Claims:1. A smart-shielded trip device for use in circuit breakers, said trip device comprising:
a bottom assembly comprising a bracket (9) such that said bracket (9) houses the bottom assembly, said bracket (9) comprising:
a rare earth permanent magnet (8) coupled to the base of the bracket (9), said permanent magnet (8) generates flux to trip the smart-shielded trip device;
wherein said permanent magnet (8) is encased within a shield (13).
a filler core (7) positioned over the permanent magnet (8) to cover said permanent magnet (8) to avoid direct contact from shock and vibration of the trip device; and
a bobbin (6) positioned over the filler core (7) to cover said filler core (7) and permanent magnet (8), said bobbin is substantially positioned such that air gaps are maintained between said bobbin (6) and permanent magnet (8);
a top assembly comprising a plunger nut (1) such that said plunger nut (1) is adapted as a force controller of the trip device, said top assembly comprising:
at least one moving plunger (2) operably coupled to said plunger nut (1) at proximal end, and operably braced against a spring force provided by a spring (3), at distal end;
wherein said spring force being greater than trip force required to trip the circuit breaker; and
a multi-polar flux generation coil (5) positioned substantially to couple the plunger (2) of the top assembly to the bottom assembly;
wherein energizing said coil (5) generates flux such that supportive and repulsive magnetic flux are generated within the trip device according to the direction of excitation of said coil (5) to latch or de-latch the plunger (2);
wherein said permanent magnet (8) generates a plurality of magnetic flux paths (10, 11) through the bottom assembly and the top assembly.

2. The shielded trip device as claimed in claim 1, wherein the plunger (2) is vertically braced, against the spring force, in closed condition by the magnetic flux from the rare earth permanent magnet (8) of the bottom assembly.

3. The shielded trip device as claimed in claim 1, wherein the proximal end of the plunger (2) is rigidly sealed to the base of the plunger nut (1).

4. The shielded trip device as claimed in claim 1, wherein working path (10, 15) of the magnetic flux passes through the rare earth permanent magnet (8), the filler core (7), the plunger (2) and the bracket (9).

5. The shielded trip device as claimed in claim 1, wherein diversion path (11) of the magnetic flux passes through the rare earth permanent magnet (8), air, and the bracket (9).

6. The shielded trip device as claimed in claim 1, comprising a calibrator (22) operably coupled to the rare earth permanent magnet (8) such that relative position of the permanent magnet (8) within the bottom assembly is substantially controlled by said calibrator (22).

7. The shielded trip device as claimed in claim 6, wherein the calibrator (22) is adapted to control trip force, holding force, and trip voltage of the trip device.

8. The shielded trip device as claimed in claim 1, wherein the plunger (2) is operably coupled to a tripping means of an MCCB.

9. The shielded trip device as claimed in claim 1, wherein the top assembly comprises a pre-defined gap (18) to adjust height of the trip device such that a plurality of trip forces is achieved.

10. The shielded trip device as claimed in claim 1, wherein position of the permanent magnet (8) is operably controlled by the calibrator (22) such that an intentional air gap (21) is maintained is created between said permanent magnet (8) and the bracket (9), to modify the operating flux of the trip device.

11. The shielded trip device as claimed in claim 1, wherein the top assembly comprises a stopper (4) positioned substantially between the plunger (2) and spring (3), said stopper (4) houses a washer (20) adapted to seal dust from inside the trip device;
wherein said stopper (4) is substantially positioned over the plunger (2) and adapted to halt said plunger (2) during de-latching; and
wherein said stopper (4) is adapted to support the bottom portion of the spring (3).

12. The shielded trip device as claimed in claim 1, wherein the plunger nut (1) is adapted to provide mechanical assembly tolerance compensation to the circuit breaker.

13. The shielded trip device as claimed in claim 1, wherein the bottom assembly is encased within an encapsulation cover (23) for dust proofing the trip device in harsh electromagnetic conditions involving magnetic dust and non-magnetic dusts.

14. The shielded test device as claimed in claim 1, wherein the shield (13) comprises a diamagnetic component to repel the incident magnetic field on the permanent magnet (8).
, Description:FIELD OF THE INVENTION

[001] The subject matter of the present invention, in general, relates to trip actuating device for circuit breakers and more particularly, pertains to a smart-shielded trip device for circuit breakers.

BACKGROUND OF INVENTION

[002] The current technology demands shielding of magnetic trip actuators for various faults occurring closer to the circuit breaker. This not only complicates the space available inside the circuit breaker but also leads to a demanding design control over assemblies considering the sensitivities and seriousness involved in the failure of such systems to act in case of a fault condition. The shield addition is generally a safe bet to solve the problem of external magnetic interference that is either creating additional holding by magnetizing the device in the direction of magnetic field or reduced holding conditions under reverse magnetization situations.

[003] For some existing state of the art trip actuator devices used in the public domain, reference is made to US Patent Number 3944957 B2, wherein a trip device comprising a permanent magnet of cobalt-rare earth material and a plunger which is normally held in a withdrawn position by the permanent magnet is disclosed. A tripping coil surrounds the plunger and, upon energization, develops tripping flux that opposes the holding flux from the permanent magnet, thereby to effect release of the plunger. In a position between the tripping coil and the permanent magnet, flux-diverting structure of highly permeable magnetic material is provided for shunting a portion of the tripping flux through a shunt path bypassing the permanent magnet. This shunt path contains a relatively large non-magnetic gap for limiting the tripping flux through the shunt path sufficiently to cause 30 percent or more of the tripping flux to pass through the permanent magnet in a direction opposite to the direction of the holding flux. When the tripping coil is de-energized, this non-magnetic gap limits the holding flux through the shunt path to 10 percent or less of the total holding flux of the permanent magnet.

[004] Reference is also made to European Patent Number 0957501 B1, wherein an actuator assembly for an electrical power switch apparatus is disclosed. The actuator assembly having housing and a wafer plunger positioned within the housing where the plunger is movable between a set position and actuated position. The plunger includes a compression Spring to provide a pre-load thereto that biases the plunger away from the Set position and toward the actuated position. A magnet contained in the housing and positioned proximate to the plunger establishes a magnetic force which overcomes the pre-load of the compression spring and maintains the plunger in a set position. A coil assembly, that when energized, produces an electromagnetic force which bucks the magnetic force established by the magnet allowing the plunger to be propelled by the compression Spring to the actuated position. A screw extends through an opening in the plunger for engagement with the compression spring so that rotation of the screw results in the adjustment or calibration of the pre-load of the compression Spring.

[005] Reference is also made to US Application Number 4583066 A, wherein a thermal release for flux shift trip unit within static trip circuit breakers is disclosed. The flux shifting circuit breaker trip device includes a permanent magnet for retaining a solenoid armature in opposition to a spring force. Energization of the solenoid winding produces a magnetic flux in opposition to the permanent magnet flux to extend the armature under the spring force. In order to provide ambient temperature response, the solenoid armature is formed from a stem part and a barrel part held together by a meltable material. Increase in ambient temperature above a predetermined value causes the material to melt allowing the stem part to extend under the spring force to trip the breaker.

[006] The drawbacks associated with these existing trip actuator devices is that the mechanical impact on the magnet results in the material losing its property and the device tending to malfunction. Moreover, insufficient shielding results in external field interference disturbing the performance of the device by demagnetizing the magnet. Accordingly, there is a need to eliminate the mechanical impact on the magnet, reduce the interference problems and reduce the leakage flux occurring in conventional magnetic trip actuating devices. To overcome said drawbacks of existing trip actuators, the present invention discloses a smart-shielded trip device for circuit breakers.

[007] The above-described need to eliminate the mechanical impact on the magnet, reduce interference problems and reduce leakage flux from magnetic actuating devices is merely intended to provide an overview of some of the shortcomings of conventional systems / mechanism / techniques, and is not intended to be exhaustive. Other problems/ shortcomings with conventional systems/ mechanism /techniques and corresponding benefits of the various non-limiting embodiments described herein may become further apparent upon review of the following description.

SUMMARY OF THE INVENTION

[008] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[009] An object of the present invention is to provide a smart-shielded trip device for circuit breakers.

[0010] Another object of the present invention is to provide a smart shielded electro-magnetic trip device for use in circuit breakers.

[0011] Yet another object of the present invention is to provide means for dust proofing the trip device from harsh electromagnetic environments that involve both magnetic and non-magnetic dusts.

[0012] Yet another object of the present invention is to increase the longevity of the trip devices by eliminating the mechanical impact on the magnet, reducing the interference problems and reducing the leakage of flux occurring therein.

[0013] According to a first aspect of the present invention, there is provided a smart-shielded trip device for circuit breakers. The trip device comprising: a bottom assembly comprising a bracket such that said bracket houses the bottom assembly, said bracket comprising: a rare earth permanent magnet coupled to the base of the bracket, said permanent magnet generates flux to trip the smart-shielded trip device, wherein said permanent magnet is encased within a shield; a filler core positioned over the permanent magnet to cover said permanent magnet to avoid direct contact from shock and vibration of the trip device; and a bobbin positioned over the filler core to cover said filler core and permanent magnet, said bobbin is substantially positioned such that air gaps are maintained between said bobbin and permanent magnet; a top assembly comprising a plunger nut such that said plunger nut is adapted as a force pre-setter of the trip device, said top assembly comprising: at least one moving plunger operably coupled to said plunger nut at proximal end, and operably braced against a spring force provided by a spring, at distal end; wherein said spring force being greater than trip force required to trip the circuit breaker; and a multi-polar flux generation coil positioned substantially to couple the plunger of the top assembly to the bottom assembly; wherein energizing said coil generates flux such that supportive and repulsive magnetic flux are generated within the trip device according to the direction of excitation of said coil to latch or de-latch the plunger; wherein said permanent magnet generates a plurality of magnetic flux paths through the bottom assembly and the top assembly.

[0014] In a possible implementation of the shielded trip device according to the first aspect, the plunger is vertically braced, against the spring force, in closed condition by the magnetic flux from the rare earth permanent magnet of the bottom assembly.

[0015] In another possible implementation of the shielded trip device according to the first aspect, the proximal end of the plunger is rigidly sealed to the base of the plunger nut.

[0016] In yet another possible implementation of the shielded trip device according to the first aspect, working path of the magnetic flux passes through the rare earth permanent magnet, the filler core, the plunger and the bracket.

[0017] In yet another possible implementation of the shielded trip device according to the first aspect, a calibrator operably coupled to the rare earth permanent magnet such that relative position of the permanent magnet within the bottom assembly is substantially controlled by said calibrator.

[0018] In yet another possible implementation of the shielded trip device according to the first aspect, the calibrator is adapted to control trip force, holding force, and trip voltage of the trip device.

[0019] In yet another possible implementation of the shielded trip device according to the first aspect, the plunger is operably coupled to a tripping means of an MCCB.

[0020] In yet another possible implementation of the shielded trip device according to the first aspect, the top assembly comprises a pre-defined gap to adjust height of the trip device such that a plurality of trip forces is achieved.

[0021] In yet another possible implementation of the shielded trip device according to the first aspect, position of the permanent magnet is operably controlled by the calibrator such that an intentional air gap is maintained is created between said permanent magnet and the bracket, to modify the operating flux of the trip device.

[0022] In yet another possible implementation of the shielded trip device according to the first aspect, the top assembly comprises a stopper substantially positioned between the plunger and spring, said stopper houses a washer adapted to seal dust from inside the trip device; wherein said stopper is substantially positioned over the plunger and adapted to halt said plunger during de-latching; and wherein said stopper is adapted to support the bottom portion of the spring.

[0023] In yet another possible implementation of the shielded trip device according to the first aspect, the plunger nut is adapted to provide mechanical assembly tolerance compensation to the circuit breaker.

[0024] In yet another possible implementation of the shielded trip device according to the first aspect, the bottom assembly is encased within an encapsulation cover for dust proofing the trip device in harsh electromagnetic conditions involving magnetic dust and non-magnetic dusts.

[0025] In yet another possible implementation of the shielded trip device according to the first aspect, the shield comprises a diamagnetic component to repel the incident magnetic field on the permanent magnet.

[0026] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0027] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0028] Figure 1 illustrates the of the trip device with and without encapsulation cover according to an implementation of the present invention.

[0029] Figure 2 illustrates the cross section view of the electro-magnetic trip device according to an implementation of the present invention.

[0030] Figure 3 illustrates the working reluctance path of the electro-magnetic trip device according to an implementation of the present invention.

[0031] Figure 4 illustrates the smart shielding feature of the electro-magnetic trip device according to an implementation of the present invention.

[0032] Figure 5 illustrates the electro-magnetic trip device’s working positions and associated flux paths according to an implementation of the present invention.

[0033] Figure 6 illustrates the eddy currents created in the electro-magnetic trip device according to an implementation of the present invention.

[0034] Figure 7 illustrates the electro-magnetic trip device along with the secondary sealing for various trip forces according to an implementation of the present invention.

[0035] Figure 8 illustrates the mechanical assembly tolerance compensation feature of the electro-magnetic trip device according to an implementation of the present invention.

[0036] Figure 9 illustrates flow-chart of the method to detect fault and trip the circuit breaker according to an implementation of the present invention.

[0037] Figure 10 illustrates the air gap at the bottom of the electro-magnetic trip device according to an implementation of the present invention.

[0038] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0039] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0040] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0041] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0042] It is to be understood that the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0043] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0044] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0045] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or component but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0046] The subject invention lies in providing a smart-shielded trip device for circuit breakers.

[0047] In particular, the present invention describes the construction of an electro-magnetic trip actuating device for use in circuit breakers that substantially eliminates the mechanical impact on the magnet present therein, and reduces interference issues and leakage of flux from the trip device.

[0048] The mechanical impact on the magnet of the existing trip actuating devices results in the material losing property and tending to malfunction. Further, insufficient shielding results in external field interferences that disturb the performance of the device by demagnetizing the magnet. Thus, there is a need to overcome these problems to improve the longevity of the trip actuating devices. Therefore, the present invention provides an improved magnetic actuating device that eliminates the mechanical impact on the magnet, reduces interference problems and reduces leakage of flux from the trip devices.

[0049] According to a first embodiment of the present invention, a smart-shielded trip device for circuit breakers is disclosed. The trip device comprises a bottom assembly comprising a bracket (9) such that said bracket (9) houses the bottom assembly, said bracket (9) comprising: a rare earth permanent magnet (8) coupled to the base of the bracket (9), said permanent magnet (8) generates flux to trip the smart-shielded trip device, wherein said permanent magnet (8) is encased within a shield (13); a filler core (7) positioned over the permanent magnet (8) to cover said permanent magnet (8) to avoid direct contact from shock and vibration of the trip device; and a bobbin (6) positioned over the filler core (7) to cover said filler core (7) and permanent magnet (8), said bobbin is substantially positioned such that air gaps around the permanent magnet (8) are maintained between said bobbin (6) and permanent magnet (8); a top assembly comprising a plunger nut (1) such that said plunger nut (1) is adapted as a force pre-setter of the trip device, said top assembly comprising: at least one moving plunger (2) operably coupled to said plunger nut (1) at proximal end, and operably braced against a spring force provided by a spring (3), at distal end; wherein said spring force being greater than trip force required to trip the circuit breaker; and a multi-polar flux generation coil (5) positioned substantially to couple the plunger (2) of the top assembly to the bottom assembly; wherein energizing said coil (5) generates flux such that supportive and repulsive magnetic flux are generated within the trip device according to the direction of excitation of said coil (5) to latch or de-latch the plunger (2); wherein said permanent magnet (8) generates a plurality of magnetic flux paths (10, 11) through the bottom assembly and the top assembly.

[0050] The bobbin (6) offers three distinctive functions as a former of multi-polar flux generation coil (5) winding that enables tripping of the device, as a protective layer around the mating area of plunger (2)-filler core (7) avoiding any exposure to dusty environment that is around the circuit breaker and as a guide for smooth movement of plunger (7) in and out of the assembly providing the clearance for the movement and at the same time keeping the symmetricity of the assembly intact.

[0051] Figure 1 illustrates the general view of the electro-magnetic trip device with and without encapsulation cover (23). The encapsulation cover (23) provides the required dust proofing expected for the harsh electromagnetic environments that involves magnetic dust and non-magnetic dusts.

[0052] Figure 2 illustrates the cross section view of the electro-magnetic trip device revealing the internal components contained therein while Figure 3 illustrates the working reluctance path (10) of the electro-magnetic trip device. The working path (10) and the diversion path (11) that is involved in the operation of the electro-magnetic trip device are provided hereinbelow:

a) The working path (10): Rare Earth Permanent Magnet (8) -> Filler Core (7) -> Plunger (2) -> Bracket (9) -> Rare Earth Permanent Magnet (8).
b) The diversion path (11): Rare Earth Permanent Magnet (8) -> Air -> Bracket (9) -> Rare Earth Permanent Magnet (8).

[0053] Figure 4 illustrates the smart shielding feature of the electro-magnetic trip device while Figure 5 (a, b, c) illustrates the electro-magnetic trip device’s working positions and associated flux paths. The rare earth permanent magnet (8) generates flux that is flowing through this circuit and the flux generated in the multi-polar flux generation coil (5) when energized makes the tripping action. The flux produced by the coil (5) is illustrated in the Figure 5b as a dotted line (14). This takes the path of Plunger (2) ? stopper (4) ? Bracket (9) ? Filler Core (7) ? Plunger (2). The rare earth magnet (8) is brittle in nature and hence, to avoid any direct contact with the shock and vibration from the operation of the electro-magnetic trip device, a filler core (7) is used. The filler core (7) covers the magnet (8) from the top side. The bottom side of the magnet (8) is attached magnetically to the base of the bracket (9).

[0054] When the multi-polar flux generation coil (5) is energized, the opposition flux (14) generated will flow in the magnetic circuit and the plunger (2) will start to move away from the rare earth permanent magnet’s (8) pull force towards the outer position because of the pull force of the spring (3). The device will reach its second operating position in a matter of time i.e., tripped position as illustrated in Figure 5c. The energization of multi-polar flux generation coil (5) makes the device shift from one stable state as illustrated in Figure 5a to the second stable state as illustrated in Figure 5c. The device will now have a new set of magnetic flux path provided hereinbelow,

c) The newer working path (15): Rare Earth Permanent Magnet (8) -> Filler Core (7) -> Plunger (2) -> Bracket (9) -> Rare Earth Permanent Magnet (8).

[0055] Significantly, the bracket (9) is the main member of magnetic flux distribution in this particular arrangement of the components. The said component carries majority of the flux available in the system. The arrangement forms a minimum leakage path when in latched condition illustrated Figure 3. The plunger (2) which is pulled against the spring force (3) required to trip the mechanism of the circuit breaker is held in closed condition by the magnetic flux from the rare earth permanent magnet (8). The working path is the complete path by nature and majority of the flux through the same. There is a clearance provided in the path for the plunger (2) to move to and fro during latching and de-latching of the MCCB.

[0056] The coil (5) is multi-directional, i.e., when energized on one direction, the coil excites the circuit and de-latches the plunger from the magnets (8) holding force thereby tripping the mechanism of the MCCB. In the opposite direction, the coil (5) energization will help in reversing the de-latched plunger (2) back to its latched condition after the event of tripping of mechanism through de-latching of the plunger (2) has occurred. Therefore, the multi polar coil (5) operates the electro-magnetic trip device in both stable conditions of latched and de-latched positions as illustrated in Figure 5.

[0057] The bracket (9) that is handling the majority of rare earth permanent magnet (8) flux also houses a copper shield (13) around the magnet (8). The copper shield (13) is the smart shield provided in the trip device. Most of the shield component in the magnetic devices are formed using magnetic materials only whereas here, the magnet is shielded using a copper based component. The copper is a diamagnetic component and therefore, is weakly repelled by the magnetic field. Because the moving magnetic field around the magnet (8) will create eddy currents, as illustrated in Figure 6, in the copper shield (13). The generated eddy current will have its own magnetic field that will oppose the incident magnetic field on the copper thereby avoiding the effect of external magnetic field (16) as illustrated in Figure 8.

[0058] The copper shield (13) plays a dual role in the present invention. By being over the permanent magnet (8), the copper shield (13) will slow down the magnetic flux variation that is happening inside the magnetic trip device. By covering the rare earth permanent magnet (8), it also covers the magnet (8) from getting disturbed by the external noise magnet fields (16). This arrangement is illustrated in Figure 6. The use of copper shield (13) around the magnet also enables the trip device to utilize low power permanent magnets in the assembly for operation. Since the external magnetic field is effectively reduced by the copper shield (13), the requirement of high power magnet is only when the output force required is higher; otherwise low power magnets such as AlNiCo, Ferrites, etc. can be used.

[0059] The spring (3) that is designed for the device’s plunger (2) also serves as a stabilizer of the components in the assembly. The spring (3) is bigger in diameter intentionally kept in order to properly balance the plunger (2) in the circuit. The spring (3) is provided with an additional support at the bottom through the stopper (4) component. The stopper (4) stops the plunger (2) during de-latching operation. The profile of the stopper (4) used for stopping the plunger (2) is used for the support of the spring (3) in the outside.

[0060] The support structure also holds a cap (19) made preferably from an elastomer or polymer based material. The cap (19) is made up of a self-lubricating material. The cap (19) rubs the plunger (2) from its outer surface. The purpose of the cap (19) is to seal the assembly from any external dust particles coming in between plunger (2) and the filler core (7). The dust entering into this critical area will hamper the performance of the electro-magnetic trip device. This arrangement is illustrated in Figure 7. The cap (19) is supported by the stopper (4) and held in place by the spring (3). The spring (3) is mounted over the cap (19) in order to arrest the cap (19) while the plunger (2) is in motion as illustrated in Figure 7.

[0061] There is an additional washer (20) inside the stopper (4) above the plunger’s (2) bigger diameter. The washer (20) forms the secondary sealing of dust from inside the trip device. The material is a breathable material because if a non-breathable material is used, the plunger (2) movement will be jammed because of an air trap that is created inside the movement chamber of the plunger (2). Its effects may range from partially slowed down tripping to complete plunger (2) movement being blocked. The arrangement along with the secondary sealing is illustrated in Figure 7.

[0062] The plunger nut (1) component is assembled on top of the electro-magnetic trip device. The component acts as a force pre-setter for the electro-magnetic trip device. The height of the assembly can be adjusted by the user within the defined gap (18) in order to achieve various trip forces as illustrated in Figure 7. The plunger nut (1) also enables the mechanical assembly tolerance compensation feature required in the circuit breaker assembly as illustrated in Figure 8. The defined gap (24) illustrated in Figure 8 corresponds to the deviation in the sub-assembly integration that can be compensated by the trip device during practical integration in the main operating system. The feature minimizes the criticality of the other sub-assemblies that are expected to interact with the trip device during the operation of circuit breaker at various times.

[0063] The electro-magnetic trip device is designed such that it is not fault specific, i.e., the electro-magnetic trip device can trip the mechanism of the circuit breaker under any condition even when there is no fault associated with the circuit breaker currents. The trip device is controlled by the electronic control system that manages the operation of the trip device. This electronic control unit is programmed such that the trip device can be used as a means for executing communication based circuit breaker command such as remote tripping, electrical interlocking and many more. The building block of the electronic trip unit is illustrated in Figure 8.

[0064] The sequence of operation of the electromagnetic trip device along with the integrated electronic control unit is illustrated Figure 9.

[0065] The trip device also has a calibration configuration for the dynamic user controlled device parameters. The calibrator (22) allows the user to control the major device parameters such as trip force, holding force of the trip device and the trip voltage at the trip device will de-latch. The calibrator (22) controls the location of the rare earth permanent magnet in the device. The magnet is moved away from the bracket to create an intentional air gap (21). The location of the intentional air gap (21) is adjustable. It can lie anywhere between the bottom of the magnet (8) and bottom of the plunger (2) to modify the force output of the trip device. This configuration is illustrated in Figure 10.

[0066] Some of the non-limiting advantages of the present invention are mentioned hereinbelow:

1. The copper shield avoids the requirement of a magnetic shield to protect the device and the permanent magnet from the external magnetic fields;

2. The use of copper shield also enables the device to use low power magnets such as AlNiCo as the magnet is protected from external magnetic fields and reverse magnetization;

3. The calibration screw pushes controls the device’s magnetic holding forces and the displacement and is user controllable. Thus fitting various requirements of the user;

4. The dust proofing features provides the device the much required ability to perform in harsh environment; and

5. The mechanical compensation features implemented in the device allows the device to easily integrate with assemblies with wider assembly tolerances thereby reducing cost of manufacturing and development cycle time.

[0067] Although a smart-shielded trip device for circuit breakers has been described in language specific to structural features and/or methods as indicated, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or components or devices or methods described therein. Rather, the specific features are disclosed as examples of implementations of an improved magnetic actuating device that eliminates mechanical impact on the magnet, reduces interference problems and reduces of leakage flux.