F0RM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - TEST KIT SIGNAL SELECTIVITY USING UNIQUE DIP SWITCH COMBINATIONS
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 generally relates to the field of circuit breaker testing. More particularly, the present invention relates to a test kit for testing circuit breaker and method thereof.
BACKGROUND AND THE PRIOR ART
MCCBs (Moulded Case Circuit Breakers) are one of the primary protection devices used in the switchgear industry. The various functions of an MCCB are: Sensing the current flowing in the circuit, to measure the current flowing in the circuit, to compare the measured current level to its pre-set trip point, to make, break and carry currents, to protect the system against abnormal conditions like overload, short circuit and earth fault, and to provide the discrimination to ensure continuous supply to all healthy feeders in case of a fault on one feeder.
The accurate functioning of circuit breakers is therefore very essential for maintaining a healthy power network. Circuit breakers are exposed to several tests before actually implementing on the field. A number of test kits are developed for testing of the circuit breakers. Some of the prior arts in the present field of invention are as follows:
US4814712 provides a test kit for a digital and analog electronic circuit breaker that determines the calibration and over current response, of the circuit breaker when connected within an electric power circuit. The test kit simulates an over current condition and provides verification of the circuit breaker response without de-energizing the circuit breaker or interfering with the circuit breakers protection functions. The test kit connects with the digital communications circuit within the digital circuit breaker to obtain status information concerning pick-up conditions, trip conditions and fault currents which are viewed on the test kit liquid crystal display. A ground fault suppression circuit is included within the test kit for

single-phase current-injection without causing ground fault tripping. The test kit circuit further includes means for optionally tripping the circuit breaker upon completion of any of the tests.
US4803434 provides a portable test device for an electronic trip unit which is electrically powered from the internal power supply of the trip unit being tested. The test unit utilizes three leads connected to the trip unit. One of the leads connects to the voltage source for the trip unit and another lead connects to the ground potential to acquire power from the test unit. The voltage is selectively adjusted within the test unit by resistors and a potentiometer to vary the input voltage which is to be carried by the third lead into the trip unit.
OBJECT OF THE INVENTION
An object of the invention is to overcome the disadvantages/ drawbacks of the prior art.
Another object of the invention is to provide the user to check whether the circuit breaker is tripping correctly.
Another object of the invention is to provide a DIP switch to select the phase to insert the signal, thereby detecting the tripping of electronic unit.
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.

In accordance with the present aspect of the invention there is provided a test kit for checking the tripping action of moulded case circuit breaker. The disclosed invention consists of DAC IC. The DIP switches are used to provide 8 bit DAC inputs to the IC. These voltage levels can be set using combinational DIP switches. The DAC gives an analog output which is fed to the signal conditioning section by means of an USB cable. Another DIP switch is used to give Rogowski signal inputs to the R, Y and B phases of the electronic trip unit of the MCCB. The user can use this DIP switch to select the phase to which he wants to insert the signal, and thereby test the tripping of the electronic trip unit.
BRIEF DESCRIPTION OF DRAWINGS
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 the general view of the test kit and signal generation.
FIG. 2 illustrates the general view of the test kit connection.
FIG. 3 illustrates the circuit diagram of the test kit.
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 aspects 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 following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary aspects 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 aspects 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 aspects 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.

This invention relates to providing a range of selectable voltage levels for inserting in the signal conditioning section of the Electronic range of trip units. The invention is the use of combination of DIP switches for selecting voltage level inputs to the DAC section.
A circuit breaker test kit comprises at least one DAC IC and a plurality of DIP switches for providing a plurality of voltage level inputs to said DAC IC. In this invention said DIP switches provides for a range of selectable voltage levels for inserting in the signal conditioning section of the electronic range of trip units thereby electronically tripping an electronic trip unit of an MCCB by means of an external power supply. DAC provides an analog output fed to a signal conditioning unit using a plurality of USB cables. Further DIP switch is configured to give Rogowski signal inputs to R, Y and B phases of said electronic trip unit of MCCB.
The test kit in accordance with the present invention is configured to test healthiness of a MCCB in a field condition without passing actual phase currents. DIP switch is provided for selecting a phase to insert a signal thereby testing the tripping of the electronic trip unit. DAC IC is DAC IC0808 for converting digital signal to corresponding analog signal.
Another aspect of the present invention provides for testing of electronic trip assembly.
Although the aspects herein are described with various specific aspects, it will be obvious for a person skilled in the art to practice the aspects 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 aspects described herein and all the statements of the scope of the aspects which as a matter of language might be said to fall there between.

WE CLAIM:
1. A circuit breaker test kit comprising:
at least one DAC IC;
a plurality of DIP switches for providing a plurality of voltage level inputs to said DAC IC;
wherein said DIP switches providing for a range of selectable voltage levels for inserting in the signal conditioning section of the Electronic range of trip units thereby electronically tripping an electronic trip unit of an MCCB by means of an external power supply;
wherein said DAC providing an analog output fed to a signal conditioning unit using a plurality of USB cables;
wherein said DIP switch configured to give Rogowski signal inputs to R, Y and B phases of said electronic trip unit of MCCB.
2. Test kit as claimed in claim 1 configured to test healthiness of a MCCB in a field condition without passing actual phase currents.
3. Test kit as claimed in claim 1 wherein said DIP switch provided for selecting a phase to insert a signal thereby testing the tripping of the electronic trip unit.
4. Test kit as claimed in claim 1 wherein said DAC IC is DAC IC0808 for converting digital signal to corresponding analog signal.
5. A method for testing circuit breaker comprising the steps of:
providing an analog output fed to a signal conditioning unit using a plurality of USB cables using at least one DAC IC;
providing a plurality of voltage level inputs to said DAC IC using a plurality of DIP switches;

wherein said DIP switches providing for a range of selectable voltage levels for inserting in the signal conditioning section of the Electronic range of trip units thereby electronically tripping an electronic trip unit of an MCCB by means of an external power supply;
wherein said DAC providing an analog output fed to a signal conditioning unit using a plurality of USB cables;
wherein said DIP switch configured to give Rogowski signal inputs to R, Y and B phases of said electronic trip unit of MCCB.
6. A circuit breaker test kit for testing electronic trip assembly assembly, said kit comprising at least one DAC IC; a plurality of DIP switches for providing a plurality of voltage level inputs to said DAC IC; wherein said DIP switches providing for a range of selectable voltage levels for inserting in the signal conditioning section of the Electronic range of trip units thereby electronically tripping an electronic trip unit of an MCCB by means of an external power supply; wherein said DAC providing an analog output fed to a signal conditioning unit using a plurality of USB cables; wherein said DIP switch configured to give Rogowski signal inputs to R, Y and B phases of said electronic trip unit of MCCB .
7. A circuit breaker test kit as herein described and illustrated with reference to accompanying drawings.