What is an Arc Chute? Working Principle

Arc chute is a set of parallel arranged metal plates which extinguishes the arc formed when the circuit breaker interrupts the high electric current. It is also known by other names such as arc dividers or arc splitters. It is an important component of the circuit breaker. These metal plates have an equal air gap between them. These metal plates are made up of ferromagnetic material. The arc chutes are placed near the circuit breaker contacts.

Arc Chutes Working Principle

When a fault occurs, a circuit breaker interrupts the electric current by moving the contacts apart. The arc is produced when the two contacts start separating from each other. This arc produces a large amount of heat. This heat is capable of melting the circuit breaker contacts. Hence this can damage the circuit breaker. So there is a need to safely extinguish this arc to prevent any damage to the circuit breaker.

Arc chute
Fig. 1 Air Break Circuit Breaker Arc Interruption

The arc produced is attracted towards the arc chute’s metal plates as it is made up of ferromagnetic material. These plates cause the arc to spread and further splits into small parts. This will increase the arc length and lead the arc to cool down. Finally, the arc extinguishes. Fig. 1(a) shows the arc interruption by an arc chute in air circuit breaker. We can see that the arc is attracted from position 1 towards position 3. The arc widens as it moves from position 1 to position 2 and further to position 3. After reaching position 3, arc chute’s plates splits the arc into small parts. This is how an arc chute works.

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