DESC:TECHNICAL FIELD

The present invention relates generally to a circuit breaker and, particularly, to a construction of the circuit breaker of moulded case circuit breakers (MCCB) type which enables high current breaking and ease of assembly.

BACKGROUND

Circuit Breaker is a mechanical switching device capable of making, carrying and breaking currents. Under normal circuit conditions it will make the circuit, carry current for a specified time and break the circuit under specified abnormal circuit conditions.

Circuit Breakers are employed for current interruption. More particularly Circuit Breakers are utilized to protect instruments from damage during adverse conditions prevailing during the operation of the circuit in which circuit breaker is employed. During adverse conditions like short circuit, the current rises to an alarmingly high level. This high current may cause damage to the parts in the electrical system. Hence during these conditions the circuit has to be opened to protect the system.

A circuit breaker can be manually opened and closed, as well as automatically opened to protect conductors or equipments from damage caused by excessive heating due to over current in abnormal conditions such as overload or short-circuit.

Switching devices like, molded case circuit breaker operating on the current limiting principle typically have a pair of solid stationary Electrical contacts joined by a solid moving Electrical contact, which provides a path to carry the electrical current in the network.

The pole of a circuit breaker consists of a rotor assembly, fixed electrical contact assembly, arc quenching chamber, and a vent outlet.

Rotor construction enables the design of double break arrangement that helps in the better make and break under normal and abnormal conditions involving very high over-currents. It consists of the moving electrical contact and provisions for providing the contact pressure so as to provide the intended repulsion threshold as well as to keep the temperature rise within allowable limit set by the relevant product standards under normal working condition. The Switching device should interrupt the over current arising due to abnormal conditions in the network, as rapidly as possible to minimize damage caused by thermal and mechanical stresses to the equipment installed downstream.

Fixed electrical contact assembly provides the path to carry the electrical current while the circuit breaker is in the on position.

The arc quenching chamber consists of deion plates stacked up that helps in the pulling, lengthening and hence the quenching of arc. Fast quenching of arc is very essential for the performance of the circuit breaker and the stability of the system.

The vent outlet provides the provision for letting out the gaseous products formed due to the arcing. Venting plays a major role in controlling the gas pressure inside the pole and hence the effectiveness of fault clearing.

Traditionally there are various circuit breakers available in the market today. In the prior-art document US 7116194 discloses an electric pole for a low-voltage power circuit breaker. Similarly, in the prior-art document US 5298874 discloses a modular low voltage multi-pole circuit breaker. Further, the prior-art document US 6933814 discloses a molded case, cassette type circuit breaker for a multi-pole electrical distribution circuit includes a number of cassettes equal to the number of poles in the multi-pole electrical distribution circuit and a pin disposed through each cassette.

However, the proposed solutions in the cited prior-art documents and the traditionally available circuit breakers / MCCB’s have certain drawbacks that may include but not limited to:
1) Loosely held contacts that result in variation of resistance and causes abnormal temperature rise.
2) Tightly held rotors/couplers in order to maintain centering of rotors which results in high friction while operation.
3) Parallel arrangement of deion plates which result in abnormal pressure build up.
4) Two or more components for accessory actuation and venting which results in complicated assembly process.

Thus, with respect to the above mentioned drawbacks, there exists a need to provide a robust circuit breaker construction as a solution to the above mentioned drawbacks and to provide double break, and ensure ease of assembly and enhance current breaking.

SUMMARY

This summary is provided to introduce concepts related to an improved double-break low voltage circuit breaker construction for high current breaking. 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.

In one implementation, a robust circuit breaker construction as a solution to the above mentioned drawbacks and to provide double break, and ensure ease of assembly and enhance current breaking is provided.

In one implementation, the proposed MCCB ensures the reduction in the variation of resistance of the current path during the normal operation as well as after the fault clearing by the circuit breaker by providing ribs on cassette for proper fixing of electrical contacts which restricts the movement of the contacts in the breaker.

In one implementation, the proposed MCCB ensures smooth rotation of rotor assembly by providing slots in the rotor region of cassette that acts as a pocket for accumulating the arc products entering in to the rotor region to prevent the rotor jamming.

In one implementation, the proposed MCCB ensures proper routing of gases through non parallel arrangement of deion plates guiding the gases to the vent area.

In one implementation, the proposed MCCB ensures proper centering of rotor assembly by coupling mechanism to the rotor through a y- shaped link which is an integral part of the mechanism.

In one implementation, the proposed MCCB ensures proper placement of mechanism with respect to the poles through the feature provided in the cassette wall that restricts the movement of mechanism.

In one implementation, the proposed MCCB eliminates unnecessary components in the breaker by developing a single component for aux actuation.

In one implementation, the proposed MCCB provisions are provided for the interchangeability of poles for different current ratings.

Accordingly, in one implementation, a moulded case circuit breakers (MCCB) is disclosed. The MCCB comprises of at least one pole assembly (1); at least one release assembly (2); at least one mechanism assembly (3); a termination (4); and at least one external periphery (5).

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most 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.

Figure 1 illustrates a cross sectional view of the new MCCB, is shown, in accordance with an embodiment of the present subject matter.

Figure 2 illustrates an isometric view of a pole is shown, in accordance with an embodiment of the present subject matter.

Figure 3 illustrates an exploded view of a pole is shown, in accordance with an embodiment of the present subject matter.

Figure 4 illustrates an isometric view of the fixed contact assembly is shown, in accordance with an embodiment of the present subject matter.

Figure 5 (a) illustrates an exploded view of the arc chute assembly and Figure 5 (b) illustrates a cross sectional view of the arc chute assembly, is shown, in accordance with an embodiment of the present subject matter.

Figure 6 (a) illustrates a cross sectional view of pole assembly and Figure 6 (b) illustrates a right view of the pole, is shown, in accordance with an embodiment of the present subject matter.

Figure 7 illustrates an isometric view of the mech-contact with a single pole, is shown, in accordance with an embodiment of the present subject matter.

Figure 8 illustrates an exploded view of assembly of mech-contact with 3 poles, is shown, in accordance with an embodiment of the present subject matter.

Figure 9 illustrates an insertion of spacers between the poles while stacking of poles, is shown, in accordance with an embodiment of the present subject matter.

Figure 10 (a) illustrates the assembly of AUX actuator to the mech-contact, is shown, in accordance with an embodiment of the present subject matter.

Figure 10 (b) illustrates the assembly of EOM actuator to the mech-contact, is shown, in accordance with an embodiment of the present subject matter.

Figure 10 (c) illustrates the guiding of AUX actuator in chassis, is shown, in accordance with an embodiment of the present subject matter.

Figure 10 (d) illustrates shows the position of AUX actuator in ON position, is shown, in accordance with an embodiment of the present subject matter.

Figure 10 (e) illustrates the position of AUX actuator in OFF position, is shown, in accordance with an embodiment of the present subject matter.

Figure 11 illustrates the insertion of the housing to the mech-contact, is shown, in accordance with an embodiment of the present subject matter.

Figure 12 (a) illustrates the insertion shows the assembly of chassis, is shown, in accordance with an embodiment of the present subject matter.

Figure 12 (b) illustrates the shows the chassis, is shown, in accordance with an embodiment of the present subject matter.

Figure 13 (a) illustrates the assembly of release, is shown, in accordance with an embodiment of the present subject matter.

Figure 13 (b) illustrates the assembly of cover on the release box, is shown, in accordance with an embodiment of the present subject matter.

Figure 13 (c) illustrates the assembly of nut retainer and nut to the release box, is shown, in accordance with an embodiment of the present subject matter.

Figure 14 illustrates the assembly of the accessories with the circuit breaker, is shown, in accordance with an embodiment of the present subject matter.

Figure 15 illustrates the assembly of extended knob to the circuit breaker, is shown, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

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.

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

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.

In the embodiments provided in the present application, it should be understood that the disclosed method, device, and data frame may be implemented in other manners. For example, the described device embodiments are merely exemplary. For example, the unit division is merely logical function division and can be other division in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features are negligible or not performed.

In one implementation, the present invention is related to an improved double-break low voltage circuit breaker construction for high current breaking.

In one implementation, a double-break low voltage circuit breaker construction for high current breaking is disclosed.

Accordingly, in one implementation, a moulded case circuit breakers (MCCB) is disclosed. The MCCB comprises of at least one pole assembly (1); at least one release assembly (2); at least one mechanism assembly (3); a termination (4); and at least one external periphery (5).

In one implementation, at least one pole assembly (1) comprises at least one electrical contact (6) that provides a path to carry an electrical current in the network and other components that ensures the efficient current breaking during the fault conditions.
In one implementation, at least one pole assembly (1) comprises at least one vent (7) that contains multiple circular openings (8) assembled in the slot provided in a cassette (15).

In one implementation, at least one pole assembly (1) comprises of a fixed contact assembly with at least one arc runner (9); at least one button (10) secured to the fixed electrical contact (11); and at least one rib (12, 13, 14) for proper constriction of said fixed contact assembly with respect to the cassette (15).

In one implementation, at least one pole assembly (1) comprises of a marking (19) to measure an over travel of rotor assembly with respect to the cassette (15); and a circular slot (20) with at least one feature (21) in the cassette (15) for collecting arc products.

In one implementation, said at least one mechanism assembly (3) is mounted onto a pole by inserting at least one screw (22) through at least one hole (23) thereby forming a mech-contact; and is coupled with said pole through a link (24), wherein a through pin (25) passes through the rotors of said at least one mechanism assembly (3) and the link.

In one implementation, the MCCB comprises an AUX actuator (32) indicating a status of said MCCB by actuating auxiliary contacts, wherein said AUX actuator (32) comprises a line (37) indicating the actuation level of AUX contacts.

In one implementation, the MCCB comprises housing (38), wherein said housing (38) forms a outer body of the MCCB, wherein the housing (38) is secured to said mech-contact through click fits (39) which gets engaged to said at least one mechanism assembly (3) pole packing screw (22) on one side and through screws on the other side which also joins said at least one release assembly (2, 40) and a chassis (41).

In one implementation, said at least one release assembly (2, 40) comprises a cover (44) enclosing a sensor assembly on at least one link (45), wherein, a mechanical joint is provided through at least one feature (46).

In one implementation, said at least one release assembly (2, 40) comprises a screw (47) is inserted to join a release acts as a joining means for securing said chassis (41) and said housing (38) to said mech-contact, and said termination (4) is done through nut retainers (48) which are replaceable to enable different types of termination. Nut retainer profile ensures the creep age required as specified in the relevant standards.

In one implementation, said at least one external peripheries (5) comprises a UV release (49), a shunt release (50) along with an actuator (51), an auxiliary contacts (52), a trip alarm (53), and a mechanism actuator (54).

In one implementation, the MCCB comprises an extended knob (55) to the MCCB to provide a locking for the front cover (56) which ensures a removal only if said MCCB indicates TRIP position.

In one implementation, the MCCB comprises an arc chute assembly, wherein said arc chute assembly comprises of a de-ion plates (16) made of mild steel attached to the support lining (17) made of glass polyester, and holders (18) that enables in the proper routing of an arc. Further, said arc chute assembly each de-ion plates (16) is inserted into the corresponding two or more slots provided in the lining and attached to it by crimping.

In one implementation, said arc chute assembly at least one bottom plates are arranged in a parallel fashion for enabling quick transition of arc to the quenching chamber and at least one top plates are arranged in an angular fashion to direct the arc products to the vent.

In one implementation, the figure 1 shows the cross sectional view of the MCCB. Pole assembly (1), release assembly (2), mechanism assembly (3) and termination (4) are modular in construction which enables the interchangeability as well as aid ease of assembly with the external peripheries (5) that forms the outer wall of the breaker.

In one implementation, figure 2 shows the isometric view of a pole 1 of the circuit breaker which constitutes the electrical contacts 6 that provides a path to carry the electrical current in the network and other components that ensures the efficient current breaking during the fault conditions.

In one implementation, figure 3 shows the exploded view of a pole. The vent (7) made of brass or any non magnetic material that contains multiple circular openings (8) is assembled in the slot provided in the cassette. This ensures the deionization of the gases formed during the arcing by cooling it. The cassettes are held together by the solid pins which get riveted.

In one implementation, figure 4 shows the pole with the fixed contact assembly that consists of the arc runner (9) and button (10) secured to the fixed electrical contact (11). The ribs (12), (13), (14) are provided for proper constriction of fixed contacts with respect to the cassette (15). Provisions are provided in the cassette to enable the assembly of a fixed contact assembly for a different current rating.

In one implementation, figure 5 shows the exploded view of the arc chute assembly that consists of de-ion plates (16) made of mild steel attached to the support lining (17) made of glass polyester. Each plate is inserted into the corresponding two or more slots provided in the lining and attached to it by crimping or by other means. The bottom plates are arranged in a parallel fashion for enabling quick transition of arc to the quenching chamber and the top (4) plates are arranged in an angular fashion to direct the arc products to the vent. It also consists of holders (18) that enables in the proper routing of arc.

In one implementation, figure 6 shows the pole assembly. Marking (19) is given to measure the over travel of rotor assembly with respect to the cassette. A circular slot (20) is provided in the cassette for the rotor assembly. Slot is given features (21) for collecting the arc products that enter into the rotor region which ensures the smooth rotation of rotor preventing the rotor jamming.

In one implementation, figure 7 shows the isometric view of the mech-contact with a single pole. Mechanism assembly (3) is mounted onto a pole by inserting the screws (22) through the holes (23). Mechanism is coupled with the pole through a link (24). The through pin (25) passes through the rotors of the (3) poles and the link. The link is riveted to the side plate (26) and the lower link (27). Hence the lower link drives the link which in turn rotates the rotor as per the movement of the knob (28).

In one implementation, figure 8 shows the exploded view of assembly of mech-contact with (3) poles. Poles are stacked together through the screws (22). The side plate which forms the outer boundary of the mechanism is restricted by the walls (29) of the poles nearby which make the assembly rigid.

In one implementation, figure 9 shows the insertion of spacers (30) between the poles while stacking of poles. This spacer ensures proper clearance between the cassettes so that the mechanism is not jammed between the poles while mech contact assembly. Cassette wall (31) acts as the spacer in the other side. The spacers also have features which are incorporated to maintain the creep age distance as per the relevant standards.

In one implementation, figure 10 shows the assembly of AUX actuator (32) to the mech-contact. It indicates the status of the breaker by actuating auxiliary contacts. The slot (33) provided gets engaged with the through pin (25) whereby the flat face (34) moves due to the cam connection formed and gives signal through the auxiliary contacts. It is guided during this motion by the ribs (35) provided in the chassis. The AUX actuator gives the indication only after the breaker is switched to OFF position as shown in the figure (10) (d) and it gives the indication even before the breaker is switched to ON position as shown in the figure (10) (c) during the operation of the circuit breaker. The line (37) is the actuation level of AUX contacts. A component of similar construction, EOM indicator is assembled onto the other side of the breaker which gives the indication of the breaker status for external accessories.

In one implementation, figure 11 shows the insertion of the housing (38) to the mech-contact. Housing forms the outer body of the circuit breaker. It is secured to the mech contact through click fits (39) which gets engaged to the (3) pole packing screw (22) on one side and through screws on the other side which also joins the release assembly (40) and chassis (41) to the mech contact.

In one implementation, figure (12) shows the assembly of chassis (41). It is connected to the poles through the screws (42) that are secured in the pole. The venting channel (43) is an integral part of the chassis which simplifies the assembly by reduction of components.

In one implementation, figure (13) shows the assembly of release (40). The cover (44) encloses the sensor assembly on the links (45) and provides a closed modular construction. The mechanical joint is done through the feature (46). The screw (47) inserted to join the release acts as a joining means for securing chassis and housing to the mech-contact as well. Termination is done through nut retainers (48) which are replaceable to enable different types of termination. Nut retainer profile ensures the creep age required as specified in the relevant standards.

In one implementation, figure (14) shows the assembly of the accessories- UV release (49) and shunt release (50) along with the actuator (51), auxiliary contacts (52) and trip alarm (53), mechanism actuator (54). All the accessories get assembled to the slot provided as shown.

In one implementation, figure (15) shows the assembly of extended knob (55) to the circuit breaker. This knob provides a locking for the front cover (56) which ensures its removal only if the circuit breaker mechanism indicates TRIP position.

Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features:

One feature for the invention is that, an enables modular design is disclosed.

Another feature of the invention is that, the proposed invention ensures the required contact pressure as well as helps in the detection of the exact travel loss of the rotor through mechanism coupling by providing over travel indication on rotor cover and cassette.

Another feature of the invention is that, using the proposed invention there is reduction in the variation of resistance of the current path during the normal operation as well as after the fault clearing by the circuit breaker by providing ribs on cassette for proper fixing of electrical contacts which restricts the movement of the contacts.

Another feature of the invention is that, the proposed invention ensures optimum pressure build up during fault clearing as well as proper deionization of gases by providing circular openings with diameter 3.2mm that accounts for 51.5% of the total vent area.

Another feature of the invention is that, the proposed invention ensures smooth rotation of rotor assembly by providing slots in the rotor region of cassette that acts as a pocket for accumulating the arc products entering in to the rotor region to prevent the rotor jamming.

Another feature of the invention is that, the proposed invention avoids the unnecessary delay in the assembly by enabling the insertion of nut for joining the chassis to the pole through an open slot provided even after the riveting of cassettes even if the insertion of nuts in the cassette was skipped during the pole assembly.

Another feature of the invention is that, the proposed invention ensures proper routing of gases through non parallel arrangement of deion plates guiding the gases to the vent area.

Another feature of the invention is that, the proposed invention ensures proper centering of rotor assembly by coupling mechanism to the rotor through a y- shaped link which is an integral part of the mechanism.

Another feature of the invention is that, the proposed invention ensures proper placement of mechanism with respect to the poles through the feature provided in the cassette wall that restricts the movement of mechanism.

Another feature of the invention is that, the proposed invention provides a special multi pole joining screw which is also used for mechanism mounting that minimizes the movement of the mechanism.

Another feature of the invention is that, the proposed invention has a housing that prevents the escape of gases and restricts the movement of AUX actuator and EOM indicator.

Another feature of the invention is that, the proposed invention has a provision for assembly of two under voltage/shunt relays which enables its simultaneous operation.

Another feature of the invention is that, the proposed invention ensures proper finger proofing of release electrical joining screws through chassis.

Another feature of the invention is that, the proposed invention has provisions for release assembly interlock with breaker operating position through front cover.

Another feature of the invention is that, the proposed invention elimination of components by developing a single component for aux actuation.

Another feature of the invention is that, the proposed invention has a provision provided for the interchangeability of poles for different current ratings.

Yet another feature of the invention is that, the proposed invention provides an integral venting channel in the chassis which reduces the number of components and ensures ease of assembly.

Yet another feature of the invention is that, the proposed invention provides an extended knob provides front cover locking by preventing the removal of front cover when the circuit breaker is in ON position.

Still another feature of the invention is that, the proposed invention release spacer which prevents the jamming of mechanism during mech pole assembly as well as helps in maintaining the creep age specified by the relevant standards.

Although a double-break low voltage circuit breaker construction for high current breaking has been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of a double-break low voltage circuit breaker construction for high current breaking.
,CLAIMS:1. A moulded case circuit breakers (MCCB), comprising:
at least one pole assembly (1);
at least one release assembly (2);
at least one mechanism assembly (3);
a termination (4); and
at least one external peripheries (5);
wherein at least one pole assembly (1) comprises at least one electrical contact (6) that provides a path to carry an electrical current in the network and other components that ensures the efficient current breaking during the fault conditions.

2. The moulded case circuit breakers (MCCB) as claimed in claim 1 and 2, wherein at least one pole assembly (1) comprises at least one vent (7) that contains multiple circular openings (8) assembled in the slot provided in a cassette (15).

3. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein at least one pole assembly (1) comprises
a fixed contact assembly with at least one arc runner (9);
at least one button (10) secured to the fixed electrical contact (11); and
at least one rib (12, 13, 14) for proper constriction of said fixed contact assembly with respect to the cassette (15).

4. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein at least one pole assembly (1) comprises
a marking (19) to measure an over travel of rotor assembly with respect to the cassette (15); and
a circular slot (20) with at least one feature (21) in the cassette (15) for collecting arc products.

5. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein said at least one mechanism assembly (3) is
mounted onto a pole by inserting at least one screw (22) through at least one hole (23) thereby forming a mech-contact; and
coupled with said pole through a link (24), wherein a through pin (25) passes through the rotors of said at least one mechanism assembly (3) and the link.

6. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, comprises an AUX actuator (32) indicating a status of said MCCB by actuating auxiliary contacts, wherein said AUX actuator (32) comprises a line (37) indicating the actuation level of AUX contacts.

7. The moulded case circuit breaker (MCCB) as claimed in any of the preceding claims, comprises housing (38), wherein said housing (38) forms a outer body of the MCC, wherein the housing (38) is secured to said mech-contact through click fits (39) which gets engaged to said at least one mechanism assembly (3) pole packing screw (22) on one side and through screws on the other side which also joins said at least one release assembly (2, 40) and a chassis (41).

8. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein said at least one release assembly (2, 40) comprises a cover (44) enclosing a sensor assembly on at least one link (45), wherein, a mechanical joint is provided through at least one feature (46).

9. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein said at least one release assembly (2, 40) comprises a screw (47) is inserted to join a release acts as a joining means for securing said chassis (41) and said housing (38) to said mech-contact, and said termination (4) is done through nut retainers (48) which are replaceable to enable different types of termination.

10. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein said at least one external peripheries (5) comprises a UV release (49), a shunt release (50) along with an actuator (51), an auxiliary contacts (52), a trip alarm (53), and a mechanism actuator (54).

11. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, comprises an extended knob (55) to said MCCB to provide a locking for the front cover (56) which ensures a removal only if said MCCB indicates TRIP position.

12. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, comprises an arc chute assembly, wherein said arc chute assembly comprises of a de-ion plates (16) made of mild steel attached to the support lining (17) made of glass polyester, and holders (18) that enables in the proper routing of an arc.

13. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein in said arc chute assembly each de-ion plates (16) is inserted into the corresponding two or more slots provided in the lining and attached to it by crimping.

14. The moulded case circuit breakers (MCCB) as claimed in any of the preceding claims, wherein in said arc chute assembly at least one bottom plates are arranged in a parallel fashion for enabling quick transition of arc to the quenching chamber and at least one top plates are arranged in an angular fashion to direct the arc products to the vent.