A centrifugal safety device that trips when elevator car speed exceeds rated limits, activating the safety gear.
Full Definition
The overspeed governor is a flyweight-based centrifugal device mounted in the machine room or hoistway. It monitors car velocity through a dedicated governor rope looped between the device and a tension sheave in the pit. When speed reaches approximately 115 % of rated velocity, the flyweights engage and clamp the governor rope, transmitting mechanical energy to the safety gear linkage beneath the car. The gear then bites into the guide rails and arrests the car. Mandatory under EN 81-20 §5.6 and ASME A17.1 Rule 2.17; must be tested annually.
