Title of Invention	A METHOD OF MAKING A THREE-PHASE TRANSFORMER WITH TRIANGULAR CORE STRUCTURE AND A THREE-PHASE TRANSFORMER WITH TRIANGULAR CORE STRUCTURE THEREOF
Abstract	The invention relates to a method of manufacturing a transformer with a triangular core structure and a transformer with triangular core structure. Laminations (2) are cut in the shape of trapeziums with predetermined sizes from a high permeability sheet material (1) and stacked to form the four sides of three rectangle frames (7) to obtain a triangular core structure with a bottom yoke (4), top yoke (5) and three vertical limbs (6). The three vertices of said bottom yoke (4) and top yoke (5) are connected. The bottom yoke (4) is clamped with bottom clamps (8). The top yoke (5) is removed and three wound coils (10) comprising primary and secondary windings are introduced through each vertical limb (6). The top yoke (5) is placed and clamped with top clamps (9). The bottom clamps (8) and top clamps (9) are clamped by tie rods (11) to obtain a transformer with a triangular core structure.

Title of Invention

A METHOD OF MAKING A THREE-PHASE TRANSFORMER WITH TRIANGULAR CORE STRUCTURE AND A THREE-PHASE TRANSFORMER WITH TRIANGULAR CORE STRUCTURE THEREOF

Abstract

The invention relates to a method of manufacturing a transformer with a triangular core structure and a transformer with triangular core structure. Laminations (2) are cut in the shape of trapeziums with predetermined sizes from a high permeability sheet material (1) and stacked to form the four sides of three rectangle frames (7) to obtain a triangular core structure with a bottom yoke (4), top yoke (5) and three vertical limbs (6). The three vertices of said bottom yoke (4) and top yoke (5) are connected. The bottom yoke (4) is clamped with bottom clamps (8). The top yoke (5) is removed and three wound coils (10) comprising primary and secondary windings are introduced through each vertical limb (6). The top yoke (5) is placed and clamped with top clamps (9). The bottom clamps (8) and top clamps (9) are clamped by tie rods (11) to obtain a transformer with a triangular core structure.

Full Text	The invention relates to a method of making a three-phase transformer with triangular core structure and a three-phase transformer with triangular core structure thereof. Conventional three phase transformers are made with cut laminations of high permeability material such as silicon steel forming a top yoke, a bottom yoke and three limbs in the same plane. The wound coils with primary and secondary windings for each phase are inserted on each of said limbs to form the transformer. The invention provides a three-phase transformer whose magnetic core is formed with trapezium shaped laminates of high permeability material. The magnetic core consists of a triangular bottom yoke, an identical triangular top yoke and three limbs connecting the vertices of the triangular bottom yoke and triangular top yoke. The magnetic core structure of such a transformer look like a triangle projected upwards. The three-phase transformer made according to the invention uses reduced quantity of high permeability material in a particular transformer compared to that in a conventional three-phase transformer of the same rating. The quantity of transformer oil and steel sheets used are also considerably less than that in a conventional three-phase transformer of equivalent rating. Thus the invention provides a method of manufacturing a transformer with a triangular core structure comprising the steps of cutting laminations in the shape of trapeziums with predetermined sizes from a high permiability sheet material; stacking the said trapezium shaped laminations to form the four sides of three rectangular frames to obtain a triangular core structure with a bottom yoke, top yoke and three vertical limbs connecting the three vertices of said bottom yoke and top yoke; clamping the said bottom yoke with clamps; removing the said top yoke and introducing three wound coils comprising primary and secondary windings through each vertical limb; replacing the said top yoke and clamping the same with clamps and clamping the bottom clamps and top clamps by tie-rods to obtain a transformer with a triangular core structure. The invention also provides a transformer with a triangular core structure made by the method hereinabove described, comprising a triangular core structure made of high permeability laminations consisting of a triangular bottom yoke, a triangular top yoke and three vertical connecting limbs connecting the three vertices of the said bottom yoke and top yoke, a wound coil with primary and secondary windings for each phase around each vertical limb and clamps to hold the triangular core structure intact wherein the said bottom yoke, top yoke and vertical connecting limbs are formed with stacks of trapezium shaped laminations of high permeability -material- The invention will be described further with reference to the accompanying drawings. Figure 1 shows the cutting lines in a strip of high permeability material to obtain trapezium shaped laminations. Figure 2 shows a typical trapezium shaped lamination. Figure 3 shows a rectangular frame formed by the trapezium shaped laminations shown in figure 2. Figure 4 shows an isometric view of a stack of rectangular frames of laminations shown in figure 3. Figure 5 shows a triangular core structure assembled with three stacks of rectangular frames of laminations shown in figure 4. Figure 6 shows a triangular core structure with clamps. Figure 7 shows the wound coils with primary and secondary windings for each phase of the transformer. Figure 8 shows the triangular core structure after removing the top yoke. Figure 9 shows the triangular core structure shown in figure 8 with wound coils inserted on each vertical limb. Figure 10 shows the triangular core structure shown in figure 9 with top yoke. Figure 11 shows an isometric view of the assembled transformer with triangular core structure according to the invention. Figure 12 shows the cross-sectional view of the assembled transformer with triangular core structure according to the invention. Trapezium shaped laminations (2, 2') are cut from strip of high permiability material (1) along the cutting lines shown in figure 1. The trapezium shaped laminations for forming bottom yoke (4) and top yoke (5) will be identical and the trapezium shaped laminations for forming each of the vertical limbs (6) will be identical. These trapezium shaped laminations are held together to form a frame (3) and such frames (3) are stacked to form each side of a triangular core structure (7) with a bottom yoke (4), top yoke (5) and vertical limbs (6) at the vertices of said triangular core structure. The triangular core structure is provided with bottom clamps (8) for holding the bottom yoke (4) and top clamps (9) for holding the top yoke (5). These bottom clamps (8) and top clamps (9) are held together by tie-rods (11). Wound coils (10) are made with primary and secondary windings in a conventional manner. The top yoke (5) is removed by removing the top clamps (9) and the wound coils (10) are introduced on each vertical limb (6). The top yoke (5) is replaced and clamped with top clamps (9). The bottom clamps (8) and top clamps are held together by tightening the tie rods (11) to complete the three phase transformer with triangular core structure. The core structure of the transformer according to the invention is preferably made with laminations of cold rolled grain oriented high permeability material. However it can also be made from laminations obtained from thin film high permeability material or any other high permeability material. The three-phase transformer according to the invention considerably reduces the quantity of high permeability material used resulting in reduced cost and reduced magnetic loss in the transformer. The cost of steel sheets is also reduced. Thus the transformer according to the invention is more efficient and cost effective compared to conventional three phase transformers. WE CLAIM: 1. A method of manufacturing a transformer with a triangular core structure comprising the steps of cutting laminations (2) in the shape of trapeziums with predetermined sizes from a high permeability sheet material (1); stacking the said trapezium shaped laminations (2) to form the four sides of three rectangle frames (7) to obtain a triangular core structure with a bottom yoke (4), top yoke (5) and three vertical limbs (6) connecting the three vertices of said bottom yoke (4) and top yoke (5); clamping the said bottom yoke (4) with bottom clamps (8); removing the top yoke (5) and introducing three wound coils (10) comprising primary and secondary windings through each vertical limb (6); placing the said top yoke (5) and clamping the same with top clamps (9) and clamping the said bottom clamps (8) and top clamps (9) by tie rods (11) to obtain a transformer with a triangular core structure. 2. The method as claimed in claim 1, wherein said high permeability sheet material (1) from which the trapezium shaped laminations (2, 2') arf cut is a cold rolled grain oriented high permeability sheet material. 3. The method as claimed in claim .1, wherein said trapezium shaped laminations (2') for the vertical limbs are cut with longer average length than the average length of the trapezium shaped laminations (2) for said top yoke (5) and bottom yoke (4). The method as claimed in claim 1, wherein said trapezium shaped laminations (2,2') are cut with equal width. A transformer with a triangular core structure made by the method claimed in claim 1, comprising a triangular core structure made of high permiability laminations with a triangular bottom yoke (4), triangular top yoke (5) and vertical connecting limbs (6) connecting the vertices of said bottom yoke (4) and top yoke (5), three wound coils (10) around each said vertical limb (6) and clamps (8, 9) to hold the triangular core structure intact wherein said bottom yoke (4), top yoke (5) and the vertical connecting limbs (6) are stacks of trapezium shaped laminations of high permeability material. The transformer as claimed in claim 5, wherein the said trapezium shaped laminations of high permeability material is cold rolled grain oriented high permeability sheet material. The transformer as claimed in claim 5, wherein the average length of trapezium shaped laminations in the vertical limbs (6) are longer than the average length of trapezium shaped laminations of said top yoke and bottom yoke. A method of manufacturing a transformer with a triangular core structure, substantially as hereinabove described and illustrated with reference to the accompanying drawings. A transformer with a triangular core structure, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Full Text

The invention relates to a method of making a three-phase transformer with triangular core structure and a three-phase transformer with triangular core structure thereof.
Conventional three phase transformers are made with cut laminations of high permeability material such as silicon steel forming a top yoke, a bottom yoke and three limbs in the same plane. The wound coils with primary and secondary windings for each phase are inserted on each of said limbs to form the transformer.
The invention provides a three-phase transformer whose magnetic core is formed with trapezium shaped laminates of high permeability material. The magnetic core consists of a triangular bottom yoke, an identical triangular top yoke and three limbs connecting the vertices of the triangular bottom yoke and triangular top yoke. The magnetic core structure of such a transformer look like a triangle projected upwards.
The three-phase transformer made according to the invention uses reduced quantity of high permeability material in a particular transformer compared to that in a conventional three-phase transformer of the same rating. The quantity of transformer oil and steel sheets used are also considerably less than that in a conventional three-phase transformer of equivalent rating.

Thus the invention provides a method of manufacturing a transformer with a triangular core structure comprising the steps of cutting laminations in the shape of trapeziums with predetermined sizes from a high permiability sheet material; stacking the said trapezium shaped laminations to form the four sides of three rectangular frames to obtain a triangular core structure with a bottom yoke, top yoke and three vertical limbs connecting the three vertices of said bottom yoke and top yoke; clamping the said bottom yoke with clamps; removing the said top yoke and introducing three wound coils comprising primary and secondary windings through each vertical limb; replacing the said top yoke and clamping the same with clamps and clamping the bottom clamps and top clamps by tie-rods to obtain a transformer with a triangular core structure.
The invention also provides a transformer with a triangular core structure made by the method hereinabove described, comprising a triangular core structure made of high permeability laminations consisting of a triangular bottom yoke, a triangular top yoke and three vertical connecting limbs connecting the three vertices of the said bottom yoke and top yoke, a wound coil with primary and secondary windings for each phase around each vertical limb and clamps to hold the triangular core structure intact wherein the said bottom yoke, top yoke and vertical connecting limbs are formed with stacks of trapezium shaped laminations of high permeability -material-

The invention will be described further with reference to the accompanying drawings.
Figure 1 shows the cutting lines in a strip of high permeability material to obtain trapezium shaped laminations.
Figure 2 shows a typical trapezium shaped lamination.
Figure 3 shows a rectangular frame formed by the trapezium shaped laminations shown in figure 2.
Figure 4 shows an isometric view of a stack of rectangular frames of laminations shown in figure 3.
Figure 5 shows a triangular core structure assembled with three stacks of rectangular frames of laminations shown in figure 4.
Figure 6 shows a triangular core structure with clamps.
Figure 7 shows the wound coils with primary and secondary windings for each phase of the transformer.
Figure 8 shows the triangular core structure after removing the top yoke.

Figure 9 shows the triangular core structure shown in figure 8 with wound coils inserted on each vertical limb.
Figure 10 shows the triangular core structure shown in figure 9 with top yoke.
Figure 11 shows an isometric view of the assembled transformer with triangular core structure according to the invention.
Figure 12 shows the cross-sectional view of the assembled transformer with triangular core structure according to the invention.
Trapezium shaped laminations (2, 2') are cut from strip of high permiability material (1) along the cutting lines shown in figure 1. The trapezium shaped laminations for forming bottom yoke (4) and top yoke (5) will be identical and the trapezium shaped laminations for forming each of the vertical limbs (6) will be identical. These trapezium shaped laminations are held together to form a frame (3) and such frames (3) are stacked to form each side of a triangular core structure (7) with a bottom yoke (4), top yoke (5) and vertical limbs (6) at the vertices of said triangular core structure. The triangular core structure is provided with bottom clamps (8) for holding the bottom yoke (4) and top clamps (9) for holding the top yoke (5). These bottom clamps (8) and top clamps (9) are held together by tie-rods (11). Wound coils (10) are made with primary and secondary windings in a conventional manner. The top yoke (5) is removed by removing the top clamps (9) and the wound coils (10)

are introduced on each vertical limb (6). The top yoke (5) is replaced and clamped with top clamps (9). The bottom clamps (8) and top clamps are held together by tightening the tie rods (11) to complete the three phase transformer with triangular core structure.
The core structure of the transformer according to the invention is preferably made with laminations of cold rolled grain oriented high permeability material. However it can also be made from laminations obtained from thin film high permeability material or any other high permeability material.
The three-phase transformer according to the invention considerably reduces the quantity of high permeability material used resulting in reduced cost and reduced magnetic loss in the transformer. The cost of steel sheets is also reduced. Thus the transformer according to the invention is more efficient and cost effective compared to conventional three phase transformers.

WE CLAIM:
1. A method of manufacturing a transformer with a triangular core structure comprising the steps of cutting laminations (2) in the shape of trapeziums with predetermined sizes from a high permeability sheet material (1); stacking the said trapezium shaped laminations (2) to form the four sides of three rectangle frames (7) to obtain a triangular core structure with a bottom yoke (4), top yoke (5) and three vertical limbs (6) connecting the three vertices of said bottom yoke (4) and top yoke (5); clamping the said bottom yoke (4) with bottom clamps (8); removing the top yoke (5) and introducing three wound coils (10) comprising primary and secondary windings through each vertical limb (6); placing the said top yoke (5) and clamping the same with top clamps (9) and clamping the said bottom clamps (8) and top clamps (9) by tie rods (11) to obtain a transformer with a triangular core structure.
2. The method as claimed in claim 1, wherein said high permeability sheet material (1) from which the trapezium shaped laminations (2, 2') arf cut is a cold rolled grain oriented high permeability sheet material.
3. The method as claimed in claim .1, wherein said trapezium shaped laminations (2') for the vertical limbs are cut with longer average length than the average length of the trapezium shaped laminations (2) for said top yoke (5) and bottom yoke (4).

The method as claimed in claim 1, wherein said trapezium shaped laminations (2,2') are cut with equal width.
A transformer with a triangular core structure made by the method claimed in claim 1, comprising a triangular core structure made of high permiability laminations with a triangular bottom yoke (4), triangular top yoke (5) and vertical connecting limbs (6) connecting the vertices of said bottom yoke (4) and top yoke (5), three wound coils (10) around each said vertical limb (6) and clamps (8, 9) to hold the triangular core structure intact wherein said bottom yoke (4), top yoke (5) and the vertical connecting limbs (6) are stacks of trapezium shaped laminations of high permeability material.
The transformer as claimed in claim 5, wherein the said trapezium shaped laminations of high permeability material is cold rolled grain oriented high permeability sheet material.
The transformer as claimed in claim 5, wherein the average length of trapezium shaped laminations in the vertical limbs (6) are longer than the average length of trapezium shaped laminations of said top yoke and bottom yoke.
A method of manufacturing a transformer with a triangular core structure, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

A transformer with a triangular core structure, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Documents:

746-che-2003-abstract.pdf

746-che-2003-claims duplicate.pdf

746-che-2003-claims original.pdf

746-che-2003-correspondnece-others.pdf

746-che-2003-correspondnece-po.pdf

746-che-2003-description(complete) duplicate.pdf

746-che-2003-description(complete) original.pdf

746-che-2003-drawings.pdf

746-che-2003-form 1.pdf

746-che-2003-form 19.pdf

746-che-2003-form 26.pdf

746-che-2003-form 3.pdf

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Patent Number

200762

Indian Patent Application Number

746/CHE/2003

PG Journal Number

8/2007

Publication Date

23-Feb-2007

Grant Date

01-Jun-2006

Date of Filing

17-Sep-2003

Name of Patentee

M/S. VIJAI ELECTRICALS LIMITED

Applicant Address

INDUSTRIAL DEVELOPMENT AREA, 28 BALANAGAR, HYDERABAD 500 037

Inventors:

#	Inventor's Name	Inventor's Address
1	JAI RAMESH DASARI	PLOT NO.173, ROAD NO.13, JUBILEE HILLS, HYDERABAD - 500 034
2	kalahasty sambu murthy	Plot No.130, jal vayu vihar, Opp. KPHB Colony, kukatapally, Hyderabad - 500 072

PCT International Classification Number

HO1F27/24

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA