MANUFACTURING OF TURBO GENERATORS AN INDUSTRY ORIENTED MINI PROJECT ON MANUFACTURING OF TURBO GENERATORS MANNAN INSTITUTE OF SCIENCE AND TECHNOLOGY PROJECT ASSOCIATES N.SAI SMARAN (08J51A0236) P.RAJU (08J51A0237)

OBJECTIVE The Project includes the assembly of Turbo-Generators (4-pole and 2-pole Generators) and various tests done at different stages and shown the performance characteristics.

Flow path… BHEL over view Principle to AC Machines Stator Rotor Insulation system Winding of stator & rotor Tests Conclusion

OVERVIEW - B.H.E.L BHEL is the largest engineering &manufacturing enterprise in India. It is one of NAVARATNA’S in India. Established 40 years ago. In 1970s: At Hyderabad with Germany Collaboration 60MW Air Cooled & 110MW Hydrogen cooled. At present it has extended up to 150MW Air Cooled.

TURBO GENERATOR PRINCIPLE The basic principle of rotating machine remains the same i.e. “Faraday’s laws of electromagnetic induction”. Hence basic essential parts required in the Production of Power by the Electrical Generator are A magnetic field A Conductor / Coil Relative motion / mechanical force In turbo Generator , the magnetic field is rotating part & the coil is stationary.

GENERATOR PARTS Stator Rotor Excitation system Cooling system Insulation system Bearings

STATOR & ROTOR ASSEMBLY WINDING, TOP & BOTTOM LAYERS LAMINATIONS SLOTS & HOLES CORE ASSEMBLY PRESSING WINDING, TOP & BOTTOM LAYERS TESTING IMPREGNATION TESTING ASSEMBLY

STATOR FRAME The stator frame is horizontally split type and welded construction and supports the lamination core and the winding. Both the air duct pieces and welded radial ribs provide for rigidly to the stator frame. These two things are provided to the stator frame to support the stator on the foundation. The stator firmly fixed to the foundation plates with bolt through the feet.

STATOR CORE Stator core is made up of “COLD ROLLED NON GRAINED ORIENTED SILICON STEEL SHEETS”, which has high permeability and low hysteresis and eddy current losses. To remove the heat, a large number of spacer segments, placed at intervals along the bore length. Stator laminations are coated with synthetic varnish.

TESTINGS CORE ASSEMBLY CORE FLUX TEST Stator laminations are stacked and held between clamping plates. CORE FLUX TEST Immediately after the core is built up and before it is wound a test is made to defect the presence of local “Hot spots”

TRANSPOSITION PUTTY OPERATION STACK CONSOLIDATION BENDING The strips are staggered and are bend for Roebel transposition. PUTTY OPERATION Each individual bar consisting of uneven surface and width space are filled with NOMAX STACK CONSOLIDATION The bars are subjected to a horizontal and vertical pressure BENDING Each of the samples is placed over the universal former & the universal former is aligned to the specifications

INSULATION SYSTEM INSULATION MATERIAL PREPARATION TEST INSULATION MATERIAL In electrical machines insulation is most important requirement to sustain high voltages and basically insulation is the heart for electrical machines CLASSIFICATION OF INSULATING MATERIAL The insulating material can be classified in the following two ways. Classification according to Substance and materials. Classification according to Temperature.

CLASSIFICATION ACCORDING TO SUBSTANCE AND MATERIALS SOLIDS LIQUIDS GASES CLASSIFICATION ACCORDING TO TEMPERATURE Class Permissible temperature Y 90 A 105 E 120 B 130 F 155 H 180 C Above

RESIN RICH SYSTEM OF INSULATION MICA PAPER TAPE -40-50% GLASS PAPER TAPE-20% EPOXY RESIN-40% RESIN POOR SYSTEM OF INSULATION MICA TAPE HYPER SEAL SPLIT MICA RESIN ORIENTED GRAPHITE INNER CORONA PROTECTION (ICP) END CORONA PROTECTION (ECP) OUTER CORONA PROTECTION (OCP)

TAPPING PROCESS FOR TWO POLE FOR FOUR POLE Mica tape one layer ICP one layer Mica eight layers OCP one layer Split mica one layer ECP at bends Hyper seal for overhangs FOR FOUR POLE Resin oriented graphite nine layer OCP one layers Hyper seal six layers OCP nine layers ECP at bends

STATOR WINDING TYPES OF WINDINGS Open circuit and Closed circuit winding Lap and Wave winding Concentrated and Distributed winding Full pitch and Fractional pitch winding Single layer and Double layer winding

WINDING DIAGRAM

STATOR WINDING ASSEMBLY FOR FOUR POLE Winding Holder Ring Holder Diamond shape coil Brazing Wedges DC HV Testing

STATOR WINDING ASSEMBLY FOR TWO POLE winding holder Ring holder Bottom bar placing HV Testing Top bar placing I Transposition Brazing Wedges Phase sequence testing Impegration process

ROTOR CORE Rotor shaft is a single piece solid forming manufactured from a vacuum casting. Longitudinal slots for insertion of the field winding are milled into rotor body. Rotor consists of electrically active portion . 60% of rotor body circumference has longitudinal slots which holds the field winding. Rotor teeth at the ends of rotor body are provided with axial and radial holes enabling the cooling air to be discharged after cooling.

ROTOR WINDING Rotor winding consists of series connected turns, each of which consists of two half turns connected by brazing in the end section. Thickness of each strip made upto 10.5mm. For ventilation purpose the slots are provided on the coil and on inter strip insulation layer on both sides of coil. Laminated epoxy glass fibre fabric with nomex filter are used for slot insulation. Slot wedges are made of high electrical conductivity material which are short circuted through rotor body and thus act as damper windings

TESTING OCC AND LOAD MAGNETISING CHARACTERISTICS OPEN CIRCUIT CHARACTERISTICS AND SHORT CIRCUIT CHARACTERISTICS LOSSES AND EFFICIENCY CHARACTERISTICS

CONCLUSION Bharat Heavy Electrical Limited is the largest engineering and Manufacturing enterprise of is kind in the public sector in India. It ranks Among the top twelve organizations in the world, engaged in the Manufacturing of power generation equipment. The sector is an important part in Turbo generators. The stator Core is assembled by the laminated sheets. The universal form facture type bar is more flexible and it’s life time more. We use the ROEBEL BAR Transposition for stator winding which is more advantageous . BHEL has acquiring the latest technology in the insulation system. “Thus turbo generator is used mostly in paper, Sugar, Cement, Petrochemical, Fertilizers, Rayon industries etc”.

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