COMPLETE AFTER PROVISIONAL
LEFT ON 10 / 8 / 2006
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)

Title of the invention.

MODULAR CONTACT SYSTEM FOR MULTI POLE BREAK CIRCUIT BREAKER

2. Applicant
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : Indian
(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 a modular semi/partially-enclosed contact system for low voltage power circuit breakers. More particularly, the invention relates to a modular semi/partially-enclosed contact system aiding in the formation of multi break multi pole breakers thereby achieving high breaking capacity, minimizing let through energy during short circuit condition and providing operational flexibility for low and high breaking capacity with amelioration in circuit breaker performance, contact inspection and easy replacement of individual unit at site location.
BACKGROUND AND PRIOR ART
Generally, in power distribution system low voltage power circuit breakers are used as protective devices. The basic function of circuit breaker is to detect abnormality and protect and isolate to faulty equipment. The circuit breaker protects downstream equipments from short circuit and in addition this limits the let through energy, which may cause damage to equipments. In order to achieve the high breaking capacity and compact circuit breaker design circuit breaker with rotary contact systems are used. These circuit breakers provide two breaks per pole for multi pole circuit breaker. The arrangement for rotary contact system includes cassette construction, formation of modular drive shaft interrupter shaft common to all poles. The whole arcing chamber is arranged enclosed in the cassette construction such that gas exhaust slot is provided to take away gases formed inside the circuit breaker during normal and faulted conditions.
2

US 4910485 discloses a breaking device for low voltage circuit breaker comprises in each pole a switching bar, a pair of stationary contacts connected to the connection terminals, a double break rotary contact extending in a housing of the bar, and two arc chutes disposed on each side of the bar. Two contact pressure springs ensure elastic positioning of the rotary contact along the longitudinal direction of pole. Pivoting of the rotary contact takes place around a fictitious axis mounted floating with respect to the fixed rotation axis of the bar.
US 6259338 Bl discloses a multipole circuit breaker includes an arcing chamber housing with a number of arcing chambers, corresponding to number of poles, arranged next to each other. Each arcing chamber has a hinged contact bridge cooperating with a stationary contact arrangement. An interrupter shaft common to poles of the multipole circuit breaker and including a number of shaft segments made of an insulating material, in each of which a contact bridge is arranged, is provided. The adjoining shaft segments are joined to each other by respective coupling elements, each coupling elements including two tab-shaped parts joined to each other by a support shaft. Each tab shaped part supports at least two first connecting pins on a side facing away from the support shaft and extending in an axial direction. The shaft segments each including recesses a side facing the coupling element, the recesses for receiving the connecting pins. A support, or bearing, for supporting the support shaft is provided in the arcing chamber housing in a transition area between adjacent arcing chambers.
US 2004/0256207 Al discloses a rotary contact supporting shaft for low voltage power circuit breaker, whose particularly
3

consist of the fact that it has a modular structure that comprises, along the rotation axis, at least one first and second supporting module, each module being functionally coupled to at least one corresponding moving contact of the circuit breaker and being provided respectively with first and second means for connection to at least one first interconnection module; the first interconnection module is interposed between the first and second supporting modules and is provided with third and fourth connections means that are suitable to be coupled respectively to the first and second connection means; the coupling between the first and third connection means and between the second and fourth connection means allows the functional connection between the first and second supporting modules and the direct structural connection of the interconnection module to the first and second supporting modules.
US 4916421 discloses a current limiting circuit interrupter consisting of a modular unit housed in an insulating case and provided with two fixed contact arms and two movable contact arms. The movable contact arms can be actuated automatically by means of a rod coupled to an operating mechanism as well as by means of an electromagnetic actuator. The operating mechanism includes a lever and a rotating bracket arranged to hold the movable contacts in an open condition when the electromagnet within the electromagnetic actuator is de-energized. In US 6084489 the circuit breaker is characterized by separable contacts operable between a closed and an open position a contact arm having a latching surface and a latch arranged to engage the latching surface when the contacts are blown-open under short-circuit conditions. The arrangement of the latch allows for a positive lock under high magnitude
4

short circuit levels while minimizing the force required by a mechanism to unlock the arm.
US 6828885 Bl discloses a circuit-breaker including a an interrupter chamber housing that includes a plastic 'material and houses an interrupter. The interrupter includes at least one stationary contact member, which, via a busbar is connected to a corresponding connecting terminal and a moveable contact member that is moveable connectable to the stationary contact member. To ensure that heat generated by the busbar is more rapidly released into the switch compartment housing the busbar is imbedded in an outer wall of the interrupter chamber housing and in contact with the housing by a form fit or a force fit.
US 6403901 Bl discloses a contact system having a two-armed contact arm equipped at its opposite ends with contact pieces that can be brought into and out of contact with corresponding contact pieces of stationary busbars. The contact arm is mounted rotatably on a central bearing axis using an elongated hole, the two lever arms being acted upon by contact force springs that brace with one end against a switching shaft or a switching shaft segment. To provide a uniform contact pressure in the presence of differing wear of the contact pieces, the elongated hole extends in a direction that differs substantially from the direction perpendicular to the longitudinal axis of the contact arm and substantially from the longitudinal axis, and the longitudinal action direction of the contact force springs extends neither perpendicular to the longitudinal axis nor perpendicular to the extension direction of the elongated hole.
5

US 6184761 Bl describes a circuit breaker rotary contact arrangement in which the ends of the line and load straps supporting the fixed contacts are hook-shaped to control the angle of the repulsive force exhibited between the fixed contacts and the movable contacts arranged at the opposing ends of the rotary contact arm. The fixed contacts face outwardly away from the central pivot of the contact arm such that a horizontal component of the popping force acts away from the center of rotation keeping the contact arm in tension for avoiding a buckling effect allowing contact arms with smaller cross sectional area to be used to increase contact arm mobility and reduce the cost.
US 6204743 Bl discloses an electrically conducting strap for use in a rotary circuit breaker cassette provides dual connectors to accommodate either an electronic or mechanical trip unit within the circuit breaker and electrical distribution system. The continuous, integral strap includes a first section including a fixed contact mounted thereon, a U-shaped second section, a third section having two apertures for connection to associated electrical equipment, and a fourth section having two apertures for connection to a line of a distribution system providing electrical power to a load. Thus, the circuit breaker has the advantage of reduced cost and increased ease of manufacturability since a common cassette is used.
US 6326868 Bl discloses a circuit breaker rotary contact arm is used within a plurality of single pole circuit breakers ganged together to form a single multi-pole circuit breaker. To provide uniform contact wear among the associated circuit breaker contacts, the rotor carrying the rotary contact arm pivot is slotted. to automatically position the rotary contact
6

arm to allow for changes in the contact geometry while maintaining constant contact compressive forces. The individual circuit breakers connect with the central operation mechanism by means of a single pin.
US 6114641 discloses a circuit breaker rotary contact assembly employs a common pivot between the rotor assembly and the rotary contact arm. A pair of off-center expansion springs directly engage the rotor at one end and engage the rotary contact arm via a linkage arrangement at an opposite end thereof.
US 6590172 discloses a circuit breaker is provided wherein the circuit breaker comprises a contact arm movable between a closed position, an open position and a blown open position wherein the contact arm is disposed in the circuit breaker. A bumper disposed to contact the contact arm when the contact arm is in the blown open position. In addition, a stop member disposed to be in contact with a linkage assembly so as to create a gap between the bumper and the contact arm when the contact arm is disposed in the open position.
The disadvantages of the pior art as described above are
circuit breaker assemblies are quite complicated and easy replacement of contact system for contact inspection function is not possible ;
assemblies are such that dismantling of the components of the assemblies is time consuming and adds to the inventory to the system ;
7

assembly sequence is such that the field replacement of any such sub assembly causes problem; and
contact inspection not at all possible.
So there . is a need to provide for a modular construction of contact system that would reduce the assembly time with easy replacement of faulty or damaged parts and achieves high breaking capacity with the minimization of let through energy during short circuit condition. The invention also provides operational flexibility for low and high breaking capacity and on the other hand improves assembly line, productivity.
The present inventors have surprisingly found that by way of an innovative integration of desired components in a definite manner a modular semi/partially-enclosed contact can be achieved that would reduce the assembly time with easy replacement of faulty or damaged parts, provide operational flexibility improves assembly line productivity.
OBJECTS OF INVENTION
Thus one object of the present invention is to provide a modular semi/partially-enclosed contact system for low voltage power circuit breakers.
Another object is to provide operational flexibility in low breaking capacity and high breaking capacity circuit breakers.
Yet another object is to minimize let through energy during short circuit condition.
Further object is to provide easy replacement of individual unit in case of any fault or damage.
8

The other object is to reduce assembly time as well as inventory of system improving line productivity.
SUMMARY OF INVENTION
According to the present invention there is provided a partially enclosed modular contact system for multipole circuit breaker, said system comprising :
contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
plate assembly operatively connected to the: said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
Another aspect of the present invention is to provide a contact system comprising plurality of units in parallel and/or in series connection, said unit comprising :
9

contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
plate assembly operatively connected to the said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
DETAILED DESCRIPTION OF INVENTION
In the present invention the semi/partially enclosed contact unit comprises main contact means comprising metallic conducting plate profiled in an ergonomical manner having a base portion and an angular projection extending to a predetermined height to meet holder means. The said holder means comprises blow out piece having rectangular projection such that it can be co-operatively disposed in slot provided in the metallic plate. The metallic plate comprises of arc runner. The main contact comprises contact button means operatively connected to it in a manner to perform resilient motion during circuit breaker operation.
The semi/partially enclosed contact unit of the present invention comprises plurality of holder means rested on the
10

metallic plate perpendicularly. The holder means comprises pair of holding components (hereinafter referred to as deion plate holders) on left and right side of the metallic plate. The inner surface of the deion plate holder comprises ergonomical projection perpendicular to the vertical plane of the holder plate. The projections on both left and right plate holder being profiled to support deion plate assembly operatively placed in between the two holders. The deion plate assembly can easily be isolated from the system by just unscrewing the two holders apart. The bottom surfaces of deion plate holders, being such that when both are placed on the metallic plate of the main contact means, the co-operative engagement of the deion plate holders and the contact button holds the metallic plate in operative fixation with the said deion plate holders. The angular projections of the metallic plate in co-operation with the ergonomical projections of deion plate holders blocks all degrees of freedom for dislocation of deion plate assembly as well as the holders and the metallic contact plate. Deion plate holders comprise slot motor adapted to enhance repulsion in circuit breaker. The system comprises arc deflector being provided in the space' between the slot motor and front wall of deion plate holder such that the arc deflector is arrested in all degrees of freedom.
Such two semi/partially enclosed units in a contact system forms double break system thereby helping in reducing time and unit inspection. Four such semi/partially enclosed units in the contact system as describe above forms quadrabreak system increasing the breaking capacity of the circuit breaker and so on. This arrangement helps in reducing cost because one unit is used for low breaking capacity and such two units are used for making higher breaking capacity.
11

Another advantage of such assembly is that one semi/partially enclosed unit of in the contact system is used for 125 Ampere low breaking capacity, such two units in parallel are used for 250 Ampere circuit breaker of low breaking capacity, such two units in series form 125 Ampere high breaking capacity and two units in series and two units in parallel forms gives 250 Ampere high breaking capacity circuit breaker. Thus extending the number of this individual one unit helps in covering a wide range of current rating as well as range of breaking capacity providing flexibility in operation.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates isometric view of the modular semi/partially enclosed contact unit of the present invention.
Figure 2 illustrates an exploded view of the contact unit.
Figure 3 illustrates an isometric view of the modular contact unit with moulded housing.
DETAILED DESCRIPTION OF ACCOMPANYING FIGURES
In figure 1 isometric view of the modular semi/partially enclosed contact system of the present invention is illustrated. In the figure the metallic main contact plate (1) operatively engaged to deion plate holders (2) comprising arc deflector (5) are realizable.
In figure 2 an exploded view of the contact system is illustrated. In the figure metallic main contact plate (1) comprising horizontal base portion (la) and projection (lb) extends to meet blow out piece (3) having rectangular
12

projection (4). The metallic main contact plate (1) comprises arc runner (6). Contact button means (7) is operatively connected to metallic main contact plate (1). Deion plate holder means (2) comprising holder components (2a, 2b) are provided with inner surface (8) comprising ergonomical projection (9). Deion plate holders (2) comprises slot motor (10). Arc deflector (5) is provided in the space between the slot motor (10) and front wall (11) of deion plate holder (2). The deion plate assembly (12) is supported by the plate holders (2).
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 true spirit. The invention is not limited to the details cited above. For example the holder means, contact means and the number of units do not restrict scope of the present invention. The improved 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.
13

WE CLAIM
1. A partially enclosed modular contact unit for multipole
circuit breaker, said unit comprising :
contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
plate assembly operatively connected to the said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
2. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claim 1, wherein the contact means comprises metallic conducting plates having contact button means.
3. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claims 1 and 2, wherein the contact button means being operatively connected to the
14

metallic conducting plates in a manner to perform resilient motion during circuit breaker operation.
4. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claim 1, wherein the holding components comprise ergonomical projection perpendicular to the vertical plane of the holding component such that angular projection of the metallic plate in co-operation with the ergonomical projections of holding components block all degrees of freedom for dislocation of the said holding components.
5. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claim 1, wherein the holder means further comprises slot motor adapted to enhance repulsion in circuit breaker.
6. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claims 4 and 5, wherein the holder means further comprises arc deflector provided in the space between the slot motor and holder means such that it is arrested in all degrees of freedom.
7. A contact system comprising plurality of units in parallel and/or in series connection, said unit comprising :
contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
15

plate assembly operatively connected to the said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
A contact system as claimed in claim 7, wherein plurality of such units in parallel connection is adapted for circuit breaker of low breaking capacity.
A contact system as claimed in claim 7, wherein plurality of such units in series connection is adapted for circuit breaker of high breaking capacity.
A contact system as claimed in claim 7, wherein plurality of such units in series and parallel connection is adapted for circuit breaker of high breaking capacity.
Dated this 9th day of August, 2006.
Sonali Bhokarikar
of S. Majumdar & Co.
Applicant's agent
16

ABSTRACT
TITLE : MODULAR CONTACT SYSTEM FOR MULTI POLE BREAK CIRCUIT BREAKER
The invention relates to a partially enclosed modular contact unit for multipole circuit breaker. The unit comprises contact means (1) comprising horizontal base portion (la) and projection (lb) wherein said projection having a predetermined angular relation with said base portion (la) travels to a predetermined height, plate assembly (12) operatively connected to the contact means (1) and holder means (2) comprising plurality of holding components (2a, 2b) being rested on the contact means (1) in a vertical manner wherein said components (2a, 2b) being such that in co-operation with the contact means (1) provide support to said plate means (12) so as to prevent dislocation of the plate means (12) adapted to achieve low and/or high breaking capacity thereby providing operational flexibility. The invention also relates to a contact system comprising plurality of such units in parallel and or series connection.
Figure 1

COMPLETE AFTER PROVISIONAL
LEFT ON 10 / 8 / 2006
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)

Title of the invention.

MODULAR CONTACT SYSTEM FOR MULTI POLE BREAK CIRCUIT BREAKER

2. Applicant
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : Indian
(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 a modular semi/partially-enclosed contact system for low voltage power circuit breakers. More particularly, the invention relates to a modular semi/partially-enclosed contact system aiding in the formation of multi break multi pole breakers thereby achieving high breaking capacity, minimizing let through energy during short circuit condition and providing operational flexibility for low and high breaking capacity with amelioration in circuit breaker performance, contact inspection and easy replacement of individual unit at site location.
BACKGROUND AND PRIOR ART
Generally, in power distribution system low voltage power circuit breakers are used as protective devices. The basic function of circuit breaker is to detect abnormality and protect and isolate to faulty equipment. The circuit breaker protects downstream equipments from short circuit and in addition this limits the let through energy, which may cause damage to equipments. In order to achieve the high breaking capacity and compact circuit breaker design circuit breaker with rotary contact systems are used. These circuit breakers provide two breaks per pole for multi pole circuit breaker. The arrangement for rotary contact system includes cassette construction, formation of modular drive shaft interrupter shaft common to all poles. The whole arcing chamber is arranged enclosed in the cassette construction such that gas exhaust slot is provided to take away gases formed inside the circuit breaker during normal and faulted conditions.
2

US 4910485 discloses a breaking device for low voltage circuit breaker comprises in each pole a switching bar, a pair of stationary contacts connected to the connection terminals, a double break rotary contact extending in a housing of the bar, and two arc chutes disposed on each side of the bar. Two contact pressure springs ensure elastic positioning of the rotary contact along the longitudinal direction of pole. Pivoting of the rotary contact takes place around a fictitious axis mounted floating with respect to the fixed rotation axis of the bar.
US 6259338 Bl discloses a multipole circuit breaker includes an arcing chamber housing with a number of arcing chambers, corresponding to number of poles, arranged next to each other. Each arcing chamber has a hinged contact bridge cooperating with a stationary contact arrangement. An interrupter shaft common to poles of the multipole circuit breaker and including a number of shaft segments made of an insulating material, in each of which a contact bridge is arranged, is provided. The adjoining shaft segments are joined to each other by respective coupling elements, each coupling elements including two tab-shaped parts joined to each other by a support shaft. Each tab shaped part supports at least two first connecting pins on a side facing away from the support shaft and extending in an axial direction. The shaft segments each including recesses a side facing the coupling element, the recesses for receiving the connecting pins. A support, or bearing, for supporting the support shaft is provided in the arcing chamber housing in a transition area between adjacent arcing chambers.
US 2004/0256207 Al discloses a rotary contact supporting shaft for low voltage power circuit breaker, whose particularly
3

consist of the fact that it has a modular structure that comprises, along the rotation axis, at least one first and second supporting module, each module being functionally coupled to at least one corresponding moving contact of the circuit breaker and being provided respectively with first and second means for connection to at least one first interconnection module; the first interconnection module is interposed between the first and second supporting modules and is provided with third and fourth connections means that are suitable to be coupled respectively to the first and second connection means; the coupling between the first and third connection means and between the second and fourth connection means allows the functional connection between the first and second supporting modules and the direct structural connection of the interconnection module to the first and second supporting modules.
US 4916421 discloses a current limiting circuit interrupter consisting of a modular unit housed in an insulating case and provided with two fixed contact arms and two movable contact arms. The movable contact arms can be actuated automatically by means of a rod coupled to an operating mechanism as well as by means of an electromagnetic actuator. The operating mechanism includes a lever and a rotating bracket arranged to hold the movable contacts in an open condition when the electromagnet within the electromagnetic actuator is de-energized. In US 6084489 the circuit breaker is characterized by separable contacts operable between a closed and an open position a contact arm having a latching surface and a latch arranged to engage the latching surface when the contacts are blown-open under short-circuit conditions. The arrangement of the latch allows for a positive lock under high magnitude
4

short circuit levels while minimizing the force required by a mechanism to unlock the arm.
US 6828885 Bl discloses a circuit-breaker including a an interrupter chamber housing that includes a plastic 'material and houses an interrupter. The interrupter includes at least one stationary contact member, which, via a busbar is connected to a corresponding connecting terminal and a moveable contact member that is moveable connectable to the stationary contact member. To ensure that heat generated by the busbar is more rapidly released into the switch compartment housing the busbar is imbedded in an outer wall of the interrupter chamber housing and in contact with the housing by a form fit or a force fit.
US 6403901 Bl discloses a contact system having a two-armed contact arm equipped at its opposite ends with contact pieces that can be brought into and out of contact with corresponding contact pieces of stationary busbars. The contact arm is mounted rotatably on a central bearing axis using an elongated hole, the two lever arms being acted upon by contact force springs that brace with one end against a switching shaft or a switching shaft segment. To provide a uniform contact pressure in the presence of differing wear of the contact pieces, the elongated hole extends in a direction that differs substantially from the direction perpendicular to the longitudinal axis of the contact arm and substantially from the longitudinal axis, and the longitudinal action direction of the contact force springs extends neither perpendicular to the longitudinal axis nor perpendicular to the extension direction of the elongated hole.
5

US 6184761 Bl describes a circuit breaker rotary contact arrangement in which the ends of the line and load straps supporting the fixed contacts are hook-shaped to control the angle of the repulsive force exhibited between the fixed contacts and the movable contacts arranged at the opposing ends of the rotary contact arm. The fixed contacts face outwardly away from the central pivot of the contact arm such that a horizontal component of the popping force acts away from the center of rotation keeping the contact arm in tension for avoiding a buckling effect allowing contact arms with smaller cross sectional area to be used to increase contact arm mobility and reduce the cost.
US 6204743 Bl discloses an electrically conducting strap for use in a rotary circuit breaker cassette provides dual connectors to accommodate either an electronic or mechanical trip unit within the circuit breaker and electrical distribution system. The continuous, integral strap includes a first section including a fixed contact mounted thereon, a U-shaped second section, a third section having two apertures for connection to associated electrical equipment, and a fourth section having two apertures for connection to a line of a distribution system providing electrical power to a load. Thus, the circuit breaker has the advantage of reduced cost and increased ease of manufacturability since a common cassette is used.
US 6326868 Bl discloses a circuit breaker rotary contact arm is used within a plurality of single pole circuit breakers ganged together to form a single multi-pole circuit breaker. To provide uniform contact wear among the associated circuit breaker contacts, the rotor carrying the rotary contact arm pivot is slotted. to automatically position the rotary contact
6

arm to allow for changes in the contact geometry while maintaining constant contact compressive forces. The individual circuit breakers connect with the central operation mechanism by means of a single pin.
US 6114641 discloses a circuit breaker rotary contact assembly employs a common pivot between the rotor assembly and the rotary contact arm. A pair of off-center expansion springs directly engage the rotor at one end and engage the rotary contact arm via a linkage arrangement at an opposite end thereof.
US 6590172 discloses a circuit breaker is provided wherein the circuit breaker comprises a contact arm movable between a closed position, an open position and a blown open position wherein the contact arm is disposed in the circuit breaker. A bumper disposed to contact the contact arm when the contact arm is in the blown open position. In addition, a stop member disposed to be in contact with a linkage assembly so as to create a gap between the bumper and the contact arm when the contact arm is disposed in the open position.
The disadvantages of the pior art as described above are
circuit breaker assemblies are quite complicated and easy replacement of contact system for contact inspection function is not possible ;
assemblies are such that dismantling of the components of the assemblies is time consuming and adds to the inventory to the system ;
7

assembly sequence is such that the field replacement of any such sub assembly causes problem; and
contact inspection not at all possible.
So there . is a need to provide for a modular construction of contact system that would reduce the assembly time with easy replacement of faulty or damaged parts and achieves high breaking capacity with the minimization of let through energy during short circuit condition. The invention also provides operational flexibility for low and high breaking capacity and on the other hand improves assembly line, productivity.
The present inventors have surprisingly found that by way of an innovative integration of desired components in a definite manner a modular semi/partially-enclosed contact can be achieved that would reduce the assembly time with easy replacement of faulty or damaged parts, provide operational flexibility improves assembly line productivity.
OBJECTS OF INVENTION
Thus one object of the present invention is to provide a modular semi/partially-enclosed contact system for low voltage power circuit breakers.
Another object is to provide operational flexibility in low breaking capacity and high breaking capacity circuit breakers.
Yet another object is to minimize let through energy during short circuit condition.
Further object is to provide easy replacement of individual unit in case of any fault or damage.
8

The other object is to reduce assembly time as well as inventory of system improving line productivity.
SUMMARY OF INVENTION
According to the present invention there is provided a partially enclosed modular contact system for multipole circuit breaker, said system comprising :
contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
plate assembly operatively connected to the: said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
Another aspect of the present invention is to provide a contact system comprising plurality of units in parallel and/or in series connection, said unit comprising :
9

contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
plate assembly operatively connected to the said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
DETAILED DESCRIPTION OF INVENTION
In the present invention the semi/partially enclosed contact unit comprises main contact means comprising metallic conducting plate profiled in an ergonomical manner having a base portion and an angular projection extending to a predetermined height to meet holder means. The said holder means comprises blow out piece having rectangular projection such that it can be co-operatively disposed in slot provided in the metallic plate. The metallic plate comprises of arc runner. The main contact comprises contact button means operatively connected to it in a manner to perform resilient motion during circuit breaker operation.
The semi/partially enclosed contact unit of the present invention comprises plurality of holder means rested on the
10

metallic plate perpendicularly. The holder means comprises pair of holding components (hereinafter referred to as deion plate holders) on left and right side of the metallic plate. The inner surface of the deion plate holder comprises ergonomical projection perpendicular to the vertical plane of the holder plate. The projections on both left and right plate holder being profiled to support deion plate assembly operatively placed in between the two holders. The deion plate assembly can easily be isolated from the system by just unscrewing the two holders apart. The bottom surfaces of deion plate holders, being such that when both are placed on the metallic plate of the main contact means, the co-operative engagement of the deion plate holders and the contact button holds the metallic plate in operative fixation with the said deion plate holders. The angular projections of the metallic plate in co-operation with the ergonomical projections of deion plate holders blocks all degrees of freedom for dislocation of deion plate assembly as well as the holders and the metallic contact plate. Deion plate holders comprise slot motor adapted to enhance repulsion in circuit breaker. The system comprises arc deflector being provided in the space' between the slot motor and front wall of deion plate holder such that the arc deflector is arrested in all degrees of freedom.
Such two semi/partially enclosed units in a contact system forms double break system thereby helping in reducing time and unit inspection. Four such semi/partially enclosed units in the contact system as describe above forms quadrabreak system increasing the breaking capacity of the circuit breaker and so on. This arrangement helps in reducing cost because one unit is used for low breaking capacity and such two units are used for making higher breaking capacity.
11

Another advantage of such assembly is that one semi/partially enclosed unit of in the contact system is used for 125 Ampere low breaking capacity, such two units in parallel are used for 250 Ampere circuit breaker of low breaking capacity, such two units in series form 125 Ampere high breaking capacity and two units in series and two units in parallel forms gives 250 Ampere high breaking capacity circuit breaker. Thus extending the number of this individual one unit helps in covering a wide range of current rating as well as range of breaking capacity providing flexibility in operation.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates isometric view of the modular semi/partially enclosed contact unit of the present invention.
Figure 2 illustrates an exploded view of the contact unit.
Figure 3 illustrates an isometric view of the modular contact unit with moulded housing.
DETAILED DESCRIPTION OF ACCOMPANYING FIGURES
In figure 1 isometric view of the modular semi/partially enclosed contact system of the present invention is illustrated. In the figure the metallic main contact plate (1) operatively engaged to deion plate holders (2) comprising arc deflector (5) are realizable.
In figure 2 an exploded view of the contact system is illustrated. In the figure metallic main contact plate (1) comprising horizontal base portion (la) and projection (lb) extends to meet blow out piece (3) having rectangular
12

projection (4). The metallic main contact plate (1) comprises arc runner (6). Contact button means (7) is operatively connected to metallic main contact plate (1). Deion plate holder means (2) comprising holder components (2a, 2b) are provided with inner surface (8) comprising ergonomical projection (9). Deion plate holders (2) comprises slot motor (10). Arc deflector (5) is provided in the space between the slot motor (10) and front wall (11) of deion plate holder (2). The deion plate assembly (12) is supported by the plate holders (2).
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 true spirit. The invention is not limited to the details cited above. For example the holder means, contact means and the number of units do not restrict scope of the present invention. The improved 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.
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WE CLAIM
1. A partially enclosed modular contact unit for multipole
circuit breaker, said unit comprising :
contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
plate assembly operatively connected to the said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
2. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claim 1, wherein the contact means comprises metallic conducting plates having contact button means.
3. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claims 1 and 2, wherein the contact button means being operatively connected to the
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metallic conducting plates in a manner to perform resilient motion during circuit breaker operation.
4. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claim 1, wherein the holding components comprise ergonomical projection perpendicular to the vertical plane of the holding component such that angular projection of the metallic plate in co-operation with the ergonomical projections of holding components block all degrees of freedom for dislocation of the said holding components.
5. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claim 1, wherein the holder means further comprises slot motor adapted to enhance repulsion in circuit breaker.
6. A partially enclosed modular contact unit for multipole circuit breaker as claimed in claims 4 and 5, wherein the holder means further comprises arc deflector provided in the space between the slot motor and holder means such that it is arrested in all degrees of freedom.
7. A contact system comprising plurality of units in parallel and/or in series connection, said unit comprising :
contact means comprising horizontal base portion and projection wherein said projection having a predetermined angular relation with said base portion travels to a predetermined height;
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plate assembly operatively connected to the said contact means; and
holder means comprising plurality of holding components being rested on the contact means in a vertical manner wherein said components being such that in co-operation with the contact means provide support to said plate means so as to prevent dislocation of the plate means;
adapted to achieve low and/or high breaking capacity thereby providing operational flexibility.
A contact system as claimed in claim 7, wherein plurality of such units in parallel connection is adapted for circuit breaker of low breaking capacity.
A contact system as claimed in claim 7, wherein plurality of such units in series connection is adapted for circuit breaker of high breaking capacity.
A contact system as claimed in claim 7, wherein plurality of such units in series and parallel connection is adapted for circuit breaker of high breaking capacity.
Dated this 9th day of August, 2006.
Sonali Bhokarikar
of S. Majumdar & Co.
Applicant's agent
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ABSTRACT
TITLE : MODULAR CONTACT SYSTEM FOR MULTI POLE BREAK CIRCUIT BREAKER
The invention relates to a partially enclosed modular contact unit for multipole circuit breaker. The unit comprises contact means (1) comprising horizontal base portion (la) and projection (lb) wherein said projection having a predetermined angular relation with said base portion (la) travels to a predetermined height, plate assembly (12) operatively connected to the contact means (1) and holder means (2) comprising plurality of holding components (2a, 2b) being rested on the contact means (1) in a vertical manner wherein said components (2a, 2b) being such that in co-operation with the contact means (1) provide support to said plate means (12) so as to prevent dislocation of the plate means (12) adapted to achieve low and/or high breaking capacity thereby providing operational flexibility. The invention also relates to a contact system comprising plurality of such units in parallel and or series connection.
Figure 1