FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
An evaluation assembly for solid insulation drying.
APPLICANTS:
Crompton Greaves Limited, CG House, Dr. Annie Besant Road, Worli, Mumbai -400030, Maharashtra, India, an Indian Company
INVENTOR
Sahasrabudhe Mayuresh, Chaudhari Sushil Ekanath and Lobo Anthony ail of Crompton Greaves Ltd, Conition Monitoring & Diagnostic Research Centre, CG Global R&D Centre, Kanjur Marg (E), Mumbai 400042, Maharashtra, India, all Indian Nationals
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

FIELD OF THE INVENTION:
This invention relates to the field of mechanical fixtures, assemblies, and engineering.
Particularly, this invention relates to an evaluation assembly for solid insulation drying.
BACKGROUND OF THE INVENTION:
Transformers are an integral part of power systems in order to step up voltage, step down voltage and the like functions. Transformer is a device which transfers electrical energy from one circuit to another through inductively coupled conductors i.e. through transformer's coils. The transformer coils are immersed in oil which acts as an insulator and dielectric medium.
Shunt reactors contain the same components as power transformers, like windings, core, tank, bushings and insulating oil and are suitable for manufacturing in transformer factories. The main difference is the reactor core limbs, which have non-magnetic gaps inserted between packets of core steel.
Both electrical equipment (transformers and shunt reactors) include windings. Windings can be appropriately designated as High Voltage (HV) and Low Voltage (LV) windings. Windings are, typically, of enamel coated copper conductors and wound in disc type arrangement. The windings have a solid insulation of refined paper, and highly refined mineral oil is the insulating and cooling medium for the entire reactor. The insulation used in the case of electrical conductors in a transformer is varnish or enamel in dry type of transformers. To improve the heat

transfer characteristics the conductors are insulated using un-impregnated paper or cloth and the whole core-winding assembly is immersed in a tank containing oil.
The oil thus has dual role. It is an insulator and also a coolant.
Excessive moisture in transformers causes problem. The solid insulation in the transformers is attacked by water, as cellulosic material is hygroscopic and attracts moisture. In transformers, the oil acts as a transfer medium and its ability to dissolve water increases with temperature. Temperature leads to molecular chain scission of cellulosic insulation and forms byproducts like carbon oxides, water and fiiranic compounds.
It is necessary to evaluate the solid insulation to observe its drying characteristics in an evaluation assembly.
OBJECTS OF THE INVENTION:
An object of the invention is to provide an assembly to evaluate the solid insulation drying parameters.
Another object of the invention is to provide an assembly to check, evaluate, and improve drying efficiency of autoclave process.
Yet another object of the invention is to provide an assembly for experimental investigation of solid insulation drying.

Still another object of the invention is to provide an assembly to evaluate the effect of temperature on insulation drying and rate of moisture removal under temperature and vacuum.
An additional object of the invention is to provide an assembly for improving the efficiency of drying process of solid cellulosic insulation.
Yet an additional object of the invention is to provide an assembly for checking the efficiency of drying process of solid cellulosic insulation.
Still an additional object of the invention is to provide an assembly for evaluating change in height during solid insulation drying in order to determine optimum load.
Another additional object of the invention is to provide an assembly for determining optimum load, for solid insulation drying, for a given configuration of disc windings and insulation medium.
Yet another additional object of the invention is to provide an assembly for determining effect of load, for solid insulation drying, for a given configuration of disc windings and insulation medium.
SUMMARY OF THE INVENTION:
According to this invention, there is provided an evaluation assembly for solid insulation drying, said assembly being an enclosure adapted to enclose stacks of

disc windings and insulation windings according to their formation of a core and further comprises:
a. roschelling wood plate adapted to be co-axially placed at the operative top
and at the operative bottom of the stacked formation of disc windings and
insulation windings;
b. metal plate adapted to be co-axially placed at the operative top and at the
operative bottom of the placed roschelling wood plate over the stacked
formation of disc windings and insulation windings;
c. load sensor adapted to be placed over said metal plate in order to sense load
application to said formed core;
d. temperature sensor adapted to sense temperature of said formed core; and
e. control panel adapted to receive sensed load readings and sensed
temperature readings in order to evaluate effect of load on drying of
insulation of said formed core.
Typically, said assembly is an enclosure adapted to hold said formed core in a spaced apart manner with respect to walls of said enclosure.
Typically, said assembly comprises locating studs; an upper stud and a lower stud, adapted to be co-axial with the formed core of disc windings and insulation windings.
Typically, said disc windings are aluminum disc wrapped with layers of kraft/creep paper and pressboards.
Typically, said formed core comprises a stack of spacers (pressboards) placed between two aluminum discs wrapped with layers kraft/creep paper.

Typically, said assembly comprises gas filling valve means in order to fill the enclosure / assembly with inert gas such as N2 or Argon.
Typically, said assembly comprises two hard steel plates at the top of said formed metal plate adapted to mount said load sensor between them
Typically, said assembly comprises a control panel adapted to read the load sensor readings.
Typically, said control panel comprises temperature control means adapted to control temperature parameters in said assembly.
Typically, said control panel comprises means to receive and store load sensor readings.
Typically, said control panel comprises means to receive and store temperature sensor readings.
Typically, said control panel comprises time duration control means adapted to control time parameters in said assembly.
Typically, said control panel comprises computation means adapted to perform computations in relation to readings received by said control panel.
Typically, said assembly comprises height measurement means adapted to measure height of said formed core during drying.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a front sectional view of the evaluation assembly; and
Figure 2 illustrates a top sectional view of the evaluation assembly.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided an evaluation assembly for solid insulation drying.
Figure 1 illustrates a front sectional view of the evaluation assembly.
Figure 2 illustrates a top sectional view of the evaluation assembly.
In accordance with an embodiment of this invention, there is provided an assembly (100) adapted to enclose stacks of disc windings (12) and insulation windings (14) according to their formation of a core. The assembly is, typically, an enclosure adapted to hold the formed core in a spaced apart manner with respect to the walls of the enclosure. The assembly includes locating studs; an upper stud (16) and a lower stud (18), adapted to be co-axial with the formed core of disc windings and insulation windings. The disc windings are aluminum disc wrapped with layers of kraft/creep paper and pressboards. Further, there is a stack of spacers (22)

(pressboards) placed between two aluminum discs wrapped with layers kraft/creep
paper.
In accordance with another embodiment of this invention, there is provided a
roschelling wood plate (20) adapted to be co-axially placed at the operative top and
at the operative bottom of the stacked formation of disc windings and insulation
windings.
In accordance with yet another embodiment of this invention, there is provided a metal plate (30) adapted to be co-axially placed at the operative top and at the operative bottom of the placed roschelling wood plate over the stacked formation of disc windings and insulation windings.
The roschelling wood plate and metal plate are adapted to put load pressure on the formed core of disc windings and insulation windings. The assembly is adapted to include a gas filling valve means in order to fill the enclosure / assembly with inert gas such as N2 or Argon.
In accordance with still another embodiment of this invention, there is provided a load sensor (50) adapted to be placed over the metal plate in order to sense load application to the formed core. Typically, the load sensor is mounted between two small hard steel plates (52a, 52b) and the locating studs at the top of the assembly.
In accordance with an additional embodiment of this invention, there is a control panel adapted to read the load sensor readings. Typically, the control panel is also adapted to control temperature parameters in the assembly. The control panel also provides time duration control.

The assembly is mainly provided to study the effect of load and temperature of solid insulation drying. It is also used evaluate effect of temperature on insulation drying and rate of moisture removal under temperature and vacuum. Further, the assembly can be used for studying the effect of load in change in height of the formed core.
The results from the control panel of this assembly can be used for improving / checking the efficiency of drying process of solid cellulosic insulation. Also, the results can be used for studying effect of load on drying and in order to find optimum load for drying.
According to a non-limiting exemplary embodiment, the following experiments were conducted:
The autoclave experiment condition and results are tabulated in Table 1: Table 1: AUTOCLAVE EXPRIMENT @ 100 degreeC Air Heating + Vaccum

Disc Bare AL Weight Weight After Weight %
no. Disk After 8 Drying loss in Moisture
weight layer of Experiments grams Reduction
creap paper in gms in gms on weight basis
3 806.65 916.7 911.61 5.09 0.55525254
4 802.86 906.8 902.43 4.37 0.48191442
5 799.04 896.29 892.15 4.14 0.46190407
6 697.24 808.8 804.04 4.76 0.58852621
3105.79 3528.59 3510.23 18.36 2.08759724
Table 1

From the above table 1, changes in moisture reduction, of creep paper, as a function of load change can be seen.
Table 2 : Observation of change in thickness of Disc during drying process:

Disc No 3
Location 1 Location
2 Location 3 Location 4
Thickness before drying in mm 15.25 15.56 15.88 16.28
Thickness After drying in mm 12.94 13.95 13.94 14.54
Change in thickness in mm 2.31 1.61 1.94 1.74
Thickness after 36 hrs atm exposure 13.64 13.56 13.79 13.68
Change in thickness in mm after 36 hrs 0.7 -0.39 -0.15 -0.86
Thickness after drying with pressboard stack impression 11.54 .11.9 11.96 12.24
Change in thickness in mm 3.71 3.66 .. 3.92 4.04
Table 2
From the above table 2, changes in thickness during the process of drying can be seen.

The technical advancement of this invention lies in provisioning an assembly which incorporates disc windings and insulation windings under added load. The assembly is further adapted to sense load, time, temperature parameters and its effects on solid insulation drying on the disc windings.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. An evaluation assembly for solid insulation drying, said assembly being an
enclosure adapted to enclose stacks of disc windings and insulation windings
according to their formation of a core and further comprising:
a. roschelling wood plate adapted to be co-axially placed at the operative
top and at the operative bottom of the stacked formation of disc
windings and insulation windings;
b. metal plate adapted to be co-axially placed at the operative top and at
the operative bottom of the placed roschelling wood plate over the
stacked formation of disc windings and insulation windings;
c. load sensor adapted to be placed over said metal plate in order to
sense load application to said formed core;
d. temperature sensor adapted to sense temperature of said formed core;
and
e. control panel adapted to receive sensed load readings and sensed
temperature readings in order to evaluate effect of load on drying of
insulation of said formed core.
2. The assembly as claimed in claim 1, wherein said assembly being an enclosure adapted to hold said formed core in a spaced apart manner with respect to walls of said enclosure.
3. The assembly as claimed in claim 1, wherein said assembly comprising locating studs; an upper stud and a lower stud, adapted to be co-axial with the formed core of disc windings and insulation windings.

4. The assembly as claimed in claim 1, wherein said disc windings being aluminum disc wrapped with layers of kraft/creep paper and pressboards.
5. The assembly as claimed in claim 1, wherein said formed core comprising a stack of spacers (pressboards) placed between two aluminum discs wrapped with layers kraft/creep paper.
6. The assembly as claimed in claim 1, wherein said assembly comprising gas filling valve means in order to fill the enclosure / assembly with inert gas such as N2 or Argon.
7. The assembly as claimed in claim 1, wherein said assembly comprising two hard steel plates at the top of said formed metal plate adapted to mount said load sensor between them
8. The assembly as claimed in claim 1, wherein said assembly comprising a control panel adapted to read the load sensor readings
9. The assembly as claimed in claim 1, wherein said control panel comprising temperature control means adapted to control temperature parameters in said assembly.
10.The assembly as claimed in claim 1, wherein said control panel comprising means to receive and store load sensor readings.
11.The assembly as claimed in claim 1, wherein said control panel comprising means to receive and store temperature sensor readings.

12.The assembly as claimed in claim 1, wherein said control panel comprising time duration control means adapted to control time parameters in said assembly.
13.The assembly as claimed in claim 1, wherein said control panel comprising computation means adapted to perform computations in relation to readings received by said control panel.
14.The assembly as claimed in claim 1, wherein said assembly comprising height measurement means adapted to measure height of said formed core during drying.