Havells MCCB Shunt Coil Connection | Why Micro Switch in Shunt Coil | How to Install | How it works

Havells MCCB (Molded Case Circuit Breaker) is a type of circuit breaker used for electrical distribution and protection. MCCB is designed to protect electrical circuits and equipment from overcurrents and short circuits. The shunt coil is an essential component of the MCCB, and it plays a crucial role in its operation like trip of MCCB with respect to external signals.

The shunt coil in an MCCB is connected in parallel to the trip unit of the circuit breaker. It is typically connected to a micro switch, which is a small electrical switch activated by mechanical means. The purpose of the micro switch is to sense the position of the circuit breaker’s operating mechanism. Micro Switch protects the shunt coil from burning when continuous signal incoming.

Here’s how the connection and installation of the shunt coil in an MCCB generally work:

Shunt Coil Connection: The shunt coil is connected in parallel to the trip unit of the MCCB. It is usually connected to the trip unit terminals or a designated shunt coil connection point provided by the manufacturer.

Micro Switch Connection: The shunt coil is connected to a micro switch. The micro switch is mounted in such a way that it is activated or triggered by the movement of the MCCB’s operating mechanism. When the operating mechanism moves, it triggers the micro switch, which sends an electrical signal to the trip unit.

Installation: The shunt coil and micro switch are typically pre-installed within the MCCB during the manufacturing process as in Havells MCCB Shunt Coil. However, in some cases, they may need to be installed separately. Proper installation instructions should be provided by the manufacturer, and it’s crucial to follow them to ensure correct functionality and safety.

Now, let’s understand how the shunt coil and micro switch work in coordination:
When an external trip signal occurs, the MCCB’s operating mechanism is actuated to trip the circuit breaker and disconnect the circuit. The movement of the operating mechanism triggers the micro switch. This micro switch operates and cut the external signal to shunt coil protecting it from burning due to continuous supply to coil.

In summary, the shunt coil in an MCCB is connected to a micro switch to sense the position of the operating mechanism. When an external trip command comes. the shunt coil external charge and pulls the trigger to trip the MCCB. The micro switch, get triggered by the movement of the operating mechanism while MCCB turns off which cut the external trip signal to the shunt coil. This mechanism ensures that the MCCB can respond to external trip command, without getting damage from continuous supply.