Identify a component responsible for maintaining elevator speed.

The governor is a crucial safety mechanism in an elevator system that is designed to monitor and maintain the elevator's speed during operation. Its primary function is to detect any variations in speed, particularly instances of overspeeding, which can occur due to mechanical failure or other issues.

When the governor senses that the car is moving too quickly, it activates the elevator’s braking system to slow down or stop the elevator cab, thus preventing accidents and ensuring passenger safety. This role is essential for maintaining a consistent and safe speed throughout the elevator's operation.

While other components such as the pulley system, control panel, and emergency brake play vital roles in overall elevator function, they do not directly manage speed. The pulley system primarily aids in raising and lowering the elevator car by redistributing weight, the control panel allows users to input their desired direction and floor, and the emergency brake functions as a last line of defense in case of a malfunction. Thus, the governor is uniquely responsible for actively monitoring and controlling the elevator’s speed.