Title of Invention	A QUADRA-BREAK CONTACT SYSTEM FOR CIRCUIT BREAKERS
Abstract	The present invention relates to a multi-break contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity. The system comprises cassette which includes plural cover portions and intermediate base portion (3) defining plural zones of the contact system, plural fixed contacts (5A) and moving contacts {6A) of which the fixed contacts comprises predetermined cut and moving contacts are rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit.

Title of Invention

A QUADRA-BREAK CONTACT SYSTEM FOR CIRCUIT BREAKERS

Abstract

The present invention relates to a multi-break contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity. The system comprises cassette which includes plural cover portions and intermediate base portion (3) defining plural zones of the contact system, plural fixed contacts (5A) and moving contacts {6A) of which the fixed contacts comprises predetermined cut and moving contacts are rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit.

Full Text	F0RM2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) Title of the invention - MULTI-BREAK CONTACT SYSTEM FOR CIRCUIT BREAKER 2. Applicant (a) NAME : LARSEN & TOUBRO LIMITED (b) NATIONALITY : An Indian Company (c) ADDRESS : L&T House, Ballard Estate, Mumbai 400 001, State of Maharashtra, India 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed: FIELD OF INVENTION The present invention relates to an electrical circuit breaker provided with multibreak contact system. More particularly, the invention relates to a multibreak contact system comprising quadra-break contacts in a circuit breaker so as to enable four arcs to be connected in series thereby causing enhancement in the rate of rise of arc voltage thus favouring a very high breaking capacity. BACKGROUND AND PRIOR ART Among technical solutions, that are currently most widely used, there are two that are often used in combination. In particular, a first solution forces the current to follow a given path, so that when short circuit occurs, electrodynamic repulsion forces occur between the contacts. These repulsion forces generate a useful thrust that helps to increase the separation speed of moving contacts with respect to the fixed contacts; in this manner, the intervention time is reduced and the presumed short-circuit current is prevented from reaching its maximum peak value. The second solution doubles the fixed contacts and the moving contacts. In this case, the flow of current is interrupted in each pole of circuit breaker in two separate regions that are arranged electrically in series to each other, so that each region is subjected to lower mechanical and thermal stresses. 2 US4910485 describes a breaking device for a low voltage molded case multipole circuit breaker, comprising a rotary switching bar. But no such compact arrangement is described which provides enhanced rate of rise of arc voltage thus favouring a very high breaking capacity. A particular critical aspect of known types of circuit breaker is the fact that the presence of electrodynamic repulsion forces, while contributing positively to the generation of the thrust useful for contact separation on one hand, on the other hand helps the moving contact structure to reach the end of its stroke at high speed and therefore with great energy. This tends to cause violent impacts against the case of circuit breaker, with the possibility of damaging it, and can therefore require the use of additional cushioning elements; moreover, bouncing of the moving contacts toward the fixed contacts and undesirable re-striking of the electric arc can occur. In the case of circuit breakers with double contacts, the likelihood of bouncing and re-striking of the electric arc can be increased by the presence of additional springs, which are usually associated with the structure of each moving contact in order to facilitate an even distribution of the mechanical pressure on the two surfaces for coupling between each moving contact the corresponding fixed contacts. The aim of the present invention is to provide a multibreak contact system with high breaking capacity that eliminates the drawbacks noted above and in particular in which opening in the short circuit condition having four series 3 arcs due to multi/quadra break type of construction results into less let through energy i.e. very low mechanical and thermal stresses on the structure. The present inventors has found that enhancement in the rate of rise of arc voltage thus ensuring high breaking capacity in the contacts of a multibreak contact system can be achieved by way of an unique construction which leads to the compactness of the whole system. OBJECTS OF INVENTION Accordingly, one object of the present invention is to provide a multibreak contact system with high breaking capacity. Another object of the present invention is to provide quadra-break type of construction. Another object of the present invention is to result into less let through energy. Another object of the present invention is to provide low mechanical thermal stress. SUMMARY OF INVENTION Accordingly, one aspect of the present invention is to provide a multi-break contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity, said system comprising : 4 cassette; said cassette comprising plural cover portions and intermediate base portion so as to define plural zones of the contact system, wherein the intermediate base portion having less width substantially at middle part; plural fixed contacts and moving contacts wherein fixed contacts comprising predetermined cut being such that thin middle part of intermediate base portion can be accommodated in said cut and wherein moving contacts being rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit. DETAILED DESCRIPTION OF INVENTION In the present invention the multi-break contact system comprises cassette which includes plural cover portions and intermediate base portion. The intermediate base portion having less width substantially at middle part splits the cassette to define plural zones of the contact system. In one embodiment the zones comprise at least four contacts which include the fixed and moving contacts. The fixed contacts comprise predetermined cut being such that thin middle part of intermediate base portion can be accommodated in said cut. The cut of the fixed contact defines two limbs of the fixed which are disposed in the separate zones. 5 The moving contacts are rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit. The moving contacts comprise a cylindrical shaft with two arms fixed on the periphery of the cylindrical shaft. In the multi break contact of the present invention the breaking capacity ranges from higher than 200kA to 25OKA. The contact system can be applied for circuit breakers having voltage ranges from 415 volts to 1000 volts. BRIEF DESCRIPTION OF ACCOMPANYING FIGURES Figure 1 illustrates the outside view of multi break contact system of the present invention. Figure 2 & 3 illustrate isometric views of the internal arrangements of the multi break system of the present invention. Figure 4 illustrates an exploded view of the multi break system of the present invention. DETAILED DESCRIPTION OF ACCOMPANYING FIGURES As shown in the fig 1, cassette (1) is splitted into three parts - first side cover (2), intermediate/middle base (3) , second side cover (4). Base (3) acts as the common wall splitting two zones for contact system. 6 As shown in fig. 2, zone one (I) consists of fixed contact (5A) , moving contact assembly (6A) comprising the contact carrier assembly/cylindrical shaft (7A) and bridge contact terminal/arms (8A) (also shown in figure 4). As shown in fig. 3, zone two (II) consists fixed contact (5B) , moving contact assembly (6B) comprising the contact carrier assembly/cylindrical shaft (7B) and bridge contact terminal/arms (8B) (also shown in figure 4). 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 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. 7 WE CLAIM 1. A mu It i-break: contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity, said system comprising : cassette; said cassette comprising plural cover portions and intermediate base portion so as to define plural zones of the contact system, wherein the intermediate base portion having less width substantially at middle part; plural fixed contacts and moving contacts wherein fixed contacts comprising predetermined cut being such that thin middle part of intermediate base portion can be accommodated in said cut and wherein moving contacts being rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit. 2. Contact system as claimed in claim 1 is preferably quadra-contact system. 3. Contact system as claimed in claim 1, wherein fixed contact comprises two limbs having distance of separation so as to hold the middle part of the intermediate base portion. 8 4. Contact system as claimed in claim 1 comprises at least two moving contacts. 5. Contact system as claimed in any preceding claims, wherein the moving contacts comprise double roto break systems being connected to each other such that increased rate of rise of arc voltage is produced. 6. Contact system as claimed in claim 5, wherein double roto break systems are connected in series adapted to produce plural series current paths. 7. Contact system as claimed in claims 1 to 6, wherein the range of breaking capacity ranges from higher than 200kA to 250kA. 8. Contact system as claimed in any preceding claims can be used for circuit breakers with voltage ranging from 415V to 1000V. 9. A multi-break contact system as herein substantially described and illustrated with reference to the accompanying figures. Dated this the 30th day of March 2007 ABSTRACT TITLE: MULTI-BREAK CONTACT SYSTEM FOR CIRCUIT BREAKER The present invention relates to a multi-break contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity. The system comprises cassette which includes plural cover portions and intermediate base portion (3) defining plural zones of the contact system, plural fixed contacts (5A) and moving contacts {6A) of which the fixed contacts comprises predetermined cut and moving contacts are rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit. Figure 2

Full Text

F0RM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
Title of the invention - MULTI-BREAK CONTACT SYSTEM
FOR CIRCUIT BREAKER
2. Applicant
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L&T House, Ballard Estate, Mumbai 400 001,
State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
The present invention relates to an electrical circuit breaker provided with multibreak contact system. More particularly, the invention relates to a multibreak contact system comprising quadra-break contacts in a circuit breaker so as to enable four arcs to be connected in series thereby causing enhancement in the rate of rise of arc voltage thus favouring a very high breaking capacity.
BACKGROUND AND PRIOR ART
Among technical solutions, that are currently most widely used, there are two that are often used in combination.
In particular, a first solution forces the current to follow a given path, so that when short circuit occurs, electrodynamic repulsion forces occur between the contacts. These repulsion forces generate a useful thrust that helps to increase the separation speed of moving contacts with respect to the fixed contacts; in this manner, the intervention time is reduced and the presumed short-circuit current is prevented from reaching its maximum peak value.
The second solution doubles the fixed contacts and the moving contacts. In this case, the flow of current is interrupted in each pole of circuit breaker in two separate regions that are arranged electrically in series to each other, so that each region is subjected to lower mechanical and thermal stresses.
2

US4910485 describes a breaking device for a low voltage molded case multipole circuit breaker, comprising a rotary switching bar. But no such compact arrangement is described which provides enhanced rate of rise of arc voltage thus favouring a very high breaking capacity.
A particular critical aspect of known types of circuit breaker is the fact that the presence of electrodynamic repulsion forces, while contributing positively to the generation of the thrust useful for contact separation on one hand, on the other hand helps the moving contact structure to reach the end of its stroke at high speed and therefore with great energy. This tends to cause violent impacts against the case of circuit breaker, with the possibility of damaging it, and can therefore require the use of additional cushioning elements; moreover, bouncing of the moving contacts toward the fixed contacts and undesirable re-striking of the electric arc can occur. In the case of circuit breakers with double contacts, the likelihood of bouncing and re-striking of the electric arc can be increased by the presence of additional springs, which are usually associated with the structure of each moving contact in order to facilitate an even distribution of the mechanical pressure on the two surfaces for coupling between each moving contact the corresponding fixed contacts.
The aim of the present invention is to provide a multibreak contact system with high breaking capacity that eliminates the drawbacks noted above and in particular in which opening in the short circuit condition having four series
3

arcs due to multi/quadra break type of construction results into less let through energy i.e. very low mechanical and thermal stresses on the structure.
The present inventors has found that enhancement in the rate of rise of arc voltage thus ensuring high breaking capacity in the contacts of a multibreak contact system can be achieved by way of an unique construction which leads to the compactness of the whole system.
OBJECTS OF INVENTION
Accordingly, one object of the present invention is to provide a multibreak contact system with high breaking capacity.
Another object of the present invention is to provide quadra-break type of construction.
Another object of the present invention is to result into less let through energy.
Another object of the present invention is to provide low mechanical thermal stress.
SUMMARY OF INVENTION
Accordingly, one aspect of the present invention is to provide a multi-break contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity, said system comprising :
4

cassette;
said cassette comprising plural cover portions and intermediate base portion so as to define plural zones of the contact system, wherein the intermediate base portion having less width substantially at middle part; plural fixed contacts and moving contacts
wherein fixed contacts comprising predetermined cut being such that thin middle part of intermediate base portion can be accommodated in said cut and
wherein moving contacts being rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit.
DETAILED DESCRIPTION OF INVENTION
In the present invention the multi-break contact system comprises cassette which includes plural cover portions and intermediate base portion. The intermediate base portion having less width substantially at middle part splits the cassette to define plural zones of the contact system.
In one embodiment the zones comprise at least four contacts which include the fixed and moving contacts. The fixed contacts comprise predetermined cut being such that thin middle part of intermediate base portion can be accommodated in said cut. The cut of the fixed contact defines two limbs of the fixed which are disposed in the separate zones.
5

The moving contacts are rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit. The moving contacts comprise a cylindrical shaft with two arms fixed on the periphery of the cylindrical shaft.
In the multi break contact of the present invention the breaking capacity ranges from higher than 200kA to 25OKA. The contact system can be applied for circuit breakers having voltage ranges from 415 volts to 1000 volts.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates the outside view of multi break contact system of the present invention.
Figure 2 & 3 illustrate isometric views of the internal arrangements of the multi break system of the present invention.
Figure 4 illustrates an exploded view of the multi break system of the present invention.
DETAILED DESCRIPTION OF ACCOMPANYING FIGURES
As shown in the fig 1, cassette (1) is splitted into three parts - first side cover (2), intermediate/middle base (3) , second side cover (4). Base (3) acts as the common wall splitting two zones for contact system.
6

As shown in fig. 2, zone one (I) consists of fixed contact (5A) , moving contact assembly (6A) comprising the contact carrier assembly/cylindrical shaft (7A) and bridge contact terminal/arms (8A) (also shown in figure 4).
As shown in fig. 3, zone two (II) consists fixed contact
(5B) , moving contact assembly (6B) comprising the contact
carrier assembly/cylindrical shaft (7B) and bridge contact
terminal/arms (8B) (also shown in figure 4).
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 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.
7

WE CLAIM
1. A mu It i-break: contact system to enhance rate of rise
of arc voltage in the contacts thus favouring a very
high breaking capacity, said system comprising :
cassette;
said cassette comprising plural cover portions and intermediate base portion so as to define plural zones of the contact system, wherein the intermediate base portion having less width substantially at middle part;
plural fixed contacts and moving contacts wherein fixed contacts comprising predetermined cut being such that thin middle part of intermediate base portion can be accommodated in said cut and
wherein moving contacts being rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit.
2. Contact system as claimed in claim 1 is preferably quadra-contact system.
3. Contact system as claimed in claim 1, wherein fixed contact comprises two limbs having distance of separation so as to hold the middle part of the intermediate base portion.
8

4. Contact system as claimed in claim 1 comprises at least two moving contacts.
5. Contact system as claimed in any preceding claims, wherein the moving contacts comprise double roto break systems being connected to each other such that increased rate of rise of arc voltage is produced.
6. Contact system as claimed in claim 5, wherein double roto break systems are connected in series adapted to produce plural series current paths.
7. Contact system as claimed in claims 1 to 6, wherein the range of breaking capacity ranges from higher than 200kA to 250kA.
8. Contact system as claimed in any preceding claims can be used for circuit breakers with voltage ranging from 415V to 1000V.
9. A multi-break contact system as herein substantially described and illustrated with reference to the accompanying figures.
Dated this the 30th day of March 2007

ABSTRACT
TITLE: MULTI-BREAK CONTACT SYSTEM FOR CIRCUIT BREAKER
The present invention relates to a multi-break contact system to enhance rate of rise of arc voltage in the contacts thus favouring a very high breaking capacity. The system comprises cassette which includes plural cover portions and intermediate base portion (3) defining plural zones of the contact system, plural fixed contacts (5A) and moving contacts {6A) of which the fixed contacts comprises predetermined cut and moving contacts are rotatably fixed on the intermediate base portion in a manner that rate of rise of arc voltage is increased rapidly when moving contacts repulsed from fixed contacts during short circuit.
Figure 2

Documents:

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Patent Number

279716

Indian Patent Application Number

623/MUM/2007

PG Journal Number

05/2017

Publication Date

03-Feb-2017

Grant Date

30-Jan-2017

Date of Filing

30-Mar-2007

Name of Patentee

LARSEN & TOUBRO LIMITED

Applicant Address

L & T HOUSE, BALLARD ESTATE, MUMBAI

Inventors:

#	Inventor's Name	Inventor's Address
1	KANNADKAR DINESH RAMESH	SWITCHGEAR DESIGN & PRODUCT DEVELOPMENT CENTER, LARSEN & TOUBRO LIMITED, ELECTRICAL SECTOR (EBG), POWAI WORKS (EAST), GATE NO 7, SAKI VIHAR ROAD, MUMBAI 400072

PCT International Classification Number

H01H33/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA