Elevator Safety Systems | Episode 5
Overspeed Governorđźš©
The First Mechanical Device to Detect Overspeed Before the Safety Gear Engages.
When an elevator exceeds its permissible speed, every fraction of a second matters.
Most people believe the Safety Gear is the first safety device to react.
In reality, the Overspeed Governor always reacts first.
The Overspeed Governor continuously monitors the elevator speed through the Governor Rope. Once the calibrated tripping speed is reached, the governor sheave locks mechanically, restraining the governor rope and initiating the engagement of the Safety Gear, which grips the guide rails and safely brings the elevator car to a controlled stop.
The safety sequence is always:
Detect âžś Trigger âžś Engage âžś Controlled Stop
✔ Overspeed Governor → Detects & Triggers
✔ Safety Gear → Engages & Safely Stops the Car
Engineering Insight
The Overspeed Governor should never be evaluated as an individual component.
It is part of an integrated safety system consisting of:
• Overspeed Governor
• Governor Rope
• Tension Pulley Assembly
• Governor Safety Switch
• Mechanical Linkage to the Safety Gear
The reliability of this complete system depends on:
âś” Accurate governor tripping speed calibration.
âś” Correct governor rope tension.
âś” Proper rope alignment throughout the system.
âś” Free movement of the tension pulley assembly.
âś” Reliable operation of the governor safety switch.
An incorrectly adjusted governor rope may delay governor tripping or reduce the mechanical force transmitted to the Safety Gear.
That’s why governor rope tension is considered a critical safety parameter not simply a maintenance adjustment.
Commissioning Perspective
Governor testing is never limited to checking whether the governor trips.
A complete commissioning test should verify:
âś” Governor tripping speed.
âś” Governor safety switch operation.
âś” Governor rope condition and tension.
âś” Tension pulley movement.
âś” Full Safety Gear engagement.
âś” Safe governor reset after activation.
Only when the entire safety chain performs correctly can the elevator be considered ready for safe operation.
According to EN 81-20 and EN 81-50, the Overspeed Governor is a certified safety component designed and type-tested to activate the Safety Gear reliably whenever the elevator exceeds its permissible operating speed.
Final Thought🌟
Passengers will probably never notice an Overspeed Governor.
Engineers hope they never have to.
Because when this device operates…
There is no second chance.
Every inspection…
Every adjustment…
Every commissioning test…
Stay tuned for Episode 6, where we’ll explore Buffers—the final energy-absorbing safety device that protects the elevator system at the end of its travel.
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