When a circuit breaker interrupts high currents, an electric arc is generated. An electric arc is the discharge of electric current through gas or air. The conduction of electric charges through gas produces plasma, which glows. Electric arc produces heat that can melt the contacts of the breaker and even damage the circuit breaker itself. In order to avoid that, the arc has to be safely and effectively extinguished. Arc chutes serve this purpose.
Definition of arc chute
It is a set of metal plates that are arranged in parallel and mutually insulated from each other, which can divide, cool and safely extinguish an electric arc. They are also known as arc splitters and arc dividers.
Arc chutes can be found inside circuit breakers, contactors, isolators and other high current interruption devices.
How do arc chutes extinguish an arc?
The electric arc is formed between the contacts of a circuit breaker when it interrupts the current flow to load during normal operation. On the event of short circuits, the arc formed will be more intensive than the normal one. The metal plates in arc chutes are made of ferromagnetic material. Hence the arc formed is attracted towards the plates and moves towards the arc chutes through the arc runners by itself.
As it reaches the arc chute, the structure of the arc chutes widens the arc further and split it into small segments. This increases the length of the arc. Hence it cools down and eventually gets extinguished.
Arc chutes are one of the key components of circuit breakers. They safeguard the breakers and other circuit interruption devices from heat and damages caused as a result of arc formation.