FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Velocity Measurement Means for Circuit Breaker Using Crystal"
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
Electrical & Automation North Wing, Gate 7, Level 0, Powai Campus, Saki Vihar Road, Mumbai 400 072, INDIA
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Velocity Measurement Means for Circuit Breaker Using Crystal
Field of the invention
The present invention relates to velocity measurement means for circuit breaker using crystal indicates using piezoelectric effect.
Background of the Invention
Conventional way for measurement of main contact timing is to use ohms law with a DC test voltage over the circuit breaker to distinguish the moment when the circuit breaker state changes from open to close or vice versa. This method is not based on a standard and there is no absolute reference point and the derived results can therefore vary from theoretical value.
With both sides of the circuit breaker connected to ground, this method does not work. The DC test voltage will only sense the connection over ground and not what happens on the circuit breaker. Therefore, safe timing (ideal value specified by manufacturer) is not possible. Also, if the ground position is loosely held or changed then the actual value will be difficult to obtain.
Thus by using a standard reference transducer which depends only on the force and momentum provided by mechanical energy of the main contacts of the circuit breaker the actual and safe timing of circuit breaker can be determined.
The main object of this invention is that when a fault occurs, current must be interrupted quickly and reliably to avoid personal injuries and minimize damage. If a breaker fails to break the circuit, the resulting damage can be very serious and fatal indeed. Moreover, large section of the power grid will have to be disconnected in order to interrupt the fault current.

A circuit breaker is the active link in the fault-clearance chain. Even though circuit breakers are comparatively reliable, faults can and do occur. Circuit breakers must thus be tested and maintained to ensure operation when a crucial need arises. During its 40+ year service life, a circuit breaker must be constantly prepared to do its duty. Long periods of idleness often elapse during which the breaker's mechanical parts never move.
There are many reasons to maintain and test a circuit breaker. Friction and wear can affect the performance of movable parts. Leaks can occur in the valves and seals used in arc-extinguishing chambers, damping devices, pneumatic and hydraulic operating mechanisms. Faults can occur in electrical control circuits, and the contact surfaces in current-carrying circuits can deteriorate, thus increasing the risk of excessive heat generation.
Object of the invention
Object of the invention is to provide a velocity measurement mean for circuit breaker using crystal, which can determine the exact velocity through which the contacts in circuit breaker open and close by using piezoelectric effect which converts the mechanical energy of the breakers into corresponding electrical energy.
Another object of the present invention is to provide a velocity measurement mean for circuit breaker using crystal, which reduces testing time, human efforts & to bring more precise results economically.
Another objective of the present invention is to provide a velocity measurement mean for circuit breaker using crystal, which contributes towards viability in green technology with use of renewable source of energy like crystal.

Brief Description of the Drawings
Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawings:
Figure 1 illustrates a sensor based on the piezoelectric effect;
Figure 2 illustrates circuit for velocity measurement timing using conventional method;
Figure 3 illustrates Timing Waveform obtained with conventional method circuit;
Figure 4 illustrates Circuit for velocity measurement timing using piezoelectric method; and
Figure 5 illustrates Timing waveform obtained with piezoelectric method circuit.
Detail description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
As shown in fig. 2 conventional technology for main contact timing is to use ohms law with a DC test voltage over the circuit breaker to distinguish the moment when the circuit breaker state changes from open to close or vice versa. This method is not based on a standard and there is, therefore, no absolute reference point and the derived results can therefore vary from actual ideal value.

With both sides of the circuit breaker connected to ground, this method does not work. The DC test voltage will only sense the connection over ground and not what happens on the circuit breaker. Therefore, safe timing is not possible. Also, if the ground position is loosely held or changed then the actual value also cannot be obtained. The resultant waveform is distorted as shown in fig.3.
Thus by using a standard reference transducer which depends only on the force and momentum provided by mechanical energy of the main contacts of the circuit breaker the actual and safe timing of circuit breaker can be determined.
When a fault occurs, current must be interrupted quickly and reliably to avoid personal injuries and minimize damage. If a breaker fails to break the circuit, the resulting damage can be very serious indeed. Moreover, a needlessly large section of the power grid will have to be disconnected in order to interrupt the fault current.
A circuit breaker is the active link in the fault-clearance chain. Even though circuit breakers are comparatively reliable, faults can and do occur. Circuit breakers must thus be tested and maintained to ensure operation when a crucial need arises.
During its 40+ year service life, a circuit breaker must be constantly prepared to do its duty. Long periods of idleness often elapse during which the breaker's mechanical parts never move.
There are many reasons to maintain and test a circuit breaker. Friction and wear can affect the performance of movable parts. Leaks can occur in the valves and seals used in arc-extinguishing chambers, damping devices, pneumatic and hydraulic operating mechanisms. Faults can occur in electrical control circuits, and the contact surfaces in current-carrying circuits can deteriorate, thus increasing the risk of excessive heat generation.

The main object of this invention is to determine the exact velocity through which the contacts in circuit breaker open and close by using piezoelectric effect which converts the mechanical energy of the breakers into corresponding electrical energy using relation
Time = Momentum / Force Where, Momentum = mass * velocity
The piezoelectric effect is understood as the electromechanical interaction between the mechanical and the electrical state in crystalline materials. The piezoelectric effect is a reversible process in that materials exhibiting the direct piezoelectric effect (the internal generation of electrical charge resulting from an applied mechanical force) also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field). For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1% of their static dimension when an external electric field is applied to the material as shown in figure 1.
As shown in figure 3 when a piezoelectric material is or mounted along the path of moving contacts the piezoelectric material will sense the mechanical energy in moving contacts and convert the corresponding mechanical energy into its electrical energy.
The resulting waveform as shown in fig.5 is less distorted and when compared with theoretical value using simulation tools like Pro-E the practical value actually matches with ±5% of error.
This invention is already established and proven for circuit breaker where the transition time of circuit breakers was checked with some simulating tools like

PRO-E where the practical value obtained through experiment matched with ideal value with ±5% error
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, 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 omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A velocity measuring means of a moving contact of a circuit breaker using
crystal, velocity measuring means comprising:
a piezoelectric material disposed along moving path of the moving contact of the circuit breaker the piezoelectric material will sense mechanical energy in the moving contact and convert the corresponding mechanical energy into its electrical energy.