FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: AN ARRANGEMENT FOR CONTACT WEAR
INDICATION FOR A CIRCUIT BREAKER
2. Applicant(s):
(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 THE INVENTION
The present invention relates generally to Circuit Breakers. More particularly, the present invention relates to an arrangement for contact wear indication for current limiting circuit Breaker such as Moulded case circuit breaker (MCCB) and miniature circuit breaker (MCB).
BACKGROUND OF THE INVENTION AND PRIOR ART
In existing MCCB there is no such provision for contact wear indication which is inbuilt with the circuit breaker. There are only electronic sensing units to sense the contact wear which can be fitted with the circuit breaker externally and that to it cannot be used for all the poles as a common unit.
In switchgear products the contacts wear during normal ON-OFF operation and the life of the contact reduces as number of operations increase. Actually the true picture is not known to the user as these contacts are in a closed chamber. In the existing systems the wear of the contact buttons cannot be known unless an electronic unit is provided as add-on unit to check the status of the contacts. Thus the customer does not know the status of the circuit breaker since the true picture of life cannot be seen from outside.
The current invention indicates the true status of the contacts when the breaker is in ON condition thus helping the user to know the true status of the contacts whichever pole is worse in the breaker. This system is an inbuilt part of the circuit breaker and also more reliable than the existing systems to determine the contact status.
US 5604437 and US 7109720 discloses an electronic means which is used to determine the wear of the contacts, whereas, the present invention is a mechanical system which is more simple and reliable and indicates the true picture of the contacts.

OBJECTIVES OF THE INVENTION
One object of the present invention is to overcome the disadvantages / drawbacks of the prior art.
The basic objective of the present invention is to provide an arrangement for contact wear indication for a circuit breaker.
Another objective of the present invention is to provide a mechanical system which is more simple and reliable and indicates the true picture of the contacts.
These and other advantages of the present invention will become readily apparent from the following detailed description taken 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.
According to one of the aspect of the present invention the system is provided an arrangement for contact wear indication in a circuit breaker, said arrangement comprising:
upper casing;

lower casing;
a contact assembly comprises :
a moving contact comprises atleast one moving contact button;
a fixed contact comprises atleast one fixed contact button;
atleast one retaining spring;
atleast one moving arm loaded on said retaining spring and operatively connected with said contact assembly and said moving arm mounted on the profile in said enclosure;
a rotating arm operatively connected with said moving arm, such that said moving arm rotates said rotating arm; and
a wear indicator operatively connected with said rotating arm and said rotating arm rotates said contact wear indicator adapted to determine the wear of the fixed and moving contacts.
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 DRAWING
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.

Fig. 1 illustrates Moulded Case Circuit Breaker.
Fig. 2 illustrates Overall view of the components used.
Fig. 3 illustrates Contact system assembly.
Fig. 4 illustrates Contact system assembly (Enclosure removed on one side).
Fig. 5 illustrates Moving Arm.
Fig. 6 illustrates Wear Indicator.
Fig. 7 illustrates Rotating arm,
Fig. 8 illustrates Detailed view of the interaction of Contact with Contact wear indicator.
Fig. 9 illustratesDetailed view of the lowered Contact wear indicator after the buttons got eroded.
Fig. 10 Top view or mounted view of the MCCB.
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 numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an arrangement for contact wear indication in a circuit breaker. The arrangement comprises upper casing; lower casing and a contact assembly, atleast one retaining spring; atleast one moving arm loaded on the retaining spring and operatively connected with the contact assembly and the moving arm mounted on the profile in the enclosure; a rotating arm operatively connected with the moving arm, such that the moving arm rotates the rotating arm and a wear indicator operatively connected with the rotating arm and the rotating arm rotates the contact wear indicator adapted to determine the wear of the fixed and moving contacts.
The contact assembly comprises a moving contact comprises atleast one moving contact button and a fixed contact comprises atleast one fixed contact button.
The wear indicator comprises a transparent window.
The moving arm moved by the moving contact as the moving contact button touches
or applies pressure on the fixed contact button.
The wear indicator comprises a color indication arrangement adapted to show the wear of the contacts in reference to a pattern of colors; a substantially circular profile (as in fig 6) and a substantially circular profile (as in fig 6).
The rotating arm comprises a substantially circular protrusion (of fig 7) adapted to get inserted in the circular profile of color indicator and plurality of substantially longitudinal profile placed horizontally on the device (of fig 7);
The moving arm comprises a substantially longitudinal protrusion (of fig 5) of the moving arm operatively connected with the contact buttons will lower to the extent to which the contact button is eroded or worn out and plurality of substantially cylindrical profile (of fig 5) operatively connected with the longitudinal profile of the rotating arm adapted to rotate therotating arm.

The longitudinal protrusion (fig 5) of the moving arm navigate through the circular profile (fig 6) of the wear indicator.
The wear indicator comprises the color pattern which is customized to show every 25% of variation and the user will view the status of thecontact buttons immediately after switching it ON through the window of thewear indicator.
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.
The present invention relates to an arrangement for contact wear indication for a circuit breaker.
The present invention has a spring loaded (9) indicator arm (8) which moves during the contact movement during ON operation and rests at a position according to the thickness of the contact button (23). As the contacts erode the indicator arm (8) moves down still further thus there will be a change of reading indicated outside the outer cover of the circuit breaker thereby giving the true picture of minimum contact thickness to the user.
This arrangement decreases the risk of circuit breaker failure while operating critical loads. If the contacts have worn out to the extent beyond which it can't be usable, the breaker may fail to perform its intended function. The present invention informs the status of the contact button to the user. While the contact button life diminishes to an end, user can replace the breaker as a precaution to save critical time lost in replacing the breaker after it fails to connect the load.
A common indicator arm which has color indications is used to show the worst contact wear among all the poles at ON condition and thereby indicating the true status of the contact button to the user.
• Moving arm (8) as shown in Fig. 5.
• Moving arm retaining spring (9) as shown in Fig. 3.
• Rotating arm (7) as shown in Fig. 7.
• Wear indicator (6) as shown in Fig. 6.

• Wear indicator window (4) as shown in Fig. 1 & Fig. 10.
When the user switches the breaker ON, the moving arm (8) which is shown in Fig. 5 and is connected to contact assembly (11,12) as shown in Fig. 3, is moved by the moving contact(12) as the moving contact button(23) touches or applies pressure on the fixed contact button(23).
The moving arm (8), in turn rotates the rotating arm (7) which is shown in Fig. 7 and is mounted on the profile in the bottom casing(2).
The rotating arm(7), in its turn rotates the Contact wear indicator (6) which is shown in Fig. 6 and is pivoted to the upper casing (1) using the profile (19) as shown in Fig. 6. The Contact wear indicator (6) shows the wear of the contacts in reference to a pattern of colours.
Contact Wear Indicator (6) is used to determine the wear of the contacts [both fixed & moving contacts (11, 12) ]. It is important to replace the worn out contacts as soon as possible, because the breaker would fail at a point of time due to failure of the contacts.
The contact button deteriorates due to the impact between the contact buttons during its lifetime. With respect to the wear of the contacts, the profile (13) provided in the moving arm(8) which is shown in Fig. 5, assembled in each contact system assembly will lower to the extent to which the contact button is eroded or worn out as shown in Fig. 8 & Fig. 9.
The profile (14) of the moving arm (8) which is shown in Fig. 5, will rotate the rotating arm (7) with the help of the profile (22) of the rotating arm (7) which is shown in Fig. 7. In turn the profile (21) of the rotating arm (7) which is shown in Fig.

7, will navigate through the profile (20) of the Contact wear indicator (6) which is shown in Fig. 6.
The contact wear indicator (6) has a pattern (18) of colors which can be customized to show the percentage of wear. Here in the Contact wear indicator (6) shown in Fig. 6, the colour pattern (18) is customized to show every 25% of variation. The user can view the status of the contact buttons immediately after switching it ON through the winow (4) provided as shown in Fig. 1 & Fig. 10.
ADVANTAGES:
• The user would be updated with the true nature of the contacts every time he switches ON the breaker.
• A preventive maintenance activity can be carried out by changing either the contacts or the whole breaker with a surprise when the breaker fails suddenly due to the wear of the contacts.
• Simple arrangement that requires no change in the present assembly.
• Less additional cost for adding this system to the product which in turn adds more value to the product.
• The wear of the worst contact can be judged with the colour pattern visible through the window in the front casing.
FEATURES:
The invention is a simple mechanical system that can be used to indicate the true nature of the worn out contacts inside the breaker without much changes in the assembly and with less additional cost to the customer.

LIST OF CONSTRUCTIONAL FEATURES:
1. Upper Casing
2. Lower Casing
3. Knob
4. Wear Indicator Transparent Window
5. Terminals
6. Wear Indicator
7. Rotating Arm
8. Moving Arm
9. Retaining spring
10. Enclosure
11. Fixed Contact
12. Moving Contact
13. Profile A of Moving Arm
14. Profile B of Moving Arm
15. Profile C of Moving Arm
16. Profile D of Moving Arm
17. Profile E of Moving Arm
18. Colour Indications of Wear indicator
19. Profile A of Wear indicator
20. Profile B of Wear indicator
21. Profile A of Rotating arm
22. Profile B of Rotating arm
23. Contact Buttons

WE CLAIM
1. An arrangement for contact wear indication in a circuit breaker, said
arrangement comprising :
upper casing(l);
lower casing(2);
a contact assembly comprises :
a moving contact(12) comprises atleast one moving contact button(23);
a fixed contact(l 1) comprises atleast one fixed contact button(23);
atleast one retaining spring(9);
atleast one moving arm(8) loaded on said retaining spring and operatively connected with said contact assembly and said moving arm mounted on the profile in said bottom casing;
a rotating arm(7) operatively connected with said moving arm,such that said moving arm rotates said rotating arm; and
a wear indicator(6) operatively connected with said rotating arm and said rotating arm rotates said contact wear indicator adapted to determine the wear of the fixed and moving contacts.
2. Arrangement as claimed in claim 1 wherein said wear indicator comprises a transparent window (4).
3. Arrangement as claimed in claim 1 wherein said moving arm moved by said moving contact as said moving contact button touches or applies pressure on said fixed contact button,

4. Arrangement as claimed in claim 1 wherein said wear indicator comprises
a color indication arrangement(18)adapted to show the wear of the contacts in
reference to a pattern of colors;
a substantially circular profile (19); and
a substantially circular profile (20).
5. Arrangement as claimed in claim 1 wherein said rotating arm comprises
a substantially circular protrusion (21) adapted to get inserted in the circular
profile of color indicator; and
plurality of substantiallylongitudinal profile placed horizontally on said
device(22).
6. Arrangement as claimed in claim 1 wherein moving arm comprises :
a substantially longitudinal protrusion (13) of said moving arm operatively
connected with said contact buttons will lower to the extent to which said
contact button is eroded or worn out; and
plurality of substantially cylindrical profile (14) operatively connected with
said longitudinal profile of said rotating arm adapted to rotate the said rotating
arm.
7. Arrangement as claimed in claim 6 wherein said longitudinal protrusion (13) of said moving arm navigate through said circular profile (14) of said wear indicator.
8. Arrangement as claimed in claim 1 wherein said wear indicator comprises thecolor pattern (18) which is customized to show every 25% of variation and the user will view the status of said contact buttons immediately after switching it ON through the window of said wear indicator.

9. An arrangement for contact wear indication in a circuit breaker as herein described and illustrated with reference to the accompanying drawings.