FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A circuit breaker with single shaft mounted backup realisation and actuation
trigger.
APPLICANT(S):
Crompton Greaves Limited, CG House, Dr. Annie Besant Road, Worli, Mumbai -400030, Maharashtra, India, an Indian Company
INVENTOR(S):
Meghavath Shivakumar of Crompton Greaves Limited, Analytics Center, CG Global R&D, Bhaskara Building, Kanjur Marg (East), Mumbai - 400042, Maharashtra, India; an Indian National
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
This invention relates to the field of mechanical engineering.
Particularly, this invention relates to switchgear equipment and circuit breakers.
More particularly, this invention relates to circuit breaker trigger and actuation
mechanism.
Still more particularly, this invention relates to tripping mechanism of an electrical switching apparatus.
Specifically, this invention relates to a circuit breaker with single shaft mounted backup realisation and actuation trigger.
BACKGROUND OF THE INVENTION:
Electrical loads, devices, circuits, assemblies, and connections may be subjected to electrical fluctuations or short-circuit due to interruptions in power supply or over load or under load. In any of these circumstances, the load or device is subjected to breakdown if the surges are not effectively prevented from acting on them. One way is to ensure seamless supply. Another way is to monitor the aberrations, and in case of faults, simply break the electrical connection.
The term 'switchgear', used in association with electric power systems, or grids, or power transmission systems and networks refers to combination of electrical

disconnects, fuses, and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults.
Circuit Breaker mechanisms are a type of switchgear equipment which are used in electrical equipment, as an adjunct mechanism, for preventing said electrical equipment from current / voltage aberrations such as overload, short circuit, underload, or the like. Basically, it is designed to detect a fault condition, and operates to interrupt the working of the associated electrical equipment upon detection, thereby saving its health.
Circuit breakers provide the breaking of power supply upon detection of faulty electrical conditions in the operation of associated assemblies. Thus, a circuit breaker acts as a safety device for said associated assemblies. As sensitivity of associated assemblies increase, it becomes imperative that circuit breakers be absolutely reliable in their working as a safeguard feature. Moreover, it is more essential that they act within specified time durations, in order to actuate its working upon detection of fault.
Once a fault is detected, contacts within the circuit breaker must open to interrupt the circuit; some mechanically-stored energy (using resilient mechanisms such as springs or compressed air) contained within the breaker is used to separate the contacts. Small circuit breakers may be manually operated; larger units have coils: trip coils to trip the mechanism; close coils to close the mechanism; and electric motors to restore energy to the springs.

It has been a constant endeavour to improve this specified time durations by attempting to reduce the time between detection and actuation. Since actuation is a mechanical process involving mechanical parts, its change of state from rest to motion is a crucial time consuming factor. This time duration to overcome inertia is a measure of goodness of the circuit breaker.
Furthermore, it is also imperative that a discharged circuit breaker be efficiently restored to its charged condition ready to be actuated upon detection of a fault. This requires aiding the mechanical storage of energy (using resilient mechanisms such as springs or compressed air) which further trigger the trip coils and / or close coils upon detection of a fault. In its charged condition, a latch mechanism is used to latch the moving parts in its energy-stored condition ready to be triggered in to action.
It is extremely important that fault be detected in all cases and the detected fault trigger or actuate the circuit breaker mechanism without fail at all times in order to prevent damage to associated equipment. Hence, back-up of some kind is required.
A trip coil is a type of solenoid in which the moving armature opens a circuit breaker or other protective device when the coil current exceeds a predetermined value. A closing coil is adapted to shut the circuit breaker completely.
In its working mode, if a power surge occurs in the electrical system, the breaker will trip. This means that a breaker that was in the "on" position will flip to the "off position and shut down the electrical power leading from that breaker. Essentially, a circuit breaker is a safety device. When a circuit breaker is tripped, it

may prevent a fire from starting on an overloaded circuit; it can also prevent the destruction of the device that is drawing the electricity.
A close coil is a coil which closes the circuit breaker electrically using an external voltage source when a specified voltage is applied across the coil.
The operating mechanism, of a circuit breaker, consists primarily a sensing mechanism and actuation mechanism which sense faults and actuate the circuit breaker mechanism, respectively. There is a need for a fail proof system to be able to perform this function.
PRIOR ART:
In the past, redundant actuation mechanisms have been used but for different purposes. There have been examples of using an additional actuator to operate a circuit breaker contact but these redundant actuators are placed along with sensing mechanisms associated with each phase (in a poly phase arrangement). These additional actuators operate in situations such as an over current or over voltage depending on the kind of sensing mechanism they are associated with. In addition to the actuators associated with the phase a primary, trip actuators for operating the circuit breaker is also used in these cases.
The primary trip actuator also receives a signal from the sensing devices associated with the redundant trip actuation mechanisms. However, associating a redundant actuation mechanism with each phase increases the assembly size of the complete switchgear assembly. Also, since the number of components in this case is

increased, so, from a reliability perspective the reliability of the system goes down since reliability of machines inversely proportional to the number of components in a machine. Thus, this may provide a redundant actuation mechanism and may prevent failure caused due to short circuit but is bringing down the overall reliability of this system as such. Further, since these actuations mechanisms are associated with the phase they are different from the primary trip actuator this increase the assembly and manufacturing time and thus the overall cycle time of assembling switchgear.
US2013015928 discloses an apparatus of modular trip mechanism and auxiliary mechanism for a circuit breaker comprises an auxiliary mechanism module.
US4635013 discloses a circuit breaker with an additive block provided which may be coupled to a circuit breaker comprising two separable contacts and a resectable tripping mechanism.
EP2546855 discloses an apparatus of modular trip mechanism and auxiliary mechanism for a circuit breaker.
According to one of the prior arts, one or more actuation coils are provided in the same actuator.
According to another prior art, two plungers are provided in the same actuator.
In either case, and in all the other prior arts, if the actuator -or plunger, itself is problematic, there is no circuit breaker action.

Hence, there exists the need of a system and apparatus that provides an additional line of defense from short circuit and at the same time improve the reliability of the system as such. Also, there is a need of using an additional actuation mechanism in such a manner so as to standardize the components related to the switchgear and thus reduce the complexity of assembling.
OBJECTS OF THE INVENTION:
An object of the invention is to provide a fail proof sensor and actuator mechanism for a circuit breaker mechanism.
Another object of the invention is to provide a back up sensor and actuator mechanism for a circuit breaker mechanism.
Yet another object of the invention is to provide a circuit breaker operation within an acceptable time delay so as to provide a safe mechanism which protects electrical equipment.
Still another object of the invention is to provide a circuit breaker mechanism which works even if there is burnout of one of the actuation coils.
An additional object of the invention is to improve reliability and backup in circuit
breaker assembly.
Another additional object of the invention is to reduce complexity in assemblies involving backup coils for sensing and actuation in a circuit breaker assembly.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a circuit breaker with single shaft mounted backup realisation and actuation trigger comprising:
a. at least a first actuation coil adapted to provide an actuation signal upon
receipt of a fault signal, said first actuation coil comprising at least a first
plunger adapted to be actuated upon receiving an actuation signal;
b. at least a second actuation coil adapted to provide an actuation signal upon
receipt of a fault signal, said second actuation coil comprising at least a
second plunger adapted to be actuated upon receiving an actuation signal;
c. at least a shaft mounted first realisation trigger adapted to be located in a
manner that it works advantageously with said at least a first plunger of said
at least a first actuation coil in order to translate said at least a first plunger's
plunging motion to said at least a first realisation trigger and further adapted
to actuate a trip mechanism;
d. at least a shaft mounted second realisation trigger adapted to be located in a
manner that it works advantageously with said at least a second plunger of
said at least a second actuation coil in order to translate said at least a second
plunger's plunging motion to said at least a second realisation trigger and
further adapted to actuate a trip mechanism; and
e. at least a shaft mounted actuation trigger adapted to be located in a manner
that it works advantageously with at least a trip coil of said circuit breaker in
order to engage said trip mechanism enabled either by said at least a first
realisation trigger or by at least a second realisation trigger;

characterised, in that, said shaft being a common shaft upon which said first realisation trigger, said second realisation trigger, and said actuation trigger are mounted, said shaft being an angularly displaceable shaft about its own longitudinal axis in order to provide angular displacement capability to each of said shaft mounted triggers.
Typically, said at least first actuation coil is an electromagnetic coil, and said first plunger adapted to move (or to plunge) from its normally resting position in order to activate or act upon at least a further assembly of the circuit breaker system.
Typically, said at least second actuation coil is an electromagnetic coil, and said second plunger adapted to move (or to plunge) from its normally resting position in order to activate or act upon at least a further assembly of the circuit breaker system.
Typically, said second actuation coil is a separate or a back-up trip coil.
Typically, said at least a second actuation coil is located adjacent said at least a first actuation coil.
Typically, said at least a second actuation coil is parallel to at least a first actuation coil.
Typically, a tip of said at least a first trigger is spaced apart from the tip of said at least first plunger, the spaced apart distance being equal to the plunging movement provided to said at least a first plunger.

Typically, a tip of said at least a second trigger is spaced apart from the tip of said at least second plunger, the spaced apart distance being equal to the plunging movement provided to said at least a second plunger.
Typically, said at least a first realisation trigger, due to its location on the shaft, is an angularly displaceable first realisation trigger.
Typically, said at least a second realisation trigger, due to its location on the shaft, is an angularly displaceable second realisation trigger.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates an existing arrangement of the circuit breaker assembly.
The invention will now be described in relation to the accompanying drawings, in
which:
Figure 2 illustrates a circuit breaker with single shaft mounted backup realisation and actuation trigger; and
Figure 3 illustrates a closer view of the arrangement of Figure 2.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates an existing arrangement of the circuit breaker assembly.

Reference numeral 40 refers to a frame on which an actuation coil 12 is located. This is a single actuation coil with a single plunger and a single trigger mechanism. Problems associated with a single actuation coil and trigger mechanism have been discussed above. There is a need for a back-up actuation coil and trigger mechanism in order to solve the problems of the prior art.
According to this invention, there is provided a circuit breaker with single shaft mounted backup realisation and actuation trigger.
Figure 2 illustrates a circuit breaker with single shaft mounted backup realisation and actuation trigger; and
Figure 3 illustrates a closer view of the arrangement of Figure 2.
In accordance with an embodiment of this invention, there is provided a first actuation coil (12) adapted to provide an actuation signal upon receipt of a fault signal. Typically, the first actuation coil is an electromagnetic coil with a first plunger (14) adapted to actuate the plunger upon, provisioning of a actuation signal. Typically, the actuation signal activates at least an associated first plunger upon receipt of an actuation signal. The activated first plunger moves (or plunges) from its normally resting position in order to activate or act upon at least a further assembly of the circuit breaker system.
In accordance with an embodiment of this invention, there is provided a second actuation coil (22) adapted to provide an actuation signal upon receipt of a fault signal. Typically, the second actuation coil is an electromagnetic coil with a

second plunger (24) adapted to actuate the plunger upon provisioning of a actuation signal. Typically, the actuation signal activates at least an associated second plunger upon receipt of an actuation signal. The activated second plunger moves (or plunges) from its normally resting position in order to activate or act upon at least a further assembly of the circuit breaker system. Typically, the second actuation coil is a separate trip coil, preferably, a backup coil device. This second actuation coil (22) is located adjacent the first actuation coil (12). In other words, the second actuation coil (22) is parallel to the first actuation coil (12). In instances that there is any sort of failure or jam or loss of function of the first actuation, coil, this second actuation coil, adjacent the first actuation coil, is adapted to sense the fault signal and to provide the actuation signal in order to enable performing a tripping action of the circuit breaker.
In accordance with an embodiment of this invention, there is provided a shaft mounted first realisation trigger (32) adapted to be located in a manner that it works advantageously with the first plunger (14) of the first actuation coil (12). The movement of the first plunger from its normal resting position, upon receipt of a fault signal or actuation signal, translates its motion to the first realisation trigger. In its normal resting position, a tip of the first trigger is spaced apart from the tip of the first plunger, the spaced apart distance being equal to the plunging movement provided to the first plunger. The first realisation trigger, due to its location on the shaft, comprises an inherent angular displaceable motion.
In accordance with an embodiment of this invention, there is provided a shaft mounted second realisation trigger (34) adapted to be located in a manner that it works advantageously with the second plunger (24) of the second actuation coil

(22). The movement of the second plunger from its normal resting position, upon receipt of a fault signal or actuation signal, translates its motion to the second realisation trigger. In its normal resting position, a tip of the second trigger is spaced apart from the tip of the second plunger, the spaced apart distance being equal to the plunging movement provided to the second plunger. The second realisation trigger, due to its location on the shaft, comprises an inherent angular displaceable motion.
In accordance with an embodiment of this invention, there is provided a shaft mounted actuation trigger (36) adapted to be located in a manner that it works advantageously with at least a trip coil of the circuit breaker mechanism. The actuation trigger, due to its location on the shaft, comprises an inherent angular displaceable motion.
Typically, the shaft (30) is a common shaft upon which the first realisation trigger (32), the second realisation trigger (34), and the actuation trigger (36) are mounted. The shaft is an angularly displaceable shaft about its own longitudinal axis and it provides angular displacement capability to the triggers (32, 34, 36). The angular displacement of the actuation trigger is commensurate with the angular displacement of the first realisation trigger and the second realisation trigger due to it being mounted on the same shaft. The assembly of shaft (30) and triggers (32, 34,36) is mounted on to a frame (40). Typically, the first realisation trigger (32) is used to actuate the trip mechanism using the first actuation coil (12). Typically, the second realisation trigger (34) is used to actuate the trip mechanism using the second actuation coil (22). Typically, the shaft mounted actuation trigger (36) is used to engage the trip mechanism using the angular displacement of the shaft (30)

enabled either by the first realisation trigger (32) or by the second realisation trigger (34). During faults, the first actuation coil as well as the second actuation coil receives a fault signal from a sensing circuit. Preferably, the second actuation coil (22) receives the fault signal after a pre-determined time delay as compared with the first actuation coil (12). This ensures lack of double hits.
The inventive step of this invention lies in providing a mechanism of a circuit breaker assembly where a backup actuation coil is provided in parallel to the existing actuation coil. Furthermore, triggers associated with the at least two actuation coils and the actuation trigger are mounted on a single shaft in similar orientation. The mechanism of this invention separates the burden of realisation from the burden of actuation by provisioning different triggers. This ensures no redundancy. Also, time delays ensure no double action. Therefore, maximum protection is provided.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. A circuit breaker with single shaft mounted backup realisation and actuation trigger comprising:
a. at least a first actuation coil adapted to provide an actuation signal
upon receipt of a fault signal, said first actuation coil comprising at
least a first plunger adapted to be actuated upon receiving an actuation
signal;
b. at least a second actuation coil adapted to provide an actuation signal
upon receipt of a fault signal, said second actuation coil comprising at
least a second plunger adapted to be actuated upon receiving an
actuation signal;
c. at least a shaft mounted first realisation trigger adapted to be located
in a manner that it works advantageously with said at least a first
plunger of said at least a first actuation coil in order to translate said at
least a first plunger's plunging motion to said at least a first realisation
trigger and further adapted to actuate a trip mechanism;
d. at least a shaft mounted second realisation trigger adapted to be
located in a manner that it works advantageously with said at least a
second plunger of said at least a second actuation coil in order to
translate said at least a second plunger's plunging motion to said at
least a second realisation trigger and further adapted to actuate a trip
mechanism; and
e. at least a shaft mounted actuation trigger adapted to be located in a
manner that it works advantageously with at least a trip coil of said
circuit breaker in order to engage said trip mechanism enabled either

by said at least a first realisation trigger or by at least a second
realisation trigger; characterised, in that, said shaft being a common shaft upon which said first realisation trigger, said second realisation trigger, and said actuation trigger are mounted, said shaft being an angularly displaceable shaft about its own longitudinal axis in order to provide angular displacement capability to each of said shaft mounted triggers.
2. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said at least first actuation coil is an electromagnetic coil, and said first plunger adapted to move (or to plunge) from its normally resting position in order to activate or act upon at least a further assembly of the circuit breaker system.
3. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said at least second actuation coil is an electromagnetic coil, and said second plunger adapted to move (or to plunge) from its normally resting position in order to activate or act upon at least a further assembly of the circuit breaker system.
4. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said second actuation coil is a separate or a back-up trip coil.

5. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said at least a second actuation coil is located adjacent said at least a first actuation coil.
6. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said at least a second actuation coil is parallel to at least a first actuation coil.
7. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein a tip of said at least a first trigger is spaced apart from the tip of said at least first plunger, the spaced apart distance being equal to the plunging movement provided to said at least a first plunger.
8. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein a tip of said at least a second trigger is spaced apart from the tip of said at least second plunger, the spaced apart distance being equal to the plunging movement provided to said at least a second plunger.
9. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said at least a first realisation trigger, due to its location on the shaft, is an angularly displaceable first realisation trigger.

10. The circuit breaker with single shaft mounted backup realisation and actuation trigger as claimed in claim 1, wherein said at least a second realisation trigger, due to its location on the shaft, is an angularly displaceable second realisation trigger.