FIELD OF INVENTION:-
The present invention relates to an improved adhesive for filling of insulation cap
in hydro generator. The adhesive is made of a combination of insulation
materials suitable for hydro generator.
BACKGROUND OF INVENTION:-
The insulation cap plays an important role of hydro generator which housed the
insulation paste inside it. The cap provides an insulation in between the two bare
joints which otherwise, a flash could occur between these joints and may
damage both the conductor as well as insulation. During assembly of insulation
cap some minimum working space is required between the caps so that a worker
can dress and assembled the insulation cap on the conductor. Sometimes due to
design constraint the minimum working space between the two caps is not
available and hence existing practice of assembly of insulation cap is not possible
in any way. So, a new method of assembly of insulation cap with different filling
material which can adopted in such type of design is invented which is not only
easy, cost effective and also improves aesthetic of the job. Presently in the
existing practice, insulation cap after assembly is filled with Epoxy insulation
liquid comprises of an Araldite and hardener mixture from the top of cap which
then solidifies within 12 - 24 hours. This insulation cap along with insulation
liquid becomes integrated part of the winding. But this system of assembly of
insulation cap does not work when the internal diameter of the stator is less,
numbers of slot is higher and slot width is more (i.e. lesser slot pitch/slot width
ratio).
One major drawback of old system is that there is chance of seepage of epoxy
material from the if cap is not sealed properly (as epoxy is in liquid form) and
entering into the slot portion having winding and damaging the winding and to
remove damage winding and clean the slot is very costly and time taking.
OBJECTS OF THE INVENTION:-
It is therefore, an object of the present invention to propose an improved
adhesive for filling of insulation cap in hydro generator which eliminates the
problems of existing state of art.
Another object of the present invention is to propose an improved adhesive for
filling of insulation cap in hydro generator which reduces the assemble time.
A further object of the present invention is to propose an improved adhesive for
filling of insulation cap in hydro generator which saves cost as quantity of costly
material has reduced drastically.
An yet further object of the present invention is to propose an improved
adhesive for filling of insulation cap in hydro generator which improves quality
aesthetic.
A still further objective of the present invention is to propose an improved
adhesive for filling of insulation cap in hydro generator which avoids seepage of
adhesive material into the slot and damage to slot and winding.
SUMMARY OF THE INVENTION:-
The present invention is provided with an improved adhesive for filling of
insulation cap in hydro generator comprising a mixture of compound of an
Araldite resin CY 230 (100 parts) a Hardener HY 951 (10-13 parts), a base
material 200-300 grams (fine silica sand powder as per IS. 67-1967 grade 2, 400
mesh), and the Araldite and the resin Hardener are mixed in a container and stir
for 10-12 minutes, thereafter the base material is added to make a
homogeneous semi-solid paste.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:-
Fig. 1: A photo figure of brazed joint of the conductor.
Fig. 2: A photo figure of insulated nose joint.
Fig. 3: A photo figure of Epoxy Compound.
Fig. 4: A photo figure of Epoxy Compound in insulation cap.
Fig. 5: A photo figure of assembly of insulation cap.
Fig. 6: A photo figure of dressing of insulation cap.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION:-
The present invention provided with an improved adhesive for filling insulation
compound made of
1. Araldite resin CY 230 (100 parts)
2. Hardener HY951 (10-13 parts)
3. Base material (Five silica powder as per Indian Standards 67-1979 grade-
2. mesh - 400) - 200 to 300 grams.
In a container, the Araldite and Hardener Components are mixed in the pre-
defined ration and stirred for 10 minutes for homogeneous solution. Thereafter,
a base material is added till the solution becomes semi-solid (Photo-3). Then this
paste is poured in the prepared insulation cap about 2/3 of the height of the cap
(Photo-4). This adhesive filled cap is put over the dress joint and pushed gently
over it, malleting is used if required. The extra adhesive which flows out of cap is
put again in the cap from inside of the cap using a strip till the paste flowing and
solidify. Likewise all the joints are covered with insulation cap with tapered
wedge (Photo-5) in between so that proper distance is maintained between the
cap.
The conductors are brazed joint. After brazing of a series of joints (See photo-1).
The joint is dressed nicely by grinding to reproduce smooth finish surface. Then
the joint is insulated around the 'nose' portion (Photo-2) so that the insulation
cap can fit tightly and no base conductor of copper is exposed. After this a cap
sealing segment (Photo-1, 2) is put in between the series connections and held
tightly by glass tape (Photo 1, 2) in between cap sealing segment a piece of
polyester felt is placed (Photo-2) so that the position of cap sealing segment do
not disturb while assembly of insulation cap.
COST SAVINGS:-
The total cost saving includes (1) material saving and (2) Man-hour saving due
to reduction in assembly which amounts to Rs. 79 lakhs for implementation of
new adhesive material of filling insulation cap in hydro generator.
WE CLAIM:-
1. An improved adhesive for filling of insulation cap in hydro generator comprises
a mixture of compound :
— an Araldite resin CY 230 (100 parts)
— a Hardener HY 951 (10-13 parts)
— a Base material 200-300 gram (Fine silica sand powder as per IS-67-1967
grade-2 400 mesh).
2. The adhesive as claimed in claim 1 wherein Araldite and Hardener are mixed
in one container and then stirred for 10 minutes and thereafter base material
is added to give a homogeneous solution.
3. The adhesive as claimed in claim wherein the filling adhesive cap solidifies
within 2-3 hours.
4. The process for sealing cap with the adhesive as claimed in claim 1 wherein
— brazed joint surfaces are smoothened by grinding
— filled the cap with adhesive upto 2/3 of the height of cap
— put the cap over the dressed joint and pushed gently over it.
— put the cap sealing segment in between the series connection and held
tightly by glass tape.
— placed a piece of polyester felt in between the cap sealing segment.

An improved adhesive for filling of insulation cap in hydro generator comprises
a mixture of compound : an Araldite resin CY 230 (100 parts); a Hardener
HY 951 (10-13 parts) and a Base material 200-300 gram (Fine silica sand
powder as per IS-67-1967 grade-2 400 mesh) and the resin Hardener are mixed
in a container and stir for 10-12 minutes, thereafter the base material is added
to make a homogeneous semi-solid paste.