Claims:1. A moulded case circuit breaker (MCCB) with true state indication, said MCCB comprising:
a rotary operating handle (ROH) provided on a rotary operating mechanism (ROM) of the MCCB, said ROH comprising an excusion plate;
a kidney-shaped slot provided on the excusion plate, said slot subtending a predetermined angle at a centre, wherein an upper limit of slot is configured to determine any of ON, OFF and TRIP positions of the MCCB; and
an indicator provided on the excusion plate to display the position of the MCCB.
2. The MCCB as claimed in claim 1, wherein, when the MCCB is in OFF position, the upper limit of the slot is before a toggle position of the MCCB such that the ON position is restricted within the limits of the slot and an actuator returns to OFF position when left free.
3. The MCCB as claimed in claim 2, wherein the toggle position is defined a position beyond which, when the actuator is operated, the state of the MCCB is changed.
4. The MCCB as claimed in claim 1, wherein, when the MCCB is in ON position, the upper limit of the slot indicated ON position due to an ON bias force, which retains the actuator in the ON position.
5. The MCCB as claimed in claim 3, wherein the ON force bias is a force exerted by the ROM which keeps the actuator in the ON position.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to operation of moulded case circuit breakers. In particular, the present disclosure relates to indication of true state of moulded case circuit breakers during operation.

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] Low voltage current limiting circuit breakers are commonly used to receive, supply, protect and isolate the current supply in an electrical circuit. The circuit breakers typically serve two basic purposes - as a switching device for switching ON/OFF during normal operating conditions for the purposes of operation and maintenance; and as a protecting device for tripping or isolating by breaking the contacts interrupting the fault current during abnormal conditions such as short-circuit, overload and under voltage.
[0004] The circuit breakers/ switching devices are designed for use in switchboards, control panels, and combination starters in separate enclosures for effective single location distribution and control. Also, the circuit breakers/switching devices are housed inside the enclosure to provide safety to users operating the same. In the most common type of installation, an operating handle is mounted on the control panel door while the circuit breaker/switching device is mounted inside the panel door. The circuit breaker device/switching device has a shaft coming out that has to be rotated to switch the circuit breaker ON and OFF.
[0005] Before attempting any maintenance on any electrically operated equipment it is essential to prevent operation of equipment. This can only be done by isolating the equipment at its power source. Electrical isolation is achieved by breaking the electrical contacts feeding the equipment. All isolation handles are fitted with a device that allows the handle to be locked in the contactor open (equipment isolated) position. To prevent removal of isolation while maintenance work is carried out on the equipment, it is to be ensured that equipment controlled by the panel is locked in OFF state.
[0006] Existing design of many rotating handles have provision for locking in the OFF position. However, in some cases, this is possible even though the contacts of the circuit breaker get welded closed (e.g. due to short circuit). Many such breakers are designed so that even moving the circuit breaker handle to the OFF position is prevented when the contacts are welded closed. Despite these modifications, a rotary handle connected to the circuit breaker handle through a spring could still be forcibly moved to and locked in the OFF position. This would provide a false indication of the state of the circuit breaker when the contacts are welded closed.
[0007] Moreover, according to IEC standard, when equipment in the OFF position is locked by a means such as padlock, it shall not be possible to switch the device in ON condition under normal operating conditions. Also, when the contacts are welded it shall not be possible to lock the equipment in OFF position. Additionally, the handle must return to indicate the ON position when it is released. To verify the effectiveness of indication a test is conducted wherein the actuator (handle) is subjected to three times the normal OFF force, however applied force shall not be less than the minimum nor more than the maximum values set by IEC standard, depending on type of actuator. The test force is applied without shock to the extremity of the actuator for 10 seconds in the direction to open the contacts (turning OFF). After the test force is removed, the actuator being left free, the actuator shall provide true indication of MCCB device. If the contacts are welded the actuator should return to ON.
[0008] There is, therefore, a requirement in the art for a means that can indicate true state of the circuit breaker in the context of circuit breakers with door mounted rotary operating mechanism, which also conforms to industry standards.
[0009] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0010] A general object of the present invention is to provide a moulded case circuit breaker (MCCB) with true state indication.
[0011] Another object of the present invention is to provide an MCCB with true state indication that can be easily installed in existing equipment.
[0012] Another object of the present invention is to provide an MCCB with true state indication that is robust and reliable.

SUMMARY
[0013] The present disclosure relates, in general, to operation of moulded case circuit breakers. In particular, the present disclosure relates to indication of true state of moulded case circuit breakers during operation.
[0014] In an aspect, the present disclosure provides a moulded case circuit breaker (MCCB) with true state indication, said MCCB comprising: a rotary operating handle (ROH) provided on a rotary operating mechanism (ROM) of the MCCB, said ROH comprising an excusion plate; a kidney-shaped slot provided on the excusion plate, said slot subtending a predetermined angle at a centre, wherein an upper limit of slot is configured to determine any of ON, OFF and TRIP positions of the MCCB; and an indicator provided on the excusion plate to display the position of the MCCB.
[0015] In an embodiment, when the MCCB is in OFF position, the upper limit of the slot is before a toggle position of the MCCB such that the ON position is restricted within the limits of the slot and an actuator returns to OFF position when left free. In another embodiment, the toggle position is defined a position beyond which, when the actuator is operated, the state of the MCCB is changed.
[0016] In another embodiment, when the MCCB is in ON position, the upper limit of the slot indicated ON position due to an ON bias force, which retains the actuator in the ON position. In another embodiment, the ON force bias is a force exerted by the ROM which keeps the actuator in the ON position.
[0017] 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
[0018] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.
[0019] FIG. 1 illustrates an exemplary schematic representation of an MCCB with a door-mounted rotary operating mechanism, in accordance with an embodiment of the present disclosure.
[0020] FIG. 2 illustrates an exemplary exploded-view representation of a rotary operating handle of the MCCB, in accordance with an embodiment of the present disclosure.
[0021] FIG. 3 illustrates an exemplary front-view representation of an excusion plate, in accordance with an embodiment of the present disclosure.
[0022] FIG. 4 illustrates an exemplary exploded-view representation of the rotary operating mechanism, in accordance with an embodiment of the present disclosure.
[0023] FIG. 5 illustrates an exemplary isometric representation of an excusion plate with rotary handle on the rear side, in accordance with an embodiment of the present disclosure.
[0024] FIG. 6 illustrates an exemplary isometric representation of an excusion plate with rotary handle on the front side, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0025] 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 spirit and scope of the present disclosure as defined by the appended claims.
[0026] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0027] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0028] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
[0029] The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non – claimed element essential to the practice of the invention.
[0030] The present disclosure relates, in general, to operation of moulded case circuit breakers. In particular, the present disclosure relates to indication of true state of moulded case circuit breakers during operation.
[0031] In an aspect, the present disclosure provides a moulded case circuit breaker (MCCB) with true state indication, said MCCB comprising: a rotary operating handle (ROH) provided on a rotary operating mechanism (ROM) of the MCCB, said ROH comprising an excusion plate; a kidney-shaped slot provided on the excusion plate, said slot subtending a predetermined angle at a centre, wherein an upper limit of slot is configured to determine any of ON, OFF and TRIP positions of the MCCB; and an indicator provided on the excusion plate to display the position of the MCCB.
[0032] In an embodiment, when the MCCB is in OFF position, the upper limit of the slot is before a toggle position of the MCCB such that the ON position is restricted within the limits of the slot and an actuator returns to OFF position when left free. In another embodiment, the toggle position is defined a position beyond which, when the actuator is operated, the state of the MCCB is changed.
[0033] In another embodiment, when the MCCB is in ON position, the upper limit of the slot indicated ON position due to an ON bias force, which retains the actuator in the ON position. In another embodiment, the ON force bias is a force exerted by the ROM which keeps the actuator in the ON position.
[0034] FIG. 1 illustrates an exemplary schematic representation of an MCCB with a door-mounted rotary operating mechanism, in accordance with an embodiment of the present disclosure.
[0035] As shall appear in the embodiments described herein, numerals, as they appear in the associated drawings, shall be used to designate the following components,
? 1 - Door-mounted ROM setup
? 1A – Moulded Case Circuit Breaker (MCCB)
? 1B – Rotary operating Mechanism (ROM)
? 1C – Coupler
? 1D – Shaft
? 1E – Door
? 2 - Rotary operating Handle (ROH)
? 2A – Padlock lever
? 2B – Padlock Pin
? 2C – Rotary Handle
? 2D – Excusion Plate
? 2E – Handle Lock Plate
? 2F – Interlocking Slider
? 2G – Back Plate
? 2H – Gasket
? 3 - Front view of Excusion plate
? 3A– Kidney-shaped slot
? 3B – Indication Label
? 3C – Slot angle
? 3D – Knock-out feature
? 4 - Exploded view of Rotary Operating Mechanism
? 4A– Front cover
? 4B – ROM Housing
? 4C – Torsion Spring
? 4D – Internal Gear
? 4E – Gear Train
? 4F – Mounting plate
? 4G – Rack
[0036] The moulded case circuit breaker (MCCB) 1A includes a rotary operating mechanism (ROM) 1B to convert toggle motion of the MCCB to rotary motion, a coupler 1C, and a shaft 1D.
[0037] FIG. 2 illustrates an exemplary exploded-view representation of a rotary operating handle of the MCCB, in accordance with an embodiment of the present disclosure. The rotary operating handle 2 (ROH) includes a rotary handle 2C with padlock lever 2A, an excusion plate 2D, a handle lock plate 2E, an interlocking slider 2F, a back plate 2G and a gasket 2H. A padlock pin 2B is insert moulded in the padlock lever 2A.
[0038] FIG. 3 illustrates an exemplary front-view representation of an excusion plate, in accordance with an embodiment of the present disclosure. The excusion plate has a kidney-shaped slot 3A which subtends a slot angle(O) 3C at the centre. An indication label 3B is present on front side of the excusion plate with clearly defined ON, OFF and TRIP zones. There is also an optional provision for a knock-out feature 3D for padlocking the MCCB in ON position.
[0039] FIG. 4 illustrates an exemplary exploded-view representation of the rotary operating mechanism, in accordance with an embodiment of the present disclosure. The ROM 1B consists of a coupler 1C mounted on the ROM housing 4B. Coupler 1C is connected to the rack and pinion assembly, which consists of an internal gear 4D, a gear train 4E, a mounting plate 4F and a rack 4G. The coupler 1C has a socket on one side for connecting shaft 1D that transmits rotary motion between ROM and ROH. A torsion spring 4C is attached to the internal gear 4D such that it biases the rack and pinion arrangement towards OFF. The rack and pinion assembly converts the rotary motion of ROH handle to linear motion of MCCB knob. A front cover 4A is snap fit on the top of housing 4B which has space for sticker/ labels.
[0040] FIG. 5 illustrates an exemplary isometric representation of an excusion plate with rotary handle on the rear side, in accordance with an embodiment of the present disclosure. The padlock pin 2B is restricted when it moves in the kidney-shaped slot. When contacts in MCCB 1A are welded and ROH 2 is padlocked by forcibly turning the handle to OFF, the actuator (rotary handle) will assume this position.
[0041] FIG. 6 illustrates an exemplary isometric representation of an excusion plate with rotary handle on the front side, in accordance with an embodiment of the present disclosure. The state of MCCB can be seen as ON as required by the design standards during welded contact condition. This can be observed on the Indication label 3B.
[0042] Referring to FIGs. 1 – 6, in the MCCB, the kidney-shaped slot 3A is incorporated in the design of excusion plate 2D primarily so that true indication can be achieved in both normal as well as contact welded condition. Changing the state (ON to OFF and vice versa) of the MCCB device is not permitted in padlocked condition for devices designed suitable for isolation. This is accomplished by setting the upper limit of the slot angle 3C before the toggle position of the MCCB device 1A. ‘Toggle position’ is a position beyond which, if the actuator (handle) is operated, the state of MCCB is changed. Thus, when a user attempts to switch ON such a padlocked MCCB, the padlock pin 2B is restricted to move within the limits of the slot and the actuator returns to the OFF position when left free since changing the state is prevented as explained above.
[0043] When the contacts are welded in the closed position (ON), padlocking the MCCB in the OFF position is prevented which would lead to false indication. This is one of the most important requirements for switchgear devices that are suitable for isolation. In order to accomplish this requirement, the slot angle 3C is chosen such that its upper limit indicates ON in welded condition with a padlock because of the ‘ON bias force’. When the MCCB device has welded contacts, a force is exerted by mechanism, which keeps the actuator in ON position; this is the ‘ON bias force’. There is an indication label 3B on the excusion plate 2D of ROH 2 which has markings that indicate whether the device is in ON, OFF or TRIP position.
[0044] The existing interlocking slider 2E was hindering an easy movement of padlock pin 2B in the slot 3A. Therefore, the outer profile of the interlocking slider is modified subsequently to avoid any interference with the padlock pin and slot.
[0045] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive patent matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “includes” and “including” 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. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practised with modification within the spirit and scope of the appended claims.
[0046] 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
[0047] The present invention provides a moulded case circuit breaker (MCCB) with true state indication.
[0048] The present invention provides an MCCB with true state indication that can be easily installed in existing equipment.
[0049] The present invention provides an MCCB with true state indication that is robust and reliable.