Claims:1. An electro-magnetic trip device for use in circuit breakers, said trip device comprising:
a shunt assembly, a voltage assembly and a splitter spring (9);
wherein said splitter spring (9) is substantially positioned to operably engage the shunt assembly to the voltage assembly;
said shunt assembly comprising:
a shunt coil (1), and a shunt core (2);
wherein said shunt coil (1) is wound over base portion of the shunt core (2);
said voltage assembly comprising:
an inverted core (6), a fixed core (4), a moving plunger (7), an under voltage spring (10), and an under voltage coil (5);
said inverted core (6) is circumferentially mounted over a base core (3), said base core (3) is releasably engaged to said inverted core (6);
wherein said inverted core (6) comprises an opening;
said fixed core (4) is rigidly mounted over the base core (3);
said moving plunger (7) is coaxially positioned over the fixed core (4) such that a gap is maintained therebetween;
wherein a portion of said plunger (7) protrudes through said opening of the inverted core (6);
said under voltage spring (10) is coaxially positioned such that said under voltage spring (10) is operably engaged to said fixed core (4) at one end and said plunger (7) at other end;
wherein said under voltage spring (10) is rigidly engaged to both fixed core (4) and plunger (7);
said under voltage coil (5) is coaxially wound over the plunger (7) such that an air gap is maintained between said coil (5) and plunger (7);
wherein energizing said under voltage coil (5) generates flux such that supportive and repulsive flux are generated within the voltage assembly according to excitation of said under voltage coil (5) to draw or release the plunger (7);
said splitter spring (9) is substantially positioned to operably engage said shunt coil (1) of the shunt assembly to said base core (3) of the voltage assembly, said splitter spring (9) is rigidly engaged to both shunt coil (1) and base core (3);
wherein energizing said shunt coil (1) generates a flux within the shunt assembly such that said splitter spring (9) is adapted to draw the base core (3) of the voltage assembly towards said shunt assembly.

2. The trip device as claimed in claim 1, wherein the inverted core (6) is substantially U-shaped and the base core (3) is substantially I-shaped.

3. The trip device as claimed in claim 1, comprising a custom source of supply signal to energize the shunt coil (1).

4. The trip device as claimed in claim 3, wherein the shunt coil (1) is energized during under voltage condition such that said shunt coil (1) energizes the shunt core (2).

5. The trip device as claimed in claim 4, wherein the energized shunt assembly operably draws the fixed core (4) of the under voltage assembly against a spring force provided by the splitter spring (9).

6. The trip device as claimed in claim 1, wherein the under voltage coil (5) houses the fixed core (4), under voltage spring (10) and plunger (7).

7. The trip device as claimed in claim 1, comprising a regulated system voltage to energize the under voltage coil (5).

8. The trip device as claimed in claim 7, wherein the under voltage coil (5) is always energized such that said under voltage coil (5) energizes the inverted core (6) and the base core (3) of the voltage assembly.

9. The trip device as claimed in claim 1, comprising a tripping mechanism, said tripping mechanism comprising at least a latch (16), a hinge (17), a trip spring (14) and a latch pin (15), wherein a trigger from the plunger (7) releases the latch (16) operably coupled to brace the latch pin (15) against the trip spring.

10. The trip device as claimed in claim 8,
wherein energizing said under voltage coil (5) during normal condition generates a flux such that the plunger (7) is operably drawn towards the fixed core (4); and
wherein during under voltage condition, generated flux from said under voltage coil (5) is reduced such that the plunger (7) is operably released to trigger the tripping mechanism.

11. The trip device as claimed in claim 9, wherein during normal condition, the retracted plunger (7) is substantially positioned to lock the latch (16) of the tripping mechanism such that the latch pin (15) of the tripping mechanism does not trip the circuit breaker.

12. The trip device as claimed in claim 6, wherein during under voltage condition, the retracted plunger (7) is released to trigger the latch (16) of the tripping mechanism such that latch pin (15) of the tripping mechanism is triggered to trip the circuit breaker.
, Description:FIELD OF THE INVENTION

[001] The subject matter of the present invention, in general, relates to trip actuating devices for circuit breakers and more particularly, pertains to an electro-magnetic trip actuating device for use in 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] Moreover, in the current scenario, the accessories associated with a circuit breaker demands separate space for accommodating them as well as different actuation points for them to interact with the circuit breaker and its control system. The volume occupied by the circuit breaker is defined by the number of accessories it can accommodate within and increase in volume directly affects the space occupied by the circuit breaker and further, the panel space. As space becomes a premium, it is necessary to combine multiple functions to a singular entity and deliver the same performance that is required when all were separately given.

[004] Most of the circuit breakers are designed such that they act upon failure automatically. But there are failures that can still happen in the network because of protocols not followed by the personnel handling the dangerous devices, machine creating faults that are not detectable, etc. For instance, a three phase short circuit is a balanced condition according to a circuit breaker with earth leakage current as there is no ground involved in the event. Also short circuit created by insulation failures and tracking are not going to be severe and thus, going to take time to clear through a circuit breaker. If a human is involved in the above fault accidentally, this will lead to fatal situations.

[005] For addressing such instances, lots of sensors are used in the automation based industries in order to properly detect the means of failure and act through the identifications. These sensors generate signals and those are transferred to the corresponding circuit breaker from the network of circuit breakers to act upon the faulty line and clear the faulty network out of current. The fault detection, communication and trip action are done through the shunt releases. Thus, shunt releases are the release used in the remote tripping, emergency button tripping, etc.

[006] For some existing state of the art trip actuator devices in the public domain, reference is made to US Application Number 4641117 A, wherein a modified electronic trip unit actuator that provides remote trip and under voltage release function without impairing the actuator reliability is disclosed. The permanent magnet of a flux shift trip unit actuator is replaced with an under voltage release coil for under voltage facility. Further, a combination of a permanent magnet with a shunt trip coil is employed for remote tripping function.

[007] Reference is also made to US Application Number 6167329 A, wherein an electronic trip unit having two microprocessors is disclosed. One microprocessor monitors the load voltage and current within the normal operating range and performs the metering and delayed trip algorithms associated with that range while the second microprocessor monitors the load current for excursions outside the normal operating range and processes those algorithms and functions associated with the instantaneous and overcurrent trip protection modes of the trip unit. Each microprocessor receives inputs representative of the monitored current that is scaled to a different factor corresponding to the range the microprocessors are assigned to monitor. The electronic trip unit is controlled by a master controller and in turn controls a number of accessory devices, wherein one of the microprocessors is a slave to the master controller network and the other is a master to the accessory slave network. These microprocessors communicate with each other and either one can trip the circuit on detection of a fault condition.

[008] Typically, circuit breakers handle many releases associated with them. There are specific spaces allocated to these releases in the circuit breaker in order to locate the releases and also integrate the same with the circuit breaker mechanism in order to successfully initiate the trip action during faulty condition.

[009] As technology advances, the need for such releases in the circuit breaker also increases, the space around the circuit breakers are also growing leading to more space covered by a single circuit breaker to perform multiple fault detection and rectification process. Accordingly, there is a need for a space sensitive design for circuit breaker releases to increase the efficiency of the circuit breaker while decreasing the space occupied by the circuit breaker. To achieve the desired objectives, the present invention discloses a n electro-magnetic trip actuating device for use in circuit breakers.

[0010] The above-described need to optimize the space occupied by a circuit breaker to increase its efficiency 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

[0011] 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.

[0012] An object of the present invention is to provide an electro-magnetic trip actuating device for use in circuit breakers.

[0013] Another object of the present invention is to optimize the space available within a trip device.

[0014] Yet another object of the present invention is to provide a multi-purpose trip device when connected to an electronic control unit of the circuit breaker.

[0015] Yet another object of the present invention is to provide a single device that contributes to multiple fault detection in circuit breakers and triggering the trip action through a single operating means.

[0016] Yet another object of the present invention is to provide combined shunt and under voltage features when the trip actuating device is normally supplied by various input terminals of the device.

[0017] Yet another object of the present invention is to provide multiple tripping features as that of fault conditions such as short circuit, overload, shunt, under voltage, over voltage, and the like wherein when supplied through an electronic control unit.

[0018] According to a first aspect of the present invention, there is provided an electro-magnetic trip device for use in circuit breakers. The trip device comprising: a shunt assembly, a voltage assembly and a splitter spring; wherein said splitter spring is substantially positioned to operably engage the shunt assembly to the voltage assembly; said shunt assembly comprising: a shunt coil, and a shunt core; wherein said shunt coil is wound over base portion of the shunt core; said voltage assembly comprising: an inverted core, a fixed core, a moving plunger, an under voltage spring, and an under voltage coil; said inverted core is circumferentially mounted over a base core, said base core is releasably engaged to said inverted core; wherein said inverted core comprises an opening; said fixed core is rigidly mounted over the base core; said moving plunger is coaxially positioned over the fixed core such that a gap is maintained therebetween; wherein a portion of said plunger protrudes through said opening of the inverted core; said under voltage spring is coaxially positioned such that said under voltage spring is operably engaged to said fixed core at one end and said plunger at other end; wherein said under voltage spring is rigidly engaged to both fixed core and plunger; said under voltage coil is coaxially wound over the plunger such that an air gap is maintained between said coil and plunger; wherein energizing said under voltage coil generates flux such that supportive and repulsive flux are generated within the voltage assembly according to excitation of said under voltage coil to draw or release the plunger; and said splitter spring is substantially positioned to operably engage said shunt coil of the shunt assembly to said base core of the voltage assembly, said splitter spring is rigidly engaged to both shunt coil and base core; wherein energizing said shunt coil generates a flux within the shunt assembly such that said splitter spring is adapted to draw the base core of the voltage assembly towards said shunt assembly.

[0019] In a possible implementation of the trip device according to the first aspect, the inverted core is substantially U-shaped and the base core is substantially I-shaped.

[0020] In another possible implementation of the trip device according to the first aspect comprising a custom source of supply signal to energize the shunt coil.

[0021] In yet another possible implementation of the trip device according to the first aspect, the shunt coil is energized during under voltage condition such that said shunt coil energizes the shunt core.

[0022] In yet another possible implementation of the trip device according to the first aspect, the energized shunt assembly operably draws the fixed core of the voltage assembly against a spring force provided by the splitter spring.

[0023] In yet another possible implementation of the trip device according to the first aspect comprising a regulated system voltage to energize the under voltage coil.

[0024] In yet another possible implementation of the trip device according to the first aspect, the under voltage coil is always energized such that said under voltage coil energizes the inverted core and the base core of the voltage assembly.

[0025] In yet another possible implementation of the trip device according to the first aspect comprising a tripping mechanism, said tripping mechanism comprising at least a latch, a hinge, a trip spring and a latch pin, wherein a trigger from the plunger releases the latch operably coupled to brace the latch pin against the trip spring.

[0026] In yet another possible implementation of the trip device according to the first aspect, energizing said under voltage coil during normal condition generates a flux such that the plunger is operably drawn towards the fixed core; and wherein energizing said under voltage coil during under voltage condition generates a flux such that the plunger is operably released to trigger the tripping mechanism.

[0027] In yet another possible implementation of the trip device according to the first aspect, during normal condition, the retracted plunger is substantially positioned to lock the latch of the tripping mechanism such that the latch pin of the tripping mechanism does not trip the circuit breaker.

[0028] In yet another possible implementation of the trip device according to the first aspect, during under voltage condition, the retracted plunger is released to trigger the latch of the tripping mechanism such that latch pin of the tripping mechanism is triggered to trip the circuit breaker.

[0029] 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

[0030] 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:

[0031] Figure 1 illustrates the general view of the electro-magnetic trip device according to an implementation of the present invention.

[0032] Figure 2 illustrates the reluctance path of the electro-magnetic trip device according to an implementation of the present invention.

[0033] Figure 3 illustrates the under voltage assembly of the electro-magnetic trip device according to an implementation of the present invention.

[0034] Figure 4 illustrates the shunt assembly of the electro-magnetic trip device according to an implementation of the present invention.

[0035] Figure 5 illustrates the sequence of operation for under shunt release according to an implementation of the present invention.

[0036] Figure 6 illustrates the sequence of operation for under voltage release according to an implementation of the present invention.

[0037] Figure 7 illustrates the zero-torque mechanism 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 an electro-magnetic trip actuating device for use in circuit breakers.

[0047] In particular, the present invention describes the construction of a single device that contributes to multiple fault detection in circuit breakers and triggering the trip action through a single operating means that substantially optimizes the space available within a trip device.

[0048] Advancement in technology demands that components be more compact and slimmer thereby making a premium. As space becomes premium, it is necessary to combine multiple functions to a singular entity and deliver the same performance that is required when all were separately given.

[0049] The under voltage (UV) release is called so because it detects the under voltage in the system and triggers the trip action upon occurrence of the event. The under voltage releases are used in areas where the system voltage is critical for the load devices. The under voltage condition, in general, will make load devices draw more current to satisfy its power needs leading to high temperatures in the wires that carry current to the concerned loads. This will in turn lead to the insulation failure and multiple failures such as ground fault, short circuit, etc. Therefore, under voltage protection is very critical for protection of the distribution network and its associated load devices. The shunt release is the one that triggers trip action upon manual command or automation related command.

[0050] According to a first embodiment of the present invention, an electro-magnetic trip device for use in circuit breakers is disclosed. The trip device comprising: a shunt assembly, a voltage assembly and a splitter spring (9); wherein said splitter spring (9) is substantially positioned to operably engage the shunt assembly to the voltage assembly; said shunt assembly comprising: a shunt coil (1), and a shunt core (2); wherein said shunt coil (1) is wound over base portion of the shunt core (2); said voltage assembly comprising: an inverted core (6), a fixed core (4), a moving plunger (7), an under voltage spring (10), and an under voltage coil (5); said inverted core (6) is circumferentially mounted over a base core (3), said base core (3) is releasably engaged to said inverted core (6); wherein said inverted core (6) comprises an opening; said fixed core (4) is rigidly mounted over the base core (3); said moving plunger (7) is coaxially positioned over the fixed core (4) such that a gap is maintained therebetween; wherein a portion of said plunger (7) protrudes through said opening of the inverted core (6); said under voltage spring (10) is coaxially positioned such that said under voltage spring (10) is operably engaged to said fixed core (4) at one end and said plunger (7) at other end; wherein said under voltage spring (10) is rigidly engaged to both fixed core (4) and plunger (7); said under voltage coil (5) is coaxially wound over the plunger (7) such that an air gap is maintained between said coil (5) and plunger (7); wherein energizing said under voltage coil (5) generates flux such that supportive and repulsive flux are generated within the voltage assembly according to excitation of said under voltage coil (5) to draw or release the plunger (7); and said splitter spring (9) is substantially positioned to operably engage said shunt coil (1) of the shunt assembly to said base core (3) of the voltage assembly, said splitter spring (9) is rigidly engaged to both shunt coil (1) and base core (3); wherein energizing said shunt coil (1) generates a flux within the shunt assembly such that said splitter spring (9) is adapted to draw the base core (3) of the voltage assembly towards said shunt assembly

[0051] Figure 1 illustrates the general view of the electro-magnetic trip device of the present invention. The shunt release is formed by the components of the electro-magnetic trip device as illustrated in Figure 1. The reluctance path of the circuit is illustrated in Figure 2. The shunt release works as follows, the coil (1) wound in the shunt C-core also called as the shunt coil (1) is energized in the event of fault or requirement, the coil (1) energizes the shunt c-core (2) and pulls the I-Base core (3) against the splitter spring (9) force. I-Base core (3) forms the integral part of the under voltage release.

[0052] The under voltage assembly comprising releases’ magnetic circuit is illustrated in Figure 3 and the shunt releases’ magnetic circuit is illustrated in Figure 4. Once I-Core base (3) is pulled towards the shunt c-core (2), there is a sudden drop of flux density in the circuit of the under voltage release. This sudden surge in the reluctance because of the drop in flux density leads to the weak magnetic force of attraction from the under voltage coil (5) in the magnetic circuit and leaves a plunger (7) to move along with a spring (10) that is pushing the same from inside, as illustrated in Figure 2. The triggers from the plunger (7) of the release will actuate the zero torque amplification mechanism illustrated in Figure 7 that is mounted on top of the under voltage coil (5).

[0053] The zero-torque mechanism, as illustrated in Figure 7, consists of the following components:
a) Hinge (17)
b) Latch (16)
c) Latch pin (15)
d) Trip Spring (14)

[0054] The line of latching (12, 14) of the high force trip spring (14) is kept intentionally close to the line of force of action (18) of the plunger (7) so that the torque developed during the latching of the trip spring (14) is overcome with the application of very minimal force that is exerted by the plunger (7) movement during trip action. The trigger from plunger will release the latch (16) of the amplification mechanism that is holding a latch pin (15) against the trip spring (14). This Latch pin (15) will trigger the mechanism of the circuit breaker in order to clear the fault condition. The complete sequence of operation for under shunt release is illustrated Figure 5 and detailed hereinbelow:

1. Normal operating state: UV coil (5) energized continuously and shunt coil (1) not energized.
2. Shunt operating state: UV coil (5) energized continuously and shunt coil (1) energized.
3. Shunt completed state: UV coil (5) energized continuously, shunt coil (1) energized, and I-base core (3) completely pulled up breaking UV magnetic circuit.
4. Shunt Tripped state: UV coil (5) energized continuously, shunt coil (1) energized, I-base core (3) completely pulled up breaking UV magnetic circuit and plunger (7) popped out.

[0055] When the under voltage release alone operates, the following components are not included in the operation:
e) Shunt C-Core (2)
f) Shunt release coil (1)

[0056] The under voltage coil (5) is always energized, i.e. it is a continuous duty coil. The UV coil (5) gets energized through a regulated system voltage. Under normal operation, the coil (5) excites the inverted U-core (6) and I-Base core (3) pulling the plunger (7) toward the fixed core (4) mounted on the bottom of I-Base core (3). This retracted plunger (7) keeps the latch (16) of the zero torque mechanism in locked condition such that the latch pin (15) does not trip the mechanism of the circuit breaker. Once there is an event of under voltage, the excitation magnetic force from the UV coil (5) reduces, leading to the release of plunger (7) to release the latch (16) of zero torque mechanism. The release of latch (16) releases the latch pin (15) from the amplification mechanism, tripping the circuit breaker mechanism to clear the fault and protect the load devices. The complete sequence of operation for under voltage release is illustrated in Figure 6 and detailed hereinbelow:

1. Normal operating state: UV coil (5) energized continuously and shunt coil (1) not energized.
2. UV Tripped state: UV coil (5) energized continuously but voltage dropped below threshold and shunt coil (1) not energized.

[0057] Significantly, as the shunt is connected to the custom source of supply signal, the shunt release can be utilized for variety of tripping features. Thus, the integrated under voltage-cum-shunt release not only saves space of the electro-magnetic trip device in the circuit breaker, but also serves as a multi-purpose trip device when connected to an electronic control unit of the circuit breaker. In particular, when normally supplied by various input terminals, the trip device will provide combined shunt and under voltage features while when supplied through an electronic control unit, it provides multiple tripping features for fault conditions such as short circuit, overload, shunt, under voltage, over voltage, etc.

[0058] Some of the non-limiting advantages of the present invention are mentioned hereinbelow:
1. It serves as an integrated under voltage and shunt trip device when used as an analog input modes serving the dual purpose tripping utilizing lesser space in the circuit breaker;
2. It serves as a multi-purpose trip device when connected to an electronic control unit of the circuit breaker tripping the circuit breaker in the event of faults such as short circuit, overload, user input tripping, etc.;
3. It saves space of the electro-magnetic trip device;
4. It offers the remote tripping feature of the circuit breakers without utilising any additional trip device mounted for specific said feature while continuously giving the under voltage protection;
5. It also saves space in the circuit breaker avoiding additional tripping devices for multiple tripping characteristics; and
5. It reduces the complexity of the circuit breaker mechanism design reducing the number of tripping features to as low as one.

[0059] Although an electro-magnetic trip actuating device for use in 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 a single device that contributes to multiple fault detection in the circuit breaker and triggering the trip action through a single operating means.