FIELD OF THE INVENTION
The present invention is related to a THRI generator (Turbogenerator having provisions of hydrogen cooled rotor winding and indirect cooled stator winding) used in thermal power plants. More particularly, the invention relates to the development of a fixture and a process by which insulating cylinders can be sleeved/circumscribed on field lead core bar of a THRI generator.
BACKGROUND OF THE INVENTION
Earlier THW (Turbogenerator hydrogen cooled rotor winding & water cooled stator winding) type of generators were very common type in use. With upgradation of technology, these THW generators are rapidly being replaced by THRI type of generator design on the same foundation at site. In a Turbogenerator rotor, transmission of current from high speed rotating part called rotor (having a field winding on it) is done through two halves of cylindrical copper bars known as field lead core bar. The field core bars are inserted in the bore of the rotor and from the rotor winding, connection of this core bar is done through 2 bolts of copper known as current carrying (CC) bolts. There are insulating cylinders in which field lead core bar has to be inserted coaxially.
Earlier, there was no particular way of inserting and hammering was done to insert field lead core bar in the insulation cylinder. In order to have minimum losses and high conductivity, copper metal is used to manufacture a lead core bar and hammering for

insertion operation often resulted in damage in the copper material as copper is a soft and malleable material and can be easily damaged bent as its strength is low.
A field lead core bar is a very critical component in a turbogenerator as all the excitation from the exciter connected to a generator is transferred to the field lead core bar and then to the current carrying bolt through conducting pins. If there is a damage/bent in the core bar, there will be a problem in locking of core bar. The present invention overcomes this problem.
OBJECTS OF THE INVENTION
An object of the present invention is to develop a device for inserting hollow insulated cylinder on the field lead core bar of exciter rotor shaft of THRI generator.
Another object of the invention is to develop a device for inserting hollow insulated cylinder on the field lead core bar of exciter rotor shaft of THRI generator easily and smoothly in quicker time without causing any damage to the field lead core bar.
SUMMARY OF THE INVENTION
According to the invention there is provided a universal fixture for safe & smooth insertion of the field lead core bar in an insulating cylinder which is generally around 2-5

meters in length. These insulated cylinders are made up of glass cloth sheet in three different parts, initially all these hollow parts of insulated cylinder are cleaned and then adjusted in a straight line. After this field lead core bar is inserted in the insulated cylinder slowly with the help of insertion fixture. After aligning the conical threaded holes it is rotated in clockwise or anti clockwise direction for insertion purpose. During insertion one has to make sure that insertion should be in a proper way so that it does not damage the cylinder and the core bar. Now the whole assembly (cylinder + core bar) is inserted in the shaft bore. The hole of core bar must be coinciding with the hole of the shaft. Now before assembling with the current carrying bolt (C.C), the subassembly is cleaned by vacuum cleaner. Then installing C.C. bolt in the hole and gently tapping by mallet from top to set it properly. Measuring the gap between C.C. bolt and wall of the bore at four places at 90 degree apart where insulating bush are to be installed. These C.C bolt are also inserted in the holes of rotor shaft and field lead core bar.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 – Shows the complete assembly of cylinder inserting fixture
Figure 1A - Insertion of hollow insulation cylinder (14) on the field lead core bar (13).
Figure 2 - Upper Table Assembly (1) in which the insulated cylinder and lead core are to be assembled.
Figure 3 - Lower Table Assembly (2) which bear the full load of the working components and the fixture. This has to be clamped with upper assembly.

Figure 4 - Roller Assembly (3) over which the cylinder slides.
Figure 5 - Side Plate Assembly (4) which does not allow the cylinder to move out.
Figure 6 - Stopper Plate (5) which sustain pressure exerted by the jack and does not
allow the cylinder assembly to come out.
Figure 7 - Support Plate (6) which is used in upper table assembly in which cylinder rests during insertion process.
Figure 8 - Cover Plate (7) used to cover the insulated cylinder and field lead core bar.
Figure 9 - Pipe Support (8) over which the component assembly is resting on.
Figure 10 – The special bolts (9) are bolted across Lower table assembly for holding the roller assembly.
Figure 11 - The special bolts (10) are attached across upper table assembly which does not allow the hollow insulated cylinder to jump out which the pressure is exerted on it.
Figure 12 - Pressing Plate (11) which is tilted on the face of the jack of hydraulic cylinder exerts pressure on hollow insulated cylinder due to which field lead core bar get inserted.
Figure 13 – Clamping Plate (12) which clamps the hydraulic jack (16) in upper table assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Accordingly there are different items which comprise this assembly.
Figure 1 – shows the complete working of the insertion of the field lead core bar in the insulating hollow cylinder according to the present invention. The whole method of working & inserting of core is as follows.

Figure 2 – shows the upper table assembly where the two angle of length (L1) are welded with support plate (1 & 2) with height (H) & length (L). Then a pair of side strips are welded at the both the ends to give the strength to the frame. Then six small pieces of block (B1) are welded at the cylinder entering side which will hold the support plate. A plate (P1) is welded on jack side which will support the hydraulic cylinder. Two angle pair of different length (L3 & L4) are welded in the lower portion of the jack side which will work as the leg of table assembly & bear the load of the assembly, after this two lower plate (LP1) are welded on this leg. Finally, 5 pairs of holes of (ØD1) are made in which pipe support & lower table are to be clamped. A side plate is welded which will support the hydraulic cylinder of the jack.
Figure 3 – In this assembly, two channels of length (L1), are welded with two angle of length (L2) to make a frame, after this four pieces of angle of length (L3) are welded at the lower part of this frame which act as legs of the frame, four pieces of angle (L4) welded at four corners for strength. Angle (L5) are welded longitudinally and two angles (L6) welded are transversely for imparting strength. Now four small pieces of block are welded which act as foot of these legs & these legs are bolted with caster wheel. After this, eight pieces of the pipe of dia. (ØD2) of particular length are welded on the channel frame in which roller assembly is bolted. A plate & two side plates of particular length & breadth are welded on the lower portion of the channel

which will constitute a tooling box in which some tools can be kept while working. Holes are provided on angle iron for fixing lower table assembly with upper table assembly with nuts & bolts.
Figure 4 – In this assembly the hollow cylinder (C1) of dia. (ØD2), length (L1) & thickness (T) is taken & machined the inner dia. (D3) both side which suit with end plate having dia. (D4). Now glass cloth sheet is glued & rolled over this cylinder at certain thickness. Now this cylinder is heated up to a certain temperature due to which all the layer of the glass cloth sheet are bound with each other & the hard cylinder (C2) is formed. After cooling of this cylinder the surfaces is machined & smoothens & desired dia. (ØD5) is achieved. Some process is done to form the adjustable pipe the difference is that it is taken out from the cylinder having dia. (ØD6) & then fitted on the cylinder (C2). In cylinder (C2) sets two pair of threaded holes are made which is screwed to hold the end plate. This assembly is bolted with special bolt on the lower table assembly.
Figure 5 – In this assembly (4), a block of height(H), length(L) & breadth(B) with a undercut was made, after this the support block was welded with the strip plate of length (L1). After this three holes of dia. (ØD2) are done. This assembly is fixed on the lower table with roller assembly in which special bolt were tightening with nut which will not allow the component to move out of the fixture.

Figure 6 – This plate (5) is fixed at the end of the upper table (2) which does not allow the component to move out.
Figure 7 – This plate (6) is used at the end portion on upper table and its main function is to give support to hollow cylinder while insertion.
Figure 8 – This plate (7) is used to cover the whole insulated cylinder & field lead core bar assembly by bolt.
Figure 9 – This pipe supports are clamped on the upper table with nut & bolt, its function is to support the whole core assembly in line.
Figure 10 – This special bolt (9) is made to hold the roller assembly. These special type of bolts are bolted across the lower table assembly on which roller can rotate freely on it.
Figure 11 – This special bolt (10) is attached across the upper table assembly, which does not allow the hollow insulated cylinder to jump out while pressure is exerted on it.
Figure 12 – Pressing plate (11) is made up of epoxy laminated glass fibre sheet which is fitted on the face of the jack of hydraulic cylinder which exert pressure eon the hollow insulated cylinder by which the filed lead core bar get inserted in straight line.

Figure 13 – This clamping plate (12) is used to clamp the hydraulic jack in the upper table assembly. It is tightened with bolt & nut due to which the hydraulic jack is fixed & the movement is restricted.
The process of circumscribing/inserting hollow insulated cylinder (14) on the field lead core bar (13) of exciter rotor comprises of following steps:
- Since the length of core bar (13) is significantly large and during compressive loads, through hydraulic jack (16), it will have the tendency to buckle, as core bar is made of copper with respect to its high electrical conductivity, which can be damaging as lead core bar is a very critical component in a turbogenerator as all the excitation from the exciter of a generator is transferred through field lead core bar and any loss in excitation shall directly result in lowered output and costly power plant operation. Therefore, the entire length of hollow insulation cylinder (14) is actually divided into plurality of hollow insulation cylinder sections and the hollow insulation cylinder is circumscribed on core bar (13) section wise covering the entire core bar ;
- placing the cylindrical field lead core bar (13) on the upper table assembly (1) in a way that the field lead core bar diameter matches the pipe support (8) (fig. 9) diameter when rested upon the same and roller assembly (3) on lower table assembly (2) and the field lead core bar, towards hydraulic jack end, makes area

- contact with pressing plate (11), of soft material such as epoxy laminated glass fiber sheet, mounted on face of hydraulic jack (16) ram in order to prevent any damage to soft field lead core bar material (e.g. copper) and to provide uniform pressure during its insertion in insulating cylinder;
- longitudinally placing a section of hollow insulation cylinder (14) on the upper table assembly (1), along the longitudinal axis of upper table, in a way that the hollow insulation cylinder section diameter matches the pipe support (8) diameter when rested upon the same and roller assembly (3) and partially inserting the free end of the field lead core bar (13) in hollow insulating cylinder section manually so as to provide initial guidance to core bar (13); therein hydraulic jack (16) or pressing plate (11), core bar (13) and cylinder section (14) shall be on the same longitudinal axis;
- Providing hydraulic pressure through hydraulic jack (16), rigidly clamped for lateral through a clamping plate (12), to press the core bar (13) into first section of cylinder (14);
- The cylinder section (14) is supported through a supporting plate (6) free to be placed and supported through collar blocks (B1) provided on upper table assembly (1), for any longitudinal movement during core bar insertion and plurality of circular profile of pipe support (8), for longitudinal movement, and rollers (3), for rotation, shall provide self-adjusting means to the assembly during the process and shall help in avoid care bar buckling;

- The process is repeated for all sections of cylinder (14) till the entire length of core bar (13) is circumscribed by hollow insulated sections;
- For last sections of cylinder (14), the core bar shall have a tendency to rise for the rise from the free end, and therefore cover plate (7) shall clamp the free end and stopper plate (5) shall act as a stopper in case of sudden release of hydraulic pressure;
- The special bolts (9) are bolted across Lower table assembly for holding the roller assembly;
- special bolts (10) are attached across upper table assembly which does not allow the hollow insulated cylinder to jump out which the pressure is exerted on it;

We Claim
1. A universal device to insert the hollow insulated cylinder on the field lead core bar
of exciter rotor shaft comprising:
- an upper table assembly (01) for holding and assembling the insulated cylinder (14) and field lead core bar (13);
- the said upper table assembly (01) placed over lower table assembly (02) and clamped therein with the help of pipe support and plurality of holes (ØD1) provided in upper table assembly;
- a plurality of roller assembly (03) being fixed with the lower table assembly (02) with nuts and bolts for easy movement of the core bar during insertion inside the hollow cylinder;
- a hydraulic jack (16) mounted on upper table assembly (02) with the help of clamping plate (11) wherein when the force is exerted by the hydraulic jack (16), the piston moves out from the cylinder when the pressing plate (11) transfer the force on hollow cylinder (14) thereby inserting the field lead core bar within the cylinder (14) and the stopper plate (5) fixed at the end of upper table (2) does not allow the field lead core bar to go out.
2. The device as claimed in claim 1 wherein the hydraulic jack (16) is mounted on
the upper table assembly ( 01)with the help of clamping plate (12).

3. The device as claimed in claim 1 wherein the hollow insulated cylinder (14) is kept on the pipe supports (8) which are fixed on the upper table assembly (01) whereas the field lead core bar (13) rolls over the plurality of roller assembly (03).
4. The device as claimed in claim 1 wherein the lower end of all the vertical support of upper table assembly (01) and lower table assembly (02) are fixed with caster wheel for easy movement.
5. A process of circumscribing/inserting hollow insulating cylinder (14) on the field
lead core bar (13) of exciter rotor by a universal device as claimed in claim 1
comprising:
- dividing the entire length of hollow insulation cylinder (14) into plurality of hollow insulation cylinder sections and then the said each hollow insulation cylinder is circumscribed on core bar (13) section wise covering the entire core bar ;
- placing the cylindrical field lead core bar (13) on pipe support (8) and roller assembly (3) such that the field lead core bar, towards hydraulic jack end, makes area contact with pressing plate (11) mounted on face of hydraulic jack (16) ram to provide uniform pressure during its insertion in insulating cylinder;

- longitudinally placing a section of hollow insulation cylinder (14) on pipe support (8) diameter and roller assembly (3) and partially inserting the free end of the field lead core bar (13) in hollow insulating cylinder section manually so as to provide initial guidance to core bar;
- providing hydraulic pressure through hydraulic jack (16) to press the core bar (13) into first section of cylinder (14);
- cylinder section (14) being supported through a supporting plate (6) free to be placed and supported through collar blocks (B1) for any longitudinal movement and circular profile of plurality of pipe support (8) and rollers (3), for rotation;
- repeating the process of inserting for all the sections of cylinder (14) till the entire length of core bar (13) is circumscribed by hollow insulated sections.