In this method the arc resistance is increases gradually so that current is reduced to such a value that heat is insufficient to maintain the arc.
Arc extinction in circuit breaker.
When opening air is required compressed air is admitted to the arc extinction chamber.
The main designing criteria of a circuit breaker is to provide appropriate technology of arc quenching in circuit breaker to fulfill quick and safe current interruption.
Principle of arc extinction.
Therefore while designing the circuit breaker provision of mechanical strength to withstand such sudden release of large quantities of energy must be made.
The air blast needs an additional compressed air system which supplies air to the air receiver.
Principles and methods of arc extinction are discussed here.
Cross section of the arc.
In high resistance method the arc resistance is made to increase gradually with the time so that the current force in between the two contacts is insufficient to maintain the arc.
In doing so the contacts are pulled apart and the air blast moves away the.
Method of arc extinction.
It pushes away the moving contacts.
As the separation between the contacts of breaker increases the arcing resistance also increases.
There are two methods of extinguishing the arc in circuit breaker.
Arc extinction when the current carrying contacts of the circuit breaker are moved apart an arc is formed which insist for a short period after the separation of contacts.
Principle of arc extinction in circuit breaker.
The arcing resistance increases with decrease in the cross sectional area of the arc.
Methods of arc extinction in circuit breaker.
Hence the current is.
In air blast circuit breaker or in breaker where a gas flow is present between the electrical contacts the heat loss of arc plasma occurs due to convection process.
There are two methods of extinguishing the arc in circuit breakers.
The arc resistance increases as the length of arc increases i e.
These are high resistance methods and low resistance or zero resistance method.
1 high resistance method.
This arc is dangerous on account of the energy generated in it in the form of heat which may result in explosive force.