FIELD OF THE INVENTION:-
The invention relates to heating arrangement to carry out core heating
process efficiently during the manufacturing of Turbo generator core
related to Turbo generators of 600/660MW rating .
BACKGROUND OF THE INVENTION:-
Turbo Generator is an integral part of Thermal Power Stations, a Turbo
Generator consists two main parts, one is stator and another is rotor.
Stator comprises main component known as core which is made up of
laminated stampings of 0.5mm thick. A good quality core is needs to be
heated three times as it has insitu gluing of end packets, to get
compactness at the ends so that core does not loosen against vibrations.
First core heating is done at 1200mm height of core followed by 6450
and 6650 mm.
The invention discusses Turbo Generator of 600/660 MW rating. Turbo
Generator is made of the following major assemblies.
1. TG Stator
2. TG Rotor
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. Stator core is heated
three times as it involves insitu gluing of end packets. High compactness
is required at the ends zone, so that core does not loose against
vibrations. First core heating is done at 1200mm height of core followed

by 6450 and 6650mm. Heating is done by attaining 80 degree
temperature and maintaining 80 to 85 degree temperature for hours.
Two angle plates are used for assembly of core diametrically opposite to
each other. Length of these angle plates are generally 10 meter. Two
heaters of 82.5 KW capacities each (Total 165KW capacity) is used to
heat the core with an arrangement of blower installed in the unit. The
whole arrangement is attached to a cover and this is kept at a height of
10 meter (i.e over the angle plate), the height of cover is itself 2000 mm
so the total height on which the heater becomes 12000 mm(Approx). A
long telescopic pipe is attached to the heater to guide the hot air in to the
bore of core. A fan is mounted on the top of heater which forces air
through the heater, hot air comes in contact of core and core gets heated
up. After heating the core, air returns back toward top and circulate in a
closed chamber made by the heating cover at the top and asbestos cloth
around the outer diameter of core as shown in Fig. 1.
During the operation of heating with the present set up, following
problems were faced (Refer fig 4(1, 2)):
1. Long time taken for heating process: Major heat loss takes place
during the travel of hot air heater to the core through telescopic pipe
Total travel length is approximately 9000 mm; as a result it takes a lot of
time to attain the required temperature. Also it consumes a lot of
electricity as 2 heaters of 82.5 KW each has been used and are working
for longer time.
2. Consumption time for arrangement of heating: As heating installation
has to be placed on the top of angle plates an extra setup is needed over
the angle plate.
3. Handling of heating installation with longer telescopic pipe: Care is
taken for handling the long telescopic pipe to avoid it from being

damaged and also extra man power is required.
4. Safety for the workman at the top: In the existing art an operator has
to work at a height of 11 to 14 meters which is unsafe without proper
safety equipment.
The heating process is carried out at top most height of angle plate,
approximately 10 meter from the base plate. At high altitude it takes
more time to achieve the desired parameter for heating and more energy
consumption.
To overcome the constraints, an alternate heating installation cover has
been developed.
OBJECT OF THE INVENTION:-
An object of invention is to reduce the cycle time involved in the core
heating process.
Another object of the invention to reduce the time cycle of operation in
600/660 MW Turbo Generator stator core.
DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS:-
Figure 1 shows Prior Art that is Process Mapping chart for Heating
operation.
Figure 2 shows pictoral view of core heating as per prior art.
Figure 3 shows pictoral Photographic view of core heating as per prior
art.
Figure 4 shows Developed heating arrangement in accordance to the
invention.
Figure 5 shows Unwound Core in accordance to the invention.

Detailed Description OF A Preferred Embodiment OF The Invention:-
Figure 4 shows the developed installation cover in accordance to the
invention. To develop cover for heating installation the following parts are
used.
1. Base Ring (item No 1}
2. Support (item No 2)
3. Body with Insulated (item No 3)
Covering
4. Ladder (item No 4)
5. Top Platform (item No 5)
6. Top Railing (item No 6)
1. Base ring:
Base ring (1) is the bottom ring on which the whole structure rests.
2. Support:
Four supports (2) are welded at the corners to provide adequate strength
to structure.
3. Body with insulated covering:
Outer body (3) consists of thin (3mm approx) MS sheet to make a casing.
Glass wool insulation will be provided around to the outer surface.
4. Ladder:
A ladder (4) is provided from the base ring through outer cover to reach
at the top for electrical connections and assembly of heating unit.
5. Top Platform:
Top plate (5) is used to hold and support heater and blower fan that
includes railing and panels for the electrical supply connections.
6. Railing:
Railing (6) is provided for the safety of workman.

Assembly of heating arrangement:
Base ring (1) is made up of 10mm thick MS sheet. This provides
foundation to the whole assembly. Four Vertical supports of approx.2
meter height (2) is welded at the corners of base ring . 3mm MS plate (3)
is welded around covering vertical support (2). Top Platform (5) is
assembled on the top of the structure. Top Railing (6) is provided on Top
Platform (5) for the safety purpose. Ladder (4) is welded to the outer side
of structure to reach up to the top of the arrangement.

We claim :-
1. A modified heating installation cover for a turbo generator stator core
comprising:
- base ring (1) to form a foundation;
- plurality of vertical support (2) welded at the corner of the base ring (1)
- outer body (3) as a casing made of thin MS sheet wherein glass wool
insulation is provided at the outer surface.
- a ladder (4) at the base ring through outer cover extended to the top
portion of the installation to access electrical connections and heating
assembly unit.
- a top plate (5) to support heater and blower fan.
- a railing (6) above the said top plate.
2. A modified heating installation cover for a turbo generator stator core
as claimed in claim 1, wherein the turbo generator stator core is within
the range 600-660 MW.
3. A modified heating installation cover as claimed in claim 1, wherein
the railing is equipped to provide safety to the operator.