Title of Invention

SYSTEM AND METHOD FOR ASSEMBLING/DISMANTLING OF ROTOR IN STATOR OF TURBOGENERATORS OF 600-800 MW INDEPENDENT OF E.O.T. CRANES

Abstract

The invention relates to a system and method for assembling and dismantling a rotor and stator of large turbogenerators upto 800 MW at test bed independent of E.O.T. cranes. The system comprises of a trailer (51) having an erection base (50) mounted thereon moves trolleys (26,27) carrying a rotor (52) towards or away from the stator and a pulling device consisting of a pulling machine (30), guide pulley (14) and wire ropes pulls the rotor into the stator for assembling and away from stator for dismantling after maintaining the alignment of rotor and stator axes. The erection base having longitudinal and transverse plates (41,47) welded and is provided with stiffeners (45,46) for rigidity. Sliding pedestal (4), skid shoe, press boards (9,30) and a supporting pedestal (59) provides support to the moving rotor (52).

Full Text

FIELD OF INVENTION: The present invention relates to a system and method for assembling and dismantling of rotor in stator of turbogenerators of 600-800 MW, independent of E.O.T. cranes. BACKGROUND OF INVENTION Conventionally the Rotors of 600-800 MW turbogenerators are assembled and dismantled at test bed. Rotor assembly into and dismantling from stator is carried out with the help of E.O.T. crane. When the positions of Rotor at test bed for its assembly into and dismantling from stator lie outside the bay of E.O.T. crane, the use of E.O.T. crane is not feasible. This necessitated to find a method which enables a process of rotor assembly into and dismantling from stator of a turbogenerator to be carried out independent of E.O.T. crane. OBJECTS OF INVENTION It is therefore an object of the invention to propose a system and method of Rotor assembly into and dismantling from a stator of a turbogenerator particularly of higher capacity of 600-800 MW independent of the E.O.T. crane when its position at the test bed is outside E.O.T. bay. SUMMARY OF THE INVENTION Accordingly, the invention provides a system comprising of an erection base placed on trailer, roller trolleys, support blocks, tie rods, guide strips and guide bars. The erection base supports the rotor at appropriate height on flat bed trailer. The centre line of stator bore is aligned with that of rotor. The roller trolley system supports and guides the rotor during its assembly and disassembly into stator frame. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig.1- shows the erection base for Turbogenerator rotor. Fig.2- shows the method of insertion of a rotor into a stator frame by steps as depicted by fig I to fig V and support details in VI to VIII. An exemplary embodiment of the invention as depicted in the accompanying drawings will now be explained in details. However, there can be several embodiments all of which are deemed covered by this specification. DESCRIPTION OF THE INVENTION This invention relates to a Rotor body assembly into a stator of a turbogenerator and dismantling from it, both being parts of a turbogenerator unit by a method without an E.O.T. crane, in a Power Plant. The system comprises of an erection base (50) which is a fabricated steel structure and is fixed on a flat bed trailer (51). The erection base (50) supports the rotor at appropriate height on flat bed trailer. The rotor (52) is supported on erection base (50) using roller trolleys (26). The roller trolleys system supports and guides the rotor (52) during its assembly and disassembly into stator frame. This construction along with various support blocks (11,12,15,16,24,32,33,34) and Tie rods (13,31) have been made for handling a rotor for example of 800 MW Turbogenerator. The same system can be used on the same erection base by simply changing the support blocks and Tie rods suiting the requirements of for example 600 and 660 MW Turbogenerator rotor assembly into and dismantling from stator. For the process of rotor (52) assembly into the stator (54), the rotor (52) is placed on the trolleys (26,27) above the trailer (51) and erection base (50) with the help of EOT crane available in shop assembly area. After rotor assembly on trolleys, the movement of roller trolleys (26,27) is locked by using suitable stoppers for transportation of the trailer (51) (with rotor and erection base assembled on it) to the test bed area. After trailer (51) has been brought to the proper position in front of support pedestals (55) (for test shaft assembly) at test bed, the stoppers are removed and erection base (50) end is locked to support pedestals (55) ensuring plane movement surface for roller trolleys (26,27) with rotor (52) mounted on them. For the process of rotor dismantling from the stator, first the trolley (27) for EE location is assembled on-to the rotor (52),after it comes out of stator bore to desired extent. Later after barrel portion comes out of stator bore to desired extent, the trolley (26) for barrel location is assembled on-to the rotor. The trailer (51) is moved by motor, which is part of it. Hence trailer can be moved from assembly area to test bed area as required. The height of the erection base (50) and roller trolleys (26) is selected to match the axis of rotor with the centerline of stator (54) at test bed. The positions of rotor for its assembly/dismantling at test bed lies outside the E.O.T. crane bay. The height of Stator axis is worked out from the stator (54) and its support pedestals (55) at test bed and reconfirmed after assembly. The height of erection base (50) is determined considering the trailer (51) and trolley (26,27) heights so as to achieve the same height of rotor axis. As the rotor (52) is pushed inside the stator (54), it gets supported in the stator bore at its TE bearing location by sliding pedestal (4) and skid plate (2). The heights of sliding pedestal (4) and skid plate (2) have been so designed that rotor axis coincides with stator bore axis. Next rotor gets supported inside stator bore at rotor barrel near TE retaining ring by skid shoe (5) and skid plate (2). The heights of skid shoe (5) and skid plate (2) have been so designed that rotor axis coincides with stator bore axis. Lastly rotor (52) is supported inside the stator bore at barrel near EE retaining ring by stack of press board shims (30) and skid plate (2). The height of stack of press board shims (30) is kept same as that of skid shoe (5),thus ensuring that rotor axis coincides with stator axis. Thus alignment is ensured during the entire processes of rotor (52) assembly as well as dismantling from the stator (54). The structure of Erection Base (50) has a number of plate items (41,42,43,44) welded suitably with one another. Two top plates (42) of the erection base are provided with guide strips (48) for guiding the movement of roller trolleys (26). The longitudinal plates (41,47) welded with transverse plates (44) are provided with stiffeners (45,46) to support the load of moving rotor (52) and transverse forces during short distance transportation respectively. The height of erection base (50) and roller trolleys (26) is selected to match the axis of rotor (52) with the centerline of stator (54) at test bed. The stress analysis of erection base (50) is carried out for conditions of moving load of rotor during its assembly and dismantling with stator as well as those of short distance transportation in shop blocks. The design of erection base (50) has been developed and optimized using Finite Element Analysis technique. Different Design variants have been analyzed using parameters like thickness and width of plates to optimise the design. Adequate factor of safety has been ensured with respect to the yield strength of the material under all loading condition. Guiding bars (3) are provided on top of Erection base (50) as well as above excitor support pedestals (55) at test bed to ensure the movement of rotor (52) in axial direction only Trolleys (27) for EE (exciter end) Journal has a base plate (22) on top of it which is assembled with two support blocks (15,24) and a channel (25) by tie rods (13) at two end allowing the EE Journal to seat. Trolleys (26) for Rotor barrel has a Base plate (8) which is assembled with two support blocks (12) and a channel (10) by tie rods (31). The sliding pedestal (4) is an assembly of fabricated steel body having 6mm thick PTFE sheet at bottom. Skid plate (2) is also an assembly of smoothly machined steel plate having PVC sheet at bottom. PTFE sheet of sliding pedestal (4) slides over the greased steel surface of skid plate (2) with a very low coefficient of friction, thus reducing the effort required for push/pull using the pulling machine. Similarly skid shoe (5) has PTFE sheet at its bottom for sliding over skid plate (2). The method of rotor (52) assembly into a stator (54) begins with the rotor (52) being assembled on top of erection base (50) and trailer (51) with roller trolleys (26,27) using base plates (8,22), tie rods (13,31), support blocks (11,12,15), channels (10,25) at barrel center and exciter end (EE) bearing positions. Also rotor (52) is assembled with sliding pedestal (4) assembly at bearing position on turbine end (TE). Trolleys (26,27) are put at EE Journal and Rotor barrel position (section A-A and B-B). Trailer (51) is brought adjacent to supporting pedestal (55) and trailer height is adjusted to align top surfaces of pedestal (55) and erection base (50). Then guide bars (3) is aligned on Pedestal (55) top surface. Blower covering is then removed but the blower protection ring is left on blower protection rim (53). Care is taken that at no time any load comes on either of retaining rings which are end-supported and enclose rotor winding overhang parts or on compressor blades. The position of these support points are so selected that during the movement of rotor (52) it always remains supported at least at two places, even when some of these supports are removed or disassembled before pushing rotor (52) further inside the stator (54). The skid plate (2) and Boards (9) are placed and Grease (23) is applied on skid plate (2), sliding pedestal (4) and skid shoe (5) to minimize the friction. End shield upper halves, shaft seals and Bearings of both turbine end (TE) and exciter end (EE) are not assembled before starting the rotor assembly process. End shield lower halves are lowered from normal position and kept hanging from sides of support pedestal (55) at test bed by specially designed brackets. Rotor (52) is gradually pushed towards stator (54) by using pulling machine (38) with wire rope anchored from stator (54). After some movement, sliding pedestal (4) supports rotor (52) inside stator (54) bore. After roller trolley (26) gets free of support from exciter support pedestals (55), it is disassembled. During the movement of rotor barrel (52) inside the stator bore (54), the rotor barrel is supported at TE by inserting skid shoe (5) by pulling with polyster cords drawn towards TE just after the retaining ring TE has entered inside stator bore (54). A stack of Press boards (30) provided with strings for guiding placement and removal, is inserted after travel of half length of rotor (52) barrel inside the stator bore (54) and an additional stack of press boards (30) is inserted just before entry of retaining ring EE in stator bore (54) on Exciter side (EE). End shield lower half TE is lifted to its normal position after TE coupling flange of rotor (52) comes out clear of end shield TE. The rotor (52) is supported by assembling rotor insertion cross beam TE (6) with end shield TE. Skid shoe (5) on TE is removed and shaft seal TE and bearing TE are assembled. Next end shield lower half EE is lifted to its normal position and rotor (52) is supported on rotor insertion cross beam EE (7) assembled with end shield lower half EE. Press boards (30) are removed. Skid plate (2) is removed after turning it around rotor (52) to upper side of bore. Press boards (9) is also removed. Then Bearing lower half TE is placed on Rotor Journal TE lifting the rotor (52) using cross beams (6,7). Similarly with rotor (52) lifted using cross beam EE (7), bearing lower half EE is placed on rotor journal EE. Cross-beams (6,7) are removed. Rotor (52) is then aligned and coupled with turbine rotor. For rotor dismantling, Generator rotor (52) is de-coupled from turbine rotor. End shield upper halves are removed. Rotor (52) is supported on rotor insertion cross beams TE and EE (6,7) and bearings and shaft seals TE and EE are removed. Skid plate (2) is inserted in the stator bore (54) above rotor (52) and turned around rotor (52) to position below rotor (52). Skid shoe (5) is inserted at TE just inside retaining ring TE and stack of press boards (30) is inserted just inside retaining ring EE. End shield EE is lowered and supported by special brackets (16) from intermediate support of exciter support pedestal (55) at test bed. Rotor insertion cross beam EE (7) is removed. End shield lower half TE is lowered and supported by special brackets (1) from intermediate support of pedestals at test bed. Rotor insertion cross beam TE (6) is removed. Sliding pedestal (4) is assembled on rotor (52) at TE bearing location. Rotor is gradually pulled out from stator (54) using pulling machine (38) with wire rope. Trolley (27) is assembled on rotor (52) at position of bearing EE (Section B-B) after it is clear of stator (54). On further pulling rotor (52) gets supported by this trolley (27) on intermediate support of support pedestal (55) at test bed and skid shoe (5) is taken out. As middle portion of rotor barrel (52) comes clear of stator (54), Trolley (26) is assembled on rotor (52) in that portion (Section A-A). Rotor (52) gets supported by this trolley (26) on intermediate support of pedestal (55) at test bed before sliding pedestal (4) comes out from Stator bore (54). Sliding pedestal (4) is disassembled. After more pulling, rotor (52) with trolleys (26,27) gets transferred into Erection base (50) and trailor (51) for further transportation of maintenance bay. WE CLAIM 1. A system for assembling and dismantling a rotor and stator of large turbogenerators upto 800 MW independent of EOT cranes comprising: a trailer with an erection base (50) mounted there on for moving trolleys (26,27) carrying the rotor (52) towards or away from the stator (54); and a pulling device consisting of a pulling machine (38) guide pulley (14) and wire ropes for assembling the rotor (52) into the stator (54) or for dismantling the rotor (52) from the stator (54); 2. The system as claimed in claim 1, wherein the height of said roller trolleys (26,27) on said erection base (50) is adjustable for alignment of rotor and stator axes. 3. The system as claimed in claim 1, wherein the erection base is a fabricated structure of steel plates (41,42,43,44). 4. The system as claimed in claim 1, wherein the two top plates of the erection base (50) are provided with guide strips (48) for the movement of the roller trolleys (26,27). 5. The system as claimed in claim 1, wherein the erection base having the longitudinal and transverse plates (41,47) is welded and provided with stiffeners (45,46) for rigidity. 6. The system as claimed in claim 1, wherein the trolleys (26,27) is guided by guide bars (3) provided on support pedestal (55) at the entry point to the stator. 7. The system as claimed in claim 1, wherein roller trolleys (26,27) having base plates (8,22) on the top is fixed with support blocks (12,15,24) and channels (10,25) by tie rods (13,31). 8. The system as claimed in claim l,wherein the rotor (52) slides on skid plate (2) is placed on stator (54). 9. The system as claimed in claim 1, wherein the rotor (52) is supported by skid shoe (5) and a plurality of press boards (30,9). 10.The system as claimed in claim 1, wherein a plurality of cross beams (6,7) are provided at two ends (TE and EE) for lifting the rotor (52). 11. A method for assembling of rotor in stator of turbogenerators in the range of 600-800 MW independent of EOT cranes comprising: an erection base (50) being mounted on trailer (51) moves the rotor (52) being held on plurality of trolleys (26,27) towards or away from the stator (54); the height of the erection base (50) and roller trolleys (26,27) is maintained to match the axis of rotor (52) with the centerline of stator (54) at test bed; a pulling m/c (38), guide pulley (14) and wire ropes pulls the rotor (52) for assembling into the stator (54) or for dismantling the rotor (52) from stator (54). 12. A method as claimed in claim 11, wherein the sliding pedestal (4), skid shoe (5) and press boards provide support to the moving rotor (52) when the retaining ring (TE) enters the stator bore (54). 13. A method as claimed in claim 11, wherein the trolley (26) is disassembled when it gets free of support from support pedestal (59). 14.A method as claimed in claim 11, wherein press boards (30) are provided below the rotor (52) reaching half of its length into the stator bore. 15. A method as claimed in claim 11, wherein additional press boards (30) are provided before entry of retaining ring (EE) in stator bore on exciter side. 16. A method as claimed in claim 11, wherein the trolley (27) positioned on bearing (EE) is removed when coming out from support pedestals (55). 17.A method as claimed in claim 11, wherein the Rotor (52) is assembled with end shield lower half TE, shaft seal and bearing TE when the rotor (52) comes out clear of end shield TE. 18. A method as claimed in claim 11, wherein end shield lower half EE, shaft seal EE, bearing EE are assembled after press boards (30), skid plate (2) and cross beams (6,7) are removed, and the rotor (52) is aligned and coupled with turbine rotor. 19. A method for dismantling of rotor (52) from stator (54) of turbogenerators in the range of 600-800 MW independent of EOT cranes comprising: a generator rotor being decoupled from Turbine rotor; skid shoe (5), skid plate (2), press boards (30) being inserted; end shields, shaft seals, bearings being removed; trolleys (26,27), sliding pedestal (4), support pedestal (55) being assembled; and the rotor (52) being dismantled by the pulling machine (38), guide pulley (14) and wire ropes; 20. A method as claimed in claim 19, wherein the rotor being clear of stator for half the length, the said rotor (52) is supported by supporting pedestal (55), the sliding pedestal (4) being removed, and the rotor (52) with trolleys (26,27) is transferred into erection base (50). The invention relates to a system and method for assembling and dismantling a rotor and stator of large turbogenerators upto 800 MW at test bed independent of E.O.T. cranes. The system comprises of a trailer (51) having an erection base (50) mounted thereon moves trolleys (26,27) carrying a rotor (52) towards or away from the stator and a pulling device consisting of a pulling machine (30), guide pulley (14) and wire ropes pulls the rotor into the stator for assembling and away from stator for dismantling after maintaining the alignment of rotor and stator axes. The erection base having longitudinal and transverse plates (41,47) welded and is provided with stiffeners (45,46) for rigidity. Sliding pedestal (4), skid shoe, press boards (9,30) and a supporting pedestal (59) provides support to the moving rotor (52).

Documents:

1341-KOL-2008-(01-12-2014)-ABSTRACT.pdf

1341-KOL-2008-(01-12-2014)-CORRESPONDENCE.pdf

1341-KOL-2008-(28-11-2014)-ABSTRACT.pdf

1341-KOL-2008-(28-11-2014)-CLAIMS.pdf

1341-KOL-2008-(28-11-2014)-CORRESPONDENCE.pdf

1341-KOL-2008-(28-11-2014)-DESCRIPTION (COMPLETE).pdf

1341-KOL-2008-(28-11-2014)-DRAWINGS.pdf

1341-KOL-2008-(28-11-2014)-FORM-1.pdf

1341-KOL-2008-(28-11-2014)-FORM-2.pdf

1341-KOL-2008-(28-11-2014)-OTHERS.pdf

1341-kol-2008-abstract.pdf

1341-kol-2008-claims.pdf

1341-kol-2008-correspondence.pdf

1341-kol-2008-description (complete).pdf

1341-kol-2008-drawings.pdf

1341-kol-2008-form 1.pdf

1341-kol-2008-form 18.pdf

1341-kol-2008-form 2.pdf

1341-kol-2008-form 3.pdf

1341-kol-2008-gpa.pdf

1341-kol-2008-specification.pdf

abstract-1341-kol-2008.jpg