Hydraulic overspeed valves activate if a downward traveling car exceeds what speed percentage range?

Hydraulic overspeed valves are critical safety devices designed to prevent a hydraulic elevator from descending too quickly, which can lead to dangerous situations. These valves are set to activate when the downward traveling elevator car exceeds a specific speed threshold, commonly defined as a percentage above the normal rated speed.

The correct answer indicating a speed range of 110% to 140% reflects the operational safety parameters established to protect users and equipment. This range allows for a buffer beyond the rated speed, such that if the elevator exceeds this speed during descent, the overspeed valve will engage to halt the car safely, thereby preventing potential accidents caused by uncontrolled descent.

Understanding this speed threshold is crucial for ensuring the appropriate safety measures are in place during elevator operations. It provides a clear benchmark for technicians and maintenance personnel when inspecting and maintaining hydraulic elevator systems.