FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
System for Testing the Electronic Trip Unit
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. 0. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

System for Testing the Electronic Trip Unit
Field of the invention
The present invention relates to an electronic trip unit for molded case circuit breakers, and more particularly, the present invention relates to system and method for testing functionality of the electronic trip unit of a circuit breaker.
Background of the invention
For testing functionality of an electronic trip unit (ETU) of a circuit breaker, there exist a technology which uses a wire harness between a test kit and the ETU for injecting necessary voltage so that a trip is issued by the ETU. However, the prior art technology for testing functionality of the ETU, has a lot of disadvantages. Specifically, reversal of connections (wrong polarity connection) at the test port might result in permanent damage to the ETU. Further, the test kit and the ETU must have a common ground and insulation coat applied on printed circuit board (PCB) sometimes block communication port due to which the ETU becomes inaccessible. Also, use of the test kit for testing the functionality of the ETU at sites is a tedious task for layman due to complex wiring and proper test kit setting and release settings.
Accordingly, there exists a need for testing the functionality of the electronic trip unit which overcomes above-mentioned drawbacks.
Object of the invention
An object of the present invention is to avoid damage to an electronic trip unit (ETU) while testing functionality thereof.

Another object of the present invention is to avoid complex wiring for testing functionality of the ETU.
Summary of the invention
Accordingly, the present invention provides a system for testing the electronic trip unit. The system comprises a test kit having an 1R transmitter configured therein. The 1R transmitter is capable of emitting a light signal. Further, the system comprises a mating connector configured within the electronic trip unit. The mating connector includes an IR receiver for detecting incoming light signal from the IR transmitter. Furthermore, the system comprises a microcontroller configured within the electronic trip unit. The microcontroller includes a look-up table stored in memory thereof corresponding to voltage to be injected for each protection setting. Also, the system comprises a hardware circuitry configured within the electronic trip unit for generating and injecting voltages to the microcontroller for tripping the electronic trip unit and, an external auxiliary module for powering up the electronic trip unit.
Brief description of drawings
Figure 1 shows a block diagram of a system for testing the electronic trip unit (ETU) in accordance with the present invention; and
Figure 2 shows a flowchart of working of the system of figure 1, in accordance with the present invention.
Detailed description of the invention

For a thorough understanding of the present invention, reference is to be made to the following detailed description, including the appended claims, in connection with the above-described drawings. Although the present invention is described in connection with exemplary embodiments, the present invention is not intended to be limited to the specific forms set forth herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
The present invention provides a system for testing functionality of an electronic trip unit (ETU) for molded case circuit breakers. The system of the present invention is used as a simulation kit to verify the functionality of the ETU. The present invention basically aims at testing the functionality of the electronic trip unit by optical means rather than through a wire harness between the test kit and the communication port of the ETU.
Referring now to figure 1, a system (100) for testing the electronic trip unit (ETU), is shown. The system (100) includes a test kit (10). The system (100) further includes a mating connector (20), a microcontroller (30), hardware circuitry (40) configured within the electronic trip unit (50). The system (100) furthermore includes an external auxiliary module (60),
The test kit (10) includes an infrared (IR) transmitter (12) configured therein. The IR transmitter (12) is capable of emitting a light signal. The light signal transmitted by the IR transmitter (12) is received by an infra red (IR) receiver (22) configured within the mating connector (20).

The mating connector (20) is configured within the electronic trip unit (50). Specifically, the mating connector (20) includes the IR receiver (22) for detecting incoming light signal from the IR transmitter (12). The mating connector (20) properly aligns the IR transmitter (12) onto the IR receiver (22).
Further, the microcontroller (30) is configured within the electronic trip unit (50). The microcontroller (30) includes a look-up table stored in memory thereof. The look-up table includes values corresponding to voltage to be injected for each protection setting of the electronic trip unit (50). The hardware circuitry (40) generates voltages and feeds them to the analog to digital converter (ADC) channels of the microcontroller (30).
The hardware circuitry (40) is configured within the electronic trip unit (50) for generating voltages (30) for tripping the electronic trip unit (50).
The system (100) also includes the external auxiliary module (60) for powering up the electronic trip unit (50).
In an operation, the light emitted by the IR transmitter (12) is detected by the IR receiver (22) with the help of the mating connector (20). On receiving the light signal, the microcontroller (30) reads the protection settings set on the electronic trip unit (50) through DIP Switch settings. After reading the protection settings set on the ETU, the microcontroller (30) refers to the look-up table to check the voltage to be injected therein corresponding to the protection settings set using the DIP switches. The microcontroller (30) then transfers the control to the hardware circuitry (40) which generates the required voltage for tripping. The generated voltage by the hardware circuitry (40) is then sensed by analog to digital converter (ADC) pin of the

microcontroller (30). The microcontroller (30) thereafter examines the protection settings of the electronic trip unit (50) and the voltage sensed and decides whether a trip command should the given to the full scale deflection (FSD) trip circuit (42), for tripping the electronic trip unit (50). Figure 2 shows a flowchart (200) of working of the system (100), in accordance with the present invention.
Following table gives the set of voltages that will be stored in the lookup table corresponding to the protection settings set on the ETU:

Protection Settings Voltages stored in look-up table (Volts)
Overload (LTS)
60% 0.7
80% 0.62
40% 0.92
60% 1.36
80% 1.27
Short Circuit (STS)
LTS=40%,STS=2.5 0.62
LTS=60%,STS=2.5 0.77
LTS=100%,STS=1.5 0.62
LTS= 40%, STS= 5.5 0.62
LTS=80%,STS=4 0.92
LTS=100%,STS=2.5 0.7
Advantages of the invention
1. The system (100) provides optical communication for testing the
functionality of the ETU of MCCB.
2. The system (100) does not require cumbersome wire harness between test
kit and ETU of MCCB.

3. The system (100] uses on-chip hardware circuitry for injecting the appropriate voltage into the ETU for trip condition.
4. The system (100) tests functionality of the ETU against all the variable protection settings, for example, long time (LTS), short time (STS), earth fault and neutral.
5. The system (100] provides smaller size of the testing equipment relatively as compared to the test kit currently being used.
6. The system (100] of the present invention is more reliable, cost effective and has many advantages over the technology that is currently being used for testing the ETU.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

We Claim:
1. A system for testing electronic trip unit, the system comprising:
a test kit having a IR transmitter configured therein, the IR transmitter
being capable of emitting a light signal;
a mating connector configured within the electronic trip unit, the mating connector having an IR receiver for detecting incoming light signal from the IR transmitter;
a microcontroller configured within the electronic trip unit, the microcontroller having a look-up table stored in memory thereof corresponding to voltage to be injected for each protection setting;
a hardware circuitry configured within the electronic trip unit for generating and injecting voltages to the microcontroller for tripping the electronic trip unit; and
an external auxiliary module for powering up the electronic trip unit;
wherein the microcontroller provides trip command to full scale deflection (FSD) circuit for tripping the electronic trip unit, upon receiving light signal from the IR receiver and upon generation of voltage required for tripping by the hardware circuitry.
2. The system for testing the electronic trip unit as claimed in claim 1, wherein on receiving the light signal from the IR transmitter, the microcontroller reads the protection settings set on the electronic trip unit through DIP Switch settings.
3. The system for testing the electronic trip unit as claimed in claim 1, wherein voltage generated by the hardware circuitry is sensed by ADC pin of the microcontroller.