FIELD OF INVENTION
The present invention relates to a lifting fixture for lifting and inserting unwound
core(s) of 600/660 MW turbo generator into a stator frame.
BACKGROUND OF INVENTION
The generator is one of the important parts of Thermal Power Stations. The
Turbo Generator consists of two main parts, one is a Stator and the another a
Rotor.
The stator has a main component known as core, which is made up of laminated
stampings of 0.5mm thickness. The length of the core is 6650 mm and the
weight of complete unwound core is 195 tons. This core is manufactured
separately, i.e. outside the stator frame and the same needs to be lifted
vertically for insertion into the stator body. The complete weight of the core after
baskets mounting becomes approximately 205 Tons. After insertion of this core
into the stator body, the bushes are welded. One side of the bush is welded on
the pad provided on the basket and the other side is welded to the stator body.
Thus, a complete unwound core is manufactured. The field of invention is related

to the development of lifting fixture for core so that it can be lifted and inserted
vertically in to the stator body.
As per present practice single stud is used and assembled to the bottom plate
through nut. This takes longer time for the assembly.
Following constraints were noticed during the process:
■ Longer time required for assembly.
■ More power consumption.
■ More manpower required to complete the job.
■ Less safe to workman.
■ Higher fatigue.
OBJECTS OF THE INVENTION
Therefore, it is an object of the present invention to propose a lifting fixture for
lifting and inserting unwound core(s) of 600/660 MW turbo generator, which is
capable of reducing the time required for assembly compared to prior art.

Another object of the present invention is to propose a lifting fixture for lifting
and inserting unwound core(s) of 600/660 MW turbo generator, which is able to
reduce power consumption and manpower requirement to complete the job
compared to prior art.
A further object of the present invention is to propose a lifting fixture for lifting
and inserting unwound core(s) of 600/660 MW turbo generator, which is capable
of providing more safety to the workmen compared to prior art.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig.l - shows a fixture assembled with lifting studs, ring, locknut and
coupler according to the invention.
Fig.2 - shows an assembled fixture according to the invention.
Fig.3 - shows a lifting stud used in the fixture.
Fig.4 - shows a coupler used in the fixture.
Fig.5 - shows a lock nut used in the fixture.

Fig.6 - shows a ring for accommodating the studs used in the fixture.
Fig.7 - shows an unwound core.
Fig.8 - shows the lifting fixture with unwound core.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Present invention is related to the Turbo Generator of 600 / 660 MW rating.
Turbo Generator is made of the following major assemblies.
1. TGStator
2. TG Rotor
The invention made is used in the TG Stator Core (Fig.7). Core is one of the
major components of Stator and is a part of Turbo - Generator, with main
function as providing path to the rotating flux produced by the rotation of rotor
in turbo generator. This core is attached to the stator body through the springs,
spring baskets & bushes to the stator body.

In order to overcome the constraints and disadvantages of prior art, a fixture (1)
is made to lift core assembly (7) after assembling of core bars and welding of
spring Baskets. The fixture (1) is manufactured with the following items: i) lifting
studs (3); ii) coupler (4); iii) lock nut (5) iv) ring (6) for stud.
Three rings (6) of mild steel are made having the hole diameter of 100 mm at
the same pitch circle diameter as in the transport, assembly plate (11) and top
lifting fixture plate (13). These rings are locked through nut (5) provided on both
sides of the rings (6).
Two studs (3) with length of 4 m each, having diameter M99 are joined with the
help of coupler (4) to make a single stud length of 8 meter. The studs (3) pass
through Pitch circle diameter (PCD) holes of the ring (6). Total 3 couplers are
required for assembling 4 studs of 4 m length to make the total length of stud as
16 m. A total No of 8 nos. of 16 m studs go inside the 8 holes of rings (6) and
transport and assembly plate (11) and lifting fixture top plate (13). Three
number of rings (6) are assembled in the fixture (1). The lock nut (5) locks the
ring (6) with the coupler (4) and the stud (3). The fixture (1) is inserted from the

Turbine end side of the core into the core through the PCD holes of the lifting
fixture plate (13) at the top attached to the lifting fixture top (12). The 8 nos,
studs (3) are locked on the top plate (13) with split nut and ring (9, 10). The
lifting fixture top is for providing facility to lift and insert the fixture (1). As the
fixture is inserted in the core, 8 nos. of lifting studs pass through 8 holes of
transport and assembly plate (11) disposed at the exciter end of the core and
the studs (3) are locked with special nut (8).
Now, as the fixture has been inserted into the core and locked with the top
plates (13) at the top and transport and assembly plate (11) at bottom, the core
can be lifted with this lifting fixture (1) for insertion into the stator frame.

WE CLAIM
1. A lifting fixture (1) fixture for lifting and inserting unwound core(s) of
600/660 MW turbo generator into stator frame comprising:
a plurality of lifting studs (3);
a plurality of couplers (4) for joining two studs (3);
a plurality of lock nuts (5) for locking the rings (6);
a plurality of rings (6) having pitch circle diameter holes;
a lifting fixture top plate (13) having PCD holes;
a transport and assembly plate (11) having PCD holes;
wherein the studs are joined with coupler (4), the ring are locked with
locking nut (5) when the studs (3) are inserted through the PCD holes of
the rings (6), transport and assembly plate (11) and lifting fixture plate
(13) and locked with special nut (8) at the exciter end and with split nut
and ring (9,10) at the turbine end.
2. A lifting fixture as claimed in claim 1, wherein the rings (6) the lifting
fixture plate (13) and the transport and assembly plate (11) have each 8
numbers of PCD holes of 100 mm diameter.

3. A lifting fixture as claimed in claim 1, wherein two studs of 4 m are joined
with a coupler (4).
4. A lifting fixture as claimed in claim 1, wherein 8 nos. of assembled studs
are used in the fixture.