Post on 29-Nov-2014
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STUDY PROJECT ON MANUFACTURE OF TURBO GENERATORS
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INTRODUCTION
•when there is a change in the flux linkages relative to a circuit, an emf is induced
FARADAYS I LAW
•The amount of emf induced is directly proportional to the rate of change of flux linkages
FARADAYS II LAW
•The direction of induced emf is such that it opposes the very cause producing it
FARADAYS III LAW
WORKING PRINCIPLE OF GENERATOR
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Components of Turbo Generators1.stator
2.Rotor
3.bearings
4.Cooling system
5.Excitation system
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stator
Stator frame
Stator core
Stator windingsEnd
covers
STATOR
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STATOR FRAME
welding steel single piece construction in order to support the laminated core and windings
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STATOR CORE
PREPARATION OF LAMINATIONS
• Compounding • Blanking and
notching
ASSEMBLY OF CORE
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OPERATIONS IN MANUFACTURING OF LAMINATIONS
A .The cold rolled non grained oriented (CRNGO) steel sheets in the required shapes according to the size of the laminations are cut by the feeding the sheet into shearing press .
B .Compounding operation or blanking ¬ching operation.
C. Deburring operation D. VarnishingE. The prepared laminations are subjected to following tests:i) Xylol test-to measure the chemical resistanceii) Mandrel test-when wound around mandrel there should not be
any cracksiii) Hardness test-minimum 7h pencil hardnessiv) Ir value test-for 20 layers of laminations insulation resistance
should not be less than 1 mega ohm
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PURPOSE OF STATOR CORETo support stator windingsTo carry the electromagnetic flux generated by rotor winding.Hence selection of material for building up of core plays a vital role. The losses in the core are of two types:•Hysteresis losses Wh a bmax 1.6ft•Eddy current losses We a bmax2 f2 t2
In order to reduce the hysteresis loss silicon alloyed steel, which has the low hysteresis constant is used for the manufacture of the core. the composition of silicon steel isSteel-95.8% Silicon-4.0%Impurities-0.2%
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STATOR COILS1. Set the straightening and cutting machine
using guide pilot 2. Cut the conductor strips as per
requirement3. Set the press for “Roebel transposition”4. Assemble strips with respect to template
and transpose5.Assembling both halves of the coil sides to
formi)One roeble half barii)Inserting insulation in straight part
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6.Baking process
7. remove insulation at the ends of the strips and testing for the inter strips and inter halves shorts8. Set the universal former as per standards and bending the stator coils in roebel shape9.Tapping process
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STATOR END COVERS
•Phase connections•Resistance
Temperature detectors
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STATOR WINDINGS
Two types of coils•Diamond pulled multiturn coil (full coiled)•Roebel bar (half coil)
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Connecting RingsStator Terminals
Insulated Copper Bars are placed in the slots to form
3Ø winding
HGL End Winding Support
Clamping Plates & Rings
STATOR WITH ALL STATOR WINDINGS INTERCONNECTIONS
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ROTOR
Rotor
Rotor shaft
Rotor windings
ConstructionRotor slot wedgesEnd winding
braces Rotor
retaining rings
Rotor fans
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ROTOR SHAFT
SINGLE PIECE SOLID ROTOR BODY MILLING THE FIELD WINDINGS INTO THE ROTOR BODY
MACHINED ROTOR
Rotor Slots
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CONSTRUCTION Several series connected coils inserted into
the longitudinal slots of rotor body.CONDUCTOR MATERIALINSULATION
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ROTOR SLOT WEDGES
•Slot wedges are made of copper alloy featuring high strength +good electric conductivity•Protect the windings against the centrifugal forces .•Windings are secured in the slots with wedges
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END WINDING BRACESROTOR RETAINING RINGSROTOR FANS
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BEARINGS High mechanical stability and reduced vibration in operation To prevent damage to the journals due to the shaft currents,
bearings and oil piping on either side of the non-drive end bearings are insulated from the foundation frame. For facilitating and monitoring the healthiness of bearing insulation, split insulation is provided
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COOLING SYSTEMThere are various methods of cooling. They arei) Air cooling –60 MWii) Hydrogen cooling – 100 MWiii) Water cooling – 500 MWiv)Hydrogen and water cooling – 100 MWDISADVANTAGES OF HYDROGEN OVER AIR
COOLING:a) Hydrogen is explosive when it combines with
oxygen.b) Greater precautions are to be taken to avoid
leakage of Hydrogen.c) Cost of cooling system is high compared to air
cooling system
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AIR COOLINGFlow path 1: is directed into the rotor end winding space and cools the rotor winding, part of the cooling air flows past the individual coils for cooling the rotor end winding and then leaves the end winding space via bores in the rotor teeth at the end of the rotor body. Flow path 2:is directed over the stator end winding to the cold air ducts and into the cold air compartments in the stator frame space between the generator housing and the rotor core. Flow path 3: is directed into the air gap via the rotor retaining ring. core.
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EXCITORSExciter is brushless and takes the form of the stationary field generators
Rotor of Brushless Exciter
Rotating Diodes &
Fuses
Permanent Magnets
E/f Monitoring Slip Rings
Armature
Diode Wheel
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EXCITATION SYSTEM COMPRISES OF•ROTOR•ROTOR WINDINGS•RECTIFIER•VARISTORS•MAIN EXCITORS•ROTATING RECTIFIER WHEEL
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CONCLUSION AND FUTURE SCOPE
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THANK YOU
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