Why a stop button is normally closed?

A stop button is typically designed as a normally closed (NC) switch to ensure safety and reliability in control circuits. This configuration allows the circuit to remain energized and operational until the stop button is pressed, which opens the circuit and stops the operation. This design helps prevent accidental shutdowns and ensures that any failure or disconnection in the system will result in a safe state, as power will be cut off when the button is activated. Additionally, it allows for immediate response to emergencies by providing a straightforward mechanism for stopping equipment.