FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention:- IMPROVED ARRANGEMENT FOR INDICATING TRIP CONDITION IN 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 breaker, more particularly the invention relates to an improved arrangement for indicating the trip condition in modular circuit breakers.
BACK GROUND AND THE PRIOR ARTS
US3596218 discloses a circuit breaker which includes a contact making and breaking assemblage mounted in housing and having a trip mechanism with a trip lever carrying an indicator. The housing has an opening through which the handle of a manual operator extends. The handle has a dust shield which underlies the opening and which has a window with a lens therein. The lens is exposed for viewing from the exterior of the housing when the operator handle is in ON and TRIPPED positions, respectively. Upon tripping of the trip mechanism, the trip lever is moved so as to dispose the indicator close to, and in alignment with, the lens and window for indicating the tripped condition. The lens and operator are suitably notched for permitting passage of the indicator into and out of alignment with the window.
US3596219 discloses a circuit breaker has a trip lever which normally is latched by a latch mechanism in an untripped position wherein it maintains the contacts in condition to be opened and closed by a manual operator. The latch mechanism releases the trip lever only upon the occurrence of abnormal current conditions whereupon the contacts are opened and the trip lever is returned to a tripped position. An indicator strip of flexible, non conducting material having an indicating portion at its outer end is carried by the trip lever. The strip is pushed thereby endwise so that the outer end of the strip engages an interior wall of the housing of the circuit breaker and is guided there along into alignment with a window in the wall, as the lever moves to tripped position, thereby indicating the tripped condition of the circuit breaker. The indicator strip flexes during its movement to and from trip indicating position to facilitate its proper movement.

US4037185 discloses a ground fault circuit interrupting (GFCI) device includes a conventional circuit breaker equipped with a trip mechanism operable automatically to open the breaker contacts in response to over current conditions. A GFCI module, responsive to ground leakage current, actuates a trip solenoid to open the breaker contacts via the trip mechanism in response to a ground fault. An indicator, carried by linkage interconnecting the solenoid and trip mechanism, is moved into registry with an opening in the breaker case only upon actuation of the solenoid to thus indicate the occurrence of a ground fault trip function.
US6104266 discloses a visible trip indication arrangement for a circuit breaker. The visible trip indication arrangement comprises a viewing window forming a part of the breaker housing, the viewing window including indicia thereon that is readily or enhanced visible when the circuit breaker has been tripped and essentially not visible when the circuit breaker is operating by way of a trip indicator that moves under and aligns with the viewing window when the circuit breaker is in the tripped condition. The trip indicator having a brightly coloured surface causes the indicia on the viewing window to be readily visible by way of the reflected light off a surface thereof.
US6107902 discloses a circuit breaker including a housing having a window, a line terminal and a load terminal, and a circuit trip assembly. The circuit trip assembly includes a rotatable cradle, a moveable armature latch and a pivotable trip support including a trip indicator. Upon the occurrence of a tripping condition in the circuit breaker, the trip indicator moves from a first position where it is not visible through the window to a second position where it is visible through the window.
US6246304 discloses a circuit breaker having an external trip indicator, having a circuit breaker housing, a trip mechanism within the housing, sensing a trip condition and being responsive thereto to mechanically break an electrical circuit, an indicator, having a selectively operable retaining mechanism and being biased outward from the circuit breaker housing, and a linkage, sensing a trip condition

of the trip mechanism and selectively releasing the selectively operable retaining mechanism to allow the indicator to move outwardly from the housing. The external trip indicator is operated by sensing an over current condition with the trip mechanism, breaking the electric circuit in response to the over current, sensing a mechanical movement of the trip mechanism, and thereby releasing a positional restraint on the mechanical indicator; and allowing the mechanical indicator to protrude from the housing. The external trip indicator is reset by first resetting the trip mechanism and then displacing the mechanical indicator into the housing.
US6803535 discloses a trip indicator of a circuit breaker is set to the tripped position through engagement by the cradle, which is unlatched by the trip mechanism. Even though the cradle is automatically reset by a reset spring, the trip member indicator is retained in the tripped position by an indicator spring. The trip indicator member is returned to the untripped position by a reset member on the circuit breaker operating member as the latter is rotated by the circuit breaker handle to the ON position. The trip indicating member is transversely displaced through an out of round pivot mount as the operating member is rotated to the off position before the cradle unlatches when the circuit breaker blows open in response to a short circuit.
US7358838 discloses a trip indicator is for a circuit breaker having a housing including first and second openings, separable contacts and an operating mechanism having an operating handle protruding from the first opening. The trip indicator includes a one-piece flag member with a first end having a trip flag and a second end with first and second integral legs. The first leg biases the trip flag away from the second opening when the separable contacts are not tripped open, and includes a latching portion to maintain the flag in a viewable position to indicate the trip condition regardless of the operating mechanism position. The second leg is disposed proximate first leg and biases the operating handle toward the OFF position, thereby assisting the handle to move from the ON position in response to the trip condition.

The disadvantages of the prior art are that there was no clear indication of trip for a particular fault. There was no mechanism to distinguish one fault from other fault. Thus, there is a need to overcome the problems of the prior art. There is therefore a need to developed an improved trip indication arrangement for the use in circuit breakers for providing clear indication of trip for a particular fault and also distinguishes one fault from other fault so that user can easily identify the reason for the tripping and take corrective actions accordingly.
OBJECT OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.
A primary object of the present invention is to provide an improved trip indication arrangement for the use in circuit breakers.
Another object of the invention is to provide a trip indicating arrangement indicating different types of tripping.
Yet another object of the invention is to provide a trip indication in Residual Current Device (RCD) to distinguish residual current fault from over current fault.
SUMMARY OF THE INVENTION
In accordance with the present embodiment of the invention, there is provided an improved arrangement for indicating trip condition in circuit breaking devices.
In accordance with another embodiment, the present invention provides a Residual current circuit breaker with over current protection (RCBO) comprising Miniature circuit breaker unit (MCB) and Residual Current Device unit (RCD)
In accordance with another embodiment, the invention provides Residual Current Device unit (RCD) comprises of a mechanism, a permanent magnetic release

(PMR), Core Balanced Current Transformers (CBCT), a contact system, a test device, terminals, Enclosure (housing and cover).
In accordance with another embodiment, the invention provides a RCD mechanism comprises of a knob, a trip plate, a side plate, a trip latch, an interlock, a moving contact carrier, a resetter, and plurality of springs and pins.
In accordance with another embodiment of the present invention there is provided a trip indicating assembly with a flag locker and a flag.
In accordance with further embodiment of the present invention, the flag is not visible in through the slot when the RCD is in ON condition and knob is in first operation position.
In accordance with further embodiment of the present invention, when tripping occurs, the RCD is moves OFF condition and knob moves to second operating position and the flag is visible through the slot.
In accordance with further embodiment of the invention, the flag moves back to its original position and not visible after resetting of the circuit breaker to its ON condition.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Other features as well as the advantages of the invention will be clear from the following description.
Fig 1 illustrates an isometric view of entire RCBO.
Fig 2 illustrates an isometric view of flag assembly.
Fig 3 illustrates a vertical elevation view of RCD after cover is removed.
Fig 4 illustrates a condition of RCD after tripping due to residual current fault

Fig 5 illustrates a resetting of flag to its original position
The drawings illustrate one preferred embodiment presently contemplated for carrying out the invention. In the drawings: (another way of writing)
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description, reference is made to the accompanying drawings that form a part thereof, and illustrate the best mode presently contemplated for carrying out the invention. Further functioning of the mechanism has been discussed below to describe the way the mechanism operates. However, such description should not be considered as any limitation of scope of the present unit. 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.
According to the invention there is provided an improved trip indication arrangement for the use in circuit breakers. Figure 1 shows the isometric view of entire RCBO in which MCB (3) and RCD units (1) are coupled together. The slot 2 is provided at the top of RCD housing (12) through which indication is visible.
Figure 2 shows the isometric view of flag assembly in which flag locker (5) is connected with flag (4) as shown in this figure.
Figure 3 shows a vertical elevation view of RCD after cover is removed. It represents ON condition of RCD unit (1). Knob (11) is in ON position and contacts are in closed position. Flag locker (5) rests on housing projection and flag (4) is behind the slot provision so that flag (4) is not visible. There will always be some pressure acting on flag locker (5) with respect to housing projection (10).
Figure 4 shows the condition of RCD after tripping due to residual current fault. Knob (11) is in OFF position and the contacts are in opened position. The resetter

(14) is in original position after driving the flag (4). The flag locker (5) is locked with housing projection (10) as shown in figure. So the flag (4) is not able to rotate in clockwise direction. Now the flag (4) is under the slot provision and it is visible.
Figure 5 shows the resetting of flag (4) to its original position. When the circuit breaker is turned on manually, the moving contact carrier (17) hits the flag locker (5) as shown in figure and makes the flag locker (5) to move upwards. Now the flag (4) rotates in clockwise direction due to spring force and comes to its original position. During this time flag locker (5) rides over the housing projection.
According to a preferred embodiment of the invention there is provided an improved trip indication arrangement for the use in circuit breakers. It relates to Modular circuit breaker with trip indication. In the present invention, the trip indication for residual current fault has been provided for RCBO (Residual current circuit with over current protection). The trip indication is in RCD side of RCBO which distinguishes residual current fault from over current fault.
The RCBO consists of a MCB (Miniature Circuit Breaker) unit (3) and a RCD (Residual Current Device) unit (1) as shown in figure 1. The MCB serves the purpose of overload and short circuit protection whereas RCD serves the purpose of residual current protection. The MCB unit (3) and RCD unit (1) is connected by an interlock (13) so that when over current or residual current fault comes, the concern unit will trip and the other unit will also trip. The RCD unit (1) comprises of a Mechanism, Permanent Magnetic Release (PMR) (15), Core Balanced Current Transformer (CBCT), Contact system, Test device, Terminals and Enclosure (Housing and Cover). The mechanism consists of knob (11), side plates, trip plate, trip latches, interlock (13), resetter (14), and moving contact (9) with contact carrier (17), springs (8) and pins.
The phase and neutral wires go through CBCT and secondary winding of CBCT is connected with PMR (15). When the residual current fault occurs (i.e., there will be a difference between phase and neutral current) the PMR (15) will be

actuated. PMR (15) will release the plunger pin which will hit the resetter (14) as well as the trip latch, which in turn de-latches the mechanism of RCD unit (1) as well as the MCB unit (3) since both are connected by an interlock (13). Subsequently opening of contacts in both the units will take place. At the same time, moving contact (9) will make the resetter (14) to come to its original position. The resetter (14) now hits the plunger of PMR (16) and reset it.
The trip indicating unit consists of three components. They are flag (4), flag locker (5) and a torsional spring (8). The top surface of the flag (4) is colored. Both flag (4) and flag locker (5) is made up of plastic wherein flag locker (5) has flexibility. Flag locker (5) is connected at the top of flag (4) using pin connection with click fit arrangement. The flag locker (5) can rotate with respect to hole of flag (4) at the top. The flag assembly which comprises flag (4) and flag locker (5) is mounted inside the RCD mechanism. The bottom side of the flag is connected through pin inside the mechanism and the flag locker (5) rests on the housing wall projection. There will always be some pressure acting on flag locker (5) with respect to housing projection (10).
When the tripping action takes place, resetter (14) will rotate and initiate tripping action. After initiating the tripping action the resetter (14) will rotate further to some extent. This rotation is utilized to drive the flag (4). Flag (4) rotates in anti clockwise direction against a Torsional spring (8). During this time flag locker (5) will slide over the housing wall projection. When flag locker (5) comes to end of housing projection (10) it will slip towards downward direction and locked in the housing projection (10). Now the flag (4) will be visible through the slot (2) provision available at the top of housing.
Trip indication will remain in place, until the Circuit breaker is turned on again. When Circuit breaker is turned on, the top of moving contact carrier (17) will make the flag locker (5) to lift upward. Due to the Torsion spring (8) force the flag (4) rotates in clockwise direction and the flag locker (5) will slide over the housing projection (10). Now the trip indication is not visible.

ADVANTAGES
1. Clear indication of Trip for particular fault
2. Distinguishing one fault from other fault
3. Easy to identify the nature of the fault.
Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with modifications. However, all such modifications are deemed to be within the scope of the claims.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

WE CLAIM:
1. An improved arrangement for indicating trip condition in circuit breaker
comprising of:
a residual current breaker with over current protection (RCBO), said RCBO comprising a Miniature circuit breaker unit (MCB) and Residual Current Device unit (RCD), said RCD unit comprising of a mechanism, a permanent magnetic release (PMR), Core Balanced Current Transformers (CBCT), a contact system, a test device, terminals, Enclosure (housing and cover), said RCD mechanism comprising a knob, a trip plate, a side plate, a trip latch, an interlock, a moving contact carrier, a resetter, and plurality of springs and pins;
wherein a trip indicating unit comprising a flag assembly and a slot in said RCD housing, and a housing projection.
2. An improved arrangement as claimed in claim 1, wherein said flag
assembly further comprising a flag and a flag locker mounted on said RCD mechanism.
3. An improved arrangement as claimed in claim 2, wherein said flag locker
rest on said housing projection and connected at top of said flag using pin connection having a one click arrangement.
4. An improved arrangement as claimed in claim 2, wherein a pin at bottom
of said flag connects it with said RCD mechanism.

5. An improved arrangement as claimed in claim 1, wherein said MCB and
RCD unit is connected together by said interlock.
6. An improved arrangement as claimed in claim 3 , wherein said flag
locker is resting on said housing projector and said flag is behind said slot when RCD unit is in ON condition and knob is in a first operating position.
7. An improved arrangement as claimed in claim 1, wherein said resetter
initiates tripping action.
8. An improved arrangement as claimed in claim 6, wherein said tripping
action turns said RCD unit to OFF condition and moving said knob to second operation position.
9. An improved arrangement as claimed in claim 6, wherein said resetter pin
rotate further moving said flag in an anti clockwise direction against a torsional spring.
10. An improved arrangement as claimed in claim 8, wherein said movement of flag locks said flag locker with said housing projection, causing said flag visible through said slot.
11. An improved arrangement as claimed in claim 1, wherein said flag locker moves upward and move in a clockwise direction making trip indication not visible during a resetting condition.

12. An improved arrangement as claimed in claim 11, wherein movement of said flag locker is aided by moving contact and torsional spring.
13. An improved arrangement for indicating trip condition in circuit breaker as herein described and illustrated with reference to accompanying drawings.