Claims:1. A circuit breaker comprising:
a fixed terminal (11) having a twisted profile;
a moving terminal (12) having a twisted profile and connected with a plurality of flexible metallic braids (13) to facilitate ON-OFF operations; and
a cradle terminal assembly (16) having a plurality of spring loaded contacts (14) mounted thereon,
wherein a set of first spring loaded contacts from said plurality of spring loaded contacts (14) are adapted to hold the fixed terminal (11); and
wherein a set of second spring loaded contacts from said plurality of spring loaded contacts (14) are adapted to hold the moving terminal 12, thereby providing a reduced length of current path and a minimum depth of the circuit breaker.

2. The circuit breaker as claimed in claim 1, wherein the cradle terminal assembly (16) comprises a plurality of springs (15) for holding the plurality of spring loaded contacts (14), and wherein the plurality of springs (15) enable the plurality of spring loaded contacts (14) to achieve any one of a contraction when terminals are removed therefrom and an expansion when the fixed and moving terminals are inserted therein.

3. The circuit breaker as claimed in claim 1, wherein the fixed terminal (11) comprises a flat base at one end, and the other end, by virtue of the twisted profile, is at a certain pre-determined angle to the flat base.

4. The circuit breaker as claimed in claim 1, wherein the moving terminal (12) comprises a flat base at one end, and the other end, by virtue of the twisted profile, is at a certain pre-determined angle to form vertical said flat base.

5. The circuit breaker as claimed in claim 1, wherein the cradle is a cassette like structure.

6. The circuit breaker as claimed in claim 1, wherein the circuit breaker further comprises a breaker housing (18), which when mounted on cradle rails (23), the fixed terminal (11) and the moving terminal (12) are adapted to get inserted inside the plurality of spring loaded contacts (14) to establish a contact.

7. The circuit breaker as claimed in claim 1, wherein the circuit breaker further comprises a breaker housing (18), which when mounted on cradle rails (23), the fixed terminal (11) and the bottom terminal (12) are adapted to move away from the plurality of spring loaded contacts (14) to establish a contact.

8. The circuit breaker as claimed in claim 1, wherein the plurality of spring loaded contacts (14) are mounted on the cradle terminal assembly (16) on one side, allowing swiveling or aligning of the plurality of spring loaded contacts (14), said swiveling of the plurality of spring loaded contacts (14) enabling insertion and orientation of the fixed terminal (11) and the moving terminal (12) there within.

9. The circuit breaker as claimed in claim 1, wherein the moving terminal (12) is connected with a plurality of flexible metallic braids (13) to facilitate ON-OFF operations.

10. The circuit breaker as claimed in claim 1, wherein the plurality of spring loaded contacts (14) are manufactured using any or combination of metallic materials having elasticity properties.
, Description:TECHNICAL FIELD
[0001] The present disclosure generally relates to circuit breaker, and more particularly relates to, but not by way of limitation, circuit breaker current paths for providing additional current capability.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Circuit breakers are generally implemented to protect equipment from overcurrent situations, for example, when a short circuit or ground fault occurs in an electrical supply conductor. Upon the occurrence of an overcurrent condition, electrical contacts within the circuit breaker will generally open, stopping the supply of electrical current to the equipment. Designs for circuit breakers generally include accommodations for both high quiescent currents and high withstand currents. To maintain a high withstand current rating, the contacts must be locked closed at the current withstand rating and be able to withstand the large electrodynamic repulsion forces generated by the current flow.
[0004] Circuit breaker is a switching device designed to make, carry and break the circuit. The main or power contact system of the circuit breaker consists of generally two parts; one of current path inside housing or breaker chamber and another mounted on cassette or cradle structure. These two electrically conducting paths are joined each other with movement of breaker inside cassette or cradle structure. One of the current paths is generally inserted inside spring loaded components of another current path to establish electrical connection under normal conditions.
[0005] Breaker current path comprises a moving terminal and a fixed terminal. Mechanism is the part of the circuit breaker used for driving power contact system of the circuit breaker to close and open. Energy stored in the mechanism by means of springs is utilized to join the moving terminal with the fixed terminal and thereby close the circuit. Under normal operating conditions i.e. in electrical current carrying state; circuit remains closed. Aforementioned mechanism is also associated with tripping linkages to open the circuit. Opening of circuit can be done intentionally by the operator or can happen automatically during an abnormal electrical condition like overload, under voltage or short circuit.
[0006] As mentioned, moving terminal and fixed terminal carry maximum upto rated operational current for which it is designed; during normal operating conditions. During operational life of the switching device, heat will be generated due to the inherent losses. Necessary cross section of terminals limits the temperature rise in the circuit breaker.
[0007] Breaker structure or housing chamber is mounted on cradle or cassette like structure. Cradle side current path comprises a terminal mounted inside it for customer interface and plurality of clusters of current carrying spring loaded components (can also be called as jaws) mounted on the cradle terminals. When Breaker side contact system or current path enters inside cradle side current path electrical connection gets established to carry under normal operating conditions.
[0008] Further, various attempts have been made to increase the current carrying capability of circuit breakers in the prior-art. However, what is observed is that existing designs of current path includes metallic terminals generally made up from complex or specialized manufacturing processes like hot forging or extrusion. Manufacturing cost of such terminals is generally high due to specialized manufacturing processes like hot forging or extrusion. Further, the existing literature provides a motivation to use several joints to increase the current carrying capability with the cost of increasing number of components making the breaker bulkier and heavier. Accordingly, one of the major drawbacks of existing prior-art is that it requires specialized manufacturing process like extrusion process or hot forging process which by default increases the manufacturing cost and maintainace cost with excess material consumption. Further, the higher current path length due to the components available in the prior-art offers higher resistance and in turn higher heat losses with limited current carrying capacity due to convection constraints and higher l/A ratio.
[0009] The aforementioned limitations of the existing the switchgears in the existing prior-art are recognized by the inventors hereof and some or all of these limitations have been addressed by various embodiments of the present invention. Due to the huge development in the field of circuit breakers, and in view of the emerging needs of advanced circuit breakers, it would be advantageous to provide a circuit breaker system with an increased current carrying capability.
[0010] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0011] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0012] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0013] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0014] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

SUMMARY
[0015] The aforementioned limitations of the existing switchgears are recognized by the inventors hereof and some or all of these limitations have been addressed by providing a new, efficient, technically advanced, circuit breaker current paths for providing additional current capability. The present invention refers to a design of electrical current carrying conductor profile in circuit breaker. It relates to a structure for suppressing rise in temperature of a current-carrying conductor at an opening and closing contact as well as in the vicinity of the contact in circuit breaker at the time of applying an electric current to the conductor under normal conditions.
[0016] An aspect of the present disclosure provides a circuit breaker. The circuit breaker includes at least one fixed terminal having a twisted profile, at least one moving terminal having a twisted profile and connected with a plurality of flexible metallic braids to facilitate ON-OFF operations, and a cradle terminal assembly having a plurality of spring loaded contacts (interchangeable referred to as “jaw” or “jaws”) mounted thereon.
[0017] In an aspect, a set of first spring loaded contacts from said plurality of spring loaded contacts holds the fixed terminal, and a set of second spring loaded contacts from said plurality of spring loaded contacts holds moving terminal, thereby providing a reduced length of current path and a minimum depth of the circuit breaker.
[0018] In an aspect, the cradle terminal assembly includes a plurality of springs for holding the plurality of spring loaded contacts. In another aspect, the plurality of springs enables the plurality of spring loaded contacts achieve any one of a contraction when terminals are removed therefrom and an expansion when terminals are inserted therein.
[0019] In an aspect, the fixed terminal can include a flat base and another end, wherein another end, by virtue of the twisted profile is at a certain pre-determined angle to form vertical to its flat base.
[0020] In an aspect, the moving terminal can include a flat base and another end, wherein another end, by virtue of the twisted profile is at a certain pre-determined angle to its flat base.
[0021] In an aspect, the cradle is a cassette like structure.
[0022] In an aspect, the circuit breaker can include breaker housing. In another aspect, when the breaker housing is mounted in cradle rails and is racked in, the fixed terminal and the bottom terminal are adapted to get inserted inside the plurality of spring loaded contacts to establish a contact. In yet another aspect, when the breaker housing is mounted in cradle rails and is racked out, the fixed terminal and the bottom terminal are adapted to move away from the plurality of spring loaded contacts to establish a contact.
[0023] In an aspect, the plurality of spring loaded contacts are mounted on the cradle terminal assembly on one side and thus allows swiveling or aligning of the plurality of spring loaded contacts, the swiveling of the plurality of spring loaded contacts enables insertion and orientation of the fixed terminal and the bottom terminal there within.
[0024] In an aspect, the plurality of spring loaded contacts is manufactured using any or combination of metallic materials.
[0025] In an aspect, the plurality of spring loaded contacts is manufactured using any or combination of metallic materials having elasticity properties.
[0026] In contrast to the existing techniques of current path, the current path arrangement provided according to the present disclosure has less number of joints and thus voltage drop across current path under normal operating conditions is least in comparison with other inventions disclosed. Also, the length of current path has been reduced due to elimination cradle terminal profile required to mount jaws in earlier arts. Reduced length enables to reduce l/A ratio and facilities to limit temperature losses and provide enhanced current carrying capacity. Further, the manufacturing processes are in accordance with the conventional techniques which reduce costs of components. In cradle jaw, a number of components are least as compared to other designs and thus provide cost saving as well. Jaw limbs provide surface contact for inserted terminals inside jaw. Convection stands improved in the disclosed invention.
[0027] Also, the existing design of current path includes metallic terminals generally made up from complex or specialized manufacturing processes like hot forging or extrusion. Manufacturing cost of such terminals is generally high due to specialized manufacturing processes like hot forging or extrusion. In contrast to this, the present invention relates to the use of simplified manufacturing process like sheet metal process for manufacturing moving terminal and still archives variable thickness at different surfaces of moving terminal. Existing arts refer to several joints which are reduced in the present invention that further lead to lower voltage drop across current path and thus having lower heat losses arising while current conduction under normal operating conditions. Further, Jaw assembly design in previous arts used has more than 2 varieties of components which are limited two in this invention.
[0028] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components

BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0030] FIG. 1 illustrates an exemplary current path having of fixed top terminal, bottom moving terminal, and a plurality of jaws mounted on cradle terminals both in top and bottom, in accordance with an embodiment of the present disclosure.
[0031] FIG. 2 illustrates a side view of an exemplary current path, in accordance with an embodiment of the present disclosure.
[0032] FIGs. 3A-3B illustrates exemplary views of jaw assemblies fixed onto cradle terminal, in accordance with an embodiment of the present disclosure.
[0033] FIG. 4 illustrates an exemplary side view of current path mounted inside housing or breaker chamber and cradle, in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION
[0034] The following is a detailed description of embodiments of the disclosure illustrated in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0035] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0036] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0037] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0038] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
[0039] Thus, for example, it will be appreciated by those of ordinary skill in the art that the diagrams, schematics, illustrations, and the like represent conceptual views or processes illustrating systems and methods embodying this invention. The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing associated software. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the entity implementing this invention.
[0040] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0041] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0042] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0043] It is well know that, the circuit breaker is a switching device designed to make, carry and break the circuit. The main or power contact system of the circuit breaker consists of generally two parts, one of current path inside housing (referenced with numeral 18 in this application)or breaker chamber and another mounted on cassette or cradle structure (referenced with numeral 17 in this application). These two electrically conducting paths are joined each other with movement of breaker inside cassette 18 or cradle structure 17. One of the current paths is generally inserted inside spring loaded components of another current path to establish electrical connection under normal conditions.
[0044] In an example, the breaker current path comprises a moving terminal and a fixed terminal. A mechanism is the part of the circuit breaker used for driving power contact system of the circuit breaker to close and open. Energy stored in the mechanism by means of springs is utilized to join the moving terminal with the fixed terminal and thereby close the circuit. Under normal operating conditions i.e. in electrical current carrying state; circuit remains closed. Aforementioned mechanism is also associated with tripping linkages to open the circuit. Opening of circuit can be done intentionally by the operator or can happen automatically during an abnormal electrical condition like overload, under voltage or short circuit.
[0045] As mentioned, moving terminal and fixed terminal carry maximum upto rated operational current for which it is designed; during normal operating conditions. During operational life of the switching device, heat will be generated due to the inherent losses. Necessary cross section of terminals limits the temperature rise in the circuit breaker.
[0046] Breaker structure or housing chamber is mounted on cradle or cassette like structure. Cradle side current path comprises a terminal mounted inside it for customer interface from rear end for busbar connection and plurality of clusters of current carrying spring loaded components (can also be called as jaws) mounted on the cradle terminals. When breaker side contact system or current path enters inside cradle side current path electrical connection gets established to carry under normal operating conditions.
[0047] Various attempts have been made to increase the current carrying capability of circuit breakers in the prior-art. However, what is observed is that existing designs of current path includes metallic terminals generally made up from complex or specialized manufacturing processes like hot forging or extrusion. Manufacturing cost of such terminals is generally high due to specialized manufacturing processes like hot forging or extrusion. Further, the existing literature provides a motivation to use several joints to increase the current carrying capability with the cost of increasing number of components making the breaker bulkier and heavier. Accordingly, one of the major drawbacks of existing prior-art is that it requires specialized manufacturing process like extrusion process or hot forging process which by default increases the manufacturing cost and maintainace cost with excess material consumption. Further, the higher current path length due to the components available in the prior-art offers higher resistance and in turn higher heat losses with limited current carrying capacity due to convection constraints and higher l/A ratio.
[0048] The aforementioned limitations (also recited in background section) of the existing protection relays are recognized by the inventors hereof and some or all of these limitations have been addressed by providing a new, efficient, technically advanced, circuit breaker current paths for providing additional current capability. The present invention refers to a design of electrical current carrying conductor profile in circuit breaker. It relates to a structure for suppressing rise in temperature of a current-carrying conductor at an opening and closing contact as well as in the vicinity of the contact in circuit breaker at the time of applying an electric current to the conductor under normal conditions.
[0049] The present disclosure generally relates to circuit breaker, and more particularly relates to, but not by way of limitation, circuit breaker current paths for providing additional current capability.
[0050] Accordingly, the present invention provides a circuit breakers current path by use of simplified manufacturing processes, optimization of material content of metal used for current carrying and emphasizes on reduction in overall length of the current path but increase in cross sectional area to limit the temperature rise or heat losses. The present invention provides least rise in temperature of a current-carrying conductor and in the vicinity of contacts when rated current is conducted through it under normal conditions.
[0051] An aspect of the present disclosure provides a circuit breaker. The circuit breaker includes at least one fixed terminal having a twisted profile, at least one moving terminal having a twisted profile and connected with a plurality of flexible metallic braids to facilitate ON-OFF operations, and a cradle terminal assembly having a plurality of spring loaded contacts (interchangeable referred to as “jaw” or “jaws”) mounted thereon.
[0052] In an aspect, a set of first spring loaded contacts from said plurality of spring loaded contacts holds the fixed terminal, and a set of second spring loaded contacts from said plurality of spring loaded contacts holds moving terminal, thereby providing a reduced length of current path and a minimum depth of the circuit breaker.
[0053] In an aspect, the cradle terminal assembly includes a plurality of springs for holding the plurality of spring loaded contacts. In another aspect, the plurality of springs enables the plurality of spring loaded contacts achieve any one of a contraction when terminals are removed therefrom and an expansion when terminals are inserted therein.
[0054] In an aspect, the fixed terminal can include a flat base and another end, wherein another end, by virtue of the twisted profile is at a certain pre-determined angle to its flat base.
[0055] In an aspect, the moving terminal can include a flat base and another end, wherein another end, by virtue of the twisted profile is at a certain pre-determined angle to form vertical its flat base.
[0056] In an aspect, the cradle is a cassette like structure.
[0057] In an aspect, the circuit breaker can include breaker housing. In another aspect, when the breaker housing is mounted in cradle rails and is racked in, the fixed terminal and the bottom terminal are adapted to get inserted inside the plurality of spring loaded contacts to establish a contact. In yet another aspect, when the breaker housing is mounted in cradle rails and is racked out, the fixed terminal and the bottom terminal are adapted to move away from the plurality of spring loaded contacts to establish a contact.
[0058] In an aspect, the plurality of spring loaded contacts are mounted on the cradle terminal assembly on one side and thus allows swiveling or aligning of the plurality of spring loaded contacts, the swiveling of the plurality of spring loaded contacts enables insertion and orientation of the fixed terminal and the bottom terminal there within.
[0059] In an aspect, the plurality of spring loaded contacts is manufactured using any or combination of metallic materials.
[0060] In an aspect, the plurality of spring loaded contacts is manufactured using any or combination of metallic materials having elasticity properties.
[0061] In contrast to the existing techniques of current path, the current path arrangement provided according to the present disclosure has less number of joints and thus voltage drop across current path under normal operating conditions is least in comparison with other inventions disclosed. Also, the length of current path has been reduced due to elimination cradle terminal profile required to mount jaws in earlier arts. Reduced length enables to reduce l/A ratio and facilities to limit temperature losses and provide enhanced current carrying capacity. Further, the manufacturing processes are in accordance with the conventional techniques which reduce costs of components. In cradle jaw, a number of components are least as compared to other designs and thus provide cost saving as well. Jaw limbs provide surface contact for inserted terminals inside jaw. Convection stands improved in the disclosed invention.
[0062] Also, the existing design of current path includes metallic terminals generally made up from complex or specialized manufacturing processes like hot forging or extrusion. Manufacturing cost of such terminals is generally high due to specialized manufacturing processes like hot forging or extrusion. In contrast to this, the present invention relates to the use of simplified manufacturing process like sheet metal process for manufacturing moving terminal and still archives variable thickness at different surfaces of moving terminal. Existing arts refer to several joints which are reduced in the present invention that further lead to lower voltage drop across current path and thus having lower heat losses arising while current conduction under normal operating conditions. Further, Jaw assembly design in previous arts used has more than 2 varieties of components which are limited two in this invention.
[0063] FIG. 1 illustrates an exemplary current path having of fixed top terminal, bottom moving terminal, and a plurality of jaws mounted on cradle terminals both in top and bottom, in accordance with an embodiment of the present disclosure. The jaws can be supported by spring on each side.
[0064] FIG. 2 illustrates a side view of an exemplary current path, in accordance with an embodiment of the present disclosure. Depth “D” of current path has been shown in the figure which is least among all similar arts.
[0065] FIGs. 3A-3B illustrates exemplary views of jaw assemblies fixed onto cradle terminal, in accordance with an embodiment of the present disclosure. In an exemplary embodiment, FIG. 3B shows a top view. Jaw assemblies are plurality in numbers mounted on one cradle terminal. Jaw is supported by springs from each end.
[0066] FIG. 4 illustrates an exemplary side view of current path mounted inside housing or breaker chamber and cradle, in accordance with an exemplary embodiment of the present disclosure. In an exemplary embodiment, FIG. 4 shows current path components’ orientation in service or connected position wherein it is able to carry current under normal operating conditions.
[0067] Broadly, the circuit breaker can be segregated into two main categories based on the functionality to shift the device. Two categories are a fixed type and a draw out type of circuit breakers. Fixed type devices are mounted on a suitable framework to facilitate the working of the device, wherein power contacts remain connected to the framework or bus bar throughout its operational life.
[0068] A draw out type device is loaded on a cassette type structure, herein after called as cradle 17 (as shown in FIG. 4) made of suitable material and sufficient mechanical arrangements will be provided in the cradle to facilitate the movement of the breaker inside the cradle. This movement allows power contacts inside breaker 18 (as shown in FIG. 4) to get detached from bus bar when breaker is not in operation. The disclosed art illustrates current path design of multipole circuit breaker (as shown in FIG. 1) for both fixed type and draw out type of switching device like circuit breakers.
[0069] The present invention provides a design and working principle of circuit breakers current path, as shown in FIG. 1, includes a fixed terminal 11, a moving terminal 12, a plurality of current carrying metallic braids 13, spring loaded metallic contacts 14 (herein after will be called as “jaws”), and customer interface terminal 16 (as shown in FIG. 2).
[0070] The present invention, which enables to provide current path of switching device like circuit breaker can include two distinct parts one inside housing or breaker chamber 18 (as shown in FIG. 4) and another outside housing chamber mounted on cassette like structure called cradle 17 (as shown in FIG. 4).
[0071] In an exemplary embodiment, breaker side current path can include a fixed terminal 11 on top, and a moving terminal 12 on bottom side. The moving terminal 12 can be fixed with plurality of flexible metallic braids 13 to facilitate ON-OFF operations of the assembly using mechanical linkages of mechanism assembly [not shown].
[0072] In an exemplary embodiment, the fixed terminal 11 is made up of current carrying metal. The fixed terminal 11 has a flat base mounted on housing 18. Terminal is designed such a way that it’s another end is at certain angle to its flat base. Preferably the angle is right angle formed from conventional manufacturing processes like twisting or bending. Vertical limb on other end of this fixed terminal is outside housing chamber.
[0073] In an exemplary embodiment, similar to the fixed terminal, the bottom placed moving terminal 12 also has vertical limb at certain angle (preferably right angle) to its flat base mounted on the lower portion of the housing. The vertical limb, whose rear end is coplanar with rear end of vertical limb of top fixed terminal 11, is outside the housing chamber 18.
[0074] In an exemplary embodiment, the moving terminal 12 can be fixed with plurality of flexible metallic braids 13 with conventional joining processes. Small contacts 20 can be attached to metal contacts 21 who in turn can be joined to braids 13, which can be connected to metallic strip 22 mounted on fixed top terminal 11 when device is closed to carry current.
[0075] In an exemplary embodiment, the cradle side current path includes flat polygonal metallic terminals 16 (as shown in FIG. 2) and spring loaded metallic contacts called jaws 14 (as shown in FIG. 2). Cradle terminals 16 (as shown in FIG. 2) are placed in top and bottom section of cradle for each pole. Cradle terminals 16 (as shown in FIG. 2) also serve user interface for terminating or connecting current carrying bus bar onto them.
[0076] In an exemplary embodiment, the cradle jaws 14 are spring loaded electrical contacts connected to cradle terminal. Plurality of jaws 14 are terminated on cradle terminal 16 based on requirement of load current. These jaws are held in-between leaf springs 15 which facilitate contraction and expansion of jaw limbs.
[0077] In an exemplary embodiment, jaw limbs with low thickness have material property such that they can regain to their original position after terminals inserted inside them are taken out (tension withdrawn). Further these limbs are supported by spring like structure; preferably but not limited to leaf springs.
[0078] In an exemplary embodiment, when breaker housing 18 (as shown in FIG. 4) is mounted in cradle rails 23 (as shown in FIG. 4) and is racked in the rear vertical surfaces of fixed top terminal 11 (as shown in FIG. 4) and bottom moving terminal 12 (as shown in FIG. 4) get inserted inside cradle jaws 14 (as shown in FIG. 4) to establish contact. Leaf springs 15 exert pressure on jaws 14 (as shown in FIG. 4) to provide desired contact pressure. When racking gets completed and breaker is closed, electrical connection is established which allows current to flow through electrical system.
[0079] In an exemplary embodiment, when breaker is racked out, breakers travel towards operator and away from jaws 14. When connection between vertical limbs of terminals and jaws is lost, by the virtue of leaf spring force; limbs of jaws regain their original shape and position.
[0080] In an exemplary embodiment, jaws 14 (as shown in FIGs. 3A-3B) are mounted with single fixation with cradle terminal 16 (as shown in FIGs. 3A-3B) and thus they swivel. When vertical terminal limbs are inserted inside jaw limbs, jaw limbs get oriented so as to establish contact. The self aligning feature of this design ensures no increase in racking torque and establishment of contact with voltage drop across joint remaining within required limits.
[0081] The present invention by virtue of jaws 14, fixed contact 11, and movable contact 12, eliminates requirement of additional profile [as required in prior-art] of cradle terminal required to mount cradle jaws 14. The jaw exerted pressure on twisted terminals 11, 12 is built using leaf springs 15 (as shown in FIG. 1). Twisting with help of conventional manufacturing process eliminates requirement of fixing separate vertical limb to flat base of fixed and moving terminals 11, 12. Both lead to offer lesser resistance of current path and thus voltage drop across entire current path gets minimized. Hence, the disclosed design helps in lower heat losses and facilitates additional current carrying capacity through same structure.
[0082] FIG. 1 and FIG. 2 depicts entire current path of circuit breaker of the present invention. FIG. 4 explains current path mounted inside breaker and cradle assembly. When breaker is racked in to connect or service position. In connect position the breaker current path gets overlapped by cradle jaws. In service position, the vertical limbs of top fixed terminal and bottom moving terminal remain inserted inside cradle jaws to complete circuit. When the breaker is switched on current flows through system under normal operating conditions. FIGs. 3A-3B shows cradle terminal assembly on which plurality of cradle jaws are mounted based on current requirements. Each jaw uses single hardware or any conventional fixing so as to facilitate its swivel or self alignment during insertion of terminals inside jaw limbs during racking in of circuit breaker.
[0083] As compared to the conventional solution available in the prior-art, the proposed solution by virtue of jaws 14, fixed contact 11, and movable contact 12, provides resistance of current path in proportion to length of current path. Also, the present invention eliminates one current path component in comparison with other previously disclosed/developed inventions in the prior-art, thus reduces length of current path. Further, the present invention enables to minimize the Depth “D” of entire switching device of breaker, which is least among all similar prior inventions in circuit breakers. Furthermore, conventional manufacturing process that twists flat horizontal terminal into vertical at other end facilitates elimination of joint and prevents potential voltage drop across such joint. In addition to this, the reduction in length of current carrying path according to the present invention reduces resistance and thus reduces heat losses arising during conduction of current. This further provides additional current carrying capacity of the switching apparatus.
[0084] One or more of the components, steps, and/or functions illustrated in the Figures may be rearranged and/or combined into a single component, step, or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from the invention.
[0085] It should be understood that the foregoing description is only illustrative of the present embodiments. Various alternatives and modifications can be devised by those skilled in the art without departing from the embodiments disclosed herein. Accordingly, the embodiments are intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.

ADVANTAGES OF THE PRESENT INVENTION
[0086] The present invention enables to provide an adequate current carrying cross section with use of optimum material consumption.
[0087] The implementation of the present invention requires less number of joints resulting in lower voltage drop across the entire current path.
[0088] According to the present invention, reduction in length of current path leads to low “length/ cross sectional area” ratio and thus lower resistance of current path which in turn results in lower heat losses, lesser temperature rise during current conduction under normal operating conditions, and also enables in enhancement of current carrying capacity through same current path.
[0089] According to the present invention, jaw limbs having lower thickness facilitate in regaining their shape on their own once contacts or terminals are disengaged from them. They gain back their original shape by the virtue of their material properties and geometry. Further, they are supported by leaf spring on both sides.
[0090] The implementation of the present invention enables to achieve performance consistency and reliability.
[0091] The implementation of the present invention enables to achieve performance consistency and reliability.
[0092] The implementation of the present invention enables to ensure consistent contact pressure between terminals and jaw limbs.
[0093] The implementation of the present invention enables to achieve improved convection i.e., open type construction of the jaw assembly enables high convection rate for the heat in the device