How does MCB works

C65 circuit breaker construction

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current, typically resulting from an overload or short circuit.

mcb bimetallic system
l7 circuit breaker bimetallic system

When the overflow of current takes place through miniature circuit breaker, the bimetallic strip gets heated and it deflects by bending. The deflection of bi-metallic strip releases a mechanical latch. The latch causes the MCB to turn off thereby stopping the current to flow in the circuit.

c65 mcb magnetic tripping mechanism 1
c65 mcb magnetic tripping mechanism

But during short circuit condition, the current rises suddenly, causing electromechanical displacement of plunger associated with a tripping coil or solenoid. The plunger strikes the trip lever causing immediate release of latch mechanism consequently open the circuit breaker contacts. 

1 XMCBE Circuit breaker Arc chamber
1 XMCB6A-125H MCB Arc chute

As the contacts are separated in the event of an overload or short circuit situation, an electric arc is formed. All modern miniature circuit breakers (MCBs) are designed to handle arc interruption processes where arc energy extraction and its cooling are provided by arc chute.

The arc chutes are held in a proper position by an insulating material. And the arc runner is provided to force the arc that is produced between the main contacts.

The most important thing that Circuit breaker is doing is to safely and reliably switches off electrical circuit during abnormal conditions of the network. Choosing a particular miniature circuit breaker (MCB) for a specific application is a careful task to ensure reliable protection against overloads and short circuits. If it is not selected according to the circuit requirements, there will be chances to lead to frequent unwanted tripping. 

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Zhejiang Ximu Intelligent Technology Co.,Ltd is a new-type manufacturing and processing enterprise which specializes in the integration of components processing including the arc chute, magnetic tripping mechanism/electromagnetic system, thermal tripping mechanism/bimetallic tripping system and etc.


Post time: May-24-2022