FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Isolator stuck indication arrangement
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Ghate Rahul Anil, Jadhav Rajendra Vitthal, both of Crompton Greaves Ltd, S3, Switchgear Complex, A-3, M1DC, Ambad, Nasik - 422010, Maharashtra, India, both Indian Nationals.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
This invention relates to an isolator stuck indication arrangement. Particularly, the present invention relates to an isolation stuck indication arrangement for' sensing the isolator position.
BACKGROUND OF THE INVENTION
An isolator is an off-load device intended to be opened only after the current has been interrupted by some other control device.
In electrical engineering, a disconnector or isolator is used to make sure that an electrical circuit can be completely de-energized for service or maintenance. High-voltage isolation switches are used in electrical sub-stations to allow isolation of apparatus such as circuit breakers, transformers and transmission lines, for maintenance. In some designs, the isolator switch has the additional ability to earth the isolated circuit, thereby providing additional safety to the circuit. Such an arrangement would apply to circuits which inter-connect power distribution systems where both ends of the circuit need to be isolated. Safety regulations of the utility must prevent any attempt to open the disconnector while it supplies a circuit.
It is important that an isolator position sensed properly for the proper functioning of the circuit.
The systems presently known get signal of either open or close position of the isolator. Currently, the position indicator gets a signal from the auxiliary switch, which is not directly mounted on the shaft, which is operating the main contact. Although this type

of an arrangement is very flexible to adjust and the cost is comparatively low, as there is
i
no additional device required, there is no intermediate signal provided by the above circuitry. Further, the IEC requirement of the correct indication is not fulfilled. The indication signal indicates wrong positioning of the isolator main contacts, due to which there is a possibility of actuator loose mounting or wrong mounting, thereby leading to wrong signal. Further, the skill required for setting the actuator at the right position is more.
OBJECTIVES OF THE INVENTION
It is an objective of the present invention to provide an arrangement which can obviate the aforesaid drawbacks by providing a system which can sense the isolator position correctly. Particularly, it is an objective of the present invention to sense when the isolator is stuck between the open and the closed condition.
DETAILED DESCRIPTION OF THE INVENTION
In order to achieve the aforesaid and other objectives, according to the invention, an isolator stuck indication arrangement is provided.
In the present invention, the auxiliary switch providing signal to the position indicator is provided with a 120° rotation, which is directly mounted on the main shaft operating the main contact with the help of coupling. This will eliminate the actuator -lever arrangement.
The present invention further relates to an isolator stuck indication circuit arrangement for sensing an isolator position, connected to a DC supply, comprising of (a)

a first circuit segment comprising of a closing contact and an auxiliary switch normally open (NO) contact connected in series; (b) a second circuit segment comprising of an opening contactor and an auxiliary switch normally closed (NC) contact connected in series; (c) a third circuit segment comprising of switches corresponding to said closing contactor and opening contactor along with the timer connected in series; and (d) a fourth circuit comprising of an indicator and timer switch corresponding to the timer, wherein the circuits are arranged in parallel configuration, such that when the isolator is in open or closed condition, the timer is inactive; and when the isolator is stuck between open and closed conditions, the timer is activated.
These and other aspects, features and advantages of the invention will be better understood with reference to the following detailed description, accompanying drawings and appended claims, in which,
Fig la illustrates a circuit arrangement of an isolator stuck indication depicting when the isolator is in an open condition.
Fig lb illustrates a circuit arrangement of an isolator stuck indication depicting when the isolator is in a closed condition.
Fig 1c illustrates a circuit arrangement of an isolator stuck indication depicting when the isolator is in a stuck condition.
Fig la illustrates a circuit arrangement of an isolator stuck indication depicting when the isolator is in an open condition. In this figure, the isolator stuck indication circuit arrangement comprises of (a) a first circuit segment comprising of a closing contact (CC) and an auxiliary switch normally open (NO) contact (89A) connected in

series; (b) a second circuit segment comprising of an opening contactor (OC) and an auxiliary switch normally closed (NC) contact (89B) connected in series; (c) a third circuit segment comprising of switches (CC1) and (OC1) corresponding to said closing contactor and opening contactor along with the timer (T) connected in series; and (d) a fourth circuit comprising of an indicator (AL) and timer switch (Tl) corresponding to the timer, wherein the circuit segments are arranged in parallel configuration. In relation to Fig la, the auxiliary switch 89A will be open and 89 B will be closed, which would make OC1 open, thereby making the switch Tl open and the timer (T) inactive.
Fig lb illustrates a circuit arrangement of an isolator stuck indication depicting when the isolator is in a closed condition. When the isolator is in a closed condition, 89A of the auxiliary switch is in a closed condition, which makes CC1 contact of the contactor to open the circuit, which makes switch Tl open and the timer (T) inactive.
Fig lc illustrates a circuit arrangement of an isolator stuck indication depicting when the isolator is in a stuck condition. The isolator is stuck between the two healthy conditions and thus neither 89A nor 89B will be in closed position and thus both OC and CC will be de energies condition and thus OC1 and CC1 will be closed thus to activate timer and after the set time delay the tl will be closed and we will get the indication of the isolator stuck with the help of an indicator, may be an alarm or a lamp.
Advantages of the present invention:
I) IEC requirement will be complied accurately;

2) The correct position of the isolator can be sensed properly so as to avoid accidents by closing CB when isolator is open
3) Can prevent fatal property damage caused by sensing wrong position.
4) Very useful in case of atomized substation / un manned sub station
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the invention as defined.

We claim:
1. An isolator stuck indication arrangement for sensing an isolator position,
connected to a DC supply, comprising of:
A. an auxiliary switch for providing signal to position indicator wherein said
auxiliary switch is mounted on a shaft operating main contact with a
rotation of 120°; and
B. a circuit arrangement comprising of:
a. a first circuit segment comprising of a closing contactor and an
auxiliary switch normally open (NO) contact connected in series;
b. a second circuit segment comprising of an opening contactor and an
auxiliary switch normally closed (NC) contact connected in series;
c. a third circuit segment comprising of switches corresponding to said
closing contactor and opening contactor along with the timer
connected in series;
d. a fourth circuit segment comprising of an indicator and timer switch
corresponding to said timer
wherein said circuit segments are arranged in parallel configuration.
2. An isolator stuck indication arrangement as claimed in Claim 1, wherein said
auxiliary switch is directly mounted on said shaft with couplings.

3. An isolator stuck indication arrangement as claimed in Claim 1, wherein said timer is inactive when said isolator is in open or closed condition.
4. An isolator stuck indication arrangement as claimed in Claim I, wherein said timer is activated when said isolator is stuck between open and closed conditions.
5. An isolator stuck indication arrangement as claimed in Claim 1, wherein said indicator comprises of an alarm or a lamp.