medium size electrical motors in Bay-3.their is a special test bed area for testing of capacity of 500 MW unit size & above .

The manufacturing products and capacity of this are as under—

PROJECT TYPE MAX. UNIT CAPACITY

1. Turbo I) Air cooled Up to 1000Generator II) h2 cooled M.W

III) Water cooled

2. Hydro Generators I) Umbrella Up to 250 II) C.M.Umbrella M.W

III) Suspension IV) Horizontal

3. Motors I) A.C. Motor 35 M.W II) D.C.Motor 12 MW 70 rpm

The manufacturing M/Cs by Block-1 in India till 2001 is as follows:- A.C.Motor—3690 D.C.Motor – 5549 Turbo Generators – 46 (Projected in India) Hydro Generators – 50 (Projected in India)

Block-1 has specially only for T.G. & H.G. of the specifications as:-

T.G. 500MW 250MW 235 MW 210MW(NPC) (THRI, THW)

Cooling THDF THRI THW Method

159 MW 80 MWX Frames 6TARI

H.G. UPTO 250 A.C.Motors: up to 10400 kWMW D.C.Motors: up to 12500 kW

Therefore the block has their own importance in whole of the HEEP family of BHEL Hardwar. The internal positional diagram of block-1 are attached, in which that the block-1 has four bay (Sections), into which there are many heavy & medium machines are positioned are also the T.G.& H.G. section are present there.

The bayside description of the above are visualize here as accordance to me.

*BAY-1

LARGE SIZE TURBOGENERATOR (LSTG AREA):--

Following facilities are available in different section of this area:-

(a.) Stator core assembly section:

Two number core pits core building & pressing facilities are available in this section .The section is also equipped with optical centering device, core heating installation & core loss testing facility.

(b.) Stator winding section:

The section is located in a dust proof area enclosure & equipped with one number winding platform two number rotating installation for assembly of windings, resistance bracing M/Cs & high voltage transformer are also available in this section.

(c.) Rotor assembly section:

This section is also in a dust proof enclosure & is equipped with number of rotators, rotor bar laying facilities & MI heating heating installation for heating & mounting of retuning rings. Rotor winding assembly & rotor assembly like retuning ring fitting, four assemblies are carried out in this section.

(d.) Bar preparation section:

This section consists of milling M/C for long preparation, installation for insulation of tension bolts for stator & preparation of stator winding before assembly.

(e.) Test bed section:

This section is equipped with bed plates, height blocks, supporting blocks & 12MW drive motors. LSTG & exciter are assembled & tested in this section.

HYDROGENERATORS:--

Following facilities are available in the various sections: ---

(a.) Machine section:

This section is equipped with large size rotor slot milling M/C , lathe convention as well as CNC vertical boring , CNC horizontal boring M/C , drilling & double column planning M/C . Small size milling, slotting M/C & a shaper are also available for manufacturing small components.

The major component M/C in this section are stator frames upper & lower brackets , rotor spider , rotor shaft, pole end plates , thrust bearing disc ,collar of hydro generator & rotor shaft of LSTG.

(b.) Iron assembly section:

This section is equipped with two centering columns & set of welding for carrying out iron assembly of hydro generators stators.

(c.) Stator winding section:

Two truck mounted brazing installation are available in this section for resistance brazing of bar head joints of stator winding bar of hydro generators.

(d.) Rotor winding section:

This section is equipped with rotators, hydraulic presses & wedge driving press for the assembly of rotor winding for turbo generator.

(e.) Rotor assembly section:

This section is equipped with bed plates & induction heating facilities for assembly of rotors of turbo generator. Assembly of retaining ring is carried out in this section.

TURBO GENERATOR:--

Modern feature of direct cooling by water & hydrogen are incorporated in the 210 MW turbo generators, thus evolving an economical & reliable design. This high efficiency M/c, together with a fast acting excitation system & dependable auxiliary service has a proven record & withstood the test of time by prolonged trouble free Operation over the years. All the materials that go into the manufacture of this M/c are subjected to rigorous tests as per international standards. Each sub assembly or component undergoes a series of stage wise tests .Each unit that rolls off the assembly line is fully assembled & tested at the plant test bed as per the standards of the standards of the international electro technical commission.

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

210 MW THW TYPE GENERATOR AT ROPAR THERMAL POWER STATION

HYDROGEN AND WATER COOLED TURBOGENERATORS OF 500 MW RANGE (TYPE: THDF ):--

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

500 MW TURBOGENERATOR ON TEST BED

STATOR:--

The stator body is a totally enclosed gastight, explosion -proof fabricated structure, suitably ribbed & stayed internally & ensure high rigidity. These are so designed that the tubes may be cleaned without removing hydrogen from the generator .Hydrogen coolers with a sufficient surface area , are mounted limitedly in the stator frame for cooling the hydrogen

The stator core is built from high alloy low loss electro-technical steel segmental stampings which are varnished on both sides. Segments of insulating material are inserted at frequent intervals to provide additional insulation & to localize shorts circuits .The stampings are assembled & pressed on core bars forming several packets .The packets are separated from each other by steel spacers of special profile to form ventilating ducts providing a gas passages to cool the stator core . In order to reduce the losses in the end packets, copper screening plates are provided at either end of the core & cooled by hydrogen passing through radial ducts provided between the core end plate & end packets.

The stator winding employs direct cooling by distilled water which permits the use of high value of current density in this M/c .The stator winding over hang fixing is designed to withstand sudden short ckts at the terminal .Each coil side consist of solid & hollow conductors through which the cooling water passes . For distributing water through the stator coils, ring type water headers insulated from the body, are provided on the turbine end. The winding is designed for double star connection. Three line & 6 neutral terminals are brought out thus enabling split phase differential protection to be provided.

HYDROGEN COOLED TURBOGENERATORS OF 140-260 MW RANGE (TYPE: THRI):--

SALIENT DESIGN FEATURES

Stator core and rotor winding directly hydrogen cooled

Indirect cooling of stator winding

Rigid core bar mounting Micalastic insulation system End shield mounted bearings Top ripple springs in stator

slots Ring type shaft seals Symmetrical ventilation. Brushless/static excitation

Integral coupling of rotor 210 MW THRI TYPE GENERATOR STATOR

ROTOR:--

The rotor is of the cylindrical type, the shaft & rotor body being forged in one piece from nickel chrome molybdenum vanadium steel. Longitudinal slots are milled in the body to house the field winding .The field winding is made of cooled rolled electrical copper which has a small percentage of silver . Slot portion of the winding are held against centrifugal forces by means of duralumin wedges & the overhang portion, by retaining rings of floating type. Retaining rings are made from high tensile nonmagnetic alloy steel forgings. An end damper winding is provided, which safeguards the asymmetrical & asynchronous operative conditions of the M/c.

The rotor winding is provided with a lateral gap pick up system of cooling in the slot part, ensuring uniform temperature distribution of the winding. The overhang part is provided with axial cooling .The slip rings are steel forgings which are shrunk on to the steel hub covered with mica, built up in positions. These are arranged side by side outside the generator bearing at the exciter end. The surfaces of the slip rings are spiral grooved & the brushes staggered to increase the life of the slip ring & brushes.

BEARING AND SHAFT SEALS:--

The generator bearing at the end is of pedestal type with high rigidity & is provided with a spherically seated shelf adjusting bush .The bearing bush is lined with anti-friction metal & is automatically lubricated by the oil supplied by the lube oil system . For checking the oil flow, sight windows are provided on the drain pipes. In order to prevent the escape of hydrogen where the shaft leaves the casing, shafts seals of the thrust type are provided at each end. For improving the reliability during all regimes of operation, the shaft seals design incorporates high pressure oil for pressing the seal liner against the shaft collar. In order to prevent the circulation of shaft currents, oil seals & the bearings on the exciter end are insulated from earth.

LSTG ROTOR WINDING

In this section the turbo-generator rotor of siemens Germany design are assembled. This section assembles TG rotor of the following ratings: a). 500 MW hydrogen cooled rotors. b). 210/250 MW hydrogen cooled rotors. c). 80 to 135 MW air cooled rotor.

After the rotor shaft matching, the shaft is received in this section for further assembly work:- The following assembly is done here:- a). Field lead assly. b). Lying of winding. c). Retaning ring mounting. d). Fan blade assembly.

Then the rotor is sent for final machine, balancing & testing & despatch.This entire cycle taken around 4.5 months to complete. DETAILS OF ASSEMBLY WORK OF LSTG a). Field lead assembly . Science the siemens design rotor is brushless type, therefore adequate arrangement is made to provide leads for carrying the D.Csupply to the winding. The consist of the field lead core bar , current carrying bolts , field lead bar & connecting piece along with various insulation & wedge .b). Laying of winding siemens rotor are 2 pole, 3000 rpm synchronous m/c having D.C concentric winding. There 28 slots cut on 2/3 periphery which houses the winding bar. There are 9 turns per slot in 500 MW (F.L current 4040A d.c 340V).Due to non uniform distribution on the circumference, different moment of inertia is obtained in main axis of the rotor shaft, causing 2f oscillations. To reduce this vibration the deflection of pole axis & neutral axis is compensated by transverse slotting of poles. Solid poles are also provided with additional longitudinal slots to hold the copper bar of damper windings. The turns of coils are trapezoidal in shape & have two semicircular ducts for cooling (hydrogen at 3.5 bars). The conductor is made up of copper with silver content 0.1% for higher mechanical strength at higher temperature. The body insulation is made of glass fiber lamination having nomex filler .To prevent the windings from centrifugal force the winding is secured in slots by copper-silicon-nickel alloy wedges which also act as damper windings. The rotor overhang is braced from centrifugal forces by the means of retaning ring on each T- side & E-side. One end of the ring is heat shrunk (at 360 degree centigrade ) on the rotor body (interface value 4.0 mm) while the other end over hangs the winding contacting the shaft .Material of retaning ring is X8 Cr Mn N1818K alloy steel . c). After completion of winding & fitting of RR the rotor is sent to machine shop for machining of T grooves on compressor hub 515 nos. fan blade are arranged in 5 stages & arc fitted in these T grooves .

d). The rotor shaft is again sent to m/c shop for final machining before balancing.

L STG (Large Scale Turbo Gen.) R OTOR

W INDING A SSEMBLY:-

This section has facilities for rotor winding of LSTG for turbo generator. This is the second last section of bay – 1, which is used for high-speed approx. 3000 rpm rotor winding. The LSTG has two-dust proof stand into an A.C. glass block. Both the stands can bear the weight of rotor approximate 68 tons and having a length of 12 mt. Long the rotor is bring to here after there slotting and well grinded, finish .

The grinding (cutting of slots) of rotor (parallel slots) also done into the bay-1 thereafter it will be come here for winding.

Firstly the rotor will lying down on to the rotor stands into the A.C. cabinet. Then the winding procedure will do as describe:--

1. Before doing the winding each slots will be cleaned and dust free.

2. The insulating material known as text lire is put into the slot in each side.

3. Thereafter one another strip of thick glass textiles are used to avoid the unnecessary vibration of rotor to field winding (glass textiles ).

Fig-Conductor with insulation & passed for hydrogen

4. Now the rectangular hollow copper conductor. to be used for parallel sides

slots each slots have 7/9 copper bars (for 500 MW) concentric multiturn coils are allow based in the slots which are a multiple of four. The slots pitches are chosen to avoid undesirable harmonies in the field form

.5. After placing the copper bars into each slot there end connection will be

joint with the gas welding or magnates bronze or stalling is driven into the mouth of each slot for the purpose of keeping the winding in place. Ultimate there are two terminals will be remain open to give the field current into them to side of exciter.

6. An additional sets of winding with placed on to the poles known as damper surface of rectangular copper conductor.

7. The end connectors of the field winding must be rigidly supported by end bells because of the large centrifugal forces due to high speed of rotation the end bells are used made of non-magnetic austenitic steel (mn-18%, cr-3%,

c-0.5%) in order to reduce the leakage flux. The end bells are mechanically strong and have an ultimate strength of1150 MN/M2 Atypical end bell and Overhang arrangement.

8. After this the rotor will packed with polythene cover due to dust and not atmosphere.

The rectangular copper conductor are manufacture a in to block-4. The conductors are of special type. Each conductors have the ventilating ducts which is inclined cut of the middle portion due to proper H2 is passed into there.

After the proper winding a fan cooling arrangement is also done into this section. At the turbine side there are many small blades of generally made up chromium nickel-steel or chromium molybdenum steel is used. The blade are placed as that there are a small gap to every blade with a spacers of same metal. The LSTG section is devoted only 250-500 MW rotor winding only. This section is providing the winding for THRI & TARI type turbo gen. This section has four brazing M/s for brazed of end connections of winding. After the winding the technological requirement will be removed. Thereafter the rotor will send to the checking department to check the proper connection and avoid ness of short circuit into any portion. After passed this department the rotor will go out on to the over speed balancing tunnel for tested of proper balance and with stand to vibration & centrifugal forces.

Assist by: -- Senior technician Mr. R. S. Prem (LSTG Winding Section) LSTG STATOR WINDING :--

It has two dust free stands for stator winding of turbo generator and an installation for heating stator bars. This section is used for stator winding of capacity 250MW, 500 MW T.G. Are as follows:--

Weight of wound stator -- 278 MW tons Weight of wound rotor -- 62 T Length of stator body -- 8.83 ml Length of rotor shaft -- 12.1 Mt No. Of slots in stator -- 48 No. Of slots in rotor -- 28

The main components of 500 MW stator winding may be:--

1. Core2. Stator bars3. Support rings4. Header5. Bus bar

Except these component there are some additional auxiliary are required for testing and cooling purpose and these are:

6. Air system7. Gas system 8. Primary water system

The constructional details of these components are as:-- 1. CORES:--

The stator core is shown as under. These cores are of segmental laminations and compress to them as per the requirement.

The cores are mounted as that they will form the required no. of slots (48 slots for 500 MW) and 1 coil for 2 slots.

2. STATOR CORES:-- The stator core is built up segmental laminations of

type. The use of grain oriented steel laminations with direction of flux being along the grains in the armature core and perpendicular in teeth result in lower core loss but it is usual to use cold rolled non-oriented steel. The desired no. of core is placed into the vertical stands stator body with the technological arrangements. The stator body is a stand with the help of umbrella like vertical stands which under ground into this section of Bay-1 and having depth of 10 MT. Approximate.

The stator cores are laminated with impregnation (varnished) then pointed with on insulated point. Every core has air gap and no. of holes for cooling purpose after placing all the cores the stator body will form the slotted shape.

1. SUPPORT RINGS: - Support rings are used to support the stator cores. These are the vertical and oval shaped iron rings with epoxy glass insulated to each are placed into stator body. 2. HEADER: - header is the round shape hollow pipe. This positioned on the header of stator body. The header is the silver color pipe into which distilled water flow for cooling of stator winding. The pipe is of Teflon tube. The distilled water circulating through the stator with radial cooling arrangement

. Fig-Retaining ring3. BUSBARS:- The bus bar is the 3 phase output connection from the 3 winding of stator.

4. STATOR WINDING: -- The stator winding of T.G. is a double-layer winding of T.G. is a double-layer winding with the pitch of winding so adjusted as to reduce the 5th and 7th harmonies. A generator designed for high voltages no doubt require a high level of slots insulation but permits used of similar size of conductors. The conductors are used of copper these are hollow and solid of two types. The hollow conductors used to flow of water and coolant.

The advantages of lesser number of parallel ckts smaller positional forces blow conductor lesser conductor sub division and case in coil

formation and installation. The generation voltages used are 20-25 KV for 250-500 M/Cs.

The electro magnetic forces developed in turbo alternators under short circuit conditions are very high on account of large pole pitch and high armature mmf per pole. The problem of bracing the overhang to with stand electromagnetism forces. Hardwood blocks with glass fiber cord or type along with nonmagnetic metallic brackets are used for bracing the overhang.

COOLING ARRANGEMENT:-- The problem of cooling of turbo-alternators is one of the most complex problem in electrical engineering since being high speed M/Cs their dimensions is much smaller than of H.G. in fact the problems associated with cooling arise because T.G. are characterized by long core lengths and small diameters. According to various methods cooling the T.G. are classified.

a. THRI -T.G. Radial, indirect coolingb. TARI - T.G. Air Radial, indirect cooling.c. THW - T.G. Hydrogen water cooled.d. THDF – T.G. Hydrogen direct cooling.

The BAY-1 is specially designed to manufacture only THRI and TARI type T.G. therefore. I will describe only both type of cooling.

1. AIR COOLED TURBO GENERATOR :-- This type of cooling of T.G. by air used for small units. Therefore this method of cooling is applicable only for rating of 30MW-60MW generator. The various methods used for air cooling of T.G. are:-- a) One sided axial ventilation: M/Cs for power output up to 3MW permit. b) Two sided axial ventilation: M/Cs rating up to 12MW.

c) Multiple inlet system: this method is more applicable than above two because of long core lengths of T.G. Therefore multiple units supplied cooled air.

AIR COOLED GENERATORS UPTO 200 MW RANGE (TYPE: TARI)

SALIENT DESIGN FEATURES

Stator core and rotor winding direct air-cooled

Indirect cooling of stator winding Horizontally split casing design

of stator Vertically side mounted coolers

in a separate housing Micalastic bar type insulation

system Separately assembled stator core

and winding for reducing the manufacturing cycle

Brushless/static excitation system

TARI 108/41 GAS TURBINE GENERATOR FOR FARIDABAD

2 HYDROGEN COOLING AND HYDROGEN COOLED T.G. :--

When the problem of increasing generator rating was talked in became clear that the air-cooled M/C did not provide the necessary scope for progress. Not only in circulating the requisite quantity of air through the M/C but also because the high fan power required to circulate the air. Thus air circulating fan power required for this duty is high and on this score alone the air cooled generator can be ruled out when it becomes necessary to increase gen. Rating. Evidently to push-up gen ratings an alternative-cooling medium had to be found. That medium was hydrogen. Following are the advantage of utilizing H2. :-

a) Increased efficiency: This because the density of H2 is only 0.07 times the density of air and therefore the power required to circulate H2 should be about 1/14 of the air.

b) Increase in rating: H2 has a heat transfer coefficient 1.5 times on its thermal conductivity is 7 times that of air. Consequently when H2 is used as a

coolant, the heat is more rapidly taken up from the M/C parts and given out. Therefore heat generated is more effectively removed and the active materials can be loaded more than is possible with air-cooling.

c) Increase in Life: The life

of M/C is mainly the life of winding in insulation and air pockets in insulation can be sources of such high local temperature that there is always the risk of insulation breakdown and free, due thermal conductivity of H 2.

Fig—Hydrogen channel

d) Elimination of fire hazard: The outbreak of fire inside the M/c is impossible us H2 does not support burning. e) Smaller size of coolers: the size of coolers requires cooling the gas core smaller in size. When hydrogen is used as a coolant.

Fig—Rotor fan

3 DIRECT COOLING AND DIRECT COOLED T.G. :

The direct cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall. Machine cooled in this manner are also called “super charged inner cooled “or “conductor cooled “by various manufacture. In this method the

coolant is in indirect contact with conductor copper or is separated only by material having negligible thermal resistance. The direct cooled method has their own advantage. It is dear how the cooling progress does.Fig—Hydrogen cooler COOLANT USED FOR DIRECT COOLING:--

The coolants normally used are H2 water and oil.

HYDROGEN GENERATOR IRON & UNIT ASSEMBLY:

The unique combination of lead discharge and water conduct system at any hydroelectric site make the design of the turbine and generator custom built for each project.

Based on the unit rating and speed selected for the turbine. The generator is designed to suit the specific requirements of rational inertia over speed system requirements, special design technique have to be used taking into account the transport limitations too site.

This section of BAY-1 is mainly to assemble the various iron arrangements of Hydro generator. Since the hydro generator is having more poles than T.G. therefore its rotor diameter will also large. Hence there are many iron accessories are needed to assemble H.G. in this section the assembly of rotor and stator iron assembly will formed.

To cover the large area of rotor used the iron spider. This spider is a spider shape hollow iron body on to which the solid rotor wedge and rotor segment will wear then the we climbed the upper and lower guide bearing on both side of rotor. Thereafter welding will be done.

After completing the wedging the places will fit on the rotor body with proper insulation. Similarly the large dia of stator cover by iron pieces and jointed to than on the site due to their large shape and heavy weight.

HYDRO GENERATOR ROTOR WINDING SECTION:--

This selection is prescribed only for rotor winding and the PMG machines for H.G. site to develop the D.C. current through rectifier. So first we concentrate on H.G. rotor winding.

THE H.G. ROTOR BODY IS USED HERE:--

1. Machined with its shaft from a forcing 2. Built up from discs shrunk on a shaft.3. Fabricates from accost steel spider mounted on shaft and carrying laminar ring of segmental plates

The forged steel construction is used for high speed M/sc. The earliest construction. Particularly of relatively low outputs (below 40 MVA) consisted of a body shaft extension made as a single forging.

.

Another type of construction employs thick roller steel discs, 120-180 in length either struck on to shaft or slighted to each other and formed into a solid ring axial through bolts.

This construction is cheeps and is used for generator running at 60 rpm.

This cheapest form of rotor body construction is the punched segmental rim carried on a fabricated steel spider. The communication use 1.8 mm thick and are in the form of over lapping segments tightly bolted. The spider is therefore relived of all required to transmitorque to the rim. The advantages of a segmental rim are that it is copy to transport and assemble at site.

After choice of specific rotor frame; we mounted the poles on it. The poles are clamp or fixed etc. to rim in different ways. They can halt to the yoke either dovetail or the T-head type of construction is used for fixing the pole to the yoke. The cross sections of the poles may be rectangular or circular. The circular pole has the following advantages.

1) The length of means turn of the winding is smallest with circular pales.2) The whole of the winding surface is uniformly exposed etc. air and therefore

ventilation is better.3) The field coils with circular poles are circular in shape and therefore they

can’t the easily deformed by centrifugal forces.

ROTOR WINDING OR FIELD WINDING:--

In hydroelectric generators, the iso-called “strip on edge” winding is used for the field coils. The field coils are formed forma fiat copper trip wounded guises with interterm insulation on the machine-operated former. The coil may have a smooth surface or may have some of the turns made of a wider copper strap so that they perfect out sick and act as cooling fins. The cooling fins substantially increase the external bare copper area the rib lowering the temperature rise.

The coils are supported by v block in order to with stand centrifugal forces alternatively; a canted coil construction may be used. In this arrangement, the construction of turn is such that the necessity of support for the coils.

DAMPER WINDING:--

In order to dam pout the oscillations damper windings are used which are housed in the pole shoes. There damper winding consist of heavy copper coils, one in each slot or hale, riveted at the ends to common bars at each and so as to form short circuited grid or the rods may be brazed to copper and bars attached us the pole and plates. In most cases copper rods in the pole shoe as adequate without inter polar cage connection.

Within the damper rods are completely buried in iron. The inductance is reduced and the of damper winding current is improved.

Special attention must be paid to connecting bars lying in the inter polar region as this portion has no either support except the support of ends in the pole shoe.

PMG SECTION:--

The PMG (permanent magnet generator) is the special type of A.C. generator trough we can exciter the field of H.G. without any external source of power. The PMG is used for low power requirement of 210-250 MW H.G. sometimes it is known as pilot exciter. In PMG the permanent magnets mounted on the rotor shaft and a three phase winding on the stator. The P.M. of the pilot exciter produces the field current of the exciter. The exciter supplies the field current of the main machine. Thus the use of pilot exciter makes the excitation of the main generator completely independent of external supplies

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, CAM etc. are used.

Use of solid modeling, finite element modeling and further down stream applications for solution of design structure, heat transfer, electro-magnetic applications etc. for optimization.

The computer software is also used for thermal network solutions and ventilation system, which are vital parameters for large capacity machines.

CONSTRUCTION:--

The rotor of PMG is on the same shaft of H.G. but is it is covered with proper insulation by stamping of cores of permanent magnets. This is the solid formation like as squired cage rotor.

The stator design is very tedious and length process due to field winding. The stepwise construction details are as: -

1 Laying of power bars.a) First check the surface is dust free and no shade edges.b) Placed and plast as-co-lite piece within every slots.c) Now placed support ring.d) Glass textulite piece.e) Distance spacers to cover up the air gap an unnecessary distance.f) Glass bring and binding the position.g) Filling the space of plast semi conductor polish to reduce vibration.

2. Laying of upper bars:a) Spacer of 3 mm thick of glass textulite.b) Joint spacerc) Copper jointer for both head.d) Slot bearinge) Brazing with brazing M/s. The brazing alloy as in ,it consists of ban

Cu p5.f) Testing the braze surface with a subsonic detector M/c. which detect

the planning of surface.g) Placed the head insulator (male & female)h) Hardliner of Epoxy kilt to fill the air gap.i) Than bind the glass tape j) Finally coursed with PVC transparent cover (hex glass or glass

maiden. k) Stand for bus bar. As in fig. 29 and ceramic paper paper

Guidance by-- Mr. A.k.Shrivastava

OVER SPEED BALANCING TUNNEL:--

The dynamic balancing of turbo generator’s rotors is done on this installation. The T.G. rotor after winding is fitted between two head and then moving it to its rated speed. Then check with the help of CNC control display where the rotor is misbalance and how much quality. This procedure also detects the vibration of rotor under rated speed.

If any type of misbalancing bis measured here then marked it and charge it to the responsible section.

The OSBT is the largest tunnel for balancing of rotor of T.G. into allover BHEL.

EXPANDING POSSIBILITIES

BHEL undertakes complete turnkey operations – ranging from systems design through manufacture and coordinated supply of equipment to erection and commissioning. The post-commissioning services include optimal planning and supply of spares, maintenance, overhauling /revamping and up rating for optimisation of generator.

BHEL has the capabilities to undertake the manufacture of any type of hydro-generator specified by the customer.

The hydro-generators have been designed for:

Underground or surface stations Attended or unattended power

stations Additional synchronous

condenser mode of operation Reversible pump storage

operation Operation in seismic areas Optimum excitation system Parameters based on power

system studies

Special features like hot air bleeding for heating of power station from heat given out by generator etc.

B AY-2

T URBO- G ENERATORS A ND H EAVY MOTORS

The following are the main sections:--

(a) Machine section:-

This section is equipped with large size CNC & conventional M/C tools such as lathes, vertical boring, horizontal boring M/C ,rotor slot milling & radial drilling M/C for machining stator body , rotor shaft end shields & bearing etc.for turbo generator.

(b.) Iron assembly section:-

This section has facility for stator core assembly of T.G & heavy electrical motor. 1000T & 200 T umbrella type presses for pressing the cores & transformer for induction heating of armature cores of large size electric are available in this section. The facilities in this section also include one 250 KW induction brazing M/C for brazing of squirrel cage induction motor. For this purpose one 250 KW medium frequency induction brazing M/C is available.

IRON ASSEMBLY (LSTG) - Two numbers core pits with two numbers hydraulic pressing & heating arrangement for pressing the core are available in this section.

(c.) Stator winding:-

This section has 2 nos. of rotators along with one no. of winding platform for the winding for the assembly of the stator winding of T.G. The winding assembly is carried under dust free atmosphere. Assembly of stator winding of heavy motor & exciter is also carried out in this section in clean atmosphere.

(d.) Armature section:-

This section is equipped with installation like bandaging M/Cs, tensioning devices, magnetic putty application M/C & 45 KW MF brazing M/C for laying windings. In large size DC armature.Rotors/Armatres up to 16 Ton weight are balanced on the dynamic balancing M/C available in this section.

(e.) Armature/stator/impregnation section:-

It has impregnation & drying ovens for large DC armatures including vacuum pressure impregnation facilities for total impregnation of AC & DC motor.

(f.) General assembly section:- General assembly of large size AC & DC motors is carried in this section.

T.G. EXCITER IRON ASSEMBLY:-

This section has facilities for shame core assembly of turbo generator and heavy electrical motor including 1000 tones umbrella type press for pressing the cores and transformer of inductions heating of retaining rings and armature cores of large size electric motor. The umbrella type stands for core pressing is done here and into Bay-1 as describe first .The procedure involve into core assembly may be describe as:

i. Hold down the T.G. stator vertically with the help of umbrella type stands.

ii. Place the stator bars with all around the stator.iii. Now placed the lower supporting core.iv. Now placed the cores in such a manner that two core will overlap to

each other in ratio of ¾: ¼ with butt joint.v. This process known as bracing of cores. After bracing the cores that

we done the punching operation.vi. Therefore, all the cores will tightly fit in the same manner and finally

cover the last layer by upper supporting ring.

For ventilation of cores the core is formed as such that same air gap will be remain between them with a special silicon sheet bar and welded it by arcing M/c.

Similar produce will adopt for exciter iron assembly but in core of exciter we used the small brushing umbrella stand. This section is done the iron assembly of T.G. of 250 MW to 500 MW and the same exciter.

Information by: Mr. Ramla Khan Verma (Sr. Tech T.G. & Exciter

Assembly)

HEAVY MOTOR WINDING:

This section is dedicated to motor winding of A.C. stator of rating 3 MW to 10 MW. Stator winding is generally done as the following procedure:-

a) First of all placed the stamping, cores into stator body with proper impregnation of each cores.

b) Put down the glass insulation into each slots (Sam 8).c) Put the copper conductor into each slots with proper

insulation of glass tape on it.d) Distribute the RTD into each slot to detect the temperature

into running condition of motor.e) Now make connection for input supply for a MW M/s the

designing dimensions are as: Slots, 8 poles and 1 pole – 3 coilsf) Now brazing is done of all three phases by brazing machine

machine.g) The entire end we rubbed the magnate kilt (iron powder) to

increase the flux into motor.h) After doing the proper connections the machine will check

by means of short circuit of winding etc.

Information by: Mr. O.L.Verma

(Sen. Tech. Heavy motor winding section)

TURBO GENRETOR:-

This section has two fully A.C. &covered stand for the stator winding of turbo generator of 210 MW capacity. The winding done here is same as that of LSTG stator winding the stamped stator is laying here horizontally and then winding, should be done. The cooling the generator is water hence it is a THW T.G.

The difference make here with 500 MW T.G. is:-

a) The bars profile is different make than 500 MW T.G.

b) The thickness of the conductor bar for 210 MW T.G. is 28-29 mm.

c) Distilled water-cooling for bars.d) The winding type used there is single bar layer lap

winding.

Guidance by:Er. Y.K.Sharma

(T.G.Stator winding 210 MW)

HEAVY ROTOR ASSEMBLY SECTION:-

SQUIRREL CAGE MOTOR SLIP RING ROTOR

This section is provide the facility of assembled the rotor for A.C. This section has a250 ton horizontal press for pressing the rotor’s stamping

cores. The stamping is manufactured by Block-6. The cores are stamped together without and insulation and supported to the entire periphery by the iron bars of rectangular type. After the formation of solid rotor it will fitted

into the horizontal press machine and press a definite pressure after pressing check the outer surface of rotor that there is no any sharp edge of cores will

be remain out of the diameter. This section is assembled rotor of rating 3 MW-10MW. Assist by:-

Mr. B.R.C.Tyagi (Sen. Tech., Heavy rotor iron

assy.)

BRUSHLESS EXCITERS:--

--: MERITS :--

Eliminates sliprings, brushgear, field breaker and excitation bus/cables

Eliminates all the problems associated with transfer of current via sliding contacts

Simple, reliable and ideally suited for large sets

Minimum operation and maintenance costs

Self generating excitation unaffected by system faults or disturbances of shaft mounted pilot exciter

Increasingly popular system the world over

500 MW BRUSHLESS EXCITER

*(BAY-3)M EDIUM S IZE M OTOR:--

Facilities available in the various sections are as follows:

(a.) Machine section – This section is equipped with medium size tools for machining components for medium size AC & DC machines & smaller components of turbo generator & hydro generators.

(b.) Iron assembly section – Umbrella type double column & four column presses are available in this section for assembly & pressing of cores of medium size electrical motors.

(c.) Commutator section – Commutators for DC M/Cs are manufacture in a dust free enclosure in this section, having ovens for static & dynamic forming, installation for brazing of risers & hydraulic presses for pressing commutators.

(d.) Hydro generator pole core section – This section is equipped with core building installation, horizontal press & special straightening plate for the assembly of hydro generator pole cores.

(e.)Rotor assembly section – This section is equipped with static & dynamic balancing installation bearing assembly installation & rotor assembly facilities for the medium size M/Cs .

(f.) Winding section – This section is equipped with bandaging M/Cs,

brazing installation, rotators for rotors & stators for winding/stators armatures /slip-ring rotors.

(g.) General assembly section – Final assembly of medium size of motors is carried out in this section. Final assembly of medium size motors is carried out in this section. Panting booth is available in this section for final panting of motors.

H-MODULE HIGH VOLTAGE AC MOTORS:--

H-module is a modular family of motors that can be flexibly adapted:

For degrees of protection and cooling arrangements For various types of construction For noise control requirements For every application

Constructional Features

The motors are provided with rolling contact/sleeve bearings depending upon the load and operating conditions. Rolling contact bearings are sealed by means of a V-section axial shaft-sealing ring that rotates with the shaft. Sleeve bearings are used when the limit for rolling contact bearings are exceeded or when specified by the customer. The terminal boxes are made short circuit proof by the cast-resin bushings and strong bolts to enable them to withstand short circuit current of 110 kA for 0.2 seconds. A pressure-relief flap provides the short circuit safety for the terminal boxes. Slipring motors are additionally provided with a rotor terminal box permitting the connection of starting resistors.

Field proven MICALASTIC insulation provides high interturn dielectric strength. The rigid end turns provide high switching withstand capability and reversal withstand strength.

Synchronous motor

The motors are suitable for open circuit cooling air/water cooling air/air cooling with separately driven fan Air/air cooling with shaft mounted fan

MOTOR IRON ASSEMBLY:--

In this section we give the unwound shape of A.C. rotor. The section has umbrella type double and four column presses are installed for assembly and pressing the iron cores of medium size electrical motors. The unwound rotor is formed with the help of silicon steel core are stamped with each other by the help of an iron cage.

The procedure iron assemblies of medium size motors may be write as:-i. Prepare the fabricated rotor, which is brought from block – 5.

ii. Now, fit it on to umbrella type stand and fitted the winding holder one upper and down head.

iii. Now stamped the cores vertical in or horizontally and pressed them tightly.

iv. Now checked the outer surface of the unwound rotor that no sharp edge is remaining of cores.

Now squirrel cage rotor will ready doing winding on it.The squirrel cage further may be of two types as per the requirement and it is.

i) Single cage rotor ii) Double cage rotor

The single cage rotor has single brucing of copper instead of it double cage rotor has double brucing. The double cage is inner cage and single cage is outer cage. The double cage rotor use to getting the high starting torque. The melting coin of the external cage is high than inner cage (cu). After select the appropriate rotor will be used as slip ring and simple motor by exerted internal resistance.

Information by:Mr.Bhupendra Singh

(Sn.Tech.Medium motor Iron Assy.)

MEDIUM MOTOR WINDING:--

This section is designed to do the wound shape of medium size motor about ratings 66 KV and 800A from the previous section. To do the wound shape of rotor first of all selects the required size of the copper conductor. The conductor is hard copper bar; this bar is plane at one side and round the other side which is

placed in to the stamping slots. After going the proper winding check the short circuit of windings.L-SERIES HIGH VOLTAGE AC MOTORS:--

These motors are medium size motors .The motors can be designed to specific customer's requirements. The motors are suitable for indoor and outdoor applications, in strongly contaminated, damp surroundings and corrosive atmosphere. The salient features of these machines are

Robust construction and non vibrating frames. Shaft heights and mounting feet as per IEC and Indian standards. Dust protected long life bearings. Degree of protection IP54 and IP55. Large size, phase segregated terminal boxes. Rotors dynamically balanced at rated speed. Non vibrating bars and inductively brazed S.C. rings to withstand heavy

stress during starting. Uniform cooling inside the motor to avoid hot spots. Low noise levels. Magnetic slot seals for high efficiency, high power factor & low noise. Highly reliable class-F insulation system.

Constructional features

The machines have closed circuit cooling with a concentric tube nest cooler, which is integral with the frame and with shaft-mounted external and external fan. The external fan is located in the fan casing on the non drive-end and forces the atmospheric air through the cooling tubes of stator frame.The two internal fans in the main compartment cause primary air to circulate in two symmetrical sub-circuits. Circulation is intensified by the radial ducts in the laminated rotor-core. The primary air circulates through the end windings and the ducts in the core packs and carries the heat to the cooling tubes.

The stator winding of HV machines is double layer lap windings and is provided with MICALASTIC® VPI insulation complying with class-F insulation requirements. The insulation system is based on integrated mica employing a special synthetic resin impregnation process. The insulation possesses high di-electric strength, high resistance to moisture, aggressive gases & vapours, excellent mechanical stability and long life.

The shafts have two bearings ( drive-end and non drive-end ) and a cylindrical shaft extension at the drive-end. The bearings are either grease lubricated rolling contact bearings or journal bearings with or without forced oil lubrication. Solid

shafts are used in 2-pole machines and ribbed shafts in machines having 4 or more poles. The laminated rotor core is pressed on to the shaft, clamped and secured against axial displacement, and carries the squirrel cage winding.

The winding bars are firmly seated in the slot of the rotor core and are connected to the cage rings by induction brazing. The rotor is dynamically balanced with a half parallel key inserted in the key way of the shaft extension.

COMMUTATOR SECTION:--

As the name refer commutator section is provide commutator for D.C. machine. This section is manufactured the commutator for motor of rating up to few hundred volt. The procedure of production of commutator is as follows:-

a) First of all, we will take a copper profile which ordered from Block-4.The copper profile is special type of copper segment which has a tunnel and one its end and smooth on other end. b) The tunnel or slitting is formed by slitting machine on the flat copper bar. The slitting is done, 50, to fix the riser on one head of bars. The riser holds the winding connection this process of placing rising is known as brooding or rising. c) After this tinning is done, to fix perfectly the riser on to segment. d.) Now the grinding is done to remove the zigzag surface of riser. e) Now Baking is done on to 150-1600C Temp. For 8 hrs. To remove the moisture. f) Now doing the cold pressing. g) Now formed and duck till joint by the M/c on to the solid round frame of iron the riser sides on top. h) Now clinning by brushes or air pressure. i) Now checking the segment by high voltage test. j) Now placed the circular segment in to bush type fixture and put the fixture into oven of 160-1500C than cold pressing k) Now confirm the H.V. test segment to segment. l) Now being the mutual fitting. m) After this we will doing credit turning by lathe machine. n) Now cleaning and heating at 1800C. o) After cold pressing we are doing the dimming and forming for smoothing the quarter surface of commutater body, then cold pressing. p) Now coining into bush. q) Ultimately we will do the tapping of bottom side.

*(BAY-4)

S MALL A ND M ISCELLANEOUS C OMPONENTS :-

Facilities available in the various sections are as follows: -

(a.) Machine section – The M/Cs section of bay-4 is equipped with small & medium size CNC & conventional tools like center lathes, milling, radial drilling cylindrical grinding, slotting, and copy.

(b.) Maching of main components is carried out in bay-2 & 3 while small components are machined in Bay-4.

(c.)Iron assembly of AC motors stator & rotor is carried out manually & pressing is done on hydraulic presses in Bay-2 & 3.

(d.) Winding of stator is done on rollers support. The phase connections are made by resistance brazing M/C & the stator is tested for phase resistance & high voltage. Wound stators are totally impregnated under vacuum & pressure.

(e.) Rotor assembly – After assembly of rotor core the rotors bar are driven & short ckt rings are mounted & brazed by induction heating. Then static & dynamic balancing of rotor is done on balancing installation.

(f.) General assembly - The coolers, headers, end shields, terminal boxes etc. are assembled manually to complete the assembly of motors.

.

TURBO GENERATOR ROTOR COIL (T.R.C.) (210MW) SECTION:-

It is mainly designed to manufacturing the T.G. rotor coils of 210 MW rating. It has block type hydraulic press installed for forming and drilling halt coils, installed for soldering and installed for straightening and cutting conductors for turbo coils.The rotor coils formation procedure is as follow: -

(a) First of all we are taking the copper then we do opt blanking & straightening.

(b) Now making(c) Now form the excel channel milling and removing the extra bars.(d) Now its hard board array (0.5 mm both side) as in Sam (12)(e) Now doing the angular array and then final milling.(f) Now handing to form the coil shop on bounding machine (fig. 44)(g) Radial drilling by radial drilling machine.(h) Former drilling(i) Now we are doing the over hand debarring (as in fig 4.5)(j) Now doing the strip polishing 3,9,11 by wire brush.(k) Now insulate bottom (varnish-VLY556) 13 layers and a proxy impregnated

glass tube bar (1x28.5,13 layers 1mm)(l) Rapping of all the copper bars by making a seat of strips for 31/4 hrs.

Technical response:Mr. Aggrawal

(Sen. Tech. T.R.C.)

MANUFACTURING PROCESS:--

Stator Bar Winding Section - In this section following process is carried out:

-- Stator Winding Bar of TG With Resin Rich - Thermo-reactive Insulation System- The self insulated hollow and solid conductors are straightened, cut to size and skinned at the ends on special machine. After manual transposition the slot portion is stack consolidation in Electrically heated hydraulic press and then tested for inter strand short circuit. The bars are shaped on formers, coil lugs are brazed by resistance brazing & bars are tested hydraulically. Bars are insulated with resin rich tape, baked, pressed in the moulds as per the regimes and finally subjected to electrical test.

-- Stator Winding Bar of TG With Resin Poor thermo-reactive Insulation System - Same process is used as for Resin Rich system up to the forming stage. After which the bars are insulated with resin poor tape, impregnated under vacuum & pressure & subsequently cured in oven followed by Electrical Testing. -- Hydro generator bars - Stator winding bars of HG with Resin Rich Thermo-reactive Insulation System: Same process is followed as in case of TG. -- Stator Winding Bars of HG with Respire System: The process followed is similar to that of TG bars expect that in case of Resiflux insulated bare, the slot portion is taped with resin rich tape & over-hang with flexible tape.

Armature winding & Stator coil section - In this section following processes are followed:

-- Pole coils - The coils are wound on wooden or steel formers on semi-automatic insulation & winding m/c. After inter turn testing the body insulation, coils are impregnated & backed as per the technological regimes & subjected to Electrical Tests. Coils are also encapsulated on pole cores epoxy resin.

-- AC Stator Coil - Conductors are wound & turn insulated on semi- automatic insulation & winding machines. These are pulled to boat shapes, diamond shapes, formed in wooden formers or on semi-automatic pulling & forming machining. The straight portion is pressed on electrically heated presses. The coils are body insulated. For epoxy coils with Resin rich system, straight portion is consolidation on electrically heated presses & after cleaning the ends the coils are subjected to electrical testing.

TRAINING & DEVELOPMENT:--

35 number employees exposed to 141 courses in HRDC during the year.

R EFERENCES

FOR GREAT THANKS—

Shri S. P. GUPTA

Shri D. N. LAL

Shri A. K. VISHWAKARMA

Shri HUSSIEN

Shri R. K. DHIMAN