FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - AN IMPROVED ARRANGEMENT IN CIRCUIT
BREAKER FOR BETTER SHORT CIRCUIT PERFORMANCE
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 relates to an improved arrangement in Circuit Breaker for better quenching of short circuit condition. More particularly, the present invention relates to an improved arrangement in Circuit Breaker achieved by improved profile/structure of arc runner which generates better blow out force on arc during short circuit condition.
BACKGROUND OF THE INVENTION
Circuit breaker protects the electrical system whenever there is a fault condition. The clearance of short circuit fault condition by circuit breaker depends upon three factors given below:
i. How fast the fault is sensed by the sensor. ii. How fast the mechanism responds to the input from actuator. iii. How fast the arc is moved into the arc chute chamber and quenched.
During fault condition, the damage caused to the electrical system is indentified by Ft let through in the system. The heavy energy going down the electrical system during fauit depends on square of fault current level (f) and the time (t) for which the fault current persist in the system.
Thus there is a need to provide an improved arrangement in circuit breaker adapted to reduce the arcing time that also helps to reduce the damage to the sensitive elements in circuit breaker like heater, bimetal and also the circuit breaker as a whole.

The present inventors have found an improved profile/structure of arc runner of circuit breaker that helps in reducing the arcing time. This in turn reduces the Ft let through and prevents severe damage to the system.
OBJECTS OF THE INVENTION
One object of the present invention is to overcome the disadvantages / drawbacks of the prior art.
A basic object of the present invention is to provide an improved arrangement in Circuit Breaker which generates better blow out force on arc during short circuit condition.
Another object of the present invention is to provide an improved profile/structure of arc runner of circuit breaker that helps in reducing the arcing time.
These and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
According to one of the aspect of the present invention there is provided an
improved arrangement in circuit breaker for better short circuit performance, said
arrangement comprising:
atleast one arc runner;
atleast one moving contact;
atleast one fix contact runner;
atleast one arc chute chamber;
wherein said arc runner comprising a pair of limb means placed substantially
parallel to each other to from an unique profile;

such that said profile of arc runner assist in weakening the magnetic flux density above the arc due to current reversal thus increasing the force acting on arc towards arc chute chamber in initial phase of an arcing.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawing:
Fig.1 illustrates the profile of arc runner.
Fig. 2 illustrates the profile of arc runner.
Fig. 3 illustrates the placement of the arc runner in the switch.
Fig. 4 illustrates the current direction when switch opens during fault condition.
Fig. 5 illustrates an angle between the arc and the current flowing through arc runner
Fig. 6 illustrates the distribution of flux density on either direction of arc
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an improved arrangement in circuit breaker for better short circuit performance, the arrangement comprising atleast one arc runner; atleast one moving contact; atleast one fix contact runner; atleast one arc chute chamber.

The arc runner comprising a pair of limb means placed substantially opposite to each other to form a unique curved profile which is substantially u-shaped. The u-shaped profile subtends angle between 45° and 60° with the vertical which increases the Lorentz Force on arc root. The unique profile of arc runner helps in weakening the magnetic flux density above the arc due to current reversal thus increasing the force acting on arc towards arc chute chamber in initial phase of an arcing.
The first limb is directed towards said arc chute chamber adapted to develop high force on plasma towards said arc chute chamber. The first limb is placed on opposite direction of said second limb.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWING
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and illustrate the best mode presently contemplated for carrying out the invention. Further the phenomenon has been discussed below to describe the way the phenomena takes place. However, such description should not be considered as any limitation of scope of the present unit. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.
In the present invention the improved profile of arc runner helps arc move faster initially in the arc chute chamber. This helps in reducing the arcing time during fault which in turn reduces overall fault clearance time.
The components in the figures are as follow:
Arc Runner (1)

Moving Contact (2) Fix Contact Runner (3) Arc Chute Chamber (4)
When the arc jumps from Moving Contact to the Arc Runner, the arc root gets initial high force towards arc chute chamber. This is due to the lower angle maintained initially between the plasma and the current flowing through the arc runner which is achieved due to the arc runner profile.
Fig.5 shows an angle between the arc and the current flowing through arc runner. The current direction in limb1 of arc runner also contributes to develop high force on plasma towards arc chute chamber. Because of this current direction the flux density below an arc is more than the flux density above an arc resulting into the resultant force direction towards the arc chute chamber.
Fig. 6 shows the distribution of flux density on either direction of arc due to the current direction in arc runner. This current reversal phenomenon is achieved due to the arc runner profile and its positioning in the circuit.
The features of this invention are as below:
• The arc runner is made of limb 1 and limb 2 forming a unique profile.
• The profile of arc runner helps in weakening the magnetic flux density above the arc due to current reversal thus increasing the force acting on arc towards arc chute chamber in initial phase of an arcing.
• The arcing time is reduced due to arc runner profile thus reducing overall fault clearing time by the switch.
• The damage caused to the electrical system during fault is reduced.

Advantages
• It helps reduce the arcing time.
• It reduce the damage caused to the electrical system during fault.

WE CLAIM:
1. An improved arrangement in circuit breaker for better short circuit
performance, said arrangement comprising
atleast one arc runner;
atleast one moving contact;
atleast one fix contact runner;
atleast one arc chute chamber;
wherein said arc runner comprising a pair of limb means limb 1 and limb 2
placed substantially opposite to each other to from an unique profile;
such that said profile of arc runner assist in weakening the magnetic flux
density above the arc due to current reversal thus increasing the force
acting on arc towards arc chute chamber in initial phase of an arcing.
2. Arrangement as claimed in claim 1 wherein said limb means comprising a curved profile connecting the limbs.
3. Arrangement as claimed in claims 1 and 2 wherein said profile is substantially u-shaped.
4. Arrangement as claimed in claims 1 to 3 wherein said profile subtends angle ranging from 45° to 60° with the vertical.
5. Arrangement as claimed in claim 1 wherein said first limb is directed towards said arc chute chamber adapted to develop high force on plasma towards said arc chute chamber.
6. Arrangement as claimed in claim 1 wherein said first limb is placed on opposite direction of said second limb.

7. An improved arrangement in circuit breaker for better short circuit performance as herein substantially described and illustrated with the accompanying drawings.