FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Sensing System For Electrical Components Of Moulded Case Circuit Breaker"
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.

Sensing System For Electrical Components Of Moulded Case Circuit
Breaker
Field of the invention
The present invention relates to circuit breakers, and more particularly, to sensing system for electrical components.
Background of the invention
It is generally known to couple any one of thermal-magnetic release and microprocessor based release to an moulded case circuit breaker (MCCB) for providing overload and short circuit protections.
The thermal-magnetic release and the microprocessor based release are mechanically coupled together and with the MCCB unit, and are provided by actuating means for actuating the operation of the electrical device (for example opening or closing of a circuit or similar).
It is also generally known that either a wound current transformer (CT) or a wound Rogowski is used to sense the current conditions. A printed circuit board (PCB) based Rogowski is being used in a variety of applications.
Specifically, the wound Rogowski is used for signaling current levels instantaneously while the wound current transformers (CT) are used to power up the release circuitry. However, the wound current transformers (CT) requires space in the printed circuit board (PCB). Also, it is difficult to wind the Rogowski in the conventional printed circuit board (PCB).
Accordingly, there is a need to provide a sensing system for releases in the MCCB which overcomes drawbacks of the prior art.

Objects of the invention
An object of the present invention to reduce space requirement for current transformers in a printed circuit board.
Another object of the present invention is reduce difficulty which exists in winding the Rogowski coil in existing printed circuit board.
Summary of the invention
Accordingly, the present invention provides a moulded case circuit breaker comprising a trip unit, a printed circuit board (PCB) integrating signal conditioning circuits, a processing circuits, a trip unit circuitry and Rogowski coil aligned on a printed circuit board (PCB), wherein the Rogowski coil makes use of flux lines by reducing inductance effect of toroidal tracks.
Brief description of the drawings
Figure 1 shows a printed circuit board with Rogowski forming a part of a trip unit board, in accordance with the present invention.
Detailed 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.
Referring now to figure 1, there is shown a printed circuit board (50) of a moulded case circuit breaker (100) comprising a trip unit, a printed circuit board (PCB) integrating signal conditioning circuits, a processing circuits, a trip unit

circuitry (10) and Rogowski coil (20) aligned on a printed circuit board (PCB) (50). The Rogowski coil (50) makes use of flux lines by reducing inductance effect of toroidal tracks.
The PCB (50) provides a magnetic isolation between each of the units and from external magnetic noise unlike traditional current transformers (CT). The thickness of the PCB (50) is the optimized considering the length of the toroidal tracks. Further, the radius of the toroidal track is maintained half the thickness of the PCB (50). In an embodiment, stacking the turns of the toroidal track as a measure for optimization of the PCB (50).
Advantages of the invention
1. Space occupied by the wound current sensor is reduced in case of PCB Rogowski and hence reduced space occupancy in the MCCB chassis.
2. Winding difficulties of the traditional Rogowski is eliminated.
3. The PCB is small, light and easy to install, and manufacturing variations and inconsistency is removed.
4. Symmetry in the PCB is achieved and hence the sense current consistency.
5. Protection in the PCB is achieved through high linearity, a characteristic of Rogowski by itself.
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 sensing system for electrical components of moulded case circuit breaker comprising a trip unit, a printed circuit board (PCB) integrating signal conditioning circuits, a processing circuits, a trip unit circuitry and Rogowski coil aligned on a printed circuit board (PCB), wherein the Rogowski coil makes use of flux lines by reducing inductance effect of toroidal tracks.
2. The moulded case circuit breaker of claim 1, wherein thickness of the PCB is optimized considering the length of the toroidal tracks and radius of the toroidal track is maintained half the thickness of the PCB.
3. The moulded case circuit breaker claim 1, wherein the toroidal tracks
turns are stacked.