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 THE INVENTION
A blanking plate for covering the turret of a power transformer
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR
Naynesh Sopan Belhekar of Crompton Greaves Ltd, Tl division, CG Global R&D Centre, Kanjur (E), Mumbai 400042, Maharashtra, India, an Indian National
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 a blanking plate for covering the turret of a power transformer. BACKGROUND OF THE INVENTION
An SFRA (sweep frequency response analysis) test is conducted on a power transformer to detect damages to the mechanical integrity of core, windings and clamping structures within the transformer. Usually, such damages may occur during the transit of the transformer from the manufacturing site to the installation site. The SFRA test of the transformer is the last electrical test prior to transportation and the first test after arrival thereof at installation site. To conduct the SFRA test at the manufacturing site, the bushings of the transformer are required to be installed on the turret of the transformer. The source lead of the SFRA testing equipment is then connected to the free end of the bushing and the test is conducted in the usual manner by the testing equipment. After the SFRA test and other tests are completed at the manufacturing site, the bushings are removed from the turret and packed separately. A blanking plate is mounted on the turret to seal the inside of the transformer. Thereafter, the transformer along with the bushings is transported to the installation site. At the installation site, the blanking plate is removed and the bushings and other components of the transformer are assembled. An SFRA test is then conducted as described above to detect damages to the mechanical integrity of core, windings and clamping structures within the transformer, if any. Therefore, there is a requirement of the bushings being installed on the transformer to conduct the SFRA test. Such is not desirable since the SFRA test may be required while the transformer is enroute,

especially when it travels through a combination of means such as by road, sea and/or air transport. For example, an SFRA test may be conducted at the sea-port or the airport where the transformer may have arrived from the manufacturing site by road or from the sea-port or while the transformer on the ship or at the destination sea-port or airport where it is unloaded. It is practically not feasible to mount the bushings on the transformer while its enroute although, SFRA test on a transformer enroute to its installation site during its transit is highly desirable. OBJECTS OF THE INVENTION
An object of the invention is to enable an SFRA test to be conducted on a transformer during transit thereof.
An object of the invention is to enable a hassle free SFRA test to be conducted on a transformer during transit thereof.
Another object of the invention is to enable an SFRA test to be conducted on a transformer during transit thereof without installing the bushings on the transformer.
Another object of the invention is to connect the SFRA test equipment to the windings of the transformer through the blanking plate. DETAILED DESCRIPTION OF THE INVENTION
According to the invention, there is provided a blanking plate for covering the turret of a power transformer, the blanking plate comprising a opening and a terminal board holding at least one terminal such that a portion of the terminal remaining disposed below the board and the rest above the board, the terminal board mounted on the opening and the terminal portion disposed below the terminal board being electrically connected to a winding lead in the turret through the opening.
Preferably, terminal board is mounted on the blanking plate through a flange mounted. The opening on the flange is smaller as compared to the opening on the

blanking plate. The portion of the terminal outside the turret is adapted to be connected to the SFRA testing equipment. The portion of the terminal inside the turret is connected to the winding lead through a connecting wire. A protective covering is provided to be placed on the terminal board.
These and other aspects,. features and advantages of the invention will be better understood with reference to the following detailed description, accompanying drawings and appended claims, in which,
Fig 1 is a cross sectional view of a blanking plate mounted on a turret of a transformer.
Fig 2 is an exploded view of a blanking plate mounted on a turret of a transformer.
Referring to the drawings, a blanking plate 1 is mounted on a turret 2 of the transformer in transit to seal the inside of the transformer. To facilitate SFRA test on the transformer during transit thereof without installing the bushings thereupon, the blanking plate 1 is adapted to be a connection medium between the SFRA testing equipment (not shown) and components such as core, windings and clamping structures (not shown) within the transformer. The blanking plate 1 is a circular plate corresponding to the shape of the opening of the turret 2 and comprises a small opening 3 carved out thereupon. A flange 4 having an opening 5 of a size less than the size of the opening 3 on the blanking plate 1 is mounted on the blanking plate 1 such that their respective openings correspond. The flange 4 is welded on blanking plate 1. Thereafter, a terminal board 6 is mounted on the flange 4 by means of nuts and studs. The terminal board 6 is a flat circular plate made up of an electrically insulating material such as epoxy and provided with a terminal 7 pierced there through such that a portion of the terminal remains disposed on the top and below the terminal board.

Within the turret 2, a connecting wire 8 is connected to the winding lead 9. The other end of the connecting wire 8 remains connected to the portion of the terminal 7 remaining disposed below the terminal board 6 mounted on the flange 4. The other end of the terminal 7 remaining disposed above the terminal board 6 is connected to the source lead of the SFRA testing equipment. A protective cap 10 is mounted on the flange 4 covering the terminal board 6.
While the transformer is in transit, to conduct the SFRA test on the transformer, the protective covering 10 is removed and the leads from the SFRA testing equipment is connected to the terminal portion remaining disposed atop of the terminal board 6. Once the SFRA test is completed, the protective covering 10 is lodged back.
It is obvious to a person skilled in the art since the SFRA test on the transformer in transit is conducted without the bushings installed on the transformer, the first and the last SFRA tests at the manufacturing and installation sites will also be required to be done without the bushings installed on the transformer. Although the SFRA test is described in the embodiment, other test(s) requiring the same setup as described herein may be carried out. The mention of only the SFRA test is not meant to be construed in a limiting sense. The blanking plate, flange, terminal board, terminal(s) and protective cover may be of a shape and/or size different from the shape and/or size described/shown herein. Use of the flange is optional. The terminal board may be mounted directly on the blanking plate. The flange and terminal board may be mounted using means other than nuts and bolts. They may also be manufactured integrated to the blanking plate. The number of terminals being provided in the terminal board corresponds to the number of winding leads in the

turret. The terminal(s) may be directly connected to the winding lead without any connecting wire(s) therebetween. The protective cover may or may not be provided.
According to the invention, the SFRA test can be conducted on a transformer during transit thereof without installing its bushings thereupon. Thus, any damage to the components within the transformer may be detected early, i.e. during transit before reaching the installation site, thereby saving a lot of transit time in returning the faulty transformer, if at all.
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the scope of the invention as defined in the appended claims.

We claim:
1. A blanking plate for covering the turret of a power transformer, the blanking plate comprising an opening and a terminal board holding at least one terminal such that a portion of the terminal remaining disposed below the board and the rest above the board, the terminal board mounted on the opening and the terminal portion disposed below the terminal board being electrically connected to a winding lead in the turret through the opening.
2. The blanking plate as claimed in claim 1, wherein the terminal portion disposed above the terminal board are adapted to be connected to an SFRA testing equipment.
3. The blanking plate as claimed in claim 1, wherein the terminal portion disposed below the terminal board are electrically connected to the winding lead in the turret through a connecting wire.
4. The blanking plate as claimed in claim 1, wherein the number of terminals in the terminal board corresponds to the number of winding leads in the turret.
5. The blanking plate as claimed in claim 1, wherein the terminal board is mounted on the opening of the blanking plate through a flange having a opening.

6. The blanking plate as claimed in claim 5, wherein the opening in the flange is smaller than the opening on the blanking plate.
7. The blanking plate as claimed in claim 1, wherein a protective cap is provided to cover the terminal board.