THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
NATURE OF THE INVENTION

A TEMPERATURE MEASUREMENT METHOD AND APPARATUS FOR
CIRCUIT BREAKERS
A) FIELD OF THE INVENTION
1. This invention relates generally to methods and systems for temperature measurement, and more particularly to, a method and apparatus for temperature measurement in circuit breaker poles.
B) BACKGROUND OF THE INVENTION
2. Generally, in a factory environment, power is received from an external source into the factory to a sub-station. From a sub-station within the factory the power is then distributed to various equipments such as, power loom, motors, welding machinery, computers, and the like.
3. To protect high cost equipments such as transformers, equipments attached to the power line and to prevent arc generation, it is quite common that these power distribution systems also are equipped with protective devices such as trip units, circuit breakers, fuses etc. These protective devices are attached to each small branch of the circuitry so that each piece of the equipment is protected and also any problems associated with a machinery is restricted only to that branch of the factory and does not affect the other parts and functionality of the factory. Thus by providing trip units in each branch and sub-branch of a factory minimize the down time of the entire production of the factory thereby creating increased efficiencies, lower operating and manufacturing costs and the Uke.

4. Typically, when trip units are utilized, they are used to detect more than just one function. To name a few, trip units monitor functions such as over current, power surge, undesired arc in power line etc. Trip units may be designed to trip just due to large over current conditions caused by short circuit faults as well.
5. Typically, when circuit breakers are utilized, they are used to detect more than just large over-current conditions caused by short circuit faults. In addition, they frequendy detect lower level long-time over-current conditions and excessive ground currents. The simplest forms of circuit breakers are thermally tripped as a result of heating caused by over current conditions and, in this regard, are basically mechanical in nature. These mechanical-type breakers are incorporated into almost all circuit breakers, regardless of whether or not additional advanced circuitry is provided since they are extremely reliable over a long life cycle and provide a default trip-type level of protection.
6. The poles of the circuit breaker have to be monitored for improper contacts, which might cause overheating. However, there exists a need in the art for a temperature measurement method and apparatus wherein (i) the measurement circuit is isolated from noisy environment prevailing inside and around the circuit breaker and hence provide accurate measurement, (ii) the apparatus is compact, and (iii) the measured temperamre is transmitted over long distances to a central trip unit.
C) OBJECTS OF THE INVENTION
7. An object of this invention is to provide a temperature measurement method and apparatus, wherein the measurement circuit is isolated from noisy environment

prevailing inside and around the circuit breaker and hence provides improved accuracy.
8. Another object of this invention is to provide a temperature measurement method and apparatus, wherein the apparatus is compact.
9. Yet another object of this invention is to provide a temperature measurement method and apparatus, wherein the measured temperature is transported over long distances to a central unit.
D) SUMMARY OF THE INVENTION
10. The above-mentioned shortcomings, disadvantages and problems are addressed herein, which will be understood by reading and studying the following specification
11. In one embodiment, a temperature measurement apparams for a circuit breaker is provided, wherein the apparatus comprises a thermistor coupled to a circuit breaker, a trip unit coupled to the thermistor at a distance via a network, a microcontroller coupled to the thermistor and trip unit, wherein the output frequency of the thermistor varies in response to the temperature near the circuit breaker, wherein the microcontroller communicates the temperature data near the circuit breaker to the trip unit in response to the variation in the output frequency.
12. In another embodiment, a temperature measurement method for a circuit breaker is provided, wherein the method comprises coupling a thermistor to a circuit

breaker, coupUng a trip unit to the thermistor at a distance via a network, and communicating the temperature data near the circuit breaker to the trip unit as a measure of a variation in the output frequency of the thermistor.
E) BRIEF DESCRIPTION OF THE DRAWINGS
13. FIG. 1 shows a block diagram of one example of an apparatus for measuring temperature in a circuit breaker according to this invention.
F) DETAILED DECRIPTION OF THE INVENTION
14. In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, ands it is to be understood that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense.
15. Various embodiments of this invention provide a temperature measurement apparatus and method for circuit breakers. However, the embodiments are not limited and may be implemented in connection with other electrical devices.
16. FIG. 1 shows a block diagram of a one example of a temperature measurement method and apparatus according to this invention.

17. Accordingly, in an embodiment, the apparatus comprises a thermistor 10 coupled to a circuit breaker 20. A trip unit 30 is coupled to the thermistor 10 at a distance via a network 40. A microcontroller 50 is coupled to the thermistor 10 and the trip unit 30, wherein the output frequency of the thermistor 10 varies in response to the temperature near the circuit breaker 20, wherein the microcontroller 50 transmits the temperature data near the circuit breaker 20 to the trip unit 30 in response to the variation in the output frequency.
18. It should be noted that the resistance of the thermistor 10 contacts changes in response to the temperature near the circuit breaker 20. The variation in the output frequency, for example the frequency of the square waves of the thermistor 10, is proportional to the change in the resistance of the thermistor 10.
19. In one embodiment, a plurality of LEDs 60, 70 are configured to provide the status of power supply and communication. The microcontroller 50 communicates to the trip unit 30 through an intelligent communication protocol.
20. In an embodiment, the temperature measurable near the circuit breaker 20 is up to 200 deg C.
21. It should be noted that the trip unit 30 may be coupled in common to a plurality of circuit breakers 20 for measuring the temperature.
22. In an embodiment, a temperature measurement method for a circuit breaker 20 comprises coupling a thermistor 10 to a circuit breaker 20 and coupling a trip unit 30 to the thermistor at a distance via a network. The temperature data near the

circuit breaker 20 is communicated to the trip unit 30 as a measure of a variation in the output frequency of the thermistor 10.
23. It should be noted that the resistance of the thermistor contacts changes in response to the temperaUore near the circuit breaker 20, wherein the variation in the output frequency is mapped on to the change in the resistance of the thermistor 10 for measuring the temperamre. A table for mapping may be stored in a memory (not shown in FIG. 1) and the memory may be associated with a microcontroller 50.
24. In a further embodiment, a plurality of LEDs 60. 70 are configured to provide the status for power supply and communication.
25. In an example, the temperamre data is communicated over a network 40 using the microcontroller 50 and an RS485 communication protocol.
26. In one example, the temperature measurable near the circuit breaker 20 is up to 200 deg C.
27. Thus, various embodiments of the present invention provide a temperature measurement apparams for a circuit breaker. Further embodiments of this invention provide a temperamre measurement method for a circuit breaker.
28. It will be obvious for a person of skilled in the art to practice the invention with modifications. However, all those modifications will be deemed to be covered within the scope of the invention as covered in the claims hereunder.

G) WE CLAIM:
1. A temperature measurement apparatus for a circuit breaker, comprising:
(i) a thermistor coupled to a circuit breaker;
(ii) a trip unit coupled to the thermistor at a distance via a network; and
(iii) a microcontroller coupled to the thermistor and the trip unit, wherein the output frequency of the thermistor varies in response to the temperature near the circuit breaker, wherein the microcontroller transmits the temperature data near the circuit breaker to the trip unit in response to the variation in the output frequency.
2. A temperamre measurement apparatus as claimed in claim 1 wherein the resistance of the thermistor contacts changes in response to the temperature near the circuit breaker, wherein the variation in the output frequency is proportional to the change in the resistance of the thermistor.
3. A temperature measurement apparatus as claimed in claim 1 or 2 wherein at least one LED is configured to provide the status of power supply and communication.

4. A temperature measurement apparams as claimed in any one of the preceding claims wherein the microcontroller communicates to the trip unit through an intelligent communication protocol,
5. A temperature measurement apparatus as claimed in any one of the preceding claims wherein the temperature near the circuit breaker is up to 200 deg C.

6. A temperature measurement method for a circuit breaker, comprising
(i) coupling a thermistor to a circuit breaker
(ii) coupling a trip unit to the thermistor at a distance via a network, and
(iii) communicating the temperature data near the circuit breaker to the trip unit as a measure of a variation in the output frequency of the thermistor.
7. A method as claimed in claim 1 wherein the resistance of the thermistor contacts
changes in response to the temperature near the circuit breaker, wherein the
variation in the output frequency is mapped on to the change in the resistance of the
thermistor for measuring the temperature.
8. A method as claimed in claim 1 wherein at least one LED is configured to provide the status for power supply and communication.
9. .A method as claimed in claim 1 communicating the temperature data over the network comprises using a microcontroller and an RS485 communication protocol.
10. A method as claimed in claim 1 wherein the temperature measured near the circuit
breaker is up to 200 deg C.