What safety feature prevents the elevator car from moving when the door is open?

The safety interlock is a crucial safety mechanism designed to prevent unintended movement of the elevator car when the doors are open. This feature ensures that the elevator cannot operate unless all access doors are securely closed. If the doors are ajar, it activates a circuit that disables the elevator's drive system, preventing it from moving either up or down. This helps to protect passengers from the risk of an accident, such as stepping into a partially open elevator shaft.

In contrast, other options, while important for overall elevator safety, serve different functions. The emergency stop switch allows for immediate stopping of the elevator in case of an emergency but does not specifically address the issue of door openings. The limit switch is typically used to determine the position of the elevator car within the hoistway and may prevent movement if the car reaches the top or bottom of travel, but again, it does not specifically monitor door status. The governor is responsible for overspeed monitoring, serving as a safety device that activates if the elevator moves too quickly, which is unrelated to door operation.