The present disclosure relates to the field of moulded case circuit
breaker (MCCB). More particularly the present disclosure relates to a driving shaft assembly for the moulded case circuit breaker.
BACKGROUND
[0002] Background description includes information that may be useful in
understanding the present invention. It is not an admission that any of the
information provided herein is prior art or relevant to the presently claimed
invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Circuit switching devices such as contactors, motor starters, motor
controllers and circuit breakers protect electrical circuitry and equipment from abnormal condition such as short circuit or fault and overload condition. Circuit breaker is capable of making, carrying and breaking currents under normal circuit conditions and also making carrying for a specified time, and breaking under specified abnormal conditions.
[0004] One such switching device used to provide over current protection
is moulded case circuit breaker (MCCB). Use of MCCB as a circuit protection device is increasing in Indian industries due to its several advantages over switch and fuse units. The surge in the manufacture of MCCB is due to number of factors, such as compactness, consistent performance, use of advanced rating insulating material and introduction of new technologies such as solid state and microprocessor-based trip and control systems. A MCCB mechanically separates the electrical circuit under continued overloads or short circuit. MCCB consists of four main parts namely release assembly, mechanism assembly, contact system and arching chamber. However, one of the most critical as well as damaging failure observed in MCCB is internal flash overs between any two phases combination viz. R-Y or Y-B phases. This is due to potentially charged mechanism assembly in Y Phase which has interconnected mechanism components with current carrying path.

[0005] There is, therefore, a need of an improved drive shaft assembly for
the MCCB that can eliminate the possibility of internal flash overs between phases.
OBJECTS OF THE PRESENT DISCLOSURE
[0006] Some of the objects of the present disclosure, which at least one
embodiment herein satisfies are as listed herein below.
[0007] It is an object of the present disclosure to provide a drive shaft
assembly for MCCB, which educe button erosion and ensures continuity in all
phases.
[0008] It is an object of the present disclosure to provide a drive shaft
assembly, which electrically isolates the mechanism cage assembly from the
charged path.
[0009] It is an object of the present disclosure to provide a drive shaft
assembly, which eliminates possibility of impulse failure between current carrying
path to fork/knob.
[0010] It is an object of the present disclosure to provide a drive shaft
assembly, which eliminates differential over travel and contact pressure between
phases. Hence reduces severity during fault clearance.
[0011] It is an object of the present disclosure to provide a drive shaft
assembly, which has higher opening of moving contact assembly and hence
reduction in let through energy during fault clearance which increases electrical
life of a circuit breaker.
[0012] It is an object of the present disclosure to provide a drive shaft
assembly, which increases safety factor to the equipment and electrical circuitry.
[0013] It is an object of the present disclosure to provide a drive shaft
assembly, which elimination of internal flash over and hence increased safety of
connected apparatus and human operating the apparatus.
[0014] It is an object of the present disclosure to provide a drive shaft
assembly, which is cost effective and requires less maintenance cost.

SUMMARY
[0015] The present disclosure relates to the field of moulded case circuit
breaker (MCCB). More particularly the present disclosure relates to a driving
shaft assembly for the moulded case circuit breaker.
[0016] An aspect of the present disclosure pertains to a drive shaft
assembly for a moulded case circuit breaker (MCCB). The drive shaft assembly
includes a plurality of cavities for accommodating a plurality of moving contact
corresponding to three phases and neutral of an input supply. At least one cavity
of the plurality of cavities comprises a first slot and a second slot such that the
first slot is electrically isolated from the second slot via a partition wall. A moving
contact, for at least one phase of the three phases, is operatively coupled with the
at least one cavity. The moving contact is pivotally coupled with the first slot of
the at least one cavity. A mechanism cage assembly is operatively coupled with
the at least one cavity. The mechanism cage assembly is coupled with the second
slot using of the at least one cavity for facilitating electrical isolation between the
mechanism cage assembly and the moving contact to avoid any flashing over
while fault clearance.
[0017] In an aspect, the drive shaft assembly may include a torsion spring
configured with a guiding surface of the at least one cavity, and an arm of the
torsion spring may be configured to rest against a sliding surface of the moving
contact.
[0018] In an aspect, the mechanism cage assembly may be operatively
configured with the second slot using one or more rivets.
[0019] In an aspect, the mechanism cage assembly may include one or
more first link arms, one or more second link arms, center pin, and latch link
assembly.
[0020] In an aspect, the one or more first link arms may include a stopping
surface to avoid slippage of the mechanism cage assembly from the drive shaft
assembly, while ON operation.
[0021] In an aspect, moving contact may be made of an electrically
conductive material.

[0022] Various objects, features, aspects and advantages of the inventive
subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF DRAWINGS
[0023] The accompanying drawings are included to provide a further
understanding of the present disclosure, and are incorporated in and constitute a
part of this specification. The drawings illustrate exemplary embodiments of the
present disclosure and, together with the description, serve to explain the
principles of the present disclosure. The diagrams are for illustration only, which
thus is not a limitation of the present disclosure.
[0024] In the figures, similar components and/or features may have the
same reference label. Further, various components of the same type may be
distinguished by following the reference label with a second label that
distinguishes among the similar components. If only the first reference label is
used in the specification, the description is applicable to any one of the similar
components having the same first reference label irrespective of the second
reference label.
[0025] FIG. 1A illustrates exemplary representation of a front-view drive
shaft assembly and FIG. IB illustrates a rear-view drive shaft assembly, in
accordance with an embodiment of the present disclosure.
[0026] FIG. 2A illustrates exemplary representation of a moving contact
and FIG. 2B illustrates an exploded view of moving contact arrangement with the
drive shaft, in accordance with an embodiment of the present disclosure.
[0027] FIG. 3A illustrates exemplary representation of one or more first
links, centre pin of the mechanism cage assembly and FIG. 3B-C illustrates a
coupling arrangement of the mechanism cage assembly with the drive shaft, in
accordance with an embodiment of the present disclosure.
[0028] FIG. 4 illustrates an exemplary representation of MCCB in "ON"
position, in accordance with an embodiment of the present disclosure.

[0029] FIG. 5 illustrates an exemplary representation of MCCB in "TRIP"
condition, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0030] The following is a detailed description of embodiments of the
disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[0031] In the following description, numerous specific details are set forth
in order to provide a thorough understanding of embodiments of the present
invention. It will be apparent to one skilled in the art that embodiments of the
present invention may be practiced without some of these specific details.
[0032] The present disclosure relates to the field of moulded case circuit
breaker (MCCB). More particularly the present disclosure relates to a driving shaft assembly for the moulded case circuit breaker.
[0033] The present disclosure elaborates upon a a drive shaft assembly for
a moulded case circuit breaker (MCCB). The drive shaft assembly includes a plurality of cavities for accommodating a plurality of moving contact corresponding to three phases and neutral of an input supply. At least one cavity of the plurality of cavities comprises a first slot and a second slot such that the first slot is electrically isolated from the second slot via a partition wall. A moving contact, for at least one phase of the three phases, is operatively coupled with the at least one cavity. The moving contact is pivotally coupled with the first slot of the at least one cavity. A mechanism cage assembly is operatively coupled with the at least one cavity. The mechanism cage assembly is coupled with the second slot using of the at least one cavity for facilitating electrical isolation between the mechanism cage assembly and the moving contact to avoid any flashing over while fault clearance.

[0034] In an embodiment, the drive shaft assembly can include a torsion
spring configured with a guiding surface of the at least one cavity, and an arm of
the torsion spring can be configured to rest against a sliding surface of the moving
contact.
[0035] In an embodiment, the mechanism cage assembly can be
operatively configured with the second slot using one or more rivets.
[0036] In an embodiment, the mechanism cage assembly can include one
or more first link arms, one or more second link arms, center pin, and latch link
assembly.
[0037] In an embodiment, the one or more first link arms can include a
stopping surface to avoid slippage of the mechanism cage assembly from the drive
shaft assembly, while ON operation.
[0038] In an embodiment, moving contact can be made of an electrically
conductive material.
[0039] FIG. 1A illustrates exemplary representation of a front-view drive
shaft assembly and FIG. IB illustrates a rear-view drive shaft assembly, in
accordance with an embodiment of the present disclosure.
[0040] FIG. 2A illustrates exemplary representation of a moving contact
and FIG. 2B illustrates an exploded view of moving contact arrangement with the
drive shaft, in accordance with an embodiment of the present disclosure.
[0041] FIG. 3A illustrates exemplary representation of one or more first
links, centre pin of the mechanism cage assembly and FIG. 3B-C illustrates a
coupling arrangement of the mechanism cage assembly with the drive shaft, in
accordance with an embodiment of the present disclosure.
[0042] As illustrated, a drive shaft assembly 100 for a moulded case
circuit breaker (MCCB) can includes a plurality of cavities for accommodating a
plurality of moving contact corresponding to three phases and neutral of an input
supply. At least one cavity 102 of the plurality of cavities can include a first slot
102-1 and a second slot 102-2. The first slot 102-1 and the second slot 102-2 are
positioned in the at least one cavity 102 such that the first slot 102-1 is electrically
isolated from the second slot 102-2 via a partition wall 102-3. A moving contact

104, for at least one phase of the three phases, can be operatively coupled with the at least one cavity 102. The moving contact 104 can be pivotally coupled with the first slot 102-1 using a pivot pin 104-1. The moving contact 104 can include a sliding surface 104-2 and a stopper 104-3.
[0043] In an embodiment, a two-fold torsion spring 106 can be operatively
configured with the moving contact 104 and the at least one cavity 102. The
spring 106 can include an arm 106-1 that can be configured to rest against a
sliding surface 104-2 of the moving contact 104. The arm 106-1 rest against the
sliding surface for facilitating self-alignment of the spring 106 with the moving
contact 104. The stopper surface 104-3 can be designed as final stop for the spring
106 during repulsion. The spring 106 can be operatively configured with a
guiding surface 102-4 of the cavity 102 using pivot pin 106-2.
[0044] In an embodimnt, the pivot pin 106-2 of the spring 106 can keep
the axis of spring same during all operating condition and does not allow two-fold torsion spring to come out during repulsion or short circuit condition. This pivot pin 106-2 can also provide a tangent surface to the spring 106 during MCCB ON condition which can result in consistent contact pressure and over travel of moving contact. This feature can increase the electrical life of a breaker. Also, the spring assembly in drive shaft assembly can be kept in such a way that it will not face direct arcing during short circuit.
[0045] In an embodiment, the spring 106 arrangement can be done in such
a way that the spring 106 will not have direct exposure to arcing zone for preventing any deformation, and contact pressure by the spring 106 can be ensured along with over travel. The stopper 104-3 for the moving contact opening during fault clearance can be changed from a compression spring's body length to moving contact itself and hence moving contact achieves its final position during opening. Along with that moving contact opening increased by 4mm. a mechanism cage assembly 108 can be operatively coupled with the at least one cavity 102. The mechanism cage assembly 108 can be coupled with the second slot 102-4 of the at least one cavity 102. This can facilitate an electrical isolation

between the mechanism cage assembly 108 and the moving contact 102 to avoid any flashing over while fault clearance.
[0046] In an embodiment, the mechanism cage assembly 108 can include
one or more first link arms 108-1, one or more second link arms 108-2, center pin
108-3, latch link assembly 108-4, and a handle knob. The mechanism cage
assembly 108 can be operatively configured with the second slot 102-4 using one
or more rivet pins 108-5. In this way the moving contact 104 and the mechanism
cage assembly can be pivotally coupled with the cavity 102 using independent
pivot pins (104-1, 108-5) unlike conventional practice in which the moving
contact and the mechanism cage assembly used to be pivotally coupled using a
common pivot pin leading compromise an isolation between both. The one or
more first link arms 108-1 can include a stopping surface 108-6 to avoid slippage
of the mechanism cage assembly 108 from the drive shaft assembly 100, while
ON operation. The one or more rivet pins 108-5 are so designed that the rivet pins
are not required to be riveted and can provide ease in assembly.
[0047] FIG. 4 illustrates an exemplary representation of MCCB in "ON"
position, in accordance with an embodiment of the present disclosure.
[0048] FIG. 5 illustrates an exemplary representation of MCCB in "TRIP"
condition, in accordance with an embodiment of the present disclosure.
[0049] As illustrated, FIG. 4-5 illustrtes a cross section view of the MCCB
in ON and TRIP condition respectively. FIG-4 illustrates how the stopper surface 108-6 provide on the one or more first link arms 108-2 gets stopped on drive shaft assembly 100 during MCCB ON condition. This can eliminate the rotating one or more first arms 108-2 getting slipped from the guiding surface 102-4 provided in cavity 102. FIG-5 illustrates the one or more first arms 108-2 position in MCCB tripped condition.
[0050] The presesnt disclosure proviers a completely isolation between the
charged path and mechanism cage aassembly and hence internal flash over can be completely eliminated during short circuit in reverse connection. Also, it provides complete isolation of mechanism assembly during impulse testing. Opening angle

of the moving contact in modified driveshaft assembly has increased compared to
the earlier one, hence more opening will help to reduce the let through energy.
[0051] Moreover, in interpreting the specification, all terms should be
interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C ....and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.
[0052] While the foregoing describes various embodiments of the
invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
ADVANTAGES OF THE INVENTION
[0053] The proposed invention provides a drive shaft assembly for
MCCB, which educe button erosion and ensures continuity in all phases.
[0054] It is an object of the present disclosure to provide a drive shaft
assembly, which electrically isolates the mechanism cage assembly from the charged path.
[0055] It is an object of the present disclosure to provide a drive shaft
assembly, which eliminates possibility of impulse failure between current carrying path to fork/knob.

[0056] It is an object of the present disclosure to provide a drive shaft
assembly, which eliminates differential over travel and contact pressure between
phases. Hence reduces severity during fault clearance.
[0057] It is an object of the present disclosure to provide a drive shaft
assembly, which has higher opening of moving contact assembly and hence
reduction in let through energy during fault clearance which increases electrical
life of a circuit breaker.
[0058] It is an object of the present disclosure to provide a drive shaft
assembly, which increases safety factor to the equipment and electrical circuitry.
[0059] It is an object of the present disclosure to provide a drive shaft
assembly, which elimination of internal flash over and hence increased safety of
connected apparatus and human operating the apparatus.
[0060] It is an object of the present disclosure to provide a drive shaft
assembly, which is cost effective and requires less maintenance cost.

We Claim:

1. A drive shaft assembly for a moulded case circuit breaker (MCCB), the
drive shaft assembly comprising:
a plurality of cavities for accommodating a plurality of moving contact corresponding to three phases and neutral of an input supply, wherein at least one cavity of the plurality of cavities comprises a first slot and a second slot such that the first slot is electrically isolated from the second slot via a partition wall;
a moving contact, for at least one phase of the three phases, is operatively coupled with the at least one cavity, wherein the moving contact is pivotally coupled with the first slot of the at least one cavity; and
a mechanism cage assembly is operatively coupled with the at least one cavity, wherein the mechanism cage assembly is coupled with the second slot using of the at least one cavity for facilitating electrical isolation between the mechanism cage assembly and the moving contact to avoid any flashing over while fault clearance.
2. The drive shaft assembly as claimed in claim 1, wherein the drive shaft assembly comprises a torsion spring configured with a guiding surface of the at least one cavity, and an arm of the torsion spring is configured to rest against a sliding surface of the moving contact.
3. The drive shaft assembly as claimed in claim 1, wherein the mechanism cage assembly is operatively configured with the second slot using one or more rivets.
4. The drive shaft assembly as claimed in claim 1, wherein the mechanism cage assembly comprises one or more first link arms, one or more second link arms, center pin, and latch link assembly.
5. The drive shaft assembly as claimed in claim 4, wherein the one or more first link arms comprise a stopping surface to avoid slippage of the mechanism cage assembly from the drive shaft assembly, while ON operation.

6. The drive shaft assembly as claimed in claim 1, wherein moving contact is made of an electrically conductive material.