How Does an Elevator Overspeed Governor Protect Passengers?
In the elevator safety system, there is a critical safety component that passengers cannot see but is extremely important—the elevator overspeed governor. Known as the “last safety device” of an elevator, it instantly intervenes when the elevator runs at an abnormal high speed, protecting passengers’ lives. So, what exactly does the overspeed governor do? Why is it so essential? Today, A-FLY Elevator & Escalator Parts Supplier will give you a full explanation.
1. What is an Elevator Overspeed Governor?
An elevator overspeed governor is a safety device used to monitor the elevator’s running speed. When the car’s upward or downward speed exceeds the safety limit, it automatically triggers the safety mechanism and forces the elevator to make an emergency stop.
The overspeed governor is generally composed of the following parts:
Tensioning device
Control switch
Linkage clamp (used together with the safety gear)
It does not control the elevator’s daily operation; instead, it saves lives in emergencies.
2. What Is the Core Function of an Overspeed Governor?
The function of the overspeed governor can be summarized in one sentence:
When the elevator speed becomes abnormal, it immediately triggers the safety gear to clamp the elevator firmly, preventing uncontrolled falling.
Its main functions include:
1. Monitoring Elevator Running Speed
The overspeed governor continuously monitors the car’s running speed. Once the speed exceeds the set value (for example, 115%–140% of the rated speed), it immediately intervenes.
This is the first speed detection safety line in the elevator system.
2. Triggering Safety Gear to Forcefully Stop the Car
When “overspeed” is detected, the overspeed governor pulls the special steel rope to activate the safety gear on both sides of the car,
allowing the elevator to be firmly stopped on the guide rails.
This effectively prevents:
Elevator out-of-control
Accelerated falling
Upward overshooting
It is a key component in preventing serious accidents.
3. Preventing Downward Overspeed
Downward overspeed is the most dangerous condition because the counterweight may drag the car downward.
The linkage structure of the governor ensures that the elevator can also be forcefully stopped during downward loss of control.
4. Preventing Upward Overspeed
Although upward overspeed occurs less frequently, the governor can still respond to abnormal upward movement to prevent the car from hitting the top of the shaft.
5. Providing Speed Information to the Control System (for certain intelligent models)
Newer governors have electronic monitoring functions and can send speed data back to the control board for secondary judgment and protection.
3. How Does an Elevator Overspeed Governor Work?
In simple terms, the overspeed governor protects passengers through two steps: “monitoring speed + pulling the safety gear.”
Working process:
Elevator runs → governor continuously detects speed
Speed exceeds set value → governor wheel instantly locks
Steel wire rope is pulled → safety gear engages
Safety gear clamps guide rails → car is forcefully stopped
This entire process is automatic and does not rely on the power supply or elevator control system.
Therefore, even in the event of a power failure or main control fault, the overspeed governor can still perform protection.
This is why it is considered one of the most important mechanical safety devices in elevators.
4. How Often Should an Overspeed Governor Be Inspected?
According to standards in various countries:
Overspeed governors must undergo at least one operational test every year.
Major inspection items include:
Whether the governor’s tripping speed is accurate
Whether the steel rope wear exceeds limits
Whether the wheel groove is worn
Whether the tensioning device works normally
Whether the linkage switch is sensitive
A faulty overspeed governor must be repaired or replaced immediately.
5. What Elevator Overspeed Governors Does A-FLY Provide?
As a professional elevator & escalator parts supplier, A-FLY provides high-quality overspeed governors compatible with different brands, including:
Upward and downward combined overspeed governors
Unidirectional or bidirectional overspeed governors
Electronic overspeed governors
Mechanical overspeed governors
Overspeed governors for high-speed elevators
Matching tensioning devices and steel ropes
A-FLY overspeed governors feature:
Precise tripping speed
High reliability and stability
Suitable for different loads, speeds, and shaft structures
Compatibility with major brands
Support for modernization and old elevator upgrades
Whether for new installations or replacements, A-FLY offers safe and reliable solutions.
6. Conclusion: The Overspeed Governor Is the Last Line of Elevator Safety
Among all elevator safety devices, the importance of the overspeed governor is self-evident.At the most critical moment, it acts as the “mechanical guardian” protecting passengers, truly determining whether the elevator can stop safely during an emergency.
Choose a high-quality overspeed governor. Choose A-FLY.Let elevator operation be safer and more reliable—ensuring every ride is worry-free.
