Claims:1. An auxiliary contact apparatus (1) for auxiliary contact changeover mechanism, the apparatus comprising:
an auxiliary contact adaptor (5);
an actuator link (15);
a coupler link (17);
a driver link (19)
wherein the auxiliary contact adaptor (5) operatively mounted on a pole shaft (4) of a circuit breaker;
wherein the auxiliary contact adaptor (5) operatively coupled to the actuator link (15); wherein the auxiliary contact adaptor (5) having a first operating link (23) and a second operating link (24), wherein the first operating link (23) is adapted for actuating the actuator link (15) in ON operation, the second operating link (24) is adapted for actuating the actuator link (15) in OFF operation;
wherein the coupler link (17) operatively coupled with the actuator link (15) at one end such that the actuator link (15) moves in substantially a vertical direction with about zero-degree angle; wherein the coupler link (17) operatively coupled with the driver link (19) at another end such that the driver link (19) being rotated according to the actuator link (15) movement;
wherein auxiliary contact adaptor (5) operatively coupled to an actuator link operating surface (28) of the actuator link (15), wherein the actuator link operating surface (28) adapted to be positioned inside a cradle compartment (27) such that the actuator link operating surface (28) is operatively coupled in between the first operating link (23) and the second operating link (24) of the auxiliary contact adaptor (5) during the circuit breaker racking from a test position to a connected position.

2. The apparatus as claimed in claim 1, wherein the actuator link (15) comprises a sliding arrangement for operatively coupling with the auxiliary contact apparatus (1).

3. The apparatus as claimed in claim 1, wherein the coupler link (17) is operatively coupled with the driver link (19) using a plurality of fasteners.

4. The apparatus as claimed in claim 1, wherein the auxiliary contact adaptor (5) is operatively mounted on a pole shaft (4) of a circuit breaker using the plurality of fasteners;

5. The apparatus as claimed in claim 1, wherein the apparatus is operatively mounted
on a cradle side plate (14) using the plurality of fasteners.

6. The apparatus as claimed in claims 3 or 4 or 5, wherein the plurality of fasteners is a plurality of screws.

7. The apparatus as claimed in claim 1, wherein the apparatus is adapted to be positioned outside of the cradle compartment (27).

8. The apparatus as claimed in claim 1, wherein the apparatus further comprises a rotary switch (2), an operating mechanism and a terminal box (3).

9. The apparatus as claimed in claim 8, wherein the rotary switch (2) comprises a substantially square shaped drive cam (20).

10. The apparatus as claimed in claim 1 or 9, wherein the driver link (19) is adapted for actuating the drive cam (20).

11. The apparatus as claimed in claim 1 or 8, wherein a plurality of termination wires (21) is adapted to be routed from the rotary switch (2) so as to contact to the terminal box (3) such that the terminal box is accessible by a user.

12. The apparatus as claimed in claim 1, wherein the actuator link (15) is operatively moved in a substantially upward direction when the auxiliary contact adaptor (5) is operatively moved in a clock wise direction during the circuit breaker ON condition.

13. The apparatus as claimed in claim 12, wherein the actuator link (15) is operatively moved in a substantially upward direction, the rotary switch (2) operatively converts a plurality of rotary switch contacts into a stage-2 from a stage-1.

14. The apparatus as claimed in claim 1, wherein the actuator link (15) is operatively moved in a substantially downward direction when the auxiliary contact adaptor (5) is operatively moved in an anti- clock wise direction during the circuit breaker OFF condition.

15. The apparatus as claimed in claim 12, wherein the actuator link (15) is operatively moved in a substantially downward direction, the rotary switch (2) operatively converts a plurality of rotary switch contacts into the stage-1 from the stage-2.

16. The apparatus as claimed in claim 15, wherein the plurality of rotary switch contacts are twelve.

17. The apparatus as claimed in claim 13 or 15 or 16, wherein the stage-1 comprises the contacts 1 to 6 are in NO condition and the contacts 7 to 12 are in NC condition.

18. The apparatus as claimed in claim 13 or 15 or 16, wherein the stage-2 comprises the contacts 1 to 6 are in NC condition and the contacts 7 to 12 are in NO condition.

19. The apparatus as claimed in claim 1, wherein the driver link (19) comprises a substantially square shaped slot, which is adapted for connecting to the drive cam (20). , Description:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to with electrical protection devices, and more particularly an external apparatus for auxiliary contact changeover mechanism.

BACKGROUND

[002] In industrial application, Air Circuit Breaker (ACB) is used in upstream device of protection immediate after transformer. Other switchgears like MCCBs, MCBs, fuses etc are used as a downstream device of protection. Air Circuit Breaker does not have to trip in each and every fault. ACB has to operate in the case when downstream devices fail to clear the fault. ACB is designed to carry, make and break the rated current as well as the fault current.

[003] Two types of circuit breakers are there one is fixed and other is draw- out. Draw out type Air Circuit breakers comprise of cradle assembly which used to carry breaker and can move and hold the breaker in four critical positions of any circuit breaker that is “connected”, “test”, “disconnected” and “maintenance”. These type of breakers offer flexibility for maintenance of the breaker without eliminating its termination.

[004] Fixed type of circuit breaker doesn’t have cradle assembly and supply and load is directly terminated with breaker terminals. These type of breakers don’t offer maintenance facility without opening termination of the breaker like draw out type.

[005] ACBs are installed in switchboard for various applications like Incomer application, feeder application and different load applications. Operation of right breaker at right time is mandatory in the power system which will help to avoid nuisance operation of the breaker and nuisance shut down of the plant. This can be implanted by using proper interlocking/operation logic between the installed breakers. For electrical interlocking and operation logics, the feedback regarding breaker ON-OFF condition is mandatory. Aux contacts of the breakers are used to give signal regarding breaker ON-OFF state. Additionally, in some critical applications it is required to blow alarm at the time of tripping of the breaker to alert the operators. This can be done by taking feedback from the aux contact regarding breaker ON-OFF status.

[006] US 7973622B2 (EP 2028674B1) entitled “Apparatus for auxiliary contact of circuit breaker” discloses the aux contact apparatus mounted on breaker body. The proposed apparatus is inbuilt in the breaker. With breaker ON-OFF operation, close/open axis (pole-shaft which drives all moving contacts) rotates. A drive rotation link is attached to the close/open axis(pole-shaft) permanently and it rotates along with the close/open axis. The rotation of drive rotation link converts its rotation into movement of the coupler link and coupler link drives “driven rotation link”. Coupler link is attached with two rotational components: drive rotation link and driven rotation link. Due to this type of connection, vertical travel of coupler link is inclined to vertical axis and not straight. This link drives the driving cam and rotation of driving cam operates ON-OFF switch by head on its profile. Thus ON/OFF switches installed at both the sides of driving cam and operated with the breaker ON-OFF operation. The stationary ON-OFF switches are used as a aux contacts. Not rotary switch contact. For NO and NC different ON-OFF switches have to be used at both the sides of the driving cam which actuates the switches simultaneously. The wire termination to be done inside the breaker in this invention and may offer space constraint for the user. There is no flexibility for the user to increase the aux contact at site as driving cam length to be change to increase the no. of aux contacts; which ask for modification in the mechanism apparatus.

[007] In the existing technology, aux contacts (25) are inbuilt part of the breaker and are operated according to the breaker pole shaft (4) rotation thru actuator spring (23). Actuator spring (23) pull or pushes the aux contact actuator (24) and actuate the clamp type aux contacts (25). Aux contacts (25) have to be assembled in the specified slots available in the mechanism top plate (26). There are 6 slots available to accommodate 6 Aux Contacts, out of which 2 dedicated aux contacts are used for inbuilt breaker accessories. Hence, only 4 aux contacts can be offered to the user for their interlocking and indication applications. Due to constraint in the breaker construction, accommodation of additional aux contact is not feasible within breaker and hence there is a need to develop an external apparatus for auxiliary contact changeover mechanism which can offer flexibility to the user to select no. of aux contacts as per their use by selecting different rotary switch and it is assembled outside the breaker compartment. With the present invention, user can increase or decrease the aux contacts as per the requirement.

SUMMARY
[008] This summary is provided to introduce concepts related to, an external apparatus for auxiliary contact changeover mechanism, and the same are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[009] The objective of the present invention is to solve the technical problems and problems associated with the existing technology. In the existing technology, due to constraint in the breaker construction increase in no. of aux contacts were not feasible within the breaker. In this situation, the customer has to connect external contactor and build the required logic for their applications which incurred in the additional cost to the user. To offer the flexibility to increase and decrease the aux contacts as per requirement, a new apparatus having aux contact actuating mechanism developed which operates standard rotary switch through operating mechanism. User will get the flexibility to select the current rating and no. of aux contact as per the requirement by replacing suitable rotary switch only. The present auxiliary contact apparatus is assembled on the cradle and outside the cradle compartment (27) which will not create any space related constraint. The apparatus includes rotary switch, operating mechanism and terminal box (3) on the same apparatus body.

[0010] According to one aspect of the invention, there is provided an auxiliary contact apparatus (1) for auxiliary contact changeover mechanism, the apparatus comprising: an auxiliary contact adaptor (5); an actuator link (15); a coupler link (17); a driver link (19) wherein the auxiliary contact adaptor (5) operatively mounted on a pole shaft (4) of a circuit breaker; wherein the auxiliary contact adaptor (5) operatively coupled to the actuator link (15); wherein the auxiliary contact adaptor (5) having a first operating link (23) and a second operating link (24), wherein the first operating link (23) is adapted for actuating the actuator link (15) in ON operation, the second operating link (24) is adapted for actuating the actuator link (15) in OFF operation; wherein the coupler link (17) operatively coupled with the actuator link (15) at one end such that the actuator link (15) moves in substantially a vertical direction with about zero-degree angle; wherein the coupler link (17) operatively coupled with the driver link (19) at another end such that the driver link (19) being rotated according to the actuator link (15) movement; wherein auxiliary contact adaptor (5) operatively coupled to an actuator link operating surface (28) of the actuator link (15), wherein the actuator link operating surface (28) adapted to be positioned inside a cradle compartment (27) such that the actuator link operating surface (28) is operatively coupled in between the first operating link (23) and the second operating link (24) of the auxiliary contact adaptor (5) during the circuit breaker racking from a test position to a connected position.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0011] The detailed description is described with reference to the accompanying figures. In the figures, the digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

[0012] Figure 1 illustrates existing technology of breaker Aux Contact Actuation mechanism; Aux contact (25) operates through Aux Contact spring (23) and Aux Contact Actuator (24)

[0013] Figure 2 illustrates draw-out breaker with three pole construction in racked-in condition (Arc chutes of 3 poles-9,10,11 is shown) with assembly of Aux Contact Actuation Apparatus with the cradle side plate and assembled with Aux Contact Adaptor with pole-shaft.

[0014] Figure 3 illustrates Aux Contact changeover apparatus where Actuator link is coupled with the Aux Contact Adaptor.

[0015] Figure 4 illustrates Aux Contact Adaptor screw mounting with the pole shaft.

[0016] Figure 5 illustrates working of Aux Contact Actuation Apparatus in breaker OFF condition.

[0017] Figure 6 illustrates working of Aux Contact Actuation Apparatus in breaker ON condition.

[0018] Figure 7 illustrates coupling of Actuator Link into the Aux Contact Adaptor in breaker Connected racked in position

[0019] Figure 8 illustrates Actuator link having the extended operating surface to allow the apparatus operation at any point between breaker connected to test position

[0020] It is to be understood that the attached drawings are for purposes of illustrating the concepts of the invention and may not be to scale.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0021] The following clearly describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

[0023] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components, modules, units and/or circuits have not been described in detail so as not to obscure the invention.

[0024] Although embodiments of the invention are not limited in this regard, the terms “plurality” and “a plurality” as used herein may include, for example, “multiple” or “two or more”. The terms “plurality” or “a plurality” may be used throughout the specification to describe two or more components, devices, elements, units, parameters, or the like. Unless explicitly stated, the method embodiments described herein are not constrained to a particular order or sequence. Additionally, some of the described method embodiments or elements thereof can occur or be performed simultaneously, at the same point in time, or concurrently.

[0025] Referring to figures 2,3 and 4, in circuit breaker, two types of contacts are there; 1. Fixed contact and 2. Moving contact. At the time ON operation, command received to the pole-shaft (4) from charged mechanism through pole shaft connector pin (12) and it drives the moving contact simultaneously with the help of pole-connectors (7). Moving contact travels towards fixed contact during breaker ON operation and make the contact. Pole-shaft (4) rotation can be detected to detect the breaker ON operation. This pole shaft (4) rotates in Direction-A with the constant angle rotation during each breaker ON operation.

[0026] Similarly, once the fault sensed and protection release initiate trip command, breaker mechanism drives pole-shaft (4) through pole-connector pin (12) and pole-shaft (4) drives moving contacts with the help of the pole connector pins (12). In trip/OFF operation of the breaker, pole shaft (4) rotates in Direction-B with the constant angle and all the moving contacts separate from the fixed contacts and trip the breaker.

[0027] By detecting the pole-shaft rotation; breaker ON-OFF can be sensed.

[0028] For draw-out type of ACB, Aux Contact Apparatus (1) is assembled on the cradle side plate (14) with the mounting screws. The apparatus along with rotary switch, operating mechanism and terminal box (3) are assembled on the outside of the cradle compartment (27). The apparatus is external accessory of the breaker. In the present invention, the apparatus is mounted outside the cradle compartment (27) in such a way that the Actuator link operating surface should be protruded inside the cradle compartment and gets coupled in between adaptor’s two operating links during breaker racking from Test to Connected position.

[0029] The Aux contact adaptor (5) assembled on the pole shaft (4) with the mounting screws (22) and it rotates along with the pole-shaft (4) rotation in both directions: Direction-A and Direction-B.

[0030] In draw-out type ACBs, user generally ensure the proper working of interlocking and indication in breaker test position to avoid any accident. Based on this requirement the apparatus (1) designed such that it can offer aux contact actuation at any point between breaker “Connected” to breaker “Test” condition.

[0031] The breaker has to be racked in the cradle to achieve ‘Test” and “Connected” position of the breaker. During racking-in of the breaker the Actuator Link (15) of Apparatus (1) comes between the Aux Contact Adaptor (5) operating links (23 & 24).

[0032] Referring to figures 5 and 6, the Aux Contact Adaptor (5) has two operating links (23 & 24) which actuates the Actuator link (15) of the Apparatus. One operating link (23) actuates Actuator link in breaker ON operation and other (24) will not be in use during ON operation. During breaker OFF operation, another operating link (24) will actuate the Actuator link (15) and another (23) will be unused. Each operating link (23 & 24) of an Aux Contact Adaptor operates apparatus mechanism individually in breaker ON & OFF operations. Hence, it is known as two coupling points actuation: In ON operation actuation occurs by one operating link (23) and in OFF operation actuation occurs by different operating link (24).

[0033] In the present invention, the adaptor (5) is mounted on breaker pole shaft and mechanism is assembled on the cradle and outside the cradle compartment which actuates the aux contact mechanism by coupling with the Actuator link operating surface (28) protruded inside the cradle compartment (27) by two operating links (23 & 24) protruded on the adaptor (5).

[0034] In the apparatus, the Actuator Link designed with extended operating surface to ensure apparatus operation in breaker Test, breaker Connected and at any point in-between these two positions as shown in the figure 8. The operation in these positions is achieved by Actuator link extended surface (28) and not by distinct interface mounted on mechanism. Operating surface of Actuator link (28) is extended such that it will be coupled with the Adaptor (5) in breaker Test, Connected and in between these two positions. It will not operate in breaker disconnected or maintenance condition.

[0035] The Actuator link gets coupled in between Adaptor operating links during racking of the breaker. The Adaptor automatically couples with the Actuator link during racking of the breaker as shown in figure 7.

[0036] Rotation of Aux Contact Adaptor (5) in Direction-A operates Actuator Link (15) in upward direction and rotation of Aux Contact Adaptor (5) in Direction-B operates Actuator link (15) in downward direction.

[0037] Referring to figure 6, travelling of Actuator link (15) in upward direction during breaker ON operation pulls the coupler link (17) in upward direction which converts into rotation of driver link (19). Because of square shaped drive cam (20) of rotary switch, driver link (19) rotates rotary switch (2) and it converts rotary switch contacts into stage-2 from stage-1.

[0038] Rotary contact used in this apparatus is 2 stage and the contact conditions are as below:

[0039] Stage:1- Contacts 1 to 6 are NO and Contacts 7 to 12 are NC

[0040] Stage:2- Contacts 1 to 6 become NC and Contacts 7 to 12 become NO

[0041] Referring to figure 5, travelling of Actuator link (15) in downward direction during breaker OFF operation forces the coupler link (17) in downward direction which converts into rotation of driver link (19). Driver link (19) rotation in opposite direction converts rotary switch (2) contacts into stage-1 from stage-2 during breaker OFF operation.

[0042] Designing of Actuator Link (15), Coupler Link (17) and Driver Link (19) is done in such a way that defined rotation of pole-shaft (4) during breaker ON and OFF condition will be converted into the defined rotation of rotary switch (2) to operate its contacts properly. The Actuator link of the invented apparatus couples with the breaker pole shaft thru Adaptor during breaker racking, from Test to Connected position. i.e. apparatus is not coupled permanently with the breaker pole shaft.

[0043] In the present invention, the driver link has screw mounted assembly with coupler link which drives the rotary switch cam according to the breaker operation. There is no over travel stoppers available on driver link.

[0044] The Actuator Link (15) is assembled on the apparatus mounting plate and it has free movement to travel in vertical direction. The coupler link (17) is assembled with the Actuator Link (15) to drive the driver link (19) according to the vertical movement of Actuator Link (15). Driver Link (19) has a square slot to drive the rotary switch drive cam. Thus finally pole shaft rotation due to breaker ON/OFF condition converts into the drive cam rotation of the rotary switch.

[0045] In the apparatus, pole shaft rotation is converted into vertical travel of Actuator link with zero-degree angle with the vertical axis through aux contact adaptor. The Operating link of adaptor exerts force on Actuator link to travel upward or downward in straight vertical direction during breaker operation.

[0046] In the present invention, any standard rotary switch can be used having same rotation angle and driver link will actuate the driving cam of the rotary switch according to the breaker ON OFF operation.

[0047] The Aux Contact Adaptor (5) is also designed in such a way that it actuates Actuator Link (15) in both the direction such that the Actuator Link (15) will drive the entire apparatus (1) in breaker ON and OFF condition.

[0048] Termination wires (21) are routed from rotary switch (2) contacts to terminal box (3) and this will offer front wire termination facility for the user.

[0049] The apparatus comprises of actuating mechanism, rotary switch and terminal box. Aux Contact wires are routed from rotary switch to terminal box assembled on the Aux Contact Mounting plate to provide easy access to the user. Terminal box is in front of the user which provides ease in wire termination for Aux Contacts. In the present invention, wire termination for aux contact apparatus made by standard connectors and assembled them on the same apparatus body in front of the user. Connectors can be selected by user based on current rating requirement.

[0050] Thus breaker ON-OFF operation feedback is converted into rotary switch (2) rotation through aux contact mechanism apparatus (1) and the user can be sensed the breaker ON/OFF status from the Terminal box(3) Connectors.

[0051] The advantages of the present invention is to offer additional NO-NC Aux Contacts assembled with the cradle but outside the cradle compartment and because of the use of rotary switch (2) in the apparatus (1), the user can use no. of aux contacts as per the requirement. Any standard rotary switch having same rotation angle with different no. of aux contacts can be assembled in the same mechanism and can be used for the required application.

[0052] The user can replace rotary switch (2) of 2,4,6,8 or 10 aux contacts in the apparatus without any modification of the apparatus mechanism at site to enhance no. of NO-NCs in the breaker.

[0053] The user can also enhance the current rating of the aux contact by selecting new rotary switch (2) having same rotation angle and can be used in the same apparatus (1) mechanism.

[0054] The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The external apparatus as described above does not limit the scope of the present invention. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

[0055] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0056] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.