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
Gapped core reactor having an improved packet density
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Shankar Ramanan, Shubhangi Kulkarni, Vikrant Joshi of Design Department, Power Transformer Division (Tl), Crompton Greaves Ltd., Kanjur Marg (East), Mumbai -400042, Maharashtra, Indian, 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
The present invention relates to a gapped core reactor having an improved packet density.
BACKGROUND OF THE INVENTION
A gapped core reactor comprises a plurality of packets arranged in a stacked manner on top of one another. Each packet is formed by packing a plurality of identical lamination sets, where each lamination set comprises a plurality of lamination sheets, preferably Silicon-steel sheets.
The packets of existing gapped core reactors have a packet density of around 89%-90% i.e. only this much amount of available packet area is occupied by the laminations, rest is occupied by casting material. In the gapped core reactor, when the area occupied by the laminations is less, more copper is required in the windings of the core.
As the packet density increases, the amount of copper required in the windings can be decreased, resulting in decrease of overall cost of the reactor. Hence, there is a need for a gapped core reactor having improved packet density.
DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION
Various embodiments of the present invention provide a gapped core reactor having an improved packet density and comprises a plurality of packets arranged in a stacked manner, each packet being of cylindrical shape and formed by packing a plurality of identical lamination sets, each lamination set comprising a plurality of laminations of

similar height and thickness, arranged adjacent to each other along their height in order of decreasing width, wherein widths of at least first five laminations of a lamination set are similar and the widths of subsequent laminations are in arithmetic progression with a negative common difference of at least 5mm.
Preferably, the packet is formed by packing 200-500 identical lamination sets, each lamination set comprising first five laminations having width of 100-500mm and subsequent laminations having widths in arithmetic progression with a negative common difference of 5-20mm.
Preferably, the area occupied by the 200-500 identical lamination sets of the packet is estimated to be 93%-98% of available area of the packet.
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.l is a front view of a gapped core reactor in accordance with various embodiments of the present invention;
Fig. 2 is a top view of a packet comprising a plurality of lamination sets in accordance with an embodiment of the present invention; and
Fig.3 is a perspective view of the packet in accordance with an embodiment of the present invention.

Referring now to Figs. 1-3, a gapped core reactor 100 is shown which comprises a plurality of packets 10(1), 10(2)....10(n) arranged in a stacked manner. The packets
10(1), 10(2) 10(n) are stacked on top of one another to form core of the reactor 100.
Every two adjacent packets of the packets 10(1), 10(2)... 10(n) are separated by a ceramic disc 11(1), 11(2), and the like.
Each of the packets 10(1), 10(2)....10(n) is of cylindrical/disc shape and is formed by packing a plurality of identical laminations sets together. For example, the packet 10(1) is formed by arranging approximate 200-500 sets of laminations together. However, only three lamination sets 20, 21 and 22 are illustrated in Fig.2 for the sake of explanation and clarity.
Each lamination set 20, 21 and 22 is made from a plurality of lamination sheets, preferably, Silicon-steel sheets. For example, the lamination set 20 comprises a plurality of laminations 20(1), 20(2), 20(3), 20(4)....20(x). The laminations 20(1), 20(2), 20(3), 20(4)....20(x) have similar height and thickness, and are arranged adjacent to each other along their height, in order of decreasing width.
Referring to Fig.3, the laminations 20(1), 20(2), 20(3), 20(4)....20(x) are joined together along their height. The width of first five laminations 20(1), 20(2)....20(5) of the lamination set 20 is similar, whereas the widths of subsequent laminations are in arithmetic progression with a negative common difference of at least 5 mm. Arranging laminations 20(1), 20(2), 20(4)....20(x) in such a manner minimizes the gap in the lamination set 20. A plurality of identical lamination sets 20 are packed together to form a packet 10(1).

Thus, improvement in alignment and dimensions of laminations has resulted in improved packet density. The packet density has improved to 93-98% of available area, which is an optimum value. Also, packing more core material into given area reduces quantity of copper used in the design.
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 gapped core reactor having an improved packet density comprising a plurality of packets arranged in a stacked manner, each packet being of cylindrical shape and formed by packing a plurality of identical lamination sets, each lamination set comprising a plurality of laminations of similar height and thickness, arranged adjacent to each other along their height in order of decreasing width, wherein widths of at least first five laminations of a lamination set are similar and the widths of subsequent laminations are in arithmetic progression with a negative common difference of at least 5 mm.
2. The gapped core reactor as claimed in claim 1, wherein a packet is formed by packing 200-500 identical lamination sets, each lamination set comprising at least first five laminations having width 100-500mm and subsequent laminations having widths in arithmetic progression with a negative common difference of 5-20mm.
3. The gapped core reactor as claimed in claim 1, wherein the area occupied by the 200-500 identical lamination sets of the packet is estimated to be 93%-98% of available area of the packet.