Turbo Generator [PDF]

Citation preview

Design & Constructional Features of Turbogenerators KAPIL NARULA Sr. Engr./EME HEEP, BHEL Hardwar



BHEL Hardwar



Index 1. History of Development 2. Power Output of Generator 3. Generator Modules & Types 4. Important Parameters of Generator Modules 5. Design Features 6. Main parts of TG/ Constructional features 7. Excitation System 8. Auxiliary Systems 9. Generator Testing 10. New Developments - Total Imp. of Stator Winding



BHEL Hardwar



History of Development - Globally • First single phase generator of 75 KW



1888



• First 3 phase generator, salient pole



1900



• First turbo type 3 phase 25 MW generator



1912



• UK made 50 Hz as standard frequency for Europe



1925



• First Hydrogen cooled 3 phase 30 MW generator



1937



• First Hydrogen cooled TG with direct cooling of rotor



1949



• First generator with water cooled stator winding



1956



• First generator with water cooling for stator and rotor wdg1959 BHEL Hardwar



History of Development in BHEL THREE PLANTS SET UP: IN 1950s: At Bhopal with British collaboration 30 MW & 120 MW Hydrogen Cooled IN 1960s: At Hardwar with Russian Collaboration 100 MW Hydrogen Cooled & 200 MW Hydrogen Cooled IN 1960s: At Hyderabad with CZECH Collaboration 60 MW Air Cooled & 110 MW Hydrogen Cooled



BHEL Hardwar



Power Output of Turbogenerator P ∝ D2 . L . B . A . n P D L B A n



BHEL Hardwar



Power in MVA Bore Diameter of Core in meters Length of Active Rotor Body in meters Air Gap Flux Density in Tesla Stator Ampere-Turn Loading in Amp./meter Speed in rpm



Power Output of Turbogenerator



No increase of utilization Same or higher mfg. Costs



BHEL Hardwar



Increased utilization Lower mfg. costs possible



Generator Modules



Air Cooled Turbogenerator - TARI Hydrogen Cooled Turbogenerator - THRI Hydrogen/Water Cooled TG - THDF



Module Nomenclature THRI 108/44 THDF 115/59



BHEL Hardwar



Module Nomenclature T H R I 108/44



Stator winding 4350 mm(≈ 44 dm) Core length 1075 mm(≈ 108 cm) Rotor dia.



Indirect Hydrogen Cooled



Stator Cooling - Indirect Rotor Cooling- Radial Cooling Gas in the Casing



H = Hydrogen Product



Turbogenerator BHEL Hardwar



Rotor winding



Radial Hydrogen Cooled



Generator cooling System



BHEL Hardwar



Stator Slot - TARI / THRI



BHEL Hardwar



Stator Slot - THDF 500 MW



BHEL Hardwar



210/235 MW THW Generator



BHEL Hardwar



Library of Designs TYPES OF GENERATORS SUPPLIED BY BHEL: # AIR COOLED # HYDROGEN COOLED # HYDROGEN/WATER COOLED



FOR APPLICATIONS:



# THERMAL # NUCLEAR # GAS BASED BHEL Hardwar



Library of Designs 1000 MW WATER COOLED STATOR



350 MW HYDROGEN COOLED



660 MW



170 MW AIR COOLED DESIRED MW CAPACITIES



80 MW



BHEL Hardwar



1000 MW



Capability of Generator Modules DESIGN VARIANT GENERATOR MODULE ORDERS/MFD./COMMD. TARI 93/38 AIR COOLED TARI 108/36 15/11/7 TARI 108/41 TARI 108/46



HYDROGEN COOLED 25/22/17



HYDROGEN/WATER COOLED 149/142/137 BHEL Hardwar



THRI 93/38 THRI 108/39 THRI 108/44 THRI 108/44 B THRI 108/55 THW-200-2 THW-210-2 THW-235-2 THDF 115/59 THDF 115/55



OUTPUT RANGE 75-92 MW 100-120 MW 120-140 MW 140-170 MW 120-150 MW 170-220 MW 200-260 MW 260-275 MW 350 MW UPTO 200 MW 200-219 MW 220-237 MW 500-585 MW 500 MW(new)



Improtant Parameters of Generator Modules SL. NO.



1. 2. 3. 4. 5. 6. 7. 8. 9. 10.



11. 12.



13. 14.



TECHNICAL PARAMETE R GENERATO R TYPE RATED MVA RATED MW RATED VOLT. KV POWER FACTOR STATOR CURRENT SPEED RPM FREQ. HZ HYDROGEN PRESSURE Kg/Cm2(g) S.C.R EXCITATIO N VOLTS AMPS NEG. SEQ. CAP. I2,% I2sq.xt WEIGHTS, T STATOR HEAV. LIFT ROTOR BRG. - BRG. DIST. IN MM TYPE OF EXCITATIO N



BHEL Hardwar



130 MW



200 MW



210 MW



235 MW



210 MW



250 MW



500 MW



560 MW



THRI 93/38 162.5 130.0



THW200-2 235.3 200.0



THW210-2 247.1 210.0



THW235-2 264.1 237.7



THRI 108/44 247.1 210.0



THRI 108/44 294.1 250.0



THDF 115/59 588.2 500.0



THDF 115/59 659.0 560.0



10.5



15.75



15.75



16.5



15.75



16.5



21.0



21.0



0.80



0.85



0.85



0.90



0.85



0.85



0.85



0.85



8935



8625



9054



9240



9054



10291



16166



18118



3000



3000



3000



3000



3000



3000



3000



3000



50



50



50



50



50



50



50



50



3.0



3.0



3.5



3.5



2.0



3.0



3.5



4.0



0.57



0.50



0.49



0.58



0.55



0.52



0.48



0.46



240 2039



300 2515



310 2600



326 2755



265 2080



319 2386



340 4040



410 4463



8 10



7 8



7 8



7 8



8 10



8 10



8 10



8 10



132 28



175 42.2



175 42.2



175 42.5



182 43.3



182 43.3



255 68



255 68



6700 STATIC



7700 STATIC / HFG



7700 STATIC / HFG



7882 STATIC / HFG



7870 B’LESS/ STATIC



7870 B’LESS



10410 B’LESS



10410 B’LESS



Improtant Parameters of Generator Modules SL. NO.



1. 2. 3. 4. 5. 6. 7. 8. 9. 10.



11. 12.



13. 14.



TECHNICAL PARAMETE R GENERATO R TYPE RATED MVA RATED MW RATED VOLT. KV POWER FACTOR STATOR CURRENT SPEED RPM FREQ. HZ HYDROGEN PRESSURE Kg/Cm2(g) S.C.R EXCITATIO N VOLTS AMPS NEG. SEQ. CAP. I2,% I2sq.xt WEIGHTS, T STATOR HEAV. LIFT ROTOR BRG. - BRG. DIST. IN MM TYPE OF EXCITATIO N



BHEL Hardwar



210 MW



250 MW



THRI 108/39 247 210



THRI 108/44(FI) 294.1 250.0



15.75



16.5



0.85



0.85



9056



10291



3000



3000



50



50



3.0



4.0



0.57



0.63



251 2260



308 2497



8 10



8 10



215.3 192 39



232 212 43



7420 B’LESS/ STATIC



7870 B’LESS/S TATIC



Improtant Parameters of Generator Modules SL. NO.



1. 2. 3. 4. 5. 6. 7. 8. 9.



10. 11.



12. 13.



TECHNICAL PARAMETE R GENERATO R TYPE BASE LOAD MVA MW RATED VOLT. KV POWER FACTOR STATOR CURRENT SPEED RPM FREQ. HZ S.C.R EXCITATIO N VOLTS AMPS NEG. SEQ. CAP. I2,% I2sq.xt WEIGHTS, T STATOR HEAV. LIFT ROTOR BRG. – BRG. DIST. IN MM TYPE OF EXCITATIO N



BHEL Hardwar



TROMBA Y STG



K’KULA M GTG



K’KULA M STG



FARIDAB AD GTG



FARIDAB AD STG



LIBYA GTG



TARI 93/38



TARI 108/36



TARI 108/36



TARI 108/41



TARI 108/46



TARI 108/46



100 80



137.5 116.8



154.3 131.1



170.1 144.6



188.2 160.0



18O.4 153.3



10.5



10.5



10.5



10.5



15.75



15.75



0.80



0.85



0.85



0.85



0.85



0.85



5499 3000



7561 3000



8484 3000



9354 3000



6900 3000



6612 3000



50 0.56



50 0.55



50 0.50



50 0.50



50 0.52



50 0.54



274 719



339 777



381 851



410 833



432 797



388 770



10 20



10 20



10 20



10 20



10 20



10 20



128 28



170 37



170 37



181 40.1



200 44



200 44



7050 B’LESS



7250 B’LESS



7250 B’LESS



7800 STATIC



7900 B’LESS



7900 STATIC



TARI Generators - Design features # DIRECT COOLING OF STATOR CORE AND ROTOR WINDING # INDIRECT COOLING OF STATOR WINDING # HORIZONTALLY SPLIT CASING DESIGN FOR STATOR # VERTICALLY SIDE MOUNTED COOLERS IN A SEPARATE HOUSING # VPI INSULATION SYSTEM # TOP RIPPLE SPRINGS IN STATOR SLOTS TO CONTAIN BAR BOUNCING FORCES # SEPARATELY ASSEMBLED STATOR CORE AND WINDING FOR REDUCING THE MANUFACTURING CYCLE # STATIC/BRUSHLESS EXCITATION SYSTEM BHEL Hardwar



THRI Generators - Design features • DIRECT HYDROGEN COOLING OF STATOR CORE AND ROTOR WINDING • INDIRECT COOLING OF STATOR WINDING • EXPLOSION PROOF SINGLE PIECE STATOR FRAME • END SHIELD MOUNTED BEARINGS • VPI INSULATION SYSTEM • TOP RIPPLE SPRINGS IN STATOR SLOTS TO CONTAIN BAR BOUNCING FORCES • COLD GAS TEMPERATURE CONTROL VALVE TO MAINTAIN COLD GAS TEMPERATURE CONSTANT • SINGLE FLOW RING TYPE SHAFT SEALS • STATIC/BRUSHLESS EXCITATION SYSTEM



BHEL Hardwar



THDF Generators - Design features • DIRECT WATER COOLING OF STATOR WINDING • DIRECT AXIAL HYDROGEN COOLING OF ROTOR WINDING • OPTIMALLY DESIGNED LEAF SPRING SUPPORT FOR CORE • END SHIELD MOUNTED BEARINGS • VPI INSULATION SYSTEM • MASSIVE SUPPORT RING FOR STATOR WINDING OVERHANG TO ABSORB SHORT CIRCUIT FORCES • SIDE AND TOP RIPPLE SPRINGS IN STATOR SLOTS TO CONTAIN BAR BOUNCING FORCES • 5 STAGE AXIAL COMPRESSOR AND VERTICAL HYDROGEN COOLERS ON TURBINE END • COLD GAS AND PRIMARY WATER TEMPERATURE CONTROL VALVES TO MAINTAIN AVERAGE INLET COOLING MEDIUM TEMPERATURES CONSTANT • DOUBLE FLOW RING TYPE SHAFT SEALS • BRUSHLESS EXCITATION SYSTEM BHEL Hardwar



Gas Turbine Generators - Design features • TERMINAL BUSHINGS ON TOP • STATIC EXCITATION SYSTEM • SFC (SYNCHRONOUS FREQUENCY CONVERTOR) STARTING SYSTEM • FORCED COOLING WATER SYSTEM (MPR SYSTEM)



BHEL Hardwar



Gas Turbine Generators - Design features TARI Generator Outline



BHEL Hardwar



Gas Turbine Generators - Design features TARI Generator Cross section



BHEL Hardwar



Gas Turbine Generators - Design features TARI Generator End View



BHEL Hardwar



Forced Cooling Water System (MPR System) A SYSTEM TO TAKE CARE OF DM COOLING WATER REQUIREMENT OF GAS TURBINE GENERATORS



1. TO DELIVER DM COOLING WATER TO GENERATOR AIR COOLERS 2. TO ENSURE HEAT TRANSFER FROM GENERATOR AIR COOLERS TO THE FIN-FAN COOLERS. 3. TO MAINTAIN COOLING WATER TEMPERATURE AND PRESSURE AT ALLOWABLE VALUES.



BHEL Hardwar



Forced Cooling Water System (MPR System)



BHEL Hardwar



Gas Turbine Generators - Experience List GENERATOR MODULE TARI 108/46 SUPPLIED / UNDER SUPPLY : BAIJI GPP, IRAQ



4 SETS



W. MOUNTAIN, LIBYA



4 SETS



GENERATOR MODULE TARI 108/41 (SUPPLIED) FARIDABAD CCPP, INDIA



1 SET



GENERATOR MODULE TARI 108/36 SUPPLIED / UNDER SUPPLY: KAYAMKULAM, INDIA



BHEL Hardwar



2 SETS - GE Turbines



Main Parts of TG / Constructional features 1. Stator - Stator Frame (Fabrication & Machining) 2. Core Assembly - Stator Core, Core Suspension Arrangement 3. End Shield 4. Stator Winding Assembly - Stator Winding , Winding Assembly, Connecting Bus bar 5. Rotor - Rotor Shaft, Rotor Wedges, Rotor Coils, Wound Rotor, Rotor Assembly 6. Completing Assembly - Bearing Assembly, Shaft Seal Assembly, Oil Catchers, Insert Cover etc 7. Exciter 8. Auxiliary System BHEL Hardwar



Main Parts of Turbogenerator Stator Core



Cooler Insert Cover



End Shield Wdg Overhang



Rotor fan



Oil Catcher Rotor



Bearing Shaft Seal



Stator



BHEL Hardwar



Terminal Bushing



Main Parts of Turbogenerator Coolers



Foundation



Terminal bushing



BHEL Hardwar



Ventilation Circuit in THRI TG



BHEL Hardwar



Ventilation Circuit in THRI TG



BHEL Hardwar



Stator Frame • Rigid fabricated cylindrical frame • Withstands weight of core & wdg, forces & torques during operation • Natural frequency away from exciting frequencies •Provision for H2/CO2 filling • Provision for temp measurements • Foot plates for supporting on foundation • provision for H2 coolers



BHEL Hardwar



Stator Frame (Fabrication & Machining)



BHEL Hardwar



Hydraulic/Pneumatic testing of Stator TURBINE SIDE END SHIELD



BHEL Hardwar



STATOR



                       



EXCITER SIDE END SHIELD



Stator Frame TARI 108/46



BHEL Hardwar



Stator Core • Made up of punched segments of thin sheets of ETS • Punchings coated by insulating varnish • Vent segments at designed intervals for flow of cooling gas • Compressed with tension bolts, pressure plate and clamping fingers • Stepped arrangement at the end for reduction in eddy current losses



BHEL Hardwar



Core Suspension - TARI/THRI TG



BHEL Hardwar



Core Suspension - Air Cooled TG Location for Spring Core Housing



Core End Plate



Core



BHEL Hardwar



Core Suspension - 500 MW



BHEL Hardwar



End Shield • Closes both ends of Stator Frame •Fabricated rigid box type structure in two parts • Supports and houses bearings • Provision for mounting Shaft seal body, Oil catchers, etc • Provision for supply of Bearing Oil, Seal oil, Thrust oil and its drain



BHEL Hardwar



End Shield (Exciter side 500 MW)



BHEL Hardwar



End Shield (Turbine side 500 MW)



BHEL Hardwar



Stator Winding • Three phase windings in two layers of individual bars • Top and bottom bar displaced by one winding pitch and connected to coil groups • Coil groups connected to Connecting Bus bar and finally to Term Bushing • Involute shape at the end of bar helps withstands various forces • Micalastic Insulation System (VPI process) - Micalastic good conductor of heat - Low flamability - High resistance to moisture and chemical action - Accommodates thermo-mechanical stresses - Retains properties even after years of operation VPI- Vacuum Pressure Impregnation



BHEL Hardwar



Stator Winding Assembly



1. 2. 3. 4. 5. 6. 7. 8. 9.



CO RE CLAM PIN G FIN GE R PRE S S URE PLAT E T OP BAR BO T T OM BAR PHASE CONN E CT OR GAS O UT LE T GAS INLE T T E RM INAL BUS H IN G



BHEL Hardwar



Stator END Winding Support



BHEL Hardwar



Stator End Winding Assembly



BHEL Hardwar



Stator End Winding 500 MW



BHEL Hardwar



Stator End Winding 500 MW



BHEL Hardwar



Rotor 1. A high strength alloy steel single forging prepared by vacuum cast steel 2. Slots for housing field windings 3. Strong coupling for withstanding short circuit forces 4. Bending critical speed away ±5% of operating speed 5. Supported on two journal Bearings 6. Provision of axial fan/compressor for forced ventilation 7. Provision of damper wedges for increasing negative sequence capability of rotor



BHEL Hardwar



Rotor Body



BHEL Hardwar



Rotor Body with cross Pole Slot Rotor Wedge



Cross Pole Slot



BHEL Hardwar



Rotor Slot Rotor Wedge Top Slot Liner Conductor



Inter turn Insulation Slot Liner



Sub Slot



BHEL Hardwar



Arrangement of Damper Wedges



1. ROTOR BODY 2. DAMPER BAR 3. SILVER PLATED ROTOR END WEDGE 4. ROTOR WINDING



BHEL Hardwar



5. RETAINING RING 6. SILVER PLATED SHRINK SEAT 7. TRANSVERSE SLOTS 8. ROTOR WEDGE



Rotor End Winding 1



2



1. ROTOR BODY 2. SNAP RING 3. TERMINAL LUG 4. ROTOR WINDING 5. FILLER



BHEL Hardwar



3



6. GAS BAFFLE 7. RETAINING RING 8. END RING 9. BALANCING BORE



4



5



6



7



8



9



Rotor End Winding



BHEL Hardwar



Rotor Fan Blades



BHEL Hardwar



Rotor Slip Ring



BHEL Hardwar



Bearing Assembly • It is sleeve Bearing • Supports Rotor weight • Reduces shaft vibrations • Minimises frictional losses • Located in End Shields or outside stator depending upon type of machine • Self aligning outer part • Insulated from Stator or End Shield to prevent flow of shaft current • Inner surface is made of babbit material (Tin alloy)



BHEL Hardwar



Bearing Assembly



BHEL Hardwar



Bearing Assembly



BHEL Hardwar



Bearing Assembly



BHEL Hardwar



Shaft Seal Assembly • Prevents escape of H2 through junction of rotor and stationary part • Maintains continuous oil film between Seal Ring and rotor journal • Clearance should be sufficient to maintain oil film without unnecessary large oil flow and with minimum frictional losses • Ring relief oil for balancing the gas pressure on seal ring • Inner surface of Babbit material



BHEL Hardwar



Shaft Seal Assembly Hydrogen Side



1. 2. 3. 4. 5. 6.



Air Side



OIL WIPE R RIN G AIR S IDE S E AL RING CHAM BE R PRE S S U RE OIL G RO OVE BABBIT S E AL OIL IN LE T BO RE S E AL OIL GROO VE



BHEL Hardwar



7. S E AL RING 8 . S E AL RIN G CARRIE R 9 . OIL W IPE R RIN G H2 S IDE 10. S E AL S T RIP 11. ROT O R S HAFT 12. IN NE R LABY RINT H RING



13. IN S UL AT ION 14. PACKIN G 15. S E AL OIL G RO OVE 16. E N D S HIE LD



Terminal Bushing • Tubular construction for gas / water cooling • High conductivity copper for taking out electrical power • Connection flanges are silver plated to minimise contact resistances • Insulated with a epoxy resin cylinder or porcelain cylinder • Differential pressure of gases or forced water for cooling • Bolted on to stator bottom/top directly or housed in a box type construction which is bolted to stator bottom



BHEL Hardwar



Terminal Bushing



BHEL Hardwar



Cooling of Terminal Bushing



1. HYDROGEN SIDE FLANGE 2. TUBULAR COPPER COND. 3. INSULATING CYLINDER 4. MOUNTING FLANGE 5. RUBBER GASKET 6. AIR SIDE TERMINAL BOLT



BHEL Hardwar



Terminal Bushings Arrangement TARI



BHEL Hardwar



Terminal Bushings Arrangement THRI



1. 2. 3. 4. 5. 6. 7. 8. 9.



CO RE CLAM PIN G FIN GE R PRE S S URE PLAT E T OP BAR BO T T OM BAR PHASE CONN E CT OR GAS O UT LE T GAS INLE T T E RM INAL BUS H IN G



BHEL Hardwar



Terminal Bushing Box 500 MW



BHEL Hardwar



Excitation System 1. Static Excitation • Rotor Field Winding is connected to Slipring mounted on rotor • Excitation is provided by current transfer by contact through Carbon Brushes, Slipring and field lead Brush Gear



BHEL Hardwar



Static Excitation System



Brush Gear Assly BHEL Hardwar



Brush Holder



Brushless Excitation System 2. Brushless Exciter •Eliminates Slip Rings, Brushgear and Field Breaker •Eliminates all problems associated with transfer of current via sliding contacts •Simple, Reliable and ideally suited for large sets •Minimum operating and maintenance cost •Self generating excitation unaffected by system fault/disturbances because of shaft mounted pilot exciter •Increasingly popular system the world over



BHEL Hardwar



Brushless Exciter •High response excitation with fast acting AVR •Multi contact electrical connections between exciter and generator field •Stroboscope for fuse failure detection •Rotor Earth fault monitoring system •RC circuit to avoid over voltages •Dehumidifier for use during shut down



BHEL Hardwar



Brushless Exciter



BHEL Hardwar



Rectifier Wheel



BHEL Hardwar



PMG Rotor & Fan



BHEL Hardwar



Auxiliary System



1. Primary Water System 2. Seal Oil System 3. Gas Flow System



BHEL Hardwar



Primary Water System Losses in wdg, bushings, bus bar are dissipated 1. PRIMARY WATER TANK 2. PRESSURE REGULATOR 3. WASTE GAS TO ATM. 4. PUMP 5. COOLER 6. FILTER 7. BYPASS LINE 8. CW FOR STATOR WDG. 9. ION EXCHANGER 10. CW FOR BUSHINGS 11. TEFLON HOSE 12. C W MANIFOLD



BHEL Hardwar



Seal Oil System Prevents H2 losses at the shaft entry into stator



BHEL Hardwar



Gas System Facilitates H2 filling & maintains gas pressure in stator



BHEL Hardwar



1. H2 BOTTLE 2. H2 PRESS REDUCER 3. N2 BOTTLE. 4. N2 PRESS REDUCER 5. PW TANK 6. PRESS CONTROLLER 7. UPR. GEN GAS HEADER 8. LWR.GEN GAS HEADER 9. GAS DRIER HEATER 10. GAS DRIER FAN 11. GAS DRIER CHAMBER 12. CO2/H2 PURITY TRANS. 13. DEHYDR. FILTER 14. PRESS REDUCER 15. COMPRD. AIR HOSE 16. COMPRD. AIR FILTER 17. CO2 FLASH EVAPORTR 18. CO2 BOTTLE



Generating testing 1. Mechanical test 2. Open Circuit test 3. Short circuit test 4. Sudden short circuit test 5. Voltage wave form 6. Tan  test 7. Vibration Measurement



BHEL Hardwar



500 MW Generator on test bed



BHEL Hardwar



Gas Turbine Generator-Faridabad



BHEL Hardwar



Gas Turbine Generator- Baiji, IRAQ



BHEL Hardwar



New dev - Total Impregnated generator STATOR WINDING AND CORE BECOMES A MONOLITHIC STRUCTURE : NO VOIDS, LESSER VIBRATIONS & BETTER HEAT TRANSFER THERMAL CONDUCTIVITY OF VPI INSU. 2.2 - 2.5 mW/Cm°C THERMAL CONDUCTIVITY OF H2 THERMAL CONDUCTIVITY OF AIR



BHEL Hardwar



1.4 - 1.5 mW/Cm°C 0.257 mW / Cm °C



Advantages of Total Impregnated generator + PARTIAL DISCHARGES ARE REDUCED, RESULTING IN BETTER LIFE OF MACHINE + NO POSSIBILITY OF CORE OR BAR LOOSENESS: Thus a major cause of failure, resulting in stator earth faults is eliminated. + NO POSSIBILTY OF LOOSENESS IN STATOR WINDING OVERHANG: Lesser overhang vibrations. Glue injection in overhang is not required. + NO POSSIBILTY OF WEDGE LOOSENESS Wedge tightness checking not required. Rotor withdrawl during initial inspection not required. + LESSER MAINTENANCE + LESSER OVERHAUL TIME + REDUCTION



IN SPARES INVENTORY - STATOR BARS AND STATOR SLOT WEDGES ARE NO MORE REQUIRED AS SPARES



BHEL Hardwar



WOUND STATOR CORE BEING LOADED FOR TOTAL IMPREGNATION



BHEL Hardwar



CURING OF TOTALLY IMPREGNATED WOUND CORE



BHEL Hardwar



INSERTION OF IMPREGNATED WOUND CORE IN STATOR



BHEL Hardwar



THANK YOU



END



BHEL Hardwar