Claims:
1. A circuit breaker comprising:
a moving contact (1) and a fixed contact (2) to allow making and breaking of an electrical current path; wherein the circuit breaker comprises a locking lever (5) to prevent the moving contact (1) from reclosing during repulsion of the moving contact (1) while occurrence of a fault condition.

2. The circuit breaker as claimed in claim 1, wherein the moving contact (1) comprises at least one first part (1a) adapted to engage with the locking lever (5) to prevent the moving contact (1) from reclosing.

3. The circuit breaker as claimed in claim 2, wherein said first part (1a) of the moving contact (1) and said locking lever (5) are adapted to avoid engagement during the normal ON-OFF operation of the circuit breaker.

4. The circuit breaker as claimed in claim 2, wherein the moving contact (1) further comprises at least one second part (1b) adapted to engage with the locking lever (5) during every ON-OFF operation to close the contacts (1,2) faster (independent of mechanism operating speed).

5. The circuit breaker as claimed in claim 1, wherein the locking lever (5) comprises an actuating link (6) adapted to get pushed by said locking lever (5) and allows rotation of a knob associated with circuit breaker from ON to OFF position.

6. The circuit breaker as claimed in claim 3, wherein the actuating link (6) is coupled with a biasing spring (7) adapted to compress and de-compress to allow the actuating link (6) to get pushed by said locking lever (5) and to regain an original position of the actuating link (6).

7. The circuit breaker as claimed in claim 1, wherein upon clearance of the fault condition, the moving contact (1) is adapted to rotate, along with a C-link (4) associated with the moving contact (1), to make the circuit.

8. The circuit breaker as claimed in claim 5, wherein the moving contact (1) rotates by utilizing actuating link (6) for the locking lever (5).

9. The circuit breaker as claimed in claim 1, wherein the prevention of the moving contact (1) from reclosing enables to ensure a contact gap for faster quenching of arc and prevents a possibility of said arc restrike.

10. The circuit breaker as claimed in claim 1, wherein the moving contact (1) recloses when there is reduction in repulsion forces causing repulsion of the moving contact (1) and the fixed contact (2).
, Description:
TECHNICAL FIELD
[0001] The present disclosure relates to contact locking mechanism, and more specifically relates to, a contact locking mechanism and a method to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.

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] The invention will be illustrated with particular reference to a preferred application in a low-voltage electrical power distribution network, although this is not to be understood as limiting, and in any event the invention applies in general to both medium and low-voltage networks.
[0004] Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as current overloads, short circuits, abnormal voltage and other fault conditions. Typically, circuit breakers include an operating mechanism which opens electrical contact assemblies to interrupt the flow of current through the conductors of an electrical system in response to such fault conditions. A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overcurrent, typically resulting from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.
[0005] Circuit breaker is a switching device designed to make, carry and break the circuit. A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overcurrent, typically resulting from an overload or short circuit. Circuit breakers are generally installed to protect equipment from overcurrent (than its rated current) situations, for example, when a short circuit or ground fault occurs in an electrical supply conductor. Upon the occurrence of any such overcurrent condition, electrical contacts inside circuit breaker get opened, and stop supply of electrical current to 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 closed at the current withstand rating and be able to withstand the large electrodynamics repulsion forces generated by the current flow. With the increase of industry size and automation, the requirement of protection devices has also increased.
[0006] Circuit breakers have sets of separable contacts which include a fixed contact and a movable contact mounted on a movable contact arm. The movable contact arm is rotated by an operating mechanism between a closed position in which the movable contact engages the fixed contact, and an open position in which the contacts are separated to interrupt current flow. Typically, the operating mechanism is spring loaded to rapidly open the contacts in response to an overload condition. The response of the typical spring driven operating mechanism is relatively slow. It is known to provide such circuit breakers with a blow open feature which utilizes the strong magnetic fields generated by very large overcurrent conditions such as accompany a short circuit to quickly open the contacts faster than the response time of the operating mechanism. Typically, in such circuit breakers with a blow open feature, the fixed conductor to which the fixed contact is secured, is positioned adjacent the movable contact arm with the contact closed to carry current in a direction opposite to the current through the movable contact arm. This generates magnetic repulsion forces tending to separate the contacts. Under normal current conditions and moderate overcurrent conditions, the contacts are held in a closed position by contact springs. However, the repulsion forces generated by a short circuit current are so high that they overcome the contact spring forces and rapidly blow the contacts open. An example of a circuit breaker incorporating a blow open feature is found in U.S. Pat. No. 5,341,191. In this circuit breaker, the movable contact arm is mounted by a two-part pivot assembly. The pivot assembly includes a main carrier which is pivotally rotated by the operating mechanism to open and close the contacts. The movable contact arm is mounted on a second carrier which is pivotally mounted on the first carrier. Normally, the operating mechanism rotates the main carrier which carries with it the secondary carrier and the main contact arm to open and close the separable contacts. In response to a short circuit current, the secondary carrier is rotated relative to the main carrier in response to the very high magnetic repulsion forces generated by the fault current. The current required for the contact arm to blow open is determined by a spring loaded cam assembly which includes cam surfaces on the secondary carrier and spring biased cam followers mounted on the main carrier.
[0007] All the “category A” circuit breakers, such as miniature circuit breakers (MCB) and molded case circuit breakers (MCCBs), (defined according to Switchgear standard IS13947 (part2) / IEC 947-2) as the circuit breakers that operate at the socket outlet end of final distribution, and in the event of a short circuit they trip immediately), use electromagnetic repulsion force between the contacts to speed up contact opening during short circuit fault. This feature helps in clearing a short circuit fault faster as the moving contact opens faster due to electrodynamics repulsion force than with the help of mechanism after getting tripping signal from relay. In the conventional circuit breakers, in the event of short circuit contacts opens by electrodynamics repulsion force. Any delay in tripping command from protection release may result in reclosing of contact and subsequently in restrike. In some of the prior arts, the possibility of reclosing is eliminated by providing contact locking feature. In these cases, the contact locking feature is achieved by means of a toggle mechanism. Separate contact spring (other than main mechanism spring) is used for toggling the contact and holds it in locked condition. However, in the conventional circuit breakers contact locking is achieved through toggling mechanism with the help of a separate a spring. Further, in the existing prior-art contacts should open more than a specified angle with respect to shaft/rotor/main carrier to be locked as the toggle mechanism is built inside main carrier itself. Furthermore, in the conventional circuit breakers, in case of bounce of main carrier, contact reclosing tendency will be there. Along with the competitive criterions such as compactness and cost-effectiveness, reliability continues to be of utmost importance in protection. Therefore, any enhancement in reliability will always be acceptable and it will be even more attractive when this is achieved without significant increase in cost or size of the product.
[0008] Whereas there is certainly nothing wrong with existing techniques or circuit breaker, nonetheless, there still exists a need to provide an efficient, effective, reliable, an improved mechanism to enhance circuit breakers performance during a short circuit fault even when the protection release performance is kept constant. Further there is a need of most efficient and reliable protection against short-circuit fault even if protection release or mechanism fails to operate. Furthermore, there is a need of circuit breaker in which there is no need of additional contact spring for contact locking.
[0009] 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.
[00010] 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.
[00011] 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.
[00012] 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.
[00013] 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 groups used in the appended claims.

OBJECTS OF THE INVENTION
[00014] An object of the present disclosure is to provide a contact locking mechanism for low voltage switchgear.
[00015] Another object of the present disclosure is to provide a contact locking mechanism or method to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00016] Another object of the present disclosure is to provide a mechanism to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00017] Another object of the present disclosure is to provide an efficient and reliable protection against short-circuit fault even if protection release or mechanism fails to operate.
[00018] Another object of the present disclosure is to provide a mechanism to ensure higher contact gap without contact toggling mechanism, in case of short-circuit fault.
[00019] Another object of the present disclosure is to provide a mechanism to improve short circuit performance by reducing arcing time and eliminating the probability of restrike.
[00020] Another object of the present disclosure is to provide a mechanism that enables the moving contact to remain in open condition by means of a locking mechanism and prevents reclosing of the contacts in case of a delayed tripping signal from protection release or failure of protection release.

SUMMARY
[00021] The present disclosure relates to contact locking mechanism, and more specifically relates to, a contact locking mechanism or method to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00022] Embodiments of the present disclosure provide an efficient, effective, reliable, improved contact locking mechanism for low voltage switchgear. Further, the contact locking mechanism for low voltage switchgear according to the embodiments enhances circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00023] Accordingly, an aspect of the present disclosure relates to a circuit breaker. In an aspect, the circuit breaker can include a moving contact and a fixed contact to allow making and breaking of an electrical current path. In another aspect, the circuit breaker can include a locking lever to prevent the moving contact from reclosing during repulsion of the moving contact while occurrence of a fault condition.
[00024] In an aspect, the moving contact can include at least one first part (also interchangeably referred to as “Protrusion-1”) that adapted to engage with the locking lever to prevent the moving contact from reclosing.
[00025] In an aspect, the first part of the moving contact and the locking lever can be adapted to avoid engagement during the normal ON-OFF operation of the circuit breaker.
[00026] In an aspect, the moving contact further can include at least one second part (also interchangeably referred to as “Protrusion-2”) adapted to engage with the locking lever during every ON-OFF operation to close the contacts faster (independent of mechanism operating speed).
[00027] In an aspect, the locking lever can include an actuating link adapted to get pushed by said locking lever and allows rotation of a knob associated with circuit breaker from ON to OFF position.
[00028] In an aspect, the actuating link can be coupled with a biasing spring adapted to compress and de-compress to allow the actuating link to get pushed by said locking lever and to regain an original position of the actuating link.
[00029] In an aspect, wherein upon clearance of the fault condition, the moving contact can be adapted to rotate, along with a C-link associated with the moving contact, to make the circuit.
[00030] In an aspect, the moving contact can rotate by utilizing actuating link for the locking lever.
[00031] In an aspect, the prevention of the moving contact from reclosing enables to ensure a contact gap for faster quenching of arc and prevents a possibility of said arc restrike.
[00032] In an aspect, the moving contact can reclose when there is reduction in repulsion forces causing repulsion of the moving contact and the fixed contact.
[00033] In contrast to the conventional circuit breaker, the present disclosure provides an improved mechanism to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant. Further, in contrast to the existing circuit breaker, the present invention provides most efficient and reliable protection against short-circuit fault even if protection release or mechanism fails to operate. Furthermore, in contrast to the existing circuit breaker, the present invention ensures higher contact gap without contact toggling mechanism in case of short-circuit fault.
[00034] Further, in contrast to the existing conventional circuit breaker, the present invention provides a contact locking is achieved through interference between a locking lever and moving contact. So, there is no requirement of additional contact spring for toggling / contact locking purpose unlike conventional prior-arts. In addition to contact locking, same components i.e. locking lever is used to make the closing speed independent of operating speed.
[00035] 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
[00036] 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. The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:
[00037] FIG. 1 illustrates a front view of MCB mechanism in OFF condition, in accordance with an exemplary embodiment of the present disclosure.
[00038] FIG. 2 illustrates a front view of MCB mechanism in OFF condition, in accordance with another exemplary embodiment of the present disclosure.
[00039] FIG. 3 illustrates a front view of MCB mechanism in ON condition, in accordance with another exemplary embodiment of the present disclosure.
[00040] FIG. 4 illustrates a front view in mechanism ON and moving contact locked condition, in accordance with another exemplary embodiment of the present disclosure.
[00041] FIG. 5 illustrates a front view in mechanism OFF and moving contact locked condition, in accordance with another exemplary embodiment of the present disclosure.
[00042] FIG. 6 illustrates a front view of moving contact, in accordance with an exemplary embodiment of the present disclosure.
[00043] FIG. 7 illustrates an Explored view of MCB mechanism, in accordance with an exemplary embodiment of the present disclosure.
[00044] FIG. 8 illustrates an explored view of moving contact and C-link assembly, in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION
[00045] The following is a detailed description of embodiments of the disclosure depicted 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 scope of the present disclosure as defined by the appended claims.
[00046] 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.
[00047] 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.
[00048] 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 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.
[00049] 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.
[00050] 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.
[00051] 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.
[00052] The present disclosure relates to contact locking mechanism, and more specifically relates to, a contact locking mechanism or method to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00053] Embodiments of the present disclosure provide an efficient, effective, reliable, improved contact locking mechanism for low voltage switchgear. Further, the contact locking mechanism for low voltage switchgear according to the embodiments enhances circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00054] Accordingly, an aspect of the present disclosure relates to a circuit breaker. In an aspect, the circuit breaker can include a moving contact and a fixed contact to allow making and breaking of an electrical current path. In another aspect, the circuit breaker can include a locking lever to prevent the moving contact from reclosing during repulsion of the moving contact while occurrence of a fault condition.
[00055] In an aspect, the moving contact can include at least one first part (also interchangeably referred to as “Protrusion-1”) that adapted to engage with the locking lever to prevent the moving contact from reclosing.
[00056] In an aspect, the first part of the moving contact and the locking lever can be adapted to avoid engagement during the normal ON-OFF operation of the circuit breaker.
[00057] In an aspect, the moving contact further can include at least one second part adapted to engage with the locking lever to close the contacts faster (independent of mechanism operating speed) and said second part (also interchangeably referred to as “Protrusion-2”) engages with the locking lever during every ON-OFF operation.
[00058] In an aspect, the locking lever can include an actuating link adapted to get pushed by said locking lever and allows rotation of a knob associated with circuit breaker from ON to OFF position.
[00059] In an aspect, the actuating link can be coupled with a biasing spring adapted to compress and de-compress to allow the actuating link to get pushed by said locking lever and to regain an original position of the actuating link.
[00060] In an aspect, wherein upon clearance of the fault condition, the moving contact can be adapted to rotate, along with a C-link associated with the moving contact, to make the circuit.
[00061] In an aspect, the moving contact can rotate by utilizing actuating link for the locking lever.
[00062] In an aspect, the prevention of the moving contact from reclosing enables to ensure a contact gap for faster quenching of arc and prevents a possibility of said arc restrike.
[00063] In an aspect, the moving contact can reclose when there is reduction in repulsion forces causing repulsion of the moving contact and the fixed contact.
[00064] In contrast to the conventional circuit breaker, the present disclosure provides an improved mechanism to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant. Further, in contrast to the existing circuit breaker, the present invention provides most efficient and reliable protection against short-circuit fault even if protection release or mechanism fails to operate. Furthermore, in contrast to the existing circuit breaker, the present invention ensures higher contact gap without contact toggling mechanism in case of short-circuit fault.
[00065] Further, in contrast to the existing conventional circuit breaker, the present invention provides a contact locking is achieved through interference between a locking lever and moving contact. So, there is no requirement of additional contact spring for toggling / contact locking purpose unlike conventional prior-arts. In addition to contact locking, same components i.e. locking lever is used to make the closing speed independent of operating speed.
[00066] The circuit breaker can include a pair of contacts to make and break a circuit. A mechanism can be used to make and break the contacts. In healthy circuit condition, contacts can carry a specified current for infinite period of time and can be open or closed by manual means. In abnormal condition such as an overload condition or a relatively high level short circuit or residual current fault condition, a protection release senses abnormality (over current or short circuit or residual current fault) and gives the trip command to mechanism in order to separate / open contacts to isolate the faulty circuit from system. Hence, the performance of a circuit breaker in a fault condition depends on the performance of the protection release. In the present invention, the mechanism can be designed to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant. The mechanism can be capable of clearing a short circuit fault on its own irrespective of performance of the protection release.
[00067] FIGs. 1 to 8 represent different operating positions of a circuit breaker and are used to explain the invention. Mechanism can be primarily responsible for operating the moving contact (1) by manual and automatic means. Moving contact (1) can be operated manually with the help of knob (3). Knob (3) can rotate around knob pivot (10) with a pre-defined angle to operate mechanism in order to close or open the circuit. A biasing spring can be assembled with Knob (3) to bring it back to OFF position after tripping operation. During ‘ON’ operation, moving contact and C-link can rotate together around kinematic hinge (11) with same velocity. After a specific travel of moving contact, locking lever engages with protrusion-2 of moving contact (1b) and restricts its further rotation. However, the knob and C-link can keep on rotating at same velocity. Just before completing angular travel of knob (3), actuator link (6) applies clockwise torque on locking lever (5). This causes clockwise rotation of locking lever and disengagement of moving contact. The moving contact can rotate in clockwise direction with high angular velocity, which is independent of knob operating velocity. During this high velocity travel, moving contact rotates with pivot 12.
[00068] In the event of short-circuit fault, the current flowing through contact system increases to a very high magnitude. This produces very high electrodynamics repulsion force between moving and fixes contact. The moving contact gets separated form fix contact with very high opening velocity. During this separation, arc strikes between contacts and fault current can flow through the arc. The magnetic protection release can sense short-circuit fault and gives trip command to mechanism. The mechanism links collapses and applies anticlockwise torque on moving contact to keeps it in open position. The relative difference between opening velocity of moving contact and mechanism is very high. During contact repulsion, the moving contacts can travel in anticlockwise direction till the maximum opening distance and then bounces back or recloses in clockwise direction towards arcing zone due to reduction in repulsion force. This circuit reclosing reignites the fault, which leads to higher, let through energy or failure of unit.
[00069] In the present invention, a new component called locking lever (5) can be introduced to prevent the moving contact (1) from reclosing. During this moving contact bounce back (clockwise rotation towards fix contact), the protrusion-1 of the moving contact (1a) engages with locking lever (5) and absorbs the impact of moving contact (1) and prevents its clockwise rotation towards arcing zone. This locking of moving contact clockwise rotation due to locking lever (5) ensure adequate contact gap for faster quenching of arc and prevents the possibility of arc restrike (as shown in FIG .5). Actuating link for locking lever (6) can be designed in such a way that it gets pushed by locking lever and allows the knob’s rotation from ON to OFF position. Actuating link for locking lever (6) comes back to its original position with help of a biasing spring (7) and gets ready to push locking lever for next operation (as shown in FIG. 4). During the next switching operation, first the locking lever (5) can be rotated by actuating link for locking lever (6) (to eliminate the restriction for moving contact-1) and then moving contact (1) along with C-link (4) rotates to close the circuit. Protrusion-1 (also interchangeably referred to as first part) on moving contact (1a) and the locking lever (5) can be designed in such a way that the locking lever (5) does not encounter with protrusion-1 of the moving contact (1a) in normal ON-OFF operation.
[00070] Referring now to FIG. 1 a front view of MCB mechanism in OFF condition is illustrated, in accordance with an exemplary embodiment of the present disclosure. In an embodiment, as shown in FIG. 1, a moving contact (1) and a fixed contact (2) can allow making and breaking of an electrical current path. The circuit breaker can include a locking lever (5) to prevent the moving contact (1) from reclosing during repulsion of the moving contact (1) while occurrence of a fault condition. In another embodiment, the locking lever (5) can include an actuating link (6) adapted to get pushed by said locking lever (5) and allows rotation of a knob associated with circuit breaker from ON to OFF position. The actuating link (6) can be coupled with a biasing spring (7) adapted to compress and de-compress to allow the actuating link (6) to get pushed by said locking lever (5) and to regain an original position of the actuating link (6). The moving contact (1) can rotate by utilizing actuating link (6) for the locking lever (5).
[00071] In an exemplary embodiment, the moving contact (1) can be operated manually with the help of knob (3). Knob (3) rotates around knob pivot (10) with a pre-defined angle to operate mechanism in order to close or open the circuit. A biasing spring assembled with Knob (3) to bring it back to OFF position after tripping operation.
[00072] Referring now to FIG. 2, a front view of MCB mechanism in OFF condition is illustrated, in accordance with another exemplary embodiment of the present disclosure. FIG. 3 illustrates a front view of MCB mechanism in ON condition, in accordance with another exemplary embodiment of the present disclosure. FIG. 4 illustrates a front view in mechanism ON and moving contact locked condition, in accordance with another exemplary embodiment of the present disclosure. FIG. 5 illustrates a front view in mechanism OFF and moving contact locked condition, in accordance with another exemplary embodiment of the present disclosure.
[00073] Referring now to FIG. 6 a front view of moving contact is illustrated, in accordance with an exemplary embodiment of the present disclosure. In an embodiment, as shown in FIG. 6, the moving contact (1) can include at least one first part (1a) adapted to engage with the locking lever (5) to prevent the moving contact (1) from reclosing. In an exemplary embodiment, the first part (1a) of the moving contact (1) and said locking lever (5) can be adapted to avoid engagement during the normal ON-OFF operation of the circuit breaker. In another embodiment, the moving contact (1) further can include at least one second part (1b) adapted to engage with the locking lever (5) to prevent the moving contact (1) from reclosing, said second part (1b) engages with the locking lever (5) if the moving contact (1) still moves for reclosing in spite of engagement with the first part (1a).
[00074] Referring now to FIG. 7 an explored view of MCB mechanism is illustrated, in accordance with an exemplary embodiment of the present disclosure. In an embodiment, the moving contact (1) can be operated manually with the help of knob (3). Knob (3) rotates around knob pivot (10) with a pre-defined angle to operate mechanism in order to close or open the circuit. A biasing spring assembled with Knob (3) to bring it back to OFF position after tripping operation. In an embodiment, during ‘ON’ operation, moving contact 1 and C-link can rotate together around kinematic hinge (11) with same velocity.
[00075] Referring now to FIG. 8 an explored view of moving contact and C-link assembly is illustrated, in accordance with an exemplary embodiment of the present disclosure. In an embodiment, the moving contact (1) can be operated manually with the help of knob (3). Knob (3) rotates around knob pivot (10) with a pre-defined angle to operate mechanism in order to close or open the circuit. A biasing spring assembled with Knob (3) to bring it back to OFF position after tripping operation. In an embodiment, during ‘ON’ operation, moving contact 1 and C-link can rotate together around kinematic hinge (11) with same velocity. After a specific travel of moving contact, locking lever engages with protrusion-2 of moving contact (1b) and restricts its further rotation. However, the knob and C-link keeps on rotating at same velocity. Just before completing angular travel of knob (3), actuator link (6) applies clockwise torque on locking lever (5). This causes clockwise rotation of locking lever and disengagement of moving contact. The moving contact rotates in clockwise direction with high angular velocity, which is independent of knob operating velocity. During this high velocity travel, moving contact rotates with pivot 12.
[00076] The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
[00077] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C ….and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the appended claims.
[00078] While embodiments of the present disclosure have been illustrated and described, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the scope of the disclosure, as described in the claims.
[00079] In the description of the present specification, reference to the term "one embodiment," "an embodiments", "an example", "an instance", or "some examples" and the description is meant in connection with the embodiment or example described The particular feature, structure, material, or characteristic included in the present invention, at least one embodiment or example. In the present specification, the term of the above schematic representation is not necessarily for the same embodiment or example. Furthermore, the particular features structures, materials, or characteristics described in any one or more embodiments or examples in proper manner. Moreover, those skilled in the art can be described in the specification of different embodiments or examples are joined and combinations thereof.
[00080] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
[00081] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
[00082] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
[00083] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[00084] The present disclosure provides a contact locking mechanism for low voltage switchgear.
[00085] The present disclosure provides a contact locking mechanism or method to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00086] The present disclosure provides a mechanism to enhance circuit breaker performance during a short circuit fault even when the protection release performance is kept constant.
[00087] The present disclosure provides an efficient and reliable protection against short-circuit fault even if protection release or mechanism fails to operate.
[00088] The present invention provides a mechanism to ensure higher contact gap without contact toggling mechanism, in case of short-circuit fault.
[00089] The present disclosure provides a mechanism to improve short circuit performance by reducing arcing time and eliminating the probability of restrike.
[00090] The present disclosure provides a mechanism that enables the moving contact to remain in open condition by means of a locking mechanism and prevents reclosing of the contacts in case of a delayed tripping signal from protection release or failure of protection release.
[00091] The present disclosure provides a locking lever that can be used for achieving high contact closing velocity during on operation and contact locking in the event of short-circuit fault.