FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF INVENTION
A CURRENT TRANSFORMER ASSEMBLY
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company.
INVENTOR (S):
Kulkarni Shashank and Gupta Himanshu; both of Crompton Greaves Ltd, Transformer (Tl) Division, Kanjurmarg (E), Mumbai - 400 042, Maharashtra, India; both 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 Power transformers and transformer assemblies.
Particularly, this invention relates to current transformer assembly.
Background of the Invention:
A turret is a raised structure on the top of cover of the transformer, usually round in section in which the bushing is mounted. Turrets are usually used to mount large bushings where the bushing would otherwise intrude excessively into the tank, requiring the tank to be increased in size. The turret is often a location for mounting current transformers on the oil side of the bushing.
A transformer turret is contained in the transformer tank and it, as well as the bottom part of the bushing, is immersed in oil. The inside of the turret contains a current transformer which measures the amount of current flowing in or out of the power transformer.
Current transformer assembly uses top and bottom plates, tightened by studs and assembled in pre-determined locations in turrets. There is a clearance provided between the internal diameter of the turret housing and the external diameter of the current transformer. These studs are typically MS studs. The clearance is necessary for insulation purposes. The plates (top and bottom) are also MS plates in a typical assembly. Transformer oil is filled in the turret to fill the gaps between the turret and the current transformer and any possible gap there-between.

The gap is also required because currently the current transformer assembly is pre-assembled, and the same is then inserted by means of a hoisting mechanism. The gap at the edges provides play for the fixture of the hoisting mechanism for easy insertion and retraction.
There is a need for having minimal turret size, optimum use of bushing current transformer mounting space, and eventually reducing the overall size of the transformer resulting in reduction of material content viz. oil, mild steel and transport dimensions of the power transformer.
Objects of the Invention:
An object of the invention is to provide a current transformer assembly with relatively reduced assembly size.
Another object of the invention is to reduce the consumption of transformer oil.
Yet another object of the invention is to have a relatively higher current transformer size within the same space as that of the prior art.
Still another object of the invention is to provide an in-built arrangement in the current transformer assembly for providing easy insertion of current transformer by means of a hoisting mechanism.

Summary of the Invention:
According to this invention, there is provided a current transformer assembly having a turret adapted to house current transformers, said assembly comprises:
a. fibreglass fasteners used in order to fasten top plate of said turret with said
current transformers located in said turret, thereby reducing the gap between
inner diameter of said turret and outer diameter of said transformers; and
b. wooden support board with fixtureless lifting arrangement provided at the
base of said turret which receives said current transformers which are
inserted into said turret, said wooden fixture includes slots and cuts running
diametrically across said fixture in order to assist the removal of lifting belts
once the said current transformers are hoisted into said turret by means of a
hoisting mechanism.
Typically, said assembly includes supporting lugs provided at turret wall to support transformer assembly.
Typically, said assembly includes wooden strips inserted in the gap between said transformers and said turret for purposes of packing.
Brief Description of the Accompanying Drawings;
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1a illustrates a top view of the current transformer assembly;

Figure lb illustrates a front view of the current transformer assembly; and Figure 2 illustrates a schematic view of the wooden support board.
Detailed Description of the Accompanying Drawings:
According to this invention, there is provided a transformer assembly adapted to house current transformers.
Figure la illustrates a top view of the transformer assembly.
Figure lb illustrates a front view of the transformer assembly.
In accordance with an embodiment of this invention fibreglass fasteners (12) are used in order to fasten current transformer assembly and engaged by top plate of turret (06) with current transformers (04) located in said turret. Fibreglass is an insulating material and hence, gap between the inner diameter of the turret and the outer diameter of the current transformer may be reduced as more insulation is not needed to the extent of which is provided in the prior art. Further, wooden strips (14) are inserted in the gap for purposes of packing. The stud of the fastener prevents movement of the current transformer in the turret.
The core of the current transformer has a central hole (16) through which bushings is inserted.

Reference numeral 19 refers to supporting lugs of turret wall to support current transformer assembly.
Figure 2 illustrates a schematic view of the wooden support board.
In accordance with another embodiment of this invention, a wooden support board (18) with fixtureless lifting arrangement is provided at the base of said turret (06) which receives the current transformers (04) which are inserted into the turret (06). This wooden fixture (16) includes slots (22) and cuts (24) running diametrically across the fixture in order to assist the removal of lifting belts once the current transformers (04) are hoisted into the turret (06) by means of a hoisting mechanism. Thus, the additional clearance is done away with from the sides.
Since the bushings are passed through the centre, in the event that the transformer size is to be increases, the length of the bushings need to be increased or the height need to be increased. This results in longer of wider bushing. In accordance with the prior art, a gap of about 100 mm is to be maintained between the transformer and the turret. Thus, as the bushing size increases in length or in height, the transformer size subsequently increased. This results in increase in capacity of oil in the current transformer assembly with turret, which subsequently results in increased costs.
Due to this invention, the gap (of about 100 mm) between the current transformer and turret is reduced. This extra gap now provided play for increase in transformer size without need to increase the turret size and without the need to increase oil amount and related costs. This results in economic significance contributing to the inventive step of this invention,

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. A current transformer assembly having a turret adapted to house current
transformers, said assembly comprising:
a. fibreglass fasteners used in order to fasten top plate of said turret with said
current transformers located in said turret, thereby reducing the gap between
inner diameter of said turret and outer diameter of said current transformers;
and
b. wooden support board with fixtureless lifting arrangement provided at the
base of said turret which receives said current transformers which are
inserted into said turret, said wooden fixture includes slots and cuts running
diametrically across said fixture in order to assist the removal of lifting belts
once the said current transformers are hoisted into said turret by means of a
hoisting mechanism.
2. An assembly as claimed in claim 1 wherein, said assembly includes supporting lugs provided at turret wall to support transformer assembly.
3. An assembly as claimed in claim 1 wherein, said assembly includes wooden strips inserted in the gap between said transformers and said turret for purposes of packing.