A tripping actuation arrangement for an actuator assembly of a molded case circuit breaker

Abstract

Described herein is a tripping actuation arrangement [200] for an actuator assembly [112] of an MCCB [100], comprising at least one trip actuation arm [202] defines a tripping accessory engagement portion [204f, 206f], and a trip bar engagement portion [204h, 206h]. Notably, upon engagement of the tripping accessory engagement portion [204f, 206f] with at least one tripping accessory, the at least one trip actuation arm [202] is resiliently and slidably adjusted relative to the at least one of the pair of side frame members [124], enabling engagement of the trip bar engagement portion [204h, 206h] with the trip bar [122], thereby causing tripping of the MCCB [100]. Refer Figure 4a.

Description

[0001] A TRIPPING ACTUATION ARRANGEMENT FOR AN ACTUATOR ASSEMBEY OF A MOEDED CASE CIRCUIT BREAKER

[0002] FIELD OF INVENTION

[0003] The present invention relates to the field of circuit breakers. The present invention, in particular, relates to a tripping actuation arrangement for an actuator assembly of a moulded case circuit breaker (MCCB).

[0004] BACKGROUND OF THE INVENTION

[0005] This section is intended to provide information relating to the field of the invention and thus, any approach or functionality described below should not be assumed to be qualified as prior art merely by its inclusion in this section.

[0006] Circuit Breakers are electro-mechanical switching devices capable of making, carrying and breaking currents and are also known as over current protective devices. Under normal circuit conditions, a circuit breaker closes the electrical circuit, carries current for a specified time and breaks the electrical circuit under specified abnormal circuit conditions. These over-current protective devices are also employed for current interruption. Accordingly, it is said that circuit breaker is an equipment which can open or close the circuit, under all conditions viz. no load, full load and fault conditions. Low voltage circuit breakers are commonly known to be deployed for low voltage applications, for example 1000 Volt or lower.

[0007] Various examples of low voltage circuit breakers are known, for example, a Miniature Circuit Breaker (MCB), a Moulded Case Circuit Breaker (MCCB), a Residual Current Circuit Breaker (RCCB), an Air Circuit Breaker (ACB), and the like. Notably, the MCB is used in applications of current rating under 125 Amperes and interrupting current rating of under 10KA, while MCCB is used in applications of current rating upto 1600 Amperes usually and interrupting current in a range of lOkA -150kA. Accordingly, it is submitted that MCCB is used for relatively high current rating applications.

[0008] Moulded case circuit breaker (MCCB) is commonly a multipolar circuit breaker, which protects the electrical network / circuit and equipment from overloading or short-circuiting. Specifically, the MCCB is capable of operating between an ON position, an OFF position, and a TRIP position. Conventionally, the MCCB includes at least a base assembly, a mid-cover assembly, a fascia plate assembly, at least one pole assembly, a trip assembly, and an actuator assembly. In one embodiment, the MCCB is a three-pole unit comprising of three (3) pole assemblies. In such embodiments, the base assembly, the mid-cover assembly, the fascia plate assembly, in combination with each other, forms a housing to house and support the three pole assemblies therein. Further, the actuator assembly is mounted on at least one of the three (3) pole assemblies, while the TRIP assembly is mounted on at least one of the three (3) pole assemblies, such that the three (3) pole assemblies are connected together and operated together between the ON position, the OFF position, and the TRIP position. Notably, each of the three (3) pole assemblies comprises a pair of electrical contact units i.e., a stationary contact unit and a rotary contact unit, wherein the rotary contact unit rotatably engages and disengages with the stationary contact unit. Particularly, the actuator assembly includes a lever switch that can be manually adjusted, to adjust the three (3) pole assemblies together between the ON position, the OFF position, and the TRIP position. More particularly, the actuator assembly is capable of breaking electrical contact between the stationary contact unit and the rotary contact unit of the three (3) pole assemblies, to interrupt the flow of current therethrough to the bus bar conductors connected to the load side, in response to normal / fault conditions.

[0009] Conventionally, in a severe fault condition, such as overcurrent, existing trip actuator cause thermal tripping of the MCCB, due to the prolonged heating of bimetal. While, in another fault condition corresponding to high inrush currents, due to very high current, the aforementioned trip actuator breaks the flow of current by means of magnetic release, thereby inducing magnetic tripping of the MCCB. A single trip actuator is capable of causing thermal and magnetic tripping of the MCCB.

[0010] Yet another existing art provides for an electronic trip unit (ETU) provided in the MCCB, which consists of a printed circuit board (PCB) and a current transformer to sense a fault condition. Typically, upon sensing a fault condition, the ETU actuates the external mechanism known as flux shifter device (FSD), coupled with the operating mechanism interface through actuators. When the current exceeds the threshold in ETU, the FSD triggers the trip mechanism. A solenoid creates a magnetic field in response to a trip signal received from the FSD, which enables release of a plunger in the FSD from a locked position. The trip mechanism is activated by the plunger, thereby actuating a flux shifter mechanism.

[0011] A solenoid mechanism known as a shunt release causes the breaker to open manually. It can be activated by a wide range of safety or control features, but is typically used for remote tripping by the application of a control supply voltage. The trip signal is produced by an electromagnetic coil in both UV and shunt releases. Under voltage releases, which are used in circuit breakers to protect downstream equipment from under voltage or low voltage conditions, cause the breaker to open when the applied voltage drops below a predetermined threshold value. An undervoltage release is frequently activated from the system and is designed to open the breaker in the event that something occurs that causes the system voltage to drop. Consequently, it serves as an internal accessory together with the circuit breaker module.

[0012] In view of the aforementioned, conventionally, the actuator assembly of the MCCB includes a trip actuating unit, wherein the trip actuating unit comprises one or more actuation members. Typically, for different accessory devices employed in the MCCB such as, but not limited to TMTU, FSD, ATU, and shunt, a separate actuation member of the trip actuating unit is employed, to facilitate tripping of the MCCB. However, such multiplicity of components for tripping of the MCCB, may result in nuisance tripping of the MCCB, which makes the MCCB prone to operational failure in the event of fault conditions. ‘Nuisance tripping’ refers to tripping of the MCCB to the TRIP position in absence of a fault condition.

[0013] Reference may be made to the following:

[0014] Patent No. US2002130743 relates to a circuit breaker modular device reset allows modular devices to be reset in a confined space with a minimal operating stroke. Modular devices include actuators such as flux shift units and accessories such as shunt trip devices and undervoltage devices. The reset device includes a support, a first leg and a second leg connected to the support via a trunk. A head is located at the distal end of the first leg. The modular device includes a reset tab. An interface used to reset an actuated modular device project from the second leg and engages the reset tab during a modular device reset stroke.

[0015] Publication no. 624 / MUM / 2007 relates to a resetting mechanism for use in flux shift tripping devices for circuit breakers. The mechanism comprises microprocessor or electronic release means in a compartment, flux shift tripping device operatively connected to said release means in the compartment and intermediate link means (3) connecting said flux shift device (1) and trip plate of the circuit breaker.

[0016] Patent No. US6421217 relates to an accessory including a trip arm biased by a spring to pivot in a clockwise direction about a trip arm pivot. A latch is arranged to pivot about a latch pivot and has the trip arm acting on a latch surface on the latch to push the latch in a counterclockwise direction about the latch pivot. Patent No. US5805041 relates to a field-installable circuit breaker trip actuator unit includes a flux shifter unit that interfaces with the circuit breaker operating mechanism and is installable without dismantling the circuit breaker components. The flux shifter unit responds to an electronic trip unit to articulate the circuit breaker operating mechanism and separate the circuit breaker contacts upon occurrence of an overcurrent condition. A reset arrangement allows the trip actuator unit to be automatically reset upon completion of the contact separation process.

[0017] Patent No. US5670923 relates to a field-installable circuit breaker trip unit conversion kit in the form of a flux shifter unit that interfaces with the circuit breaker operating mechanism that is installable without dismantling the circuit breaker components. The flux shifter unit responds to an electronic trip unit to articulate the circuit breaker operating mechanism and separate the circuit breaker contacts upon occurrence of an overcurrent condition. Expansion springs achieve tolerance take-up for different operating mechanism assemblies to correctly interface with the associated electronic trip unit.

[0018] Patent No. US4913503 relates to an integrated protection unit is a circuit breaker which includes basic overcurrent protection facility along with selective electrical accessories. A molded plastic accessory access cover secured to the integrated protection unit cover protects the accessory components contained within the integrated protection unit cover from the environment. A combined overcurrent trip actuator and multiple accessory unit can be field-installed within the integrated protection unit. The combined actuator-accessory unit includes electronic control circuitry for the accessories along with mechanical trip and reset interface components. The reset mechanism allows the actuator-accessory unit to become reset without interferring with the operation of the integrated protection unit.

[0019] Patent No. US5122771 relates to a molded case circuit breaker combined accessory actuatorreset lever. Since industrial-rated circuit breakers are often located remote from the associated protected electrical equipment it is often times necessary to monitor the operation of such electrical equipment by observing the condition of the circuit breaker contacts to ensure that such equipment remains operational. When a plurality of such circuit breakers are mounted within a common enclosure, an auxiliary device within each of the circuit breakers readily provides visual indication of the ON-OFF condition of the circuit breaker contacts. With such auxiliary devices, an actuator-reset lever is used to interface between the circuit breaker operating mechanism, the circuit breaker trip mechanism and the auxiliary device to activate the auxiliary device when the circuit breaker contacts are open and closed and to reset the trip mechanism when the circuit breaker contacts are opened. Patent No. US5014025 relates to an integrated protection unit is a circuit breaker which includes basic overcurrent protection facility along with selective electrical accessories. A molded plastic accessory access cover secured to the integrated protection unit cover protects the accessory components contained within the integrated protection unit cover from the environment. A combined overcurrent trip actuator and multiple accessory unit can be field-installed within the integrated protection unit. The combined actuator-accessory unit includes electronic control circuitry for the accessories along with mechanical trip and reset interface components. The reset mechanism allows the actuator-accessory unit to become reset without interfering with the operation of the integrated protection unit.

[0020] It is generally well known in the art of circuit breakers to provide a reset mechanism to reset a tripping device such as given tripping units - shunt trip, under Voltage device , Flux shifter , Alternate MAG trip And TMTU. During normal operation, (i.e. when the circuit breaker contacts are closed to allow the flow of electrical current) the operating handle of an operating mechanism is in the “ON” position. To stop the current flow manually, the handle may be shifted to the “OFF1position thereby opening the electrical contacts. Upon attainment of a predetermined condition (trip event), like ground fault or overload, the operating mechanism of the circuit breaker will release the forces of the mechanism operating springs and release the operating handle to a tripped position which lies between the “ON” position and the “OFF1position. Before the circuit breaker may be turned “ON”, the operating mechanism must be manually reset. This is accomplished by rotating the operating handle beyond the “OFF1position against the bias of the operating mechanism Springs, thereby locking the operating mechanism in position. The same mechanical forces used to direct the operating mechanism from the tripped position to the reset position, are used to reset any attached tripping unit. However, as tripping unit are generally separate components mounted proximate to the operating mechanism, positional variations at the interface of the tripping units and the circuit breaker operating mechanism are possible due to manufacturing tolerances or different location. These positional variations can affect the magnitude of Trip or reset forces translated to the accessory and the range of motion of the provided trip or reset forces.

[0021] In view of the various problems and numerous prior arts enlisted hereinabove, there is a well felt need to provide for a multifunctional, reliable, easy to assembly, and improved actuating unit for the actuator assembly of the MCCB, with fewer components, capable of efficiently tripping the MCCB, by engaging with one or more accessory devices employed in the MCCB.

[0022] SUMMARY OF THE INVENTION This section is intended to introduce certain objects of the disclosed system in a simplified form and is not intended to identify the key advantages or features of the present disclosure.

[0023] The present disclosure relates to a tripping actuation arrangement for an actuator assembly of a moulded case circuit breaker (MCCB). The actuator assembly comprising a trip bar and a pair of side frame members. The tripping actuation arrangement comprising at least one trip actuation arm resiliently and slidably installed on at least one of the pair of side frame members. The at least one trip actuation arm defining a tripping accessory engagement portion being adapted to receive a TRIP command from at least one tripping accessory of the MCCB, by way of engagement therebetween; and a trip bar engagement portion. Upon engagement of the tripping accessory engagement portion thereof with the at least one tripping accessory, the at least one trip actuation arm is adapted to be resiliently and slidably adjusted relative to at least one of the pair of side frame members, to enable the trip bar engagement portion of the at least one trip actuation arm to engage with the trip bar of the actuator assembly, to thereby cause tripping of the MCCB.

[0024] According to an aspect of the present disclosure the at least one trip actuation arm comprises a first trip actuation arm and a second trip actuation arm, the pair of side frame members comprise a first side frame member and a second side frame member, such that the first trip actuation arm is slidably installed on the first side frame member, and the second trip actuation arm is slidably installed on the second side frame member.

[0025] According to another aspect of the present disclosure each of the first and second side frame members include an actuator mounting rivet and an actuator stopper portion, such that the actuator mounting rivet slidably guides the first trip actuation arm and the second trip actuation arm on the first and second side frame members respectively, and the actuator stopper portion restricts a travel of the first trip actuation arm and the second trip actuation arm along the first and second side frame members respectively.

[0026] According to yet another aspect of the present disclosure the first trip actuation arm defines a first end portion, an intermediate portion and a second end portion, such that the first end portion extends along a same plane as that of the intermediate portion and the second end portion extends laterally from the intermediate portion.

[0027] According to yet another aspect of the present disclosure the first end portion defines a forkshaped protrusion, the intermediate portion defines a grooved section and the second end portion defines a cut-out section adapted to receive at least a portion of the first side frame member. According to yet another aspect of the present disclosure the intermediate end portion engages with the actuator mounting rivet of the first side frame member, enabling sliding motion of the first trip actuation arm relative to first side frame member, and the fork- shaped protrusion of the first end portion is adapted to engage with the actuator stopper portion of the actuating lever to restrict travel of the first trip actuation arm.

[0028] According to yet another aspect of the present disclosure the first trip actuation arm is connected to a first type of tripping accessory of the at least one tripping accessory to receive a tripping command thereof.

[0029] Still another aspect of the present disclosure is that the second trip actuation arm defines a first end portion, an intermediate portion and a second end portion, such that the first end portion extends along a same plane as that of the intermediate portion and the second end portion extends laterally from the intermediate portion.

[0030] According to an aspect of the present disclosure the first end portion defines a fork-shaped protrusion, the intermediate portion defines a grooved section and the second end portion defines a cut-out section adapted to receive at least a portion of the second side frame member.

[0031] According to another aspect of the present disclosure the intermediate end portion engages with the actuator mounting rivet of the second side frame member, enabling sliding motion of the second trip actuation arm relative to second side frame member, and the fork-shaped protrusion of the first end portion is adapted to engage with the actuator stopper portion of the actuating lever to restrict travel of the second trip actuation arm.

[0032] According to yet another aspect of the present disclosure the second actuation arm is connected to a second type of tripping accessory of the at least one tripping accessory to receive a tripping command thereof.

[0033] BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to explain the technical solution in the embodiments of the present disclosure more clearly, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only some embodiments of the present disclosure. For those skilled in the art, without any creative work, other drawings can be obtained based on these drawings. Figure 1 illustrates a perspective view of a moulded case circuit breaker (MCCB), in accordance with the concepts of the present disclosure.

[0035] Figure 2 illustrates an exploded view of an arrangement of an actuator assembly, three (3) pole assemblies, and a TRIP assembly, in accordance with the concepts of the present disclosure.

[0036] Figure 3a illustrates a perspective view of an arrangement of the actuator assembly and the three (3) pole assemblies, in accordance with the concepts of the present disclosure.

[0037] Figure 3b illustrates an exploded view of the arrangement of figure 3a, in accordance with the concepts of the present disclosure.

[0038] Figure 4a illustrates a first perspective view of the actuator assembly, in accordance with the concepts of the present disclosure.

[0039] Figure 4b illustrates a second perspective view of the actuator assembly of figure 4a, in accordance with the concepts of the present disclosure.

[0040] Figure 4c illustrates an exploded view of the actuator assembly of figure 4a, in accordance with the concepts of the present disclosure.

[0041] Figure 5 illustrates an enlarged sectional side view of the actuator assembly of figure 4a, in accordance with the concepts of the present disclosure.

[0042] Figure 6 illustrates a perspective view of an embodiment of at least one trip actuation arm of the actuator assembly, in accordance with the concepts of the present disclosure.

[0043] Figure 6a illustrates a perspective view of the at least one actuation arm of figure 6, in accordance with the concepts of the present disclosure.

[0044] DETAILED DESCRIPTION

[0045] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, that embodiments of the present invention may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only one of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Exemplified embodiments of the present invention are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.

[0046] Figure 1 shows a perspective view of a moulded case circuit breaker (MCCB)

[0100] , in accordance with the concepts of the present disclosure. FIG. 2 shows an exploded view of an arrangement between three pole assemblies

[0102] , an actuator assembly

[0112] , and TRIP assembly

[0114] of the MCCB

[0100] of FIG. 1, in accordance with the concepts of the present disclosure. Figures 1 and 2 should be referred to in conjunction with each other, in order to clearly understand the concepts of the present disclosure. The MCCB

[0100] is a low-voltage and high-current circuit breaker, employed to protect electrical networks / circuits from over-load or short-circuit conditions. The MCCB

[0100] is positioned between at least one load phase on a load side and at least one line phase on a line side, for providing protection during over-load or short-circuit conditions. The MCCB

[0100] operates between each of an ON position, an OFF position, and a TRIP position, wherein the MCCB

[0100] is manually adjusted between the ON position and the OFF position, whereas MCCB

[0100] is automatically adjusted to the BEOW OPEN position followed by TRIP position due to short-circuit fault at the line side or the load side of the MCCB

[0100] , In the ‘ON’ position, the MCCB

[0100] allows a flow of current therethrough. In the ‘OFF’ position, the MCCB

[0100] restricts the flow of current therethrough. In the each of the ‘BEOW OPEN’ position and the ‘TRIP’ position, the MCCB

[0100] restricts the flow of current therethrough.

[0047] Commonly, the MCCB

[0100] is a multipolar circuit breaker. Although, in the present disclosure the MCCB

[0100] is described as a three-pole circuit breaker, it may be obvious to a person ordinarily skilled in the art that the MCCB

[0100] may also be a single-pole circuit breaker, a four-pole circuit breaker, or a circuit breaker with any number of poles. The MCCB

[0100] includes three (3) pole assemblies

[0102] , a base assembly, a mid-cover assembly, a fascia plate assembly, an actuator assembly

[0112] , and a TRIP assembly

[0114] .

[0048] Each of the three pole assemblies

[0102] are independent units capable of protecting the electrical networks / circuits from over-load or short-circuit conditions. In particular, each of the three pole assemblies

[0102] transmits electric current from one of the line phases to one of the load phases, while providing protection from overcurrent or short-circuit. Each of the three pole assemblies

[0102] operate in each of the ‘ON’ position, the ‘OFF’ position, and the ‘TRIP’ position. Notably, the three pole assemblies

[0102] are connected together with one or more components of the actuator assembly

[0112] , to adjust each of the three pole assemblies

[0102] together between the ‘ON’ position, the ‘OFF’ position, and the ‘TRIP’ position. A structure and arrangement of the three pole assemblies

[0102] will be described later in detail.

[0049] The base assembly is a lower structure that provides a mounting base and support structure for holding and supporting each of the three pole assemblies

[0102] therein. In particular, the base assembly defines pole holding cavities to mount and support each of the three pole assemblies

[0102] therein. Notably, the three pole assemblies

[0102] are fixedly attached within the pole holding cavities defined by the base assembly by conventionally known attachment means.

[0050] The mid-cover assembly is an upper structure that is engaged with the base assembly, to at least partially cover the three pole assemblies

[0102] and protect the same from external environment. The mid-cover assembly is usually fittingly engaged with the base assembly, to at least partially cover the three pole assemblies

[0102] and protect the same from external environment.

[0051] The fascia plate assembly is fittingly mounted on the mid-cover assembly, to cover the midcover assembly. The fascia plate assembly defines portions to define electrical parameters related to MCCB

[0100] . Notably, the fascia plate assembly defines a cavity to allow at least a portion of the actuator assembly

[0112] to extend therethrough, such that the portion of the actuator assembly

[0112] is accessible to a user to manipulate the actuator assembly

[0112] between an ON position and an OFF position.

[0052] A structure and arrangement of one of the three (3) pole assemblies

[0102] will be described in detail hereinafter. Similar structure and arrangement of the remaining pole assemblies

[0102] may be envisioned. Although, the present disclosure is described as applied to the pole assembly

[0102] of single break contact type assembly, it may be obvious to a person skilled in the art that the concepts of the present disclosure may also extend to the pole assembly

[0102] of multiple break contact type assembly. The pole assembly

[0102] includes a cassette casing unit, a stationary contact unit, a rotary contact unit, and an arc chute unit.

[0053] The cassette casing unit houses and supports the stationary contact unit, the rotary contact unit, and the arc chute unit of the pole assembly

[0102] . In particular, the cassette casing unit defines various dedicated sections for housing and supporting the stationary contact unit, the rotary contact unit, and the arc chute unit of the pole assembly

[0102] .

[0054] The stationary contact unit is an electric contact plate structure that may be positioned within a defined portion in the cassette casing unit. In particular, in complete assembly of the MCCB

[0100] , the electrical wires from the line side are usually connected to the stationary contact unit. The rotary contact unit is a moving structure that engages / disengages with the stationary contact unit, to allow / restrict the flow of electric current therethrough. The rotary contact unit is rotatably positioned within a defined portion in the cassette casing unit, and is provided to connect to electrical wires from the load side. Further, the rotary contact unit is rotatably adjusted while being positioned within the cassette casing unit, to make / release a contact relative to the stationary contact unit, in order to allow / restrict the flow of electric current therebetween. Notably, the rotary contact unit makes a contact relative to the stationary contact unit to allow the flow of electric current (the ‘ON’ position), the rotary contact unit releases a contact relative to the stationary contact unit, to restrict the flow of electric current (the ‘OFF’ position). Additionally, the rotary contact unit is adjusted without rotation, to release a contact relative to the stationary contact unit, to restrict the flow of electric current (the ‘BLOW OPEN’ position).

[0055] The arc chute unit is positioned within a defined portion in the cassette casing unit and comprises of a two-wall shaped arc chute holder member and an arc chute member. The arc chute holder member and an arc chute member are arranged together, to vent out gases generated by an arc caused due to engagement / disengagement of the rotary contact unit relative to the stationary contact unit through a vent channel.

[0056] Figures 4a and 4b illustrate a first and second perspective views of the actuator assembly

[0112] , respectively, while figure 4c illustrates an exploded view of the actuator assembly

[0112] , and figure 5 illustrates an enlarged sectional view of the actuator assembly

[0112] , in accordance with the concepts of the present disclosure. Figures 4a, 4b, 4c, and 5 are to be viewed in conjunction with each other, in order to better understand the concepts of the present disclosure.

[0057] The actuator assembly

[0112] is a multi-part assembly mounted on one of the pole assemblies

[0102] . The actuator assembly

[0112] connects together the three pole assemblies

[0102] , such that the three pole assemblies

[0102] are adjusted together between the ON position, the OFF position, and the TRIP position corresponding to command transmitted by the actuator assembly

[0112] . The actuator assembly

[0112] includes a manual lever that may be manually adjusted to adjust the three pole assemblies

[0102] together between the ON position, the OFF position. In particular, the manual lever of the actuator assembly

[0112] may be manipulated, to adjust the three pole assemblies

[0102] together from the ON position to the OFF position and vice versa. Moreover, one or more of the three pole assemblies

[0102] may be adjusted to the BLOW OPEN position, during short-circuit conditions. Additionally, TRIP assembly

[0114] is mounted and supported on one of the three pole assemblies

[0102] such that the TRIP assembly

[0114] triggers the actuator assembly

[0112] to adjust the three pole assemblies

[0102] together from the BLOW OPEN position to the TRIP position. Further, the manual lever of the actuator assembly

[0112] may be manipulated to reset the three pole assemblies

[0102] together from the TRIP position to the OFF position. A structure and arrangement of the actuator assembly

[0112] will be described hereinafter in detail.

[0058] Referring to figure 4c, the actuator assembly

[0112] comprises a trip bar

[0122] , a pair of side frame members

[0124] , an operating mechanism, a tripping actuation arrangement

[0200] , and a latching mechanism

[0128] . The trip bar

[0122] defines a flange section [122a] on either ends thereof. The operating mechanism comprises an actuating lever

[0126] adjustably manipulated to manipulate the MCCB

[0100] among the ON position, the OFF position, the TRIP position, and the RESET position. Notably, the actuating lever

[0126] comprises an actuator stopper portion [126a] and a pivot cut-out portion [126b] on either side thereof. The latching mechanism

[0128] comprises a latching pin [128a] and a latching means [128b], wherein the latching means [128b] is adapted to latch the latching pin [128a] thereto, and release the latching pin [128a] therefrom, upon tripping of the MCCB

[0100] . The pair of side frame members

[0124] includes a first side frame member [124a] and a second side frame member [124b]. Each of the first and second side frame members [124a, 124b] includes an actuator mounting rivet [124c] and an actuator pivoting rivet [124d]. Notably, the actuator mounting rivet [124c] of each of the first and second frame members [124a, 124b] is adapted to slidably guide the tripping actuation arrangement

[0200] on the first and second side frame members [124a, 124b]. While the actuator stopper portion [126a] of the actuating lever

[0126] is adapted to restrict travel of the tripping actuation arrangement

[0200] along the first and second side frame members [124a, 124b], and the actuator pivoting rivet [124d] is adapted to enable pivotal mounting of the actuating lever

[0126] . The pivot cut-out portion [126b] of the actuating lever

[0126] rests on the actuator pivoting rivet [124d] of the pair of side frame members

[0124] , enabling pivoting motion of the actuating lever

[0126] . A structure and arrangement of the latching mechanism and the operating mechanism is known to a person skilled in the art, and therefore, the details of the same are not repeated herein for sake of brevity. A structure and arrangement of the tripping actuation arrangement

[0200] will be described hereinafter in detail.

[0059] Notably, as seen in figures 4a and 4b, the tripping actuation arrangement

[0200] comprises at least one trip actuation arm

[0202] adapted to trip the MCCB

[0100] . Particularly, the least one trip actuation arm

[0202] is adapted to pivotally manipulate the trip bar

[0122] , to release the latching pin [128a] from the latching means [128b], thereby manipulating the MCCB

[0100] to the TRIP position thereof. The at least one trip actuation arm

[0202] is resiliently and slidably installed on at least one of the pair of side frame members

[0124] , the at least one trip actuation arm

[0202] . The at least one trip actuation arm

[0202] defines a tripping accessory engagement portion [204f, 206f] being adapted to receive a TRIP command from at least one tripping accessory of the MCCB

[0100] , by way of engagement therebetween, and a trip bar engagement portion [204h, 206h]. More particularly, the second end portion [204c, 206c] of the first and second trip actuation arms [204, 206] includes the tripping accessory engagement portion [204f, 206f] and the trip bar engagement portion [204h, 206h]. Upon engagement of the tripping accessory engagement portion [204f, 206f] thereof with the at least one tripping accessory, the at least one trip actuation arm

[0202] is adapted to be resiliently and slidably adjusted relative to at least one of the pair of side frame members

[0124] , to enable the trip bar engagement portion [204h, 206h] of the at least one trip actuation arm

[0202] to engage with the trip bar

[0122] of the actuator assembly

[0112] , to thereby cause tripping of the MCCB

[0100] .

[0060] The at least one trip actuation arm

[0202] includes a first trip actuation arm

[0204] and a second trip actuation arm

[0206] , such that the first trip actuation arm

[0204] is installed on the first side frame member [124a], while the second trip actuation arm

[0206] is installed on the second side frame member [124b]. In particular, the arrangement of first and second trip actuation arms [204, 206] on the first and second side frame members [124a, 124b] respectively is such that the first and second trip actuation arms [204, 206] are slidably guided along the first and second side frame members [124a, 124b], by means of the actuator mounting rivet [124c] of each of the first and second side frame members [124a, 124b], respectively.

[0061] In an embodiment, the first trip actuation arm

[0204] is connected to a first type of tripping accessory, particularly, a thermal tripping accessory, to enable thermal tripping of the MCCB

[0100] . More particularly, the first trip actuation arm

[0204] is adapted to enable manipulation of the MCCB

[0100] to the TRIP position thereof, in the event of a thermal overload fault condition. In the said embodiment, the second trip actuation arm

[0206] is connected to a second type of tripping accessory, to enable magnetic tripping of the MCCB

[0100] . More particularly, the second trip actuation arm

[0206] is adapted to enable manipulation of the MCCB

[0100] to the TRIP position thereof, in the event of an overcurrent fault condition, by magnetic release. Notably, each of the first and second trip actuation arms [204, 206] function independently of the other. In an alternate embodiment, the first trip actuation arm

[0204] is adapted to enable magnetic tripping of the MCCB

[0100] , while the second trip actuation arm

[0206] is adapted to enable thermal tripping of the MCCB

[0100] . A structure and arrangement of the first trip actuation arm

[0204] of the tripping actuation unit

[0200] will be described hereinafter in detail. The first trip actuation arm

[0204] defines a first end portion [204a], an intermediate portion [204b], and a second end portion [204c]. The intermediate portion [204b] of the first trip actuation arm

[0204] is adapted to engage with the actuator mounting rivet [124c] of the first side frame member [124a], such that a slidable motion of the actuator mounting rivet [124c] along the first side frame member [124a], corresponds to a slidable motion of the first trip actuation arm

[0204] . Additionally, the intermediate portion [204b] defines a grooved section [204f]. The second end portion [204c] extends laterally from the intermediate portion [204b], and defines a cut-out section [204d] adapted to receive at least a portion of the first side frame member [124a] therein. The first end portion [204a] extends from the intermediate portion [204b] along the same plane as that of the intermediate portion [204b]. Notably, the first end portion [204a] defines a fork-shaped protrusion [204e], wherein the fork-shaped protrusion [204e] is adapted to engage with the actuator stopper portion [126a] of the actuating lever

[0126] , to thereby restrict travel of the first trip actuation arm

[0204] along the first side frame member [124a].

[0062] In particular, upon actuation of the first trip actuation arm

[0204] , the actuator mounting rivet [124c] engages with the flange section [122a] of the trip bar

[0122] , thereby pivotally manipulating the trip bar

[0122] , to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof. A structure and arrangement of the second trip actuation arm

[0206] of the trip actuating unit

[0200] will be described hereinafter in detail.

[0063] The second trip actuation arm

[0206] defines a first end portion [206a], an intermediate portion [206b], and a second end portion [206c]. The intermediate portion [206b] of the second actuation arm

[0206] is adapted to engage with the actuator mounting rivet [124c] of the second side frame member [124b], such that a slidable motion of the actuator mounting rivet [124c] along the second side frame member [124b], corresponds to a slidable motion of the second trip actuation arm

[0206] . Additionally, the intermediate portion [206b] defines a grooved section [206f]. The second end portion [206c] extends laterally from the intermediate portion [206b], and defines a cut-out section [206d] adapted to receive at least a portion of the second side frame member [124b] therein. The first end portion [206a] extends from the intermediate portion [206b] along the same plane as that of the intermediate portion [206b]. Notably, the first end portion [206a] defines a fork-shaped protrusion [206e], wherein the fork-shaped protrusion [206e] is adapted to engage with the actuator stopper portion [126a] of the actuating lever

[0126] , to thereby restrict travel of the second trip actuation arm

[0206] along the second side frame member [124b]. In particular, upon actuation of the second trip actuation arm

[0206] , the actuator mounting rivet [124c] engages with the flange section [122a] of the trip bar

[0122] , thereby pivotally manipulating the trip bar

[0122] , to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof.

[0064] Each of the first and second trip actuation arms [204, 206] may be in connection with one or more tripping accessory devices employed in the MCCB

[0100] to facilitate tripping thereof, such as, but not limited to a thermal and magnetic tripping unit (TMTU), an undervoltage or shunt tripping device, an automatic magnetic (AMT) tripping or resetting device, an FSD tripping or resetting device, and the like. Various embodiments of the present invention encompassing the aforementioned feature will be described hereinafter in brief.

[0065] Referring to figures 6 and 6a, an embodiment of the at least one trip actuation arm

[0202] is depicted, the embodiment will be explained with reference to the second trip actuation arm

[0206] . A person skilled in the art may envision the embodiment for the first trip actuation arm

[0204] . The second trip actuation arm

[0206] defines the first end portion [206a], the intermediate portion [206b], and the second end portion [206c]. The intermediate portion [206b] of the second actuation arm

[0206] is adapted to engage with the actuator mounting rivet [124c] of the second side frame member [124b], such that a slidable motion of the actuator mounting rivet [124c] along the second side frame member [124b], corresponds to a slidable motion of the second trip actuation arm

[0206] . Additionally, the intermediate portion [206b] defines a grooved section [206f]. The second end portion [206c] extends laterally from the intermediate portion [206b], and defines a cut-out section [206d] adapted to receive at least a portion of the second side frame member [124b] therein. The first end portion [206a] extends from the intermediate portion [206b], along the same plane as that of the intermediate portion [206b]. Notably, the first end portion [206a] defines a fork-shaped protrusion [206e] and an extension [206i] . The fork-shaped protrusion [206e] is adapted to engage with the actuator stopper portion [126a] of the actuating lever

[0126] , to thereby restrict travel of the second trip actuation arm

[0206] along the second side frame member [124b]. The extension [206i] defines a slot [206j], wherein the slot [206j] is adapted to slidably engage with the actuator pivoting rivet [124d]. The slot [206j] with its relative arrangement with the actuator pivoting rivet [124d] aids in improved guiding of the second trip actuating arm

[0206] preventing any tilting of thereof. Further, the relative arrangement between the slot [206j] and the actuator pivoting rivet [124d] prevents any loss of stroke of the second trip actuating arm

[0206] during resetting and tripping. In particular, upon actuation of the second trip actuation arm

[0206] , the actuator mounting rivet [124c] engages with the flange section [122a] of the trip bar

[0122] , thereby pivotally manipulating the trip bar

[0122] to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof.

[0066] In an embodiment, each of the second end portions [204c, 206c] of the first and second trip actuation arms [204, 206] are in connection with the TMTU (not shown). In such an embodiment, a TRIP command by the TMTU actuates each of the first and second trip actuation arms [204, 206], thereby pivotally manipulating the trip bar

[0122] , to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof.

[0067] In an embodiment, each of the intermediate portions [204b, 206b] of the first and second trip actuation arms [204, 206] are in connection with the AMT tripping or resetting device (not shown). In such an embodiment, a TRIP command by the AMT tripping or resetting device actuates each of the first and second actuation arms [204, 206], thereby pivotally manipulating the trip bar

[0122] , to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof.

[0068] In an embodiment, the intermediate portion [204b] of the first trip actuation arm

[0204] is in connection with the shunt tripping device (not shown), such that the shunt tripping device engages with the grooved section [204f] of the intermediate portion [204b]. In such an embodiment, a TRIP command by the shunt tripping device actuates the first trip actuation arm

[0204] , thereby pivotally manipulating the trip bar

[0122] , to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof.

[0069] In an embodiment, the intermediate portion [206b] of the second trip actuation arm

[0206] is in connection with the FSD tripping or resetting device (not shown), such that the FSD tripping or resetting device engages with the grooved section [206f] of the intermediate portion [206b]. In such an embodiment, a TRIP command by the FSD tripping or resetting device actuates the second trip actuation arm

[0206] , thereby pivotally manipulating the trip bar

[0122] , to further disengage the latching pin [128a] from the latching means [128b], and thus, manipulate the MCCB

[0100] to the TRIP position thereof.

[0070] In another embodiment, each of the second end portions [204c, 206c] of the first and second trip actuation arms [204, 206] are in connection with the TMTU (not shown), while each of the intermediate portions [204b, 206b] of the first and second trip actuation arms [204, 206] are in connection with the AMT tripping or resetting device (not shown). Further, in the said embodiment, the intermediate portion [204b] of the first trip actuation arm

[0204] is in connection with the shunt tripping device (not shown), such that the shunt tripping device engages with the grooved section [204f] of the intermediate portion [204b]. In addition to the above, the intermediate portion [206b] of the second trip actuation arm

[0206] is in connection with the FSD tripping or resetting device (not shown), such that the FSD tripping or resetting device engages with the grooved section [206f] of the intermediate portion [206b]. In such embodiment, the tripping of the MCCB

[0100] may be facilitated by the TMTU, the AMT tripping or resetting device, the shunt tripping device, the undervoltage tripping device and the FSD tripping or resetting device, either alone or in combinations thereof.

[0071] In operation, in the event of any fault condition such as, but not limited to thermal overload, overcurrent, and undervoltage, one or more of the tripping accessory devices provide a TRIP command to the first trip actuation arm

[0204] and the second trip actuation arm

[0204] , thereby actuating the first and second trip actuation arms [204, 206]. Upon actuation, the slidable motion of the first and second trip actuation arms [204, 206] is translated to the slidable motion of the actuator mounting rivet [124c]. The actuator mounting rivet [124c] engages with the flange section [122a] defined on either ends of the trip bar

[0122] , thereby causing pivotal manipulation of the trip bar

[0122] . Notably, the pivotal manipulation of the trip bar

[0122] corresponds to the disengagement of the latching pin [128a] from the latching means [128b], thereby causing manipulation of the MCCB

[0100] to the TRIP position thereof.

[0072] Various advantages of the tripping actuation arrangement

[0200] as disclosed in the present invention exist. One such advantage is reduced number of components, which further reduces part-to-part variation, thereby ensuring efficiency and eliminating the problem of nuisance tripping in the existing MCCBs. Another advantage is that the tripping actuation arrangement

[0200] is adaptive, such that the tripping actuation arrangement

[0200] facilitates connection of multiple tripping accessory devices therewith. Yet another advantage is the sturdy structure of the trip actuating unit

[0200] capable of withstanding any lateral movement thereof.

[0073] While the preferred embodiments of the present invention have been described hereinabove, it should be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention. It will be obvious to a person skilled in the art that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.

[0074] LIST OF COMPONENTS

[0075] 100 - Moulded case circuit breaker (MCCB)

[0076] 102 - Pole assembly

[0077] 112 - Actuator assembly

[0078] 114 - Trip assembly

[0079] 122 - Trip bar

[0080] 122a - Flange section

[0081] 124 - Pair of side frame members

[0082] 124a - First side frame member

[0083] 124b - Second side frame member

[0084] 124c - Actuator mounting rivet

[0085] 124d - Actuator pivoting rivet

[0086] 126 - Actuating lever

[0087] 126a - Actuator stopper portion

[0088] 126b - Pivot cut out portion

[0089] 128 - Latching mechanism

[0090] 128a - Latching pin

[0091] 128b - Latching means

[0092] 200 - Tripping actuation arrangement

[0093] 202 - Trip actuation arm

[0094] 204 - First trip actuation arm a - First end portion b - Intermediate portion c - Second end portion d - Cut-out section e - Fork-shaped protrusion f - Grooved section / Tripping accessory engagement portionh - Tripping bar engagement portion - Second trip actuation arm a - First end portion b - Intermediate portion c - Second end portion d - Cut-out section e - Fork-shaped protrusion f - Grooved section / Tripping accessory engagement portionh - Tripping bar engagement portion i - Extension j - Slot

Claims

We Claim:

1. A tripping actuation arrangement [200] for an actuator assembly [112] of a molded case circuit breaker [100], the actuator assembly [112] comprising a trip bar [122] and a pair of side frame members [124], the tripping actuation arrangement [200] comprising: at least one trip actuation arm [202] resiliently and slidably installed on at least one of the pair of side frame members [124], the at least one trip actuation arm [202] defining: o a tripping accessory engagement portion [204f, 206f] being adapted to receive a TRIP command from at least one tripping accessory of the MCCB [100], by way of engagement therebetween; and o a trip bar engagement portion [204h, 206h], wherein upon engagement of the tripping accessory engagement portion [204f, 206f]thereof with the at least one tripping accessory, the at least one trip actuation arm [202] is adapted to be resiliently and slidably adjusted relative to at least one of the pair of side frame members [124], to enable the trip bar engagement portion [204h, 206h] of the at least one trip actuation arm [202] to engage with the trip bar [122] of the actuator assembly [112], to thereby cause tripping of the MCCB [100].

2. The tripping actuation arrangement [200] as claimed in claim 1, wherein the at least one trip actuation arm [202] comprises a first trip actuation arm [204] and a second trip actuation arm [206], the pair of side frame members [124] comprise a first side frame member [124a] and a second side frame member [124b], such that the first trip actuation arm [204] is slidably installed on the first side frame member [124a], and the second trip actuation arm [206] is slidably installed on the second side frame member [124b].

3. The tripping actuation arrangement [200] as claimed in claim 1 or 2, wherein each of the first and second side frame members [124a, 124b] includes an actuator mounting rivet [124c], an actuator pivoting rivet [124d], and an actuator stopper portion [126a], such that the actuator mounting rivet [124c] slidably guides the first trip actuation arm [204] and the second trip actuation arm [206] on the first and second side frame members [124a, 124b] respectively, and the actuator stopper portion [126a] restricts a travel of the first trip actuation arm [204] and the second trip actuation arm [206] along the first and second side frame members [124a, 124b] respectively.

4. The tripping actuation arrangement [200] as claimed in claim 1 or 2, wherein the first trip actuation arm [204] defines a first end portion [204a], an intermediate portion [204b] and a second end portion [204c], such that the first end portion [204a] extends along a same plane as that of the intermediate portion [204b] and the second end portion [204c] extends laterally from the intermediate portion [204b].

5. The tripping actuation arrangement [200] as claimed in claim 4, wherein the first end portion [204a] defines a fork-shaped protrusion [204e], the intermediate portion [204b] defines a grooved section [204f] and the second end portion [204c] defines a cut-out section [204d] adapted to receive at least a portion of the first side frame member [124a].

6. The tripping actuation arrangement [200] as claimed in any of the claims 1 to 5, wherein the intermediate end portion [204b] engages with the actuator mounting rivet [124c] of the first side frame member [124a], enabling sliding motion of the first trip actuation arm [204] relative to first side frame member [124a], and the fork-shaped protrusion [124e] of the first end portion [204a] is adapted to engage with the actuator stopper portion [126a] of the actuating lever [126] to restrict travel of the first trip actuation arm [204].

7. The tripping actuation arrangement [200] as claimed in any of the claims 1 to 6, wherein the first trip actuation arm [204] is connected to a first type of tripping accessory of the at least one tripping accessory to receive a tripping command thereof.

8. The tripping actuation arrangement [200] as claimed in claim 1 or 2, wherein the second trip actuation arm [206] defines a first end portion [206a], an intermediate portion [206b] and a second end portion [206c], such that the first end portion [206a] extends along a same plane as that of the intermediate portion [206b] and the second end portion [206c] extends laterally from the intermediate portion [206b].

9. The tripping actuation arrangement [200] as claimed in claim 8, wherein the first end portion [206a] defines a fork-shaped protrusion [206e], the intermediate portion [206b] defines a grooved section [206f] and the second end portion [206c] defines a cut-out section [206d] adapted to receive at least a portion of the second side frame member [124b].

10. The tripping actuation arrangement [200] as claimed in any of the claims 1, 2, 8 and 9, wherein the intermediate end portion [206b] engages with the actuator mounting rivet [124c] of the second side frame member [124b], enabling sliding motion of the second trip actuation arm [206] relative to second side frame member [124b], and the fork-shaped protrusion[124e] of the first end portion [206a] is adapted to engage with the actuator stopper portion[126a] of the actuating lever [126] to restrict travel of the second trip actuation arm [206].

11. The tripping actuation arrangement [200] as claimed in any of the claims 1, 2, and 8 to 10, wherein the second actuation arm [206] is connected to a second type of tripping accessory of the at least one tripping accessory to receive a tripping command thereof.

12. The tripping actuation arrangement [200] as claimed in any of claim 3 or 9, wherein the first end portion [206a] defines an extension [206i] having a slot [206j], wherein the slot [206j] is adapted to slidably engage with the actuator pivoting rivet [124d].

Images