Claims:1. A circuit breaker with a calibration mechanism for thermo-magnetic release of the circuit breaker, the circuit breaker comprising:
a magnetic release unit comprising a fixed core, and a moving core with an air gap between the fixed core and the moving core, wherein the moving core is configured to move with respect to the fixed core through the air gap and actuate a latching mechanism of a thermo-magnetic release of the circuit breaker when a current flowing through the circuit breaker crosses a predefined limit;
a first calibration means configured at a first predefined position on the moving core and adapted to adjust the air gap between the moving core and the fixed core to a first predetermined value; and
a second calibration means configured at a second predefined position on the moving core and adapted to adjust an impact gap between the moving core and a magnetic shaft of the magnetic release unit to a second predetermined value;
wherein the adjustment of any or a combination of the air gap and the impact gap facilitates calibration of the magnetic release unit of the circuit breaker.
2. The circuit breaker as claimed in claim 1, wherein the movement of the moving core with respect to the fixed core moves the magnetic shaft to actuate the latching mechanism to enable tripping of the circuit breaker, and wherein the second calibration means is adapted to adjust the impact gap between the moving core and the magnetic shaft.
3. The circuit breaker as claimed in claim 1, wherein the magnetic release unit comprises one or more biasing means operatively coupled to the moving core and configured to bias the moving core at a slider of the magnetic release unit, and wherein the first calibration means is configured to adjust a biasing force of the one or more biasing means.
4. The circuit breaker as claimed in claim 3, wherein the slider has a slope such that the moving core is biased on the slope of the slider, and wherein the slope of the slider determines the air gap between the moving core and the fixed core.
5. The circuit breaker as claimed in claim 3, wherein the one or more biasing means is a spring, and wherein the first calibration means is configured to adjust a spring force of the spring.
6. The circuit breaker as claimed in claim 1, wherein the first calibration means is a first screw, and the second calibration means is a second screw.
7. The circuit breaker as claimed in claim 1, wherein the moving core comprises a first hole at the first predefined position to accommodate the first calibration means, and wherein the first calibration means is adapted to move inwards and outwards from the first hole to facilitate adjustment of the air gap between the moving core and the fixed core to the first predetermined value.
8. The circuit breaker as claimed in claim 1, wherein the moving core comprises a second hole at the second predefined position to accommodate the second calibration means, and wherein the second calibration means is adapted to move inwards and outwards from the second hole to facilitate adjustment of the impact gap between the moving core and the magnetic shaft to the first predetermined value.
9. The circuit breaker as claimed in claim 1, wherein the circuit breaker comprises a thermal release unit comprising:
a bimetal operatively coupled to a thermal element, the thermal element configured to heat the bimetal due the current flowing through the circuit breaker, and wherein the heated bimetal is adapted to bend and actuate the trip unit to enable tripping of the circuit breaker.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of circuit breaker calibration system. More particularly, the present disclosure relates to a calibration mechanism for a thermo-magnetic release unit of a circuit breaker.

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 incorporated in electric power system to break a circuit to protect the electric power system and circuit in event of a dangerous situation such as a short circuit, an over current, and the like, and it is designed by utilizing breaking, insulating and arc-extinguishing mechanisms.
[0004] Circuit breakers are incorporated in a power supply circuit for protection against potential damage that may be caused to electrical circuit and connected load by potentially damaging occurrences such as but not limited to overload, short-circuit etc. Circuit breakers are designed to detect such potentially dangerous conditions and operate to disconnect the load automatically. After a fault has been diagnosed and rectified, circuit breaker can be reset and power supply circuit can resume its normal operations/ functioning
[0005] The circuit breakers are designed to carry a particular rated current for a period of time based on its duty cycle. If higher current (overload current) flows in the system for longer periods, then the system will not be able to dissipate the excess heat generated because of the overload and ultimately the system will break down. Therefore, the circuit breakers are designed to trip if a current beyond a threshold value flows beyond a certain period of time. In case of short circuit resulting in current beyond the threshold, the system trips the circuit immediately.
[0006] The circuit breakers function on electronic or thermo-magnetic systems for detecting the short circuit/overload currents and causing the circuit breaker to trip. The thermo-magnetic systems typically use electromagnetic coils to provide short circuit protection, and bimetal to provide overload protection.
[0007] Property of bimetals to deflection under high temperature is used in thermo magnetic release to protect the circuit from overload current. Typically, a heater element is used that carries the current and provides necessary heat to bimetal. Alternatively, the current may pass through the bimetal to cause direct heating. The bimetal in turn deflects and gives a signal to a thermal shaft to actuate a latch mechanism to cause the circuit breaker to trip.
[0008] For short circuit protection, thermo-magnetic systems typically use a fixed magnet and a moving magnet. A pre-determined air gap is maintained between the fixed and the moving magnet. During high currents such as those caused by a short circuit, the magnetic energy due to high current helps to overcome the pre-determined gap. The moving magnet in turn deflects and gives a signal to a magnetic shaft to actuate the latch mechanism to cause the circuit breaker to trip. Thus, during any fault, overload or short circuit, the thermo magnetic release issuesthe break command and the circuit breaker trips to protect the connected device.
[0009] Any deviations that arise during assembly viz., fixed core position, moving core position, rotation of magnetic shaft, latch mechanism, and dimensional deviations etc. add up to contribute for the loss of the magnetic release’s primary function. Although these deviations independently do not cause any loss of function but causes major problem when stacked up.
[0010] Most of the magnetic releases consists of provision for changing the spring force. But it does not address the issue completely because there can be cases where the magnetic release still does not trip the circuit breaker in desired band, as there are other factors which contribute for the loss of its function. Also, the spring force adjustment gives only coarse adjustment which is difficult to calibrate the magnetic release within desired band.
[0011] Generally, calibration tests are done on magnetic release unit of the circuit breakers in order to make it trip the circuit breaker in the desired current band. Such calibration tests normally take three to four iterations. In conventional calibration method, the spring force are increased or decreased after every iteration based on the tripping current. This is a coarse adjustment because spring force cannot be varied very precisely.
[0012] There is, therefore, a need to provide an improved calibration mechanism for thermo-magnetic release of a circuit breaker for reliable tripping of the circuit breaker.

OBJECTS OF THE PRESENT DISCLOSURE
[0013] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.
[0014] It is an object of the present disclosure to provide a calibration mechanism for thermo-magnetic release of a circuit breaker.
[0015] It is an object of the present disclosure to minimize deviations arise during assembling or stacking of the circuit breaker to improve functioning of the thermo-magnetic release of the circuit breaker.
[0016] It is an object of the present disclosure to provide a calibration mechanism for magnetic release of a circuit breaker to calibrate an air gap between a fixed core and a moving core.
[0017] It is an object of the present disclosure to provide a calibration mechanism for magnetic release of a circuit breaker to calibrate an impact air gap between a moving core and a magnetic shaft of the thermo-magnetic release of the circuit breaker.
[0018] It is an object of the present disclosure to provide a calibration mechanism for magnetic release of a circuit breaker to calibrate spring force of biasing means of the moving core.

SUMMARY
[0019] The present disclosure relates to the field of circuit breaker calibration system. More particularly, the present disclosure relates to a calibration mechanism for a thermo-magnetic release unit of a circuit breaker.
[0020] An aspect of the present disclosure pertains to a circuit breaker with a calibration mechanism for thermo-magnetic release of the circuit breaker, the circuit breaker comprising: a magnetic release unit comprising a fixed core, and a moving core with an air gap between the fixed core and the moving core, wherein the moving core may be configured to move with respect to the fixed core through the air gap and actuate a latching mechanism of a thermo-magnetic release of the circuit breaker when a current flowing through the circuit breaker crosses a predefined limit; a first calibration means configured at a first predefined position on the moving core and may be adapted to adjust the air gap between the moving core and the fixed core to a first predetermined value; and a second calibration means configured at a second predefined position on the moving core and may be adapted to adjust an impact gap between the moving core and the magnetic shaft of the thermo-magnetic release to a second predetermined value; wherein the adjustment of any or a combination of the air gap and the impact gap facilitates calibration of the magnetic release unit of the circuit breaker.
[0021] In an aspect, the movement of the moving core with respect to the fixed core moves the magnetic shaft to actuate the latching mechanism of the thermo-magnetic release to enable tripping of the circuit breaker, and wherein the second calibration means may be adapted to adjust the impact gap between the moving core and the magnetic shaft.
[0022] In an aspect, the magnetic release unit comprises one or more biasing means operatively coupled to the moving core and may be configured to bias the moving core at a slider of the magnetic release unit, and wherein the first calibration means may be configured to adjust a biasing force of the one or more biasing means.
[0023] In an aspect, the slider may have a slope such that the moving core may be biased on the slope of the slider, and wherein the slope of the slider may determine the air gap between the moving core and the fixed core.
[0024] In an aspect, the one or more biasing means may be a spring, and wherein the first calibration means may be configured to adjust a spring force of the spring.
[0025] In an aspect, the first calibration means may be a first screw, and the second calibration means may be a second screw.
[0026] In an aspect, the moving core may comprise a first hole at the first predefined position to accommodate the first calibration means, and wherein the first calibration means may be adapted to move inwards and outwards from the first hole to facilitate adjustment of the air gap between the moving core and the fixed core to the first predetermined value.
[0027] In an aspect, the moving core may comprise a second hole at the second predefined position to accommodate the second calibration means, and wherein the second calibration means may be adapted to move inwards and outwards from the second hole to facilitate adjustment of the impact gap between the moving core and the magnetic shaft to the first predetermined value.
[0028] In an aspect, the circuit breaker may comprise a thermal release unit comprising: a bimetal operatively coupled to a thermal element, the thermal element may be configured to heat the bimetal due the current flowing through the circuit breaker, andwherein the heated bimetal may be adapted to bend and actuate the trip unit to enable tripping of the circuit breaker.

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] In the figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
[0031] FIG. 1A to 1C illustrate exemplary perspective views of a thermo-magnetic release of the proposed circuit breaker having a calibration mechanism for the thermo-magnetic release, in accordance with an embodiment of the present disclosure.
[0032] FIG. 2A to 2B illustrates exemplary inner views of the thermo-magnetic release, in accordance with an embodiment of the present disclosure.
[0033] FIG. 3A to 3C illustrates exemplary views of a modular thermo-magnetic release of the proposed circuit breaker, in accordance with an embodiment of the present disclosure
[0034] FIG. 4 illustrates an exemplary view of the moving core of the thermo-magnetic release having provisions for attachment of calibration means, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0035] 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 spirit and scope of the present disclosure as defined by the appended claims.
[0036] 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.
[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] 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.
[0039] 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.
[0040] In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the devices, members, devices, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction.
[0041] The present disclosure relates to the field of circuit breaker calibration system. More particularly, the present disclosure relates to a calibration mechanism for a thermo-magnetic release unit of a circuit breaker.
[0042] According to an aspect, the present disclosure elaborates upon a circuit breaker with a calibration mechanism for thermo-magnetic release of the circuit breaker, the circuit breaker including: a magnetic release unit including a fixed core, and a moving core with an air gap between the fixed core and the moving core, wherein the moving core can be configured to move with respect to the fixed core through the air gap and actuate a latching mechanism of a thermo-magnetic release of the circuit breaker when a current flowing through the circuit breaker crosses a predefined limit; a first calibration means configured at a first predefined position on the moving core and can be adapted to adjust the air gap between the moving core and the fixed core to a first predetermined value; and a second calibration means configured at a second predefined position on the moving core and can be adapted to adjust an impact gap between the moving core and the magnetic shaft of the thermo-magnetic release to a second predetermined value; wherein the adjustment of any or a combination of the air gap and the impact gap facilitates calibration of the magnetic release unit of the circuit breaker.
[0043] In an embodiment, the magnetic release unit can include a magnetic shaft such that the movement of the moving core with respect to the fixed core moves the magnetic shaft to actuate the latching mechanism of the thermo-magnetic release to enable tripping of the circuit breaker, and wherein the second calibration means can be adapted to adjust the impact gap between the moving core and the magnetic shaft.
[0044] In an embodiment, the magnetic release unit includes one or more biasing means operatively coupled to the moving core and can be configured to bias the moving core at a slider of the magnetic release unit, and wherein the first calibration means can be configured to adjust a biasing force of the one or more biasing means.
[0045] In an embodiment, the slider can have a slope such that the moving core can be biased on the slope of the slider, and wherein the slope of the slider can determine the air gap between the moving core and the fixed core.
[0046] In an embodiment, the one or more biasing means can be a spring, and wherein the first calibration means can be configured to adjust a spring force of the spring.
[0047] In an embodiment, the first calibration means can be a first screw, and the second calibration means can be a second screw.
[0048] In an embodiment, the moving core can include a first hole at the first predefined position to accommodate the first calibration means, and wherein the first calibration means can be adapted to move inwards and outwards from the first hole to facilitate adjustment of the air gap between the moving core and the fixed core to the first predetermined value.
[0049] In an embodiment, the moving core can include a second hole at the second predefined position to accommodate the second calibration means, and wherein the second calibration means can be adapted to move inwards and outwards from the second hole to facilitate adjustment of the impact gap between the moving core and the magnetic shaft to the first predetermined value.
[0050] In an embodiment, the circuit breaker can include a thermal release unit including: a bimetal operatively coupled to a thermal element, the thermal element can be configured to heat the bimetal due the current flowing through the circuit breaker, andwherein the heated bimetal can be adapted to bend and actuate the trip unit to enable tripping of the circuit breaker.
[0051] FIG. 1A to 1C illustrate exemplary perspective views of a thermo-magnetic release of the proposed circuit breaker having a calibration mechanism for the thermo-magnetic release, in accordance with an embodiment of the present disclosure.
[0052] As illustrated, in an embodiment, the magnetic part of the thermo-magnet release can be configured to trip the circuit breaker on occurrence of short circuit current. In the exemplary embodiment, a fixed core 102 (also referred to as fixed magnet 102, herein) and a moving core (also referred to as moving magnet 104, herein) can be used for short circuit protection. A pre-determined air gap can be maintained between fixed core 102 and the moving core 104. On occurrence of high current caused by a short circuit, the magnetic energy due to higher currents can help to overcome the pre-determined gap causing the moving core 104 to move and give signal to a magnetic shaft 106 meant for short circuit.The magnetic shaft 106 in turn can give signal to a latching mechanism 108 to trip the circuit breaker
[0053] In another exemplary embodiment, the thermal part of the thermo magnet release, that is usually configured to trip the circuit breaker on occurrence of overload current, uses property of bimetals to deflection under high temperature. It can include a heater 114, a bimetal 1116, a calibration screw, a thermal shaft and a latching mechanism. The heater 114 can be used to heat the bimetal 116 and carries the current and provides the necessary heat to the bimetal 116. In certain configurations the bimetal 116 can itself carry the current and get heated up. On heating, the bimetal 116 can deflect and give a signal to the thermal shaft and in turn to the latch mechanism to trip the circuit breaker. The thermal and magnetic parts can use separate shafts for overload and short circuit protection respectively.
[0054] In an embodiment, the circuit breaker can include a first calibration means 110 configured at a first predefined position on the moving core 104. The first calibration means can be adapted to adjust the air gap between the moving core 104 and the fixed core 102 to a first predetermined value. The calibration of the air gap between the moving core 104 and the fixed core 102 can facilitate configuration/adjustment of the tripping current value of the thermo-magnetic release of the circuit breaker.
[0055] In an embodiment, the circuit breaker can include a second calibration means 112 configured at a second predefined position on the moving core 104. The second calibration means can be adapted to adjust an impact gap between the moving core 104 and the magnetic shaft 106 to a second predetermined value. The calibration of the impact air gap between the moving core 104 and the magnetic shaft 106 can facilitate configuration/adjustment of the tripping current value of the thermo-magnetic release of the circuit breaker.
[0056] FIG. 2A to 2B illustrates exemplary inner views of the thermo-magnetic release, in accordance with an embodiment of the present disclosure.
[0057] As illustrated, in an embodiment, the magnetic part of the thermo-magnet release can be configured to trip the circuit breaker on occurrence of short circuit current. In the exemplary embodiment, the circuit breaker can include 102-1 to 102-3 (collectively referred to as fixed cores herein) and one or more moving core (collectively referred to as moving core 104, herein) can be used for short circuit protection. A predetermined air gap can be maintained between fixed cores 102 and the moving cores 104. The moving cores 104 can be configured to rest on a slider 202 to maintain the predetermined air gap between the moving cores 104 and the fixed cores 102. A slope of the slider 202 can determine the predetermined air gap between he moving cores 104 and the fixed cores 102. On occurrence of high current caused by a short circuit, the magnetic energy due to higher currents can help to overcome the pre-determined gap causing the moving core 104 to move and give signal to a magnetic shaft 106 meant for short circuit. The magnetic shaft 106 in turn can give signal to a latching mechanism 108 to trip the circuit breaker
[0058] In an embodiment, the magnetic release unit of the proposed circuit breaker can include one or more biasing means 204-1 to 204-3 (collectively referred to as biasing means 204, herein) operatively coupled to the moving core 104 and configured to bias the moving cores 104 at the slope of the slider 202. Each of the moving cores 104 can include a separate first calibration means 110, which can be configured to adjust the predetermined air gap between the moving core 104 and the fixed core 102 to calibrate the magnetic release unit to a predefined tripping current
[0059] In an embodiment, each of the moving cores 104 can include a separate second calibration means 112, which can be configured to adjust an impact gap between the moving core 104 and the magnetic shaft 106.
[0060] In an embodiment, the slider 202 can be provided with a slope such that the moving cores 104 can be biased on the slope of the slider 202. The slope of the slider can determine the air gap between the moving core 104 and the fixed core 102, thereby calibrating the magnetic release unit to the predefined tripping current. In an exemplary embodiment, the biasing means can be a spring, but not limited to the likes. The first calibration means 110 can be configured to adjust a spring force of the spring.
[0061] FIG. 3A to 3C illustrates exemplary views of a modular thermo-magnetic release of the proposed circuit breaker, in accordance with an embodiment of the present disclosure. As illustrated, the thermo-magnetic release of the proposed circuit breaker can include a housing 302 to accommodate the components of the thermo-magnetic release. The housing can be provided with provisions for attachment of power supply lines to the thermo-magnetic release. In an exemplary embodiment, the housing 302 can be provided with one or more slots in line with the first calibration means 110 and the second calibration means 112 such that the first calibration means 110 and the second calibration means 112 can be accessed by a user from outside to adjust the air gap, impact gap and spring force, without opening the circuit breaker. In an exemplary embodiment, the housing 302 can facilitate rotation of the screw 110 and the screw 112 by the user from outside to calibrate the thermo-magnetic release from outside. Further, the housing can be provided with provisions for accommodating switches and indicators for performing one or more operations such as ON, OFF, RESET and TRIP on the circuit breaker.
[0062] FIG. 4 illustrates an exemplary view of the moving core of the thermo-magnetic release having provisions for attachment of calibration means, in accordance with an embodiment of the present disclosure.
[0063] As illustrated, the moving core 104 of the proposed circuit breaker can include a first hole 402 at a first predefined position on the moving core 104 to accommodate the first calibration means 110. The first calibration means 110 can be adapted to move inwards and outwards from the first hole 402 to facilitate adjustment of the air gap between the moving core 106 and the fixed core 104 to the first predetermined value. In an exemplary embodiment, the first hole 402 can be a threaded hole and the first engaging means 110 can be a screw. The rotation of the screw in the threaded first hole can facilitate inward and outward movement of the screw 110 from the moving core 104. The inward and outward movement of the screw 110 from the moving core 104 can facilitate adjustment of the air gap between the fixed core 104 and the moving core 106, thereby calibrating the magnetic release unit of the circuit breaker.
[0064] In an embodiment, the moving core 104 of the proposed circuit breaker can include a second hole 404 at a second predefined position on the moving core 104 to accommodate the second calibration means 112. The second calibration means 112 can be adapted to move inwards and outwards from the second hole 402 to facilitate adjustment of the air gap between the moving core 106 and the fixed core 104 to the second predetermined value. In an exemplary embodiment, the second hole 402 can be a threaded hole and the second engaging means 112 can be a screw. The rotation of the screw in the threaded second hole can facilitate inward and outward movement of the screw from the moving core 104.The inward and outward movement of the screw 112 from the moving core 104 can facilitate adjustment of the impact gap between the fixed core 104 and the magnetic, thereby calibrating the magnetic release unit of the circuit breaker.
[0065] 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.

ADVANTAGS OF THE INVENTION
[0066] The present disclosure providesa calibration mechanism for thermo-magnetic release of a circuit breaker.
[0067] The present disclosure minimizes deviations arise during assembling or stacking of the circuit breaker to improve functioning of the thermo-magnetic release of the circuit breaker.
[0068] The present disclosure provides a calibration mechanism for magnetic release of a circuit breaker to calibrate an air gap between a fixed core and a moving core.
[0069] The present disclosure provides a calibration mechanism for magnetic release of a circuit breaker to calibrate an impact air gap between a moving core and a magnetic shaft of a thermo-magnetic release of the circuit breaker.
[0070] The present disclosure provides a calibration mechanism for magnetic release of a circuit breaker to calibrate spring force of biasing means of the moving core.