Claims:WE CLAIM

1. A device for transferring holes from turbo generator rotor to field lead core bar (12) comprising:
threaded bush (1) having external threads corresponding to internal thread available in rotor current carrying (CC) bolt threaded hole and maintain other dimension.;
plain bush (2) having outer diameter (OD) in transition fit with plain CC bolt hole available in rotor;
slip bush for drilling (3) having OD in transition fit with inner diameter (ID) of threaded/plain bush and ID according to drill (10) size;
slip bush for co-drilling (4) having OD in transition fit with ID of threaded/plain bush and ID according to co-drill (9) size;
slip bush for reaming (5) having OD in transition fit with ID of threaded/plain bush and ID according to reamer size;
locking pin (6) having OD in transition fit with ID of slip bush reaming (5) that get fitted in the pre-reamed holes of Field Lead Core Bar (12) and locks with respect to slip bush (5).
2. A method for transferring holes from turbo generator rotor to field lead core bar (12) comprising:
preparing a finish hole of dia 20 in Field Lead Core Bar (12) at the position where first CC bolt is to be mounted by approximate measurement;
inserting the Field Lead Core Bar (12) into rotor in such a manner that this hole gets aligned with rotor hole of first CC bolt;
inserting a plain bush (2) in the rotor hole;
inserting a slip bush (reaming) (5) in the plain bush hole (2);
inserting a locking pin (6) in the slip bush (5) hole;
inserting a threaded bush (1) in third hole and slip bush for drilling (3) is fitted into it and a hole is drilled of size 19.5mm;
replacing slip bush drilling (3) with slip bush co-drilling (4) and that predrilled hole get enlarged up to size of 19.7mm;
replacing the slip bush co-drilling (4) with slip bush reaming (5) and final hole of dia 20 is reamed in the Field Lead Core Bar (12);
repeating above steps to transfer the holes at slip bush for co-drilling (4), slip bush for reaming (5) and locking pin (6);
inserting the plain bush (2) in second hole position and slip bush for drilling (3) is fitted into it and a hole is drilled of size 19.5mm;
replacing slip bush drilling (3) with slip bush co-drilling (4) and that predrilled hole get enlarged up to size of 19.7mm;
replacing slip bush co drilling (4) with slip bush reaming (5) and final hole of dia 20 is reamed in the Field Lead Core Bar (12);
repeating above steps to transfer the holes at plain bush (2), 7 and 8;
wherein the transfer of holes from turbo generator rotor to field lead core bar (12) is done without disturbing the other assemblies and balancing of rotor of a turbo generator.
3. The method as claimed in claim 1, wherein the slip bush for reaming (5) hole gets fitted in the pre reamed hole of Field Lead Core Bar (12).
4. The method as claimed in claim 1, wherein the rotation and translation of Field Lead Core Bar (12) is locked with rotor to perform rest of the operations.
5. The method as claimed in claim 1, wherein all the holes are got transferred from rotor to Field Lead Core Bar (12) for dia 20.
6. The method as claimed in claim 1, wherein the Field Lead Core Bar (12) is taken out from the rotor and all the hole are enlarged to make it M60x2 and threads are made to complete the detail.
7. The method as claimed in claim 1, wherein the Field Lead Core Bar (12) is reinserted into its position and CC bolts are mounted to complete the assembly.
, Description:FIELD OF THE INVENTION:
[001] The present invention relates to the field of development of suitable tooling and methodology for achieving high accuracy in assembly of a new Field Lead Core Bar and Current Carrying Bolts in the old Turbo Generator Rotor in case of repair as these are high speed moving components their perfect alignment and griping is highly critical and sensitive.

BACKGROUND/PRIOR ART OF THE INVENTION:
[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[003] BHEL has a rich legacy of manufacturing Power Plant Equipment’s of various rating started with collaboration of Russia and shifted to super critical technology in collaboration with Germany. The old Russian designed power plants have completed a long span of service are coming in frequent Breakdown and permanent shutdown where component replacement becoming necessary for the power generating organizations.

[004] In turbo generator rotor for the transmission of current from high speed rotating part called rotor (having a field winding on it) is done through two half of cylindrical bars of copper known as Field Lead Core Bar. Failure due to seize of Field Lead Core Bar inside Rotor is a rare & critical problem and needs to be repaired very carefully as it is a crucial member of Turbo Generator. Field Lead Core Bar are made in two semi-cylindrical halves (refer item no.1 fig-2) through which field current passes from Exciter to Generator Rotor.

[005] The Field Lead Core Bar are inserted in the bore of the rotor and from the rotor winding, connection of this core bar is done through bolts of copper know as current carrying (CC) bolts. These CC bolts can be 2, 4 or 8 in numbers depending on the design of Turbo Generator. The exact matching, marking, drilling and threading of the holes in the core bar for connection of:
1. CC Bolt,
2. conducting pin in the core bar inside rotor /exciter shaft makes it the most critical component of Turbo-Generator.

[006] A core bar undergoes many machining operations before being used in Generator assembly. A core bar is a cylindrical shaped object generally in two identical halves because of two magnetic poles of the Generator. Between these two halves is a separator. In large size of Generator, the practice is to join two halves of core bar by dummy/technological rings during the time of machining. The core bar is inserted in the rotor and CC Bolt hole is initially transferred on the core bar from the rotor. Now the core bar is brought out of the rotor and CC bole hole is done exact as per design through boring and reaming. After this threads are made so that the bolt can be locked. After this, the core bar the bar is taken to a lathe machine for cutting of the technological rings. Then it comes for making a hole of M-60x2 to fit CC bolt in it.

[007] In case of a new Rotor, Core Field Lead Core Bar is inserted axially into bore of Rotor and locked with coupling flange with the help of fixture and all the required holes are made in conjunction with the holes of Rotor in the same setting, this is why holes of Field Lead Core Bar get automatically transferred at exact location with respect to rotor.

[008] It is to be noted that lead core bar is a very critical component in a turbo Generator as all the excitation from the exciter of a generator is transferred to the Field Lead Core Bar and then to the current carrying bolt through conducting pins. Copper is a soft and malleable material and can be easily damaged/bend as its strength is low. Due to multiple handlings during Field Lead Core Bar machining as described earlier, damage in soft copper material is generally unavoidable. Any such damage or bend in core bar is not allowable as per design requirement as a damage/bend can lead to mismatch of M60x2 hole and CC bolt leading to rejection of core bar. Any mismatch or gap leads sparking and finally damage the field lead bar as well as CC bolt hence accuracy of positions of holes is crucial for assembly and functionality of turbo Generator.

[009] Measure challenge in case of repair is that, holes for CC bolt are already drilled in Rotor and that holes needs to be transferred accurately in the filed lead core bar to avoid any malfunction such as mechanical, electrical or operational losses.

[0010] In view of the above, there is requirement to devise an apparatus which can address the aforesaid shortcoming(s). Hence, the present invention has been introduced.

[0011] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

OBJECTS OF THE INVENTION:

[0012] It is therefore the object of the present subject matter to overcome the aforementioned and other drawbacks in prior method/product/apparatus.

[0013] The present invention is based on the object of providing a device and method of replacing the damaged Field Lead Core Bar with new one inside the rotor of a turbo generator.

[0014] Another object of the present invention is to provide a method of mounting the CC bolts accurately to perform its intended function.

[0015] Still another object of the present invention is to provide an accurate method and means to replace the Field Lead Core Bar and CC bolts without dismantling the coupling flange, slip rings and without disturbing the balancing of rotor.

[0016] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION:

[0017] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

[0018] There are two challenges during transfer of hole from rotor with complete winding to new Field Lead Core Bar without disturbing the balancing of rotor assembly.
Locking of Field Lead Core Bar with rotor so that it cannot rotate or slide or change its position during hole transfer.
Also there are four number of threaded CC bolt hole and four number of plain CC bolt hole in rotor which have to be transferred in such a way that centre line of all the CC bolt hole in rotor should be exactly same as centre lines of transferred hole in Field Lead Core Bar.
[0019] Present invention provides an accurate method and means to replace the Field Lead Core Bar and CC bolts without dismantling the coupling flange, slip rings and without disturbing the balancing of rotor.

[0020] In Russian Deign of Generators there are 8 nos. of CC bolt holes which have to exactly get transferred in Field Lead Core Bar with accurate positioning to avoid any functional loss. CC bolt hole size is M60x2 but to avoid any damage only hole of Ø20 is transferred from rotor to Field Lead Core Bar and that transferred holes get enlarged to exact size of M60x2 after taking the Field Lead Core Bar out form the rotor. It is very important that centre line of transferred hole in Field Lead Core Bar and centre line of existing cc bolt of rotor must be exactly same.

[0021] The present invention is achieved by the features of principal claim and subsequent claims.

[0022] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

[0023] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.

[0024] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

[0025] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:-

[0026] Figure 1 shows the isometric view of the arrangement.

[0027] Figure 2 shows the exploded view of the arrangement.

[0028] Figure 3 shows the front view of the arrangement.

[0029] Figure 4 shows the top view of the arrangement.

[0030] Figure 5 shows the left side view of the arrangement.

[0031] Figure 6 shows the right side view of the arrangement.

[0032] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S) OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

[0033] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0034] The present invention makes a disclosure regarding a technology pertinent to of replacing the damaged Field Lead Core Bar with new one inside the rotor of a turbo generator and mounting the CC bolts accurately to perform its intended function.

[0035] The invented fixture as shown in figure -2 comprises of following items:
Threaded Bush. (1 no.)
Plain Bush (2 no.)
Slip bush for Drilling (1 no.)
Slip bush for co-Drilling (1 no.)
Slip bush for Reaming (2 no.)
Locking pin (1 no.)
threaded bush (1) designed in such a way that its external threads corresponding to internal thread available in rotor CC bolt threaded hole and maintain other dimension. (as shown in fig-2)
plain bush (2) designed in such a way that its outer diameter (OD) is in transition fit with plain cc bolt hole available in rotor. (shown in fig-2)
slip bush for drilling (3) OD of this slip bush is in transition fit with inner diameter (ID) of threaded/plain bush and ID according to drill size. (shown in fig-2)
slip bush for co-drilling (4) OD of this slip bush is in transition fit with ID of threaded/plain bush and ID according to co-drill size. (shown in fig-2)
slip bush for reaming (5) OD of this slip bush is in transition fit with ID of threaded/plain bush and ID according to reamer size. (shown in fig-2)
Locking pin (6) OD of this locking pin is in transition fit with ID of slip bush reaming (5) which exactly get fitted in the pre-reamed holes of Field Lead Core Bar and locks is with respect to slip bush (5). (shown in fig-2)

[0036] Threaded bush is designed in such a way that it has external thread corresponding to internal thread available in rotor. Plain bushes are designed in such a way that its OD is in transition fit with ID of plain hole available in rotor. Slip bushes are of three types to perform the hole transfer activity accurately. OD of slip bushes are in transition fit with ID of threaded/plain bush and IDs are as follows.
1. ID of three Slip Bushes are kept as per below dimensions.
2. ID of slip bush for drilling (Id diameter-19.50).
3. ID of slip bush for Co-drilling (Id diameter-19.80).
4. ID of slip bush for Reaming (Id diameter-20.0).

[0037] In Russian Deign of Generators there are 8 nos. of CC bolt holes which have to exactly get transferred in Field Lead Core Bar with accurate positioning to avoid any functional loss. CC bolt hole size is M60x2 but to avoid any damage only hole of Ø20 is transferred from rotor to Field Lead Core Bar and that transferred holes get enlarged to exact size of M60x2 after taking the Field Lead Core Bar out form the rotor. It is very important that centre line of transferred hole in Field Lead Core Bar and centre line of existing cc bolt of rotor must be exactly same, to find that accuracy the Process of transferring the holes of rotor into Field Lead Core Bar is as per steps given below.

1. By approximate measurement a finish hole of dia 20 is made in Field Lead Core Bar at the position where first CC bolt is to be mounted.
2. Now Field Lead Core Bar is inserted into rotor in such a manner that this hole gets aligned with rotor hole of first CC bolt.
3. Plain bush is inserted in the rotor hole and a slip bush (reaming) (5) is inserted in the plain bush hole (2).
4. A locking pin (6) is inserted in the slip bush (5) hole which gets fitted in the pre reamed hole of Field Lead Core Bar. Now rotation and translation of Field Lead Core Bar is locked with rotor to perform rest of the operations. By completing this step, the first challenge gets resolved.
5. Threaded bush (1) is inserted in third hole and slip bush (3) for drilling is fitted into it and a hole is drilled of size 19.5mm.
6. Slip Bush drilling (3) is replaced with slip bush co-drilling (4) and that predrilled hole get enlarged up to size of 19.7mm.
7. Finally Slip Bush co-drilling (4) is replaced with slip bush reaming (5) and final hole of dia 20 is reamed in the Field Lead Core Bar.
8. Step 5, 6, 7 are repeated to transfer the holes at position no. 4, 5 and 6. (hole positions are mentioned in fig-5 & 6)
9. Plain bush (2) is inserted in second hole position and slip bush (3) for drilling is fitted into it and a hole is drilled of size 19.5mm.
10. Now slip bush drilling (3) is replaced with slip bush co-drilling (4) and that predrilled hole get enlarged up to size of 19.7mm.
11. Finally slip bush co drilling (4) is replaced with slip bush reaming (5) and final hole of dia 20 is reamed in the Field Lead Core Bar.
12. Step 9, 10, 11 are repeated to transfer the holes at position no. 2, 7 and 8.
13. In this way all the holes are got transferred from rotor to Field Lead Core Bar for dia 20.
14. Now Field Lead Core Bar is taken out from the rotor and all the hole are enlarged to make it M60x2 and threads are made to complete the detail.
15. Now Field Lead Core Bar is reinserted into its position and CC bolts are mounted to complete the assembly.

[0038] The advantage of present invention is to replace the Field Lead Core Bar and CC bolts without dismantling the coupling flange, slip rings and without disturbing the balancing of rotor.

[0039] The material above has been given as an example without restricting scope of the invention to the same. Thus, other materials readily apparent to a person skilled in the art are within scope of the invention.

[0040] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims

[0041] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0042] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0043] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

[0045] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

[0046] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.