FORM 2
THE PATENTS ACT, 1970 (39 of l970)
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)
1. TITLE OF THE INVENTION
An intelligent controller of the plunger of a vacuum interrupter
2. APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Prabhadevi,
Mumbai 400030, Maharashtra, India, an Indian Company
3.. INVENTORS
Name : Nirody Jaishankar
Address : Crompton Greaves Limited, Electronic Development Centre,
Global R&D, Kanjur Marg (E), Mumbai 400042, Maharashtra,
India
Nationality : Indian national
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

BACKGROUND OF THE INVENTION
The function of the Vacuum interrupter is to open or close single or multiple high current / high voltage contacts using an isolated AC or DC supply operated contactor coil. The current required by the contactor coil is initially high to pull in the plunger. However, during the holding position of the plunger a smaller flux is required to be produced for holding the plunger in the closed position.
Therefore, in event of a high current passing through the coil for a longer time there is unnecessary wastage of power and the coil has to be designed for carrying higher continuous current resulting in a larger / costlier vacuum Interrupter. Further, if the coil is designed for the lower hold on current and the current is not reduced after the initial hold on period, the coil is likely to burn,
To overcome the above problems in controlling of the plunger a few methods are proposed in the prior art such as use of a series dropping power resistor to drop the voltage which will dissipate a lot of heat which results in wastage of power. In other methods a fixed PWM voltage is applied to the contactor coil to reduce the voltage and this may be insufficient for holding the coil if the supply voltage drops or the current in the coil will be higher than necessary in case the supply voltage increases.
Further, the coils in the vacuum interrupter generally need-a separate configuration depending on the power supply they operate on. Generally, the appropriate connection of

the coils is left to the discretion of the customer who can possibly make a mistake in the configuration resulting in either the Vacuum Interrupter not operating due to low current or the coil burning due to a high current.
Furthermore, the contactor coil may be activated by the controller but the plunger may not be pulled. In such event the vacuum interrupter stops operating which may be dangerous.
There is therefore required a system which provides a safe, efficient means for controlling a plunger of a vacuum interrupter having ease of configuration.
SUMMARY
An intelligent controller of the plunger of a vacuum interrupter is described. In one embodiment the intelligent controller allows auto configuration depending on the supply voltage the vacuum interrupter works in.
In one embodiment the intelligent controller comprises of a first contactor coil and a second contactor coil configured to provide electromagnetic flux for pulling and holding of the plunger. A first switch is provided in series with the first contactor coil and a second switch provided in series with the second contactor coil allowing parallel connection of the said coils when both the first switch and the second switch are closed.

A diode is provided between the junction of the first contactor coil with the first switch and the junction of the second contactor coil with the second switch to allow for series connection of the said contactor coil when the first switch and the second switch are open. A voltage divider is configured to output a proportional voltage dependent on system supply voltage. A microcontroller is configured to signal closing of the first switch and the closing of second switch on receiving said proportional voltage in a predefined lower band, and to signal opening of the first switch and the opening of the second switch on receiving said proportional voltage in a predefined higher band.
The intelligent controller of the plunger of a vacuum interrupter as per the present invention enables an ease of configuration for different voltage supplies. A user thus does not have to manually set the coils for operation in different voltage supplies. Also, the intelligent controller takes care of the change in voltage during holding position keeping the flux required in the holding position constant. Any error in the system is rightly detected through the input received from the auxiliary contact which when processed with the current value available through current sensor enables error indication to the user through the error indicator,
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these

embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments
Fig. 1 illustrates An intelligent controller of the plunger of a vacuum interrupter as per one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An intelligent controller of the plunger of a vacuum interrupter is described. In one embodiment the intelligent controller allows auto configuration depending on the supply voltage the vacuum interrupter works in,
In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the invention. It will be apparent, however, to one skilled in the art that the invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into various vacuum interrupters. It is understood that one skilled in art may modify or change the data used in the examples described in the specification.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of

the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.
An intelligent controller of the plunger of a vacuum interrupter as per one exemplary embodiment of the present invention is described with reference to figure 1. The intelligent controller 100 of the plunger of a vacuum interrupter takes an input from of the supply voltage 111 which may be passed through the bridge rectifier 110. The intelligent controller as per one embodiment comprises of a first contactor coil 105 and a second contactor coil 115 % configured to provide electromagnetic flux for pulling and holding of the plunger. A person skilled in the art would realize that various vacuum interrupters may be operated by a plunger.
A first switch 107 is provided in series with the first contactor coil and a second switch 117 provided in series with the second contactor coil allowing parallel connection of the said coils when both the first switch and the second switch are closed. Further, a diode 131 is provided between the junction of the first contactor coil with the first switch and the junction of the second contactor coil with the second switch to allow for series connection of the said contactor coil when the first switch and the second switch are open.
The supply voltage under which the intelligent controller works may be varied for example the ideal supply voltages may be 220 V or 110V. For operation of the interrupter a fixed flux is required from the coils. During the operation of the intelligent

controller in 220 V the required flux is needed to be produced for which the two contractor coil would have to work in series. However, during the operation of the intelligent controller in 110 V the same flux is required to be produced with respect to 220V version and therefore the two contractor coils would be in parallel configuration.
The sensing of the system voltage is done by a voltage divider 101 configured to output a proportional voltage dependent on system supply voltage. For example, when the system voltage is of the order of 220V then the voltage divider would have proportional voltage output of 5 V, and while the system voltage is of the order of 110 V the voltage divider would have proportional voltage of 2.5 V.
A microcontroller 121 is configured to signal closing of the first switch and the closing of second switch on receiving said proportional voltage in a predefined lower band. In an exemplary embodiment the lower band may be defined to be 60 V to 140 V. This band may be provided to cater to system voltages of the order of 110 V. The microcontroller is also configured to signal opening of the first switch and the opening of the second switch on receiving said proportional voltage in a predefined higher band. In an exemplary embodiment the higher band may be defined to be 190 V to 240 V.
In one embodiment a MOSFET 141 may be provided for controlled powering of the first contractor coil and the second contractor coil during holding position of the plunger. The flux required during holding position of the plunger is considerably lesser as compared to

that during closing of the plunger where a high flux needs to be produced to close the plunger and further the vacuum interrupter.
In one embodiment a current sensor 151 is provided. The current sensor is configured to sense the current through the MOSFET and provide a feedback to the microcontroller about the current passing through the contactor coils. During holding position of the plunger in event of shift of the voltage in the predefined higher band or lower band the MOSFET may be signaled by the microcontroller to reduce or increase the pulse width modulation thereby keeping the flux constant and as required in holding position inspite of variation in voltage.
In one embodiment the microcontroller is also configured to receive an input from the auxiliary contact 171 of contractor coil for checking opening and closing of the plunger. An error indicator 181 can also be configured to alert a user of erroneous operation of the coils. The microprocessor configured to signal user of the erroneous operation through said indicator.
The intelligent controller of the plunger of a vacuum interrupter as per the present invention therefore enables an ease of configuration for different voltage supplies. A user thus does not have to manually set the coils for operation in different voltage supplies. Also, the intelligent controller takes care of the change in voltage during holding position keeping the flux required in the holding position constant. Any error in the system is rightly detected through the input received from the auxiliary contact which when

processed with the current value available through current sensor enables error indication to the user through the error indicator,
The foregoing description of the invention has been described for purposes of clarity and understanding. Although embodiments of the present invention have been described relative to a few standards, and associated attributes therein, one skilled in the art will recognize that the present invention is also very much applicable to other such methods and systems. It is not intended to limit the invention to the precise form disclosed. Various modifications may be possible within the scope and equivalence of the appended claims.

We Claim:
1. An intelligent controller of the plunger of a vacuum interrupter comprising:
a first contactor coil and a second contactor coil configured to provide electromagnetic
flux for pulling and holding of the plunger;
a first switch provided in series with the first contactor coil and a second switch provided
in series with the second contactor coil allowing parallel connection of the said coils
when both the first switch and the second switch are closed;
a diode provided between the junction of the first contactor coil with the first switch and
the junction of the second contactor coil with the second switch to allow for series
connection of the said contactor coil when the first switch and the second switch are
open;
a voltage divider configured to output a proportional voltage dependent on system supply
voltage;
a microcontroller configured to signal closing of the first switch and the closing of second
switch on receiving said proportional voltage in a predefined lower band, and to signal
opening of the first switch and the opening of the second switch on receiving said
proportional voltage in a predefined higher band.
2. The intelligent controller of plunger of a vacuum interrupter as in claim 1, further
comprising a MOSFET controlled by the microcontroller for controlled powering of the
first contractor coil and the second contractor coil during holding position of the plunger.

3. The intelligent controller of plunger of a vacuum interrupter as in claim 2, further comprising a current sensor configured to sense the current through the MOSFET and provide a feedback to the microcontroller about the current passing through the contactor coils.
4. The intelligent controller of plunger of a vacuum interrupter as in claim 1, wherein the microcontroller is also configured to receive an input from the auxiliary contact of contractor coil for checking opening and closing of the plunger, and the microprocessor configured to signal user of the erroneous operation.