Title of Invention	ARC CHUTE ENHANCING THE BREAKING CAPACITY OF AIR CIRCUIT BREAKER
Abstract	The present invention relates to a de-ion plate for use in arc chute assembly of circuit breakers. The de-ion plate (5) comprises cut profile (23) defining plurality of angular sides traveling radially inward to a predetermined distance, wherein one side of plurality of angular sides comprises edge portion (26) traveling to an appropriate distance. The another side of said plurality of angular sides comprises a rounded portion (27) having suitable curvature, said sides communicating with each other so as to provide misalignment area (22) adapted to give arc a suitable angular deviation. The edge portion (26) and rounded portion (27) unite providing notch means (21) such that arcs are stretched in a predetermined horizontal direction. The invention also relates to an arc chute assembly comprising sides walls (2,3) where the de-ion plates (5) are appropriately spatially located.

Title of Invention

ARC CHUTE ENHANCING THE BREAKING CAPACITY OF AIR CIRCUIT BREAKER

Abstract

The present invention relates to a de-ion plate for use in arc chute assembly of circuit breakers. The de-ion plate (5) comprises cut profile (23) defining plurality of angular sides traveling radially inward to a predetermined distance, wherein one side of plurality of angular sides comprises edge portion (26) traveling to an appropriate distance. The another side of said plurality of angular sides comprises a rounded portion (27) having suitable curvature, said sides communicating with each other so as to provide misalignment area (22) adapted to give arc a suitable angular deviation. The edge portion (26) and rounded portion (27) unite providing notch means (21) such that arcs are stretched in a predetermined horizontal direction. The invention also relates to an arc chute assembly comprising sides walls (2,3) where the de-ion plates (5) are appropriately spatially located.

Full Text	FORM2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - ARC CHUTE ENHANCING THE BREAKING CAPACITY OF AIR CIRCUIT BREAKER 2. Applicant (a) NAME : LARSEN & TOUBRO LIMITED (b) NATIONALITY : An Indian Company (c) ADDRESS : L& T House, Ballard Estate, Mumbai 400 001, State of Maharashtra, India 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed: FIELD OF INVENTION The present invention relates to arc chutes for air circuit breakers. More particularly, the invention relates to an arc chute assembly comprising unique de-ion plate arrangement and unique de-ion plate profile adapted to facilitate stronger force of attraction to the arc drawn between contacts of the circuit breaker thereby significantly elongating the length of arc produced reducing the arc staying time. BACKGROUND AND PRIOR ART Generally, in air circuit breakers an accepted means for interrupting the arc drawn between the current carrying contacts has been to provide an arc chute containing a plurality of spaced de-ion plates. These de-ion plates are usually made of magnetic metallic material and positioned immediately above the contacts of the circuit breaker. Thus as an arc is drawn between the contacts upon separation thereof, the magnetic field of the arc passes through the low reluctance path provided by the magnetic de-ion plates of the arc chute. This, in turn, creates a force which tends to pull the arc up into the arc chute thereby exposing the arc and its associated ionized gases to the stack of de-ion plates where the arc is elongated and split into small series arcs and henceforth cooled to achieve circuit interruption. Government and industry are placing increasing demands upon the electrical industry for interrupters with improved performance in a smaller package and with numerous new and 2 novel features. Hence, a desirable characteristic in these circuit breakers is to provide an efficient arc chamber to maximize the interrupting current, increase the breaker operating voltage, and reduce the arc-staying time on the contacts and to decrease the let-through energy of the circuit breaker in a given size so that higher current ratings ca be achieved safely. Normally, if in a circuit breaker it is required to achieve any of the above mentioned features by making changes in the arc chamber, then the common practice is to increase the number of de-ion plates or increase the size of de-ion plates. However, these two modifications have a limitation. The total space available to make these modifications is constant and hence improved to only a certain level can be obtained by making these changes. If further improvement is required, then these methods are not sufficient. US6479781B1 demonstrates an arc chute with de-ion plates having normal V-cut profile. A normal V-cut also provides a force of attraction to the arc but then this modification is not sufficient if breaking at higher voltages and currents is desired. US5898152 demonstrates an arc chute with de-ion plates having a square cut. Such an arc chute has several disadvantages. Firstly, as mentioned above, the forces provided by a normal cut are not sufficient for breaking at higher currents and voltages. Also the square cut leaves very less amount of thermal mass as most of the plate is cut off to impart the profile. This reduction in thermal mass significantly hampers the performance of the arc 3 chute, and restricts its utilization for higher breaking capacities. In none of the existing technologies and the prior art as described above there exist teaching of considerably increasing force which would significantly reduce the arc staying time on the contacts and in the elongation of arc. The present inventor has now found that the magnitude of the force imparted by the plate arrangement of the arc chute on the arc necessarily depends on the profile of cut on the de-ion plates and by suitably varying the profile of the cut on the de-ion plate, considerable increase in the force can be achieved which would significantly reduce the arc staying time on the contacts. Thus there is a need to provide for an arc chute assembly adapted to facilitate stronger force of attraction to the arc drawn thereby significantly elongating the length of arc produced reducing the arc staying time. OBJECTS OF INVENTION Thus one object of the present invention is to provide an arc chute assembly for elongation of arc. Another object of the present invention is to provide a unique profile of de-ion plates in the arc chute assembly. Yet another object of the present invention is to provide unique arrangement of de-ion plates. 4 Yet one more object of the present invention is to provide easier penetration of arc. Yet one more object of the present invention is to reduce the arc staying time on contacts. The other object of the present invention is to provide faster quenching of the arc. SUMMARY OF INVENTION According to one aspect of the present invention there is provided a de-ion plate for use in arc chute assembly of circuit breakers, said de-ion plate comprising cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc-wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so as to provide misalignment area adapted to give arc a suitable angular deviation and wherein said sides unite providing notch means such that arcs are stretched in a predetermined horizontal direction. 5 According to another aspect of the present invention there is provided a arc chute assembly comprising housing having plurality of wall portions comprising top and plurality of side wall portion wherein said side walls being provided with plurality of apertures/holes and slot means spatially distributed on the wall surfaces, said top wall portion comprising plurality of slot means; plurality of de-ion plates intermediately located between said walls and disposed in said slots maintaining predetermined distance of separation between each plate, wherein said de-ion plate comprising cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc; wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so as to provide misalignment area adapted to give arc a suitable angular deviation; wherein said sides unite providing notch means such that arcs are stretched in a predetermined horizontal direction 6 said plates being located in a manner that said misalignment areas provide non linear arc path. DETAILED DESCRIPTION OF INVENTION The arc chute assembly of the present invention comprises plurality of de-ion plates in a spaced relation with each other and are positioned and crimped within slots contained in the side walls. An arc runner is provided that is also supported and crimped within slots contained in the side walls. De-ion plate comprises V-shaped cut of opening angle a, the force of attraction that the arc experiences, which is directly proportional to ^B', which is magnetic force produced due to current conduction through contacts of circuit breaker is increased by a factor of (n-1) where n = 360°/ a. Thus by carefully adjusting the profile of the de-ion plate, significant impact can be done on the force of attraction that it imparts on the arc. The V-shaped cut profile defines plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc. One side of the cut comprises edge portion traveling to an appropriate distance transverse to base of the plate. The other side of the cut profile comprises a rounded portion having suitable curvature. These two sides provide misalignment area adapted to give arc a suitable angular deviation. The misalignment area comprises notch means such that arcs are stretched in a predetermined horizontal direction. The notch means comprises predetermined groove located in such angular disposition that the pulling force 7 over the arc is increased. The plates are located in the assembly such that the misaligned cuts/areas provide a zig zag path to the arc thereby resulting in elongation in the horizontal plane too. A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF ACCOMPANYING FIGURES Figure 1 illustrates an isometric view of an arc chute in accordance with the present invention. Figure 2 illustrates a vertical section through a circuit breaker incorporating the arc chute of figure 1. Figure 3 illustrates a front view of the de-ion plate of the present invention. Figure 4 is the front view of the arc chute assembly of the present invention. Figures 5a and 5b illustrate isometric views of an arc chute with aligned de-ion plates. Figure 6a and 6b illustrate isometric views of arc chute assembly with misaligned de-ion plates of the present invention. DETAILED DESCRIPTION OF ACCOMPANYING FIGURES Referring now more particularly FIG.l, therein is shown an arc chute utilizing the teachings of this invention. The 8 arc chute (1) contains a plurality of de-ion plates (5) crimped within slots contained in the side walls (2, 3) Arc runner (4) is within slots (2, 3). FIG. 2 exhibits an air circuit breaker (10) employing the arc chute (1) of FIG.l. The circuit breaker includes the power terminals (11) and (12), a stationary contact (13) electrically connected to (11); a movable contact (14) electrically connected to the terminal (12) via a suitable flexible conductor (16) and pole finger (15) . It is the separation of these two contacts (13) and (14), under excited condition, that leads to formation of arc which is then transferred to the de-ion plates (5) via arc runner (4) and fixed arc runner (17) . The de-ion plates (5) are specially designed to facilitate a significant force of attraction on the generated arc and also to encourage the arc to enter the de-ion plate formation. FIG 7 gives a theoretical explanation behind imparting a cut profile on the de-ion plate (5). It can be seen that by imparting a V-shaped cut of opening angle a, the force of attraction that the arc experiences, which is directly proportional to XB', is increased by a factor of (n-1) where n = 360°/ a. Thus by carefully adjusting the profile of the de-ion plate, significant impact can be done on the force of attraction that it imparts on the arc. FIG 3 demonstrates a single de-ion plate (5) with its details. Necessarily the plate has 3 focus areas: initial V-cut (23) which, based on the theory mentioned above, is responsible for imparting the force of attraction to the arc; misalignment area (22), which provides the channel for 9 stretching the arc in the horizontal plane, and the notch (21) which is responsible for providing the improved force to pull the arc in the misalignment area (22) and to stretch it horizontally. One side of the cut (23) comprises edge portion (26) . The other side of cut (23) comprises a rounded portion (27) . Besides these, the plate has protrusions (24, 25) which facilitate the crimping of the de-ion plates in the side walls (2, 3) as illustrated in FIG 1. Fig. 4 illustrates adjacent de-ion plates (5) assembled in a misaligned fashion. The reason for misalignment can be understood by referring to FIG.5 and FIG.6. Also demonstrated in FIG 4 are four arc positions A', B','C','D'. Initially when the arc is at point A, it experiences a force in the direction indicated. Necessarily in this position, the effects due to the V-cut (23) is predominant with very little effects by the area (22) and notch (21) . Under the influence of this indicated force of attraction, the arc moves up to the position B. At this position, the forces due to the notch (21) come into picture and they tend to pull the arcs in the indicated directions which results in positions C and D, position C in plane of first de-ion plate which position D in the plane of second de-ion plate. A point to note here is that position C and D are in two different planes. Adjacent planes have their notches misaligned as indicated and hence when the arc reaches positions C and D respectively in the two adjacent plates, it experiences a horizontal elongation too. This elongation is evident in FIG.6. 10 FIG. 5 a. is an isometric view of an arc chute having adjacent plates aligned to each other. FIG 5.b. is the bottom view of the arc chute of FIG. 5.a with a black line depicting the probable arc elongation achieved. It can be seen that the arc necessarily takes a straight line. FIG. 6 a. is an isometric view of the arc chute (1) of FIG.l, which has adjacent plates (5) misaligned according to the current invention, FIG 6.b. is the bottom view of the arc chute of FIG. 6.a with the black line depicting the probable arc elongation achieved. In this case, due to the back to back disposition of the two consecutive misaligned areas in an opposed manner, the arc takes a zig-zag path (20), and hence the elongation achieved in greater than in the case of FIG.5 The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The misaligned area and notch profile herein described may be replaced by its technical equivalence and yet the invention can be performed. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit. 11 CLAIM A de-ion plate for use in arc chute assembly of circuit breakers, said de-ion plate comprising cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc; wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so as to provide misalignment area adapted to give arc a suitable angular deviation and wherein said sides unite providing notch means such that arcs are stretched in a predetermined horizontal direction. A de-ion plate as claimed in claim 1, wherein misalignment area is adapted to provide channel adapted to direct the arc to a predetermined angle. 12 A de-ion plate as claimed in claims 1 and 2, wherein notch means comprises predetermined suitable groove in appropriate angular disposition such that it provide improved pulling force on the arc. A arc chute assembly comprising housing having plurality of wall portions comprising top and plurality of side wall portion wherein said side walls being provided with plurality of apertures/holes and slot means spatially distributed on the wall surfaces, said top wall portion comprising plurality of slot means; plurality of de-ion plates intermediately located between said walls and disposed in said slots maintaining predetermined distance of separation between each plate, wherein said de-ion plate comprising cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc; wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so 13 as to provide misalignment area adapted to give arc a suitable angular deviation; wherein said sides unite providing notch means such that arcs are stretched in a predetermined horizontal direction said plates being located in a manner that said misalignment areas provide non linear arc path. 5. A arc chute assembly as claimed in claim 4, wherein said de-ion plates being spatially disposed in a manner such that misaligned areas of two consecutive plates are located back to back in an opposed manner adapted to provide zigzag path to the arc, thereby reducing arc staying time. 6. A de-ion plate as claimed in any of the preceding claims further comprises of protrusions in lateral directions so as to operatively engage with the apertures of side walls of the housing. 7. A de-ion plate and arc chute assembly as herein substantially described and illustrated with reference to the accompanying figures. Dated this the 18th day of December 2006. Abhishek Sen Of S. Majumdar & Co. Applicant's Agent 14 ABSTRACT TITLE : ARC CHUTE ENHANCING THE BREAKING CAPACITY OF AIR CIRCUIT BREAKER The present invention relates to a de-ion plate for use in arc chute assembly of circuit breakers. The de-ion plate(5) comprises cut profile (23) defining plurality of angular sides traveling radially inward to a predetermined distance, wherein one side of plurality of angular sides comprises edge portion (26) traveling to an appropriate distance. The another side of said plurality of angular sides comprises a rounded portion (27) having suitable curvature, said sides communicating with each other so as to provide misalignment area (22) adapted to give arc a suitable angular deviation. The edge portion (26) and rounded portion (27) unite providing notch means (21) such that arcs are stretched in a predetermined horizontal direction. The invention also relates to an arc chute assembly comprising sides walls (2,3) where the de-ion plates (5) are appropriately spatially located. Figure 3

Full Text

FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - ARC CHUTE ENHANCING THE BREAKING CAPACITY OF AIR CIRCUIT BREAKER
2. Applicant
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L& T House, Ballard Estate, Mumbai 400 001,
State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
The present invention relates to arc chutes for air circuit breakers. More particularly, the invention relates to an arc chute assembly comprising unique de-ion plate arrangement and unique de-ion plate profile adapted to facilitate stronger force of attraction to the arc drawn between contacts of the circuit breaker thereby significantly elongating the length of arc produced reducing the arc staying time.
BACKGROUND AND PRIOR ART
Generally, in air circuit breakers an accepted means for interrupting the arc drawn between the current carrying contacts has been to provide an arc chute containing a plurality of spaced de-ion plates. These de-ion plates are usually made of magnetic metallic material and positioned immediately above the contacts of the circuit breaker. Thus as an arc is drawn between the contacts upon separation thereof, the magnetic field of the arc passes through the low reluctance path provided by the magnetic de-ion plates of the arc chute. This, in turn, creates a force which tends to pull the arc up into the arc chute thereby exposing the arc and its associated ionized gases to the stack of de-ion plates where the arc is elongated and split into small series arcs and henceforth cooled to achieve circuit interruption.
Government and industry are placing increasing demands upon the electrical industry for interrupters with improved performance in a smaller package and with numerous new and
2

novel features. Hence, a desirable characteristic in these circuit breakers is to provide an efficient arc chamber to maximize the interrupting current, increase the breaker operating voltage, and reduce the arc-staying time on the contacts and to decrease the let-through energy of the circuit breaker in a given size so that higher current ratings ca be achieved safely.
Normally, if in a circuit breaker it is required to achieve any of the above mentioned features by making changes in the arc chamber, then the common practice is to increase the number of de-ion plates or increase the size of de-ion plates. However, these two modifications have a limitation. The total space available to make these modifications is constant and hence improved to only a certain level can be obtained by making these changes. If further improvement is required, then these methods are not sufficient.
US6479781B1 demonstrates an arc chute with de-ion plates having normal V-cut profile. A normal V-cut also provides a force of attraction to the arc but then this modification is not sufficient if breaking at higher voltages and currents is desired.
US5898152 demonstrates an arc chute with de-ion plates having a square cut. Such an arc chute has several disadvantages. Firstly, as mentioned above, the forces provided by a normal cut are not sufficient for breaking at higher currents and voltages. Also the square cut leaves very less amount of thermal mass as most of the plate is cut off to impart the profile. This reduction in thermal mass significantly hampers the performance of the arc
3

chute, and restricts its utilization for higher breaking capacities.
In none of the existing technologies and the prior art as described above there exist teaching of considerably increasing force which would significantly reduce the arc staying time on the contacts and in the elongation of arc.
The present inventor has now found that the magnitude of the force imparted by the plate arrangement of the arc chute on the arc necessarily depends on the profile of cut on the de-ion plates and by suitably varying the profile of the cut on the de-ion plate, considerable increase in the force can be achieved which would significantly reduce the arc staying time on the contacts.
Thus there is a need to provide for an arc chute assembly adapted to facilitate stronger force of attraction to the arc drawn thereby significantly elongating the length of arc produced reducing the arc staying time.
OBJECTS OF INVENTION
Thus one object of the present invention is to provide an arc chute assembly for elongation of arc.
Another object of the present invention is to provide a unique profile of de-ion plates in the arc chute assembly.
Yet another object of the present invention is to provide unique arrangement of de-ion plates.
4

Yet one more object of the present invention is to provide easier penetration of arc.
Yet one more object of the present invention is to reduce the arc staying time on contacts.
The other object of the present invention is to provide faster quenching of the arc.
SUMMARY OF INVENTION
According to one aspect of the present invention there is provided a de-ion plate for use in arc chute assembly of circuit breakers, said de-ion plate comprising
cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc-wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate
wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so as to provide misalignment area adapted to give arc a suitable angular deviation and
wherein said sides unite providing notch means such that arcs are stretched in a predetermined horizontal direction.
5

According to another aspect of the present invention there is provided a arc chute assembly comprising
housing having plurality of wall portions comprising top and plurality of side wall portion wherein said side walls being provided with plurality of apertures/holes and slot means spatially distributed on the wall surfaces, said top wall portion comprising plurality of slot means;
plurality of de-ion plates intermediately located between
said walls and disposed in said slots maintaining
predetermined distance of separation between each plate,
wherein
said de-ion plate comprising
cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc;
wherein one side of plurality of angular sides comprises
edge portion traveling to an appropriate distance in
transverse relation to base of the plate
wherein another side of said plurality of angular sides
comprises a rounded portion having suitable curvature, said
sides communicating with each other so as to provide
misalignment area adapted to give arc a suitable angular
deviation;
wherein said sides unite providing notch means such that
arcs are stretched in a predetermined horizontal direction
6

said plates being located in a manner that said misalignment areas provide non linear arc path.
DETAILED DESCRIPTION OF INVENTION
The arc chute assembly of the present invention comprises plurality of de-ion plates in a spaced relation with each other and are positioned and crimped within slots contained in the side walls. An arc runner is provided that is also supported and crimped within slots contained in the side walls.
De-ion plate comprises V-shaped cut of opening angle a, the force of attraction that the arc experiences, which is directly proportional to ^B', which is magnetic force produced due to current conduction through contacts of circuit breaker is increased by a factor of (n-1) where n = 360°/ a. Thus by carefully adjusting the profile of the de-ion plate, significant impact can be done on the force of attraction that it imparts on the arc. The V-shaped cut profile defines plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc. One side of the cut comprises edge portion traveling to an appropriate distance transverse to base of the plate. The other side of the cut profile comprises a rounded portion having suitable curvature. These two sides provide misalignment area adapted to give arc a suitable angular deviation. The misalignment area comprises notch means such that arcs are stretched in a predetermined horizontal direction. The notch means comprises predetermined groove located in such angular disposition that the pulling force
7

over the arc is increased. The plates are located in the
assembly such that the misaligned cuts/areas provide a zig
zag path to the arc thereby resulting in elongation in the
horizontal plane too.
A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates an isometric view of an arc chute in accordance with the present invention.
Figure 2 illustrates a vertical section through a circuit breaker incorporating the arc chute of figure 1.
Figure 3 illustrates a front view of the de-ion plate of the present invention.
Figure 4 is the front view of the arc chute assembly of the present invention.
Figures 5a and 5b illustrate isometric views of an arc chute with aligned de-ion plates.
Figure 6a and 6b illustrate isometric views of arc chute assembly with misaligned de-ion plates of the present invention.
DETAILED DESCRIPTION OF ACCOMPANYING FIGURES
Referring now more particularly FIG.l, therein is shown an arc chute utilizing the teachings of this invention. The
8

arc chute (1) contains a plurality of de-ion plates (5) crimped within slots contained in the side walls (2, 3) Arc runner (4) is within slots (2, 3).
FIG. 2 exhibits an air circuit breaker (10) employing the arc chute (1) of FIG.l. The circuit breaker includes the power terminals (11) and (12), a stationary contact (13) electrically connected to (11); a movable contact (14) electrically connected to the terminal (12) via a suitable flexible conductor (16) and pole finger (15) . It is the separation of these two contacts (13) and (14), under excited condition, that leads to formation of arc which is then transferred to the de-ion plates (5) via arc runner (4) and fixed arc runner (17) . The de-ion plates (5) are specially designed to facilitate a significant force of attraction on the generated arc and also to encourage the arc to enter the de-ion plate formation.
FIG 7 gives a theoretical explanation behind imparting a cut profile on the de-ion plate (5). It can be seen that by imparting a V-shaped cut of opening angle a, the force of attraction that the arc experiences, which is directly proportional to XB', is increased by a factor of (n-1) where n = 360°/ a. Thus by carefully adjusting the profile of the de-ion plate, significant impact can be done on the force of attraction that it imparts on the arc.
FIG 3 demonstrates a single de-ion plate (5) with its details. Necessarily the plate has 3 focus areas: initial V-cut (23) which, based on the theory mentioned above, is responsible for imparting the force of attraction to the arc; misalignment area (22), which provides the channel for
9

stretching the arc in the horizontal plane, and the notch (21) which is responsible for providing the improved force to pull the arc in the misalignment area (22) and to stretch it horizontally. One side of the cut (23) comprises edge portion (26) . The other side of cut (23) comprises a rounded portion (27) . Besides these, the plate has protrusions (24, 25) which facilitate the crimping of the de-ion plates in the side walls (2, 3) as illustrated in FIG 1.
Fig. 4 illustrates adjacent de-ion plates (5) assembled in a misaligned fashion. The reason for misalignment can be understood by referring to FIG.5 and FIG.6.
Also demonstrated in FIG 4 are four arc positions *A', *B','C','D'. Initially when the arc is at point A, it experiences a force in the direction indicated. Necessarily in this position, the effects due to the V-cut (23) is predominant with very little effects by the area (22) and notch (21) . Under the influence of this indicated force of attraction, the arc moves up to the position B. At this position, the forces due to the notch (21) come into picture and they tend to pull the arcs in the indicated directions which results in positions C and D, position C in plane of first de-ion plate which position D in the plane of second de-ion plate. A point to note here is that position C and D are in two different planes. Adjacent planes have their notches misaligned as indicated and hence when the arc reaches positions C and D respectively in the two adjacent plates, it experiences a horizontal elongation too. This elongation is evident in FIG.6.
10

FIG. 5 a. is an isometric view of an arc chute having adjacent plates aligned to each other. FIG 5.b. is the bottom view of the arc chute of FIG. 5.a with a black line depicting the probable arc elongation achieved. It can be seen that the arc necessarily takes a straight line.
FIG. 6 a. is an isometric view of the arc chute (1) of FIG.l, which has adjacent plates (5) misaligned according to the current invention, FIG 6.b. is the bottom view of the arc chute of FIG. 6.a with the black line depicting the probable arc elongation achieved. In this case, due to the back to back disposition of the two consecutive misaligned areas in an opposed manner, the arc takes a zig-zag path (20), and hence the elongation achieved in greater than in the case of FIG.5
The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The misaligned area and notch profile herein described may be replaced by its technical equivalence and yet the invention can be performed. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.
11

CLAIM
A de-ion plate for use in arc chute assembly of circuit breakers, said de-ion plate comprising
cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc;
wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate
wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so as to provide misalignment area adapted to give arc a suitable angular deviation and
wherein said sides unite providing notch means such that arcs are stretched in a predetermined horizontal direction.
A de-ion plate as claimed in claim 1, wherein misalignment area is adapted to provide channel adapted to direct the arc to a predetermined angle.
12

A de-ion plate as claimed in claims 1 and 2, wherein notch means comprises predetermined suitable groove in appropriate angular disposition such that it provide improved pulling force on the arc.
A arc chute assembly comprising
housing having plurality of wall portions comprising top and plurality of side wall portion wherein said side walls being provided with plurality of apertures/holes and slot means spatially distributed on the wall surfaces, said top wall portion comprising plurality of slot means;
plurality of de-ion plates intermediately located between said walls and disposed in said slots maintaining predetermined distance of separation between each plate, wherein said de-ion plate comprising
cut profile defining plurality of angular sides traveling radially inward to a predetermined distance from base of the plate such that force of attraction being imparted on arc;
wherein one side of plurality of angular sides comprises edge portion traveling to an appropriate distance in transverse relation to base of the plate
wherein another side of said plurality of angular sides comprises a rounded portion having suitable curvature, said sides communicating with each other so
13

as to provide misalignment area adapted to give arc a suitable angular deviation;
wherein said sides unite providing notch means such
that arcs are stretched in a predetermined horizontal
direction
said plates being located in a manner that said
misalignment areas provide non linear arc path.
5. A arc chute assembly as claimed in claim 4, wherein said de-ion plates being spatially disposed in a manner such that misaligned areas of two consecutive plates are located back to back in an opposed manner adapted to provide zigzag path to the arc, thereby reducing arc staying time.
6. A de-ion plate as claimed in any of the preceding claims further comprises of protrusions in lateral directions so as to operatively engage with the apertures of side walls of the housing.
7. A de-ion plate and arc chute assembly as herein substantially described and illustrated with reference to the accompanying figures.
Dated this the 18th day of December 2006.
Abhishek Sen Of S. Majumdar & Co. Applicant's Agent
14

ABSTRACT
TITLE : ARC CHUTE ENHANCING THE BREAKING CAPACITY OF AIR CIRCUIT BREAKER
The present invention relates to a de-ion plate for use in arc chute assembly of circuit breakers. The de-ion plate(5) comprises cut profile (23) defining plurality of angular sides traveling radially inward to a predetermined distance, wherein one side of plurality of angular sides comprises edge portion (26) traveling to an appropriate distance. The another side of said plurality of angular sides comprises a rounded portion (27) having suitable curvature, said sides communicating with each other so as to provide misalignment area (22) adapted to give arc a suitable angular deviation. The edge portion (26) and rounded portion (27) unite providing notch means (21) such that arcs are stretched in a predetermined horizontal direction. The invention also relates to an arc chute assembly comprising sides walls (2,3) where the de-ion plates (5) are appropriately spatially located.
Figure 3

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=x71jMW/nqecf+ICbXu9RlA==&loc=vsnutRQWHdTHa1EUofPtPQ==

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Patent Number

271114

Indian Patent Application Number

2072/MUM/2006

PG Journal Number

06/2016

Publication Date

05-Feb-2016

Grant Date

03-Feb-2016

Date of Filing

18-Dec-2006

Name of Patentee

LARSEN & TOUBRO LIMITED

Applicant Address

L & T HOUSE, BALLARD ESTATE, MUMBAI

Inventors:

#	Inventor's Name	Inventor's Address
1	AWADHIYA, AJITESH KUMAR	SWITCHGEAR DESIGN & PRODUCT DEVELOPMENT CENTRE LARSEN & TOUBRO LIMITED, ELECTRICAL SECTOR-(EBG), POWAI WORKS (EAST),GATE NO.7, SAKI VIHAR ROAD, MUMBAI 400 072

PCT International Classification Number

H01H9/34

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA