DESC:TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to Under-voltage release and Shunt Release working in the circuit breaker.

BACKGROUND AND THE PRIOR ART

Conventional Moulded Case Circuit Breakers (referred here after as MCCB or breaker) have provisions for Under-voltage Release as well as Shunt Release. They are not a part of basic breaker assembly, instead they come as separate package. They have to be inserted in the cavities designed to accommodate them in the basic breaker for their functional operation. Generally they have to be inserted in the trip condition of breaker, then they get aligned with basic breaker and starts functioning as desired.

Both Under voltage release (referred here after as UV) and Shunt release (referred here after as Shunt) have provision of connecting two wires into it. UV is generally connected across supply voltage, as it performs the function of tripping the MCCB as the supply voltage drops below predetermined value. Shunt also has similar construction as UV, but it gets actuated when voltage pulse is applied across its terminals. It is normally used as a remote tripping means. Both have two stable conditions Trip and latch, during normal operation they are in latch condition and goes to trip condition when actuated.

The normal operation includes following steps, when the breaker is switched on with UV or Shunt pre-assembled, and UV or Shunt is actuated, it will trip the breaker. After trip breaker has to be reset, while resetting the MCCB, the mechanism also resets the UV or Shunt whatever is present. Then the MCCB can be switched on again, if the actuating conditions of UV or Shunt are removed otherwise while switching on the MCCB UV or Shunt will trip it again.

The basic information regarding MCCB and UV Shunt operation can be referred from following two patents based on UV and SH.

Patent 1: Under voltage release device for a MCCB (US 6201460 B1)

Patent 2: Shunt Trip Device for MCCB (US 2002/0050887 A1)

Conventional breakers can accommodate single UV or Shunt , either of them but one at a time only. When UV is mounted on the breaker, Shunt cannot be mounted and vice versa. So their operation is very simple, one part of UV/SH engages with tripping medium and other gets engaged with resetting medium.

Then there comes a situation when there is a need of both functions in the same breaker. Then the provision for assembling both UV & Shunt in a single breaker has to be there. When both accessories are present in the same breaker, complexity increases as their operation (both trip and reset) has to be independent of each other but they have to share common trip and reset provisions from the basic breaker.

OBJECTS OF THE INVENTION

One object of the invention is to overcome the disadvantages/drawbacks of the prior art.

A basic object of the present invention is to facilitate provision of assembling two devices (UV and shunt) in single breaker in any combination and designing an actuator for ensuring independent operation as well as assembly of under-voltage release & shunt release inmoulded case circuit breaker.

These and other advantages of the present invention will become readily apparent from the following detailed description read in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
In an aspect of the present invention, there is provided an assembly for under-voltage release & shunt release in a moulded case circuit breaker, the assembly comprising:

an under-voltage release accessory and/or a shunt release accessory comprises at least two terminal for connected input wire (s); a tripper plate having an interface feature;

an actuator means having an accessory interface means, a spring mounting means, a trip plate interface means, an accessory insertion interface means, and a resetting interface means, facilitating interfacing with the under-voltage release & shunt release accessory;

wherein the actuator means providing ON, OFF and tripping mechanism of the circuit breaker in combination with the under-voltage release accessory and/or shunt release accessory.

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

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.

Figure 1 illustrates a basic breaker assembly.

Figure 2 illustrates planer and isometric view of a chassis.

Figures 3 and 4 illustrate UV/Shunt assembly.

Figure 5 illustrates different views of the actuator.

Figure 6 illustrates interfacing of the actuator and the UV/Shunt assembly.

Figure 7 illustrates interfacing of the mechanism and the actuator.

Figure 8 illustrates breaker tripping by the actuator.

Figure 9 illustrates independent tripping of both accessories and the tripper.

Figure 10 shows actuator resetting arrangement.
Figure 11 shows actuator resetting start and end position.
Figure 12 illustrates Resetting Force on the Actuator has no vertical component.
Figure 13 illustrates Inserting UV / Shunt in different conditions of breaker.
Figure 14 illstrates Inserting tripped UV / Shunt in a breaker in Reset (OFF) condition.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numerals are used to depict the same or similar elements, features and structures.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

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.

Accordingly, present invention provides an assembly for under-voltage release & shunt release in a moulded case circuit breaker.

Figure 1 shows Basic Breaker assembly with contact system 1, operating mechanism2 & Chassis 3. The Contact system 1 forms actual current carrying path of the breaker. Mechanism 2 performs the functions of making contact system open & close. Chassis 3 is the part where the accessories can be mounted. The mechanism has three stable states
a. ON : Contacts Closed & Mechanism Latched
b. OFF : Contacts Open & Mechanism Latched
c. Trip : Contacts Open & Mechanism De-latched

The present invention relates to provision of both the accessories (UV and Shunt) in the same breaker and still achieving their independent operation. A component is designed to achieve their independent operation, also it takes care that accessory insertion in the breaker does not affect each other`s presence.

Referring to figures 2 to 4 there are two cavities (Upper Cavity 31 & lower cavity 32) designed in the breaker to accommodate UV 4 and Shunt 4. So that breaker can work with UV 4 and shunt 4 simultaneously and give functionality of both. The cavities 31, 32 are independent of type of accessory, so UV 4 or shunt 4 can go in any of the cavities 31,32. This gives the advantage of having any combination of accessories in the breaker and still achieving the functionality. The breaker can now have one UV 4 & one Shunt 4 also their positions can be interchanged or it can have two UVs 4, two Shunts 4 simultaneously.

An additional component is added to coordinate interaction of UV / Shunt 4 with the basic breaker. This component can have some linear motion or rotary motion. Again the additional component can come as a part of basic breaker or as an extra component but not a part of UV or Shunt. The component referred hereafter as actuator 5 has linear motion and comes as a part of basic breaker.

The fig.3 shows UV 4 assembly. It consists of two terminals 41,42 where input wires can be connected and tripper plate 43 which engages with actuator. The actuator interface feature 431 shown in fig engages with accessory interface features 511,512 of actuator5. The actuator 5 is assembled in the chassis 3. It slides in the slot 33 designed for its movement. A spring is connected in between Spring mounting 55 feature in actuator 5 and chassis 3. The trip plate interface feature 53 of actuator 5 interacts with mechanism 2 trip plate 21.

The care is taken that the presence of actuator 5 in basic breaker when no UV / Shunt 4 is inserted does not affect its functionality. In the absence of UV / Shunt 4 actuator 5 has no interaction with the breaker, it will come in picture only when any UV / Shunt4 is inserted in the breaker. This function is important as each breaker will not have UV or Shunt 4. In the absence of this feature the actuator 5 must be a separate component like UV / Shunt 4, which then might be inserted before inserting UV / Shunt 4, which will not be very user friendly.

The actuator 5 guarantees independent operation of both the accessories independent of their type (UV /Shunt 4), number or presence in any of the cavities 31,32.

1. The actuator 5 can trip the breaker with any one of the accessories present in any one of the cavities 31,32 in the breaker and similarly it can reset the accessory with breaker reset.

2. The actuator 5 can trip the breaker with any one accessory when both are present in the breaker and reset the same without affecting the other.

3. The actuator 5 can trip the breaker with both the accessories tripping at the same time and also reset both of them simultaneously.

The resetting of accessories is improvised by designing a pin 221 which will be mounted on the mechanism fork 22, which will interact with the actuator 5. The resetting feature 54 is a plane smooth surface on the actuator 5 which acts as a cam to convert rotary movement of the pin 221 to linear movement required for accessory resetting. Use of pin 221 has another advantage that the force applied on the actuator 5 is always horizontal, vertical component (or unwanted component) is completely avoided which will cause extra friction between chassis and actuator.

The actuator is self adjusting. When the first accessory is being inserted in the breaker the actuator will come in its desired position automatically, by sliding action of Actuator interface feature 431 of UV / Shunt 4 and Accessory insertion features 521,522 of actuator 5. If the accessory is inserted in tripped condition in a ON breaker actuator 5 will trip the breaker. If the accessory is inserted in latched condition in ON / OFF breaker actuator 5 will keep the breaker condition intact. If the accessory is inserted in tripped condition in Reset (OFF) condition breaker the accessory will get latched while inserting due cam action as shown in fig. 14. This feature enables the insertion of the accessory in breaker in all the three conditions of breaker (ON, OFF, Trip), unlike conventional breakers in which accessory has to be inserted in Trip condition. Again when one accessory is already inserted in the breaker and another is being inserted, the presence of first accessory in the breaker in any cavity and in any condition of the accessory will not affect its operation mentioned above. This feature makes assembly of accessories a lot more user friendly than conventional breakers.

Breaker Condition Accessory Condition Resultant breaker Condition Resultant Accessory condition
ON / OFF / Trip Latched Intact as before Latched
ON Tripped Trip Tripped
Trip Tripped Trip Tripped
OFF Tripped OFF Latched

ADVANTAGES:
- Provision of assembling two accessories (UV / Shunt) in MCCB
- Provision of assembling any accessory (UV / Shunt) in any cavity
- Interchangeability of accessories in cavities
- Use of extra component as actuator a part of basic breaker or external component not a part of UV
- Use of actuator for independent coordination of accessories (UV / Shunt) with basic breaker
- Independent trip operation of accessories (UV / Shunt)
- Independent reset operation of accessories
- Insertion of accessories possible in all three (ON, OFF, Trip) conditions of breaker
- Self adjustment of actuator while inserting accessories
- Tripping of breaker when tripped accessory inserted in On breaker
- Breaker condition intact when latched accessories inserted in ON / OFF condition of breaker
- Latching of tripped accessories when inserted in breaker in OFF condition
- No interaction of actuator with basic breaker in absence of accessories
- Use of reset pin for resetting to reduce unwanted component ,CLAIMS:1. An assembly for under-voltage release & shunt release in a moulded case circuit breaker, the assembly comprising:
an under-voltage release accessory and/or a shunt release accessory comprises at least two terminals for connecting input wire (s); and a trip plate ;
an actuator means having an accessory interface means, a spring mounting means, a trip plate interface means, an accessory insertion interface means, and a resetting interface means, facilitating interfacing with the under-voltage release and/or shunt release accessory;
wherein the actuator means providing ON, OFF and tripping mechanism of the circuit breaker in combination with the under-voltage release accessory and/or shunt release accessory.
2. The assembly as claimed in claim 1, wherein the under-voltage release accessory and the shunt release accessory are assembled in at least two cavity(s) provided on the circuit breaker.
3. The assembly as claimed in claim 1, wherein the actuator is inserted in a cavity provided in chassis of the circuit breaker.
4. The assembly as claimed in claim 1, wherein the interface means on the trip plate is connected with the accessory interface means facilitating sliding of the actuator.
5. The assembly as claimed in claim 1, wherein the trip plate interface means of the actuator interacting with a trip plate of the circuit breaker.
6. The assembly as claimed in claim 1, wherein the resetting interface means is a plane smooth surface on the actuator acting as a cam for converting rotary movement of a pin to linear movement, therefore resetting the under-voltage release accessory and/or a shunt release accessory.

7. The assembly as claimed in claim 6, wherein the pin is mounted on a mechanism fork for applying perpendicular force to the actuator, therefore reducing friction between the chassis and the actuator.
8. The assembly as claimed in claim 1, wherein a spring is connected in between a spring mounting feature on the actuator and in the chassis, therefore the actuator adjusts its position on the chassis.
9. The assembly as claimed in claim 1, wherein the actuator facilitates tripping of the circuit breaker, when the under-voltage release accessory and/or a shunt release accessory is inserted in tripped condition during ON condition of the circuit breaker.
10. The assembly as claimed in claim 1, wherein the under-voltage release accessory and/or a shunt release accessory is latched, when the under-voltage release accessory and/or a shunt release accessory is inserted in tripped condition during Reset (OFF) condition of the circuit breaker
11. The assembly as claimed in claims 1 and 2, wherein said cavities optionally interchangeably accommodate under-voltage release accessory and a shunt release accessory or two under-voltage release accessory simultaneously or two shunt release accessory simultaneously.