FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(Section 10)
"AN IMPROVED MOTOR OPERATOR ASSEMBLY WITH STORED ENERGY FEATURE FOR A MOULDED CASE CIRCUIT BREAKER (MCCB)
LARSEN & TOUBRO LIMITED,
L&T House,
Ballard Estate,
MUMBAI-400 001. Maharashtra State, India
An Indian Company registered under the
Provisions of the Companies Act, 1956
The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed :-

Present invention relates to a motor operator with stored energy feature for all three positions of a moulded case circuit breaker (MCCB). More particularly present invention relates to a motor operator with stored energy feature for all three positions of a moulded case circuit breaker namely "ON", "OFF" and "TRIPPED".
In the 'ON' position, the contacts of the MCCB are closed and in the 'OFF' position the contacts are open. The MCCB comes to TRIPPED' position in the event of an abnormal situation, such as short circuit or overload. The MCCB can also be brought to TRIPPED' position by a separate push to trip button located on MCCB. The MCCB needs to be reset from tripped position to off position by moving its operating knob.
In prior art the MCCB can be brought to the above mentioned various states namely "ON", "OFF" and "TRIPPED" by directly operating motor geared to its operating knob. The obvious drawback of this system is that the operating time of the MCCB is comparatively high.
Also there are many types of stored energy motor operator for MCCB in prior art, which reduces its operating time. But the short fall in these mechanisms is that the stored energy feature is only for closing operation i.e. moving the MCCB knob from OFF position to ON position. The MCCB is brought to "TRIPPED" position, as explained above and then is brought to the OFF position by operation of the motor, which results in simultaneously charging the spring for next closing operation. Drawback of this system is that there is no stored energy operation for "TRIPPED " to OFF position.
Another prior art mechanism, which has stored energy feature for all the three positions necessarily, requires simultaneous charging of the closing and opening springs. Broadly speaking if the MCCB is closed from open position, the closing springs have to wait for opening springs to get discharged and then only both closing and opening springs can be charged. This has a unique disadvantage that in the event of non-availability of power supply to motor, the

8 JAN 2004

discharged springs can not to be charged even manually till the other charged springs are discharged. Thus there is no readily available spring energy for the MCCB operation.
It is object of the present invention to develop a motor operator with stored energy feature for all three positions of a moulded case circuit breaker (MCCB).
It is also the object of the present invention to overcome the shortcoming and disadvantages of the prior art.
According to this invention therefore an improved motor operator assembly with stored energy feature for a moulded case circuit breaker comprises a motor, a system of gears being activated by the said motor, plurality of cranks are mechanically coupled to cams and held in position by means of a system of roller latches. The said system of gears rotates the said cranks. The plurality of springs of which one set of plurality of springs is connected to one crank for closing operation and one set of plurality of springs being connected to the other crank for opening operation. The said springs are held by a crank pin and a spring anchoring pin and they get charged due to the rotation of the said cranks. The supply to the motor is cut off by the said cam when the said springs are fully charged. The said springs are discharged on delatching of the said roller latches. Two sliders are connected to the said cranks for closing and opening operations. The said cranks rotate due to the energy released upon delatching of roller latches and in turn move the respective slider for closing or opening operations and the said slider subsequently operates the MCCB knob.
The invention will now be described with reference to the drawings and the accompanying specification wherein the salient features have been shown by suitable numerals referred to appropriately in the description.
The drawings consists of 7 figures:

8 JAN 2004
Fig. 1 : The motor operator assembly.
Fig.2: Latching position df the crank.
Fig. 3: Coupling of Cranks arid cam.
Fig.4: Isometric view of the motor operator assembly.
Fig. 5:501 – Position of crankpin at the end of working Stroke.
502 - spring deflection
503 - Position of crank pin when the spring is fully stretched.
504 - Locus of crank pin.
505 - Maximum permissible solid length.
506 - Spring anchdoring pin.
507 - Spring.
Figs: 601 - Position df crank: pin at the end df working stroke.
602 - LOCUS df crank pin.
603 - Position df crank pin when the spring is fully stretched. 604-Solid length.
Fig. 7:701 -Spring caps.
702 - crank pin
703-spring body
704 - spring anchoring point
Referring td fig: 1 the said; invention comprises" of two sets df springs (107) (only one set df spring is shown ion fig; 1). one df the said sets df spring for dosing and other set df spring for opening/reset operation. The said sets df springs (107) are charged by a motor (too). The said motor (too) is responsible for driving two sets of cranks {104 & 104a) (only one set df 104 is shown in fig. 1), through a system df gears (net shown in fig.). The crank pins (105) are connected to a fixed point {98) in the frame (99) df the mechanism through a set df springs (107).
The said set df springs' (107) are held in place by a unique mounting arrangement The said mounting arrangement is such that it permits the plurality df the springs td be mounted. The number of assembled springs on tne

mounting arrangement can be easily varied depending on the force requirement This arrangement has a unique advantage of meeting the higher or lower force necessary to operate the MCCBs Of varying number Of poles as" compared to conventional 3 pore MCCBs. This arrangement permits higher force spring without exceeding their permissible stress in the available space. An arrangement is also being made to permit the motor (100) to overrun till it is switched off; after the springs (to?) am charged fully.
Refer to figure 2. When the set of springs (to?) are charged, the said cranks t04 are held in place by a system of roller latches (111). The said system of roller latches < 111) and <112), upon detaching of roller latches, discharges the set of springs (107). The energy released rotates the said crank (104). The crank in turn moves a slider (102), which in turn operates the MCCB knob (tot).
The said slider (T02) is designed in such a way, that it returns to home position immediately after performing each operation. The slider (102) may be provided with the restoring spring (not shown) to effect this home bound position This design also ensures that each slider does not obstruct other slider during their respective operation.
When the said crank (104) comes back to initial position, then the motor (too) is again switched en to charge the said spring (107) for the next operation.
Similar mechanism is used for bringing the MCCB knob (101) from Tripped position to OFF position after resetting the MCCB mechanism.
Referring to figure 3, the said cranks 104 & 104a (not shown) are also mechanically coupled to cams (113) & (113a) (only 113 shown in fig. 3) which actuate micro switches (not shown) for energizing tm motor (too) in a predetermined sequence.

Both closing and opening springs (107 & 107a) are charged independently; This has m advantage that me does not have to wait for charging of spring till both closing and opening operations are performed.
Figure 4 is the isometric view of the motor operator assembly showing me motor (100) connected" to the system of gears (114), two sets of cranks (104y and (104a) springs {107), cam {113) and other parts, in this figure only me important parts have been shown by the numerals.
Uhidue spring arrangement (Refer to figures 5,6 and 7);
The said mechanism requires a high spring force m operate. There sire limitations in designing such a spring. As shown in figure" 5, because of the limited space available; there is a limitation en the size of the solid length of the spring that can be used. The maximum spring solid length possible is the distance between" the crank pin at the end of the working stroke and the spring anchoring pin. With the limited solid length and a high operating stroke Of the mechanism, the spring would get stretched beyond its permissible" working stress value. This can be a very severe limitation for designing a spring.
As shown in the above figure 6, if the solid length of the spring is large, then the body of the spring would obstruct the movement of the crank pin. This is achieved by splitting a spring into plurality of springs acting in parallel, allowing unrestricted space for the movement of the crank pin. {Refer to figure 7). When a higher force MCCB (because of higher rating or 4 pole version) is used, the spring force required is even higher, posing a constraint of accommodating the larger value spring iN the available space, it is another objective of this invention to allow flexibility in assembling the springs in order to obtain &n increased or decreased total spring force value. This is achieved by unique spring anchoring construction.

Advantages
1. It has stored energy operation for TRIPPED and OFF position
2. It reduces the operating, time.
3. It has stored energy even if there is non-availability of power.
4. It allows flexibility in assembling the springs.

We claim:
1. An improved motor operator assembly with stored energy feature for a moulded case circuit breaker comprising a motor, a system of gears being adivated by the said motor, plurality of cranks mechanically coupled to cams and held in position by means of a system of roller latches, the said system of gears rotates the said cranks, plurality of springs of which one set of plurality of springs being connected to one crank for closing operation and one set of plurality of springs being connected to the other crank for opening operation, the said springs being held by a crank pin and a spring anchoring pin, the said springs getting charged due to the rotation of the said cranks, the supply to the motor being cut off by the said cam when the said springs are fully charged, the said springs being discharged on delatching of the said roller latches, two sliders connected to the said cranks for dosing and opening operations, the said cranks rotate due to the energy released upon delatching of roller latches and in turn move the respective slider for dosing or opening operations and the said slider subsequently operates the MCCB knob.
2. An improved motor operator assembly as claimed in claim 1, wherein the said cranks are two cranks being used for charging one set of plurality of springs for closing operation and one set of plurality of springs for opening operation.
3. An improved motor operator assembly as claimed in claim 1, wherein the said plurality of springs is achieved by splitting a spring into plurality of springs acting in parallel thereby allowing unrestricted space for the movement of the crank pin.
4. An improved motor operator assembly as claimed in claim 1, wherein the said sliders return to their original position immediately after performing closing or opening operation.

5. An improved motor operator assembly as claimed in claims 1 to 5 above substantially as herein described with the help of the accompanying specification and drawings.

FORM-2
THE PATENTSACT.1970
(39 of 1970)
COMPLETE SPECIFICATION
(Section 10)
"AN IMPROVED MOTOR OPERATOR ASSEMBLY WITH STORED ENERGY FEATURE FOR A MOULDED CASE CIRCUIT BREAKER'(MCCB)
LARSEN & TOUBRO LIMITED,
L&T House,
Ballard Estate,
MUMBAI-400 001. Maharashtra State, India
An Indian Company registered under the
Provisions of the Companies Act, 1956
The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed :-

Present invention relates to a motor operator with stored energy feature for all three p®sitions of a moulded case circuit breaker (MCCB)» More particularly present invention relates to a motor operator with stored energy feature for all three positions of a moulded case circuit breaker namely "ON", "OFF" and "TRIPPED".
Jn the 'ON' position, the contacts of the MCCB are closed and in the 'OFF' position the contacts are open. The MCCB comes to 'TRIPPED' position in the event of an abnormal situation, such as short circuit or overload. The MCCB can also be brought to 'TRIPPED' position by a separate push to trip button located on MCCB. The MCCB needs to be reset from tripped position to off position by moving its operating knob.
In prior art the MCCB can be brought to the above mentioned various states namely "ON", "OFF" and "TRIPPED" by directly operating motor geared to its operating knob. The obvious drawback of this system is that the operating time of the MCCB is comparatively high.
Also there are many types of stored energy motor operator for MCCB in prior art, which reduces its operating time. But the short fall in these mechanisms is that the stored energy feature is only for closing operation i.e. moving the MCCB knob from OFF position to ON position. The MCCB is brought to "TRIPPED" position, as explained above and then is brought to the OFF position by operation of the motor, which results in simultaneously charging the spring for next closing operation. Drawback of this system is that there is no stored energy operation for "TRIPPED " to OFF position.
Another prior art mechanism, which has stored energy feature for all the three positions necessarily, requires simultaneous charging of the closing and opening springs. Broadly speaking if the MCCB is closed from open position, the closing springs have to wait for opening springs to get discharged and then only both closing and opening springs can be charged. This has a unique disadvantage that in the event of non-availability of power supply to motor, the

discharged springs can not to be charged even manually till the other charged springs are discharged. Thus there is no readily available spring energy for the MCCB operation.
It is object of the present invention to develop a motor operator with stored energy feature for all three positions of a moulded case circuit breaker (MCCB).
It is also the object of the present invention to overcome the shortcoming and disadvantages of the prior art.
According to this invention therefore an improved motor operator assembly with stored energy feature for a moulded case circuit breaker comprises a motor, a system of gears being activated by the said motor, plurality of cranks are mechanically coupled to cams and held in position by means of a system of roller latches. The said system of gears rotates the said cranks. The plurality of springs of which one set of plurality of springs is connected to one crank for closing operation and one set of plurality of springs being connected to the other crank for opening operation. The said springs are held by a crank pin and a spring anchoring pin and they get charged due to the rotation of the said cranks. The supply to the motor is cut off by the said cam when the said springs are fully charged. The said springs are discharged on deiatching of the said roller latches. Two sliders are connected to the said cranks for closing and opening operations. The said cranks rotate due to the energy released upon deiatching of roller latches and in turn move the respective slider for closing or opening operations and the said slider subsequently operates the MCCB knob.
The invention will now be described with reference to the drawings and the accompanying specification wherein the salient features have been shown by suitable numerals referred to appropriately in the description.
The drawings consists of 7 figures:

We daim:
1. An improved motor operator assembly with stored energy feature for a

moulded case drcuit breakerlcompnsing a motor, a sy^em of gears being adivated by the said motor, pluralify of cranks mechanically coupled to cams and held in position t>y means of a system of roller iaiches, the said sy^em of gears rotates the said cranks, phirality of springs of whk:h one set of plurality of springs beir^ conneded to one crank for dosing operation and one set of plurality of springs being conneded to the c^her crank for opening operatk>n, the sakj springs being hekl by a crank pin and a sprir^ seichoring pin, the said springs getting charged due to the rotatkin of the saki cranks, ttie s^>pty to flie motcMT beir^ cut off by flie said cam when the saki Sfvlngs are fully charged, the sakt springs being discharged on delatching of flie sakI roller t^^ies, two sikl^rs conneded to tt% said amrSf^ for dosing and qp^ing qperatienif^ (H3^atk}n.

5. An improved motor operator assembly as claimed in claims 1 to 5 above substantially as herein described with the help of the accompanying specification and drawings.

Dated this 7TH day of January 2004


(M.D.BHATE) AGENT FOR APPLICANT