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Elevator control system failures, traction sheave slippage, or braking malfunctions can lead to uncontrolled movement—either downward overspeed or unintended movement upwards or at the landing. The overspeed governor acts as an independent, purely mechanical backup safety device, detecting such failures and initiating a safe stop when electronic controls cannot.
Elevator Overspeed Detection and Governing Systems
-- Steady & Reliable Manufacturer --
The overspeed governor is the primary monitoring device in an elevator's safety chain. It continuously tracks the elevator car's speed via a rotating governor rope. If a predetermined overspeed threshold is exceeded, it mechanically triggers the safety gear system to engage and stop the car.
This category includes mechanical governors for machine room (MR) and machine roomless (MRL) configurations, units with integrated encoders for control system feedback, and specialized governors for UCMP (Unintended Car Movement Protection) systems.
Recommended Products
The Key Problem We Solve
Typical Applications
- All traction-driven electric passenger and freight elevators.
- Machine room and machine roomless (MRL) elevator installations.
- Modernizations and upgrades of existing elevator systems.
- Systems requiring UCMP compliance according to EN 81-20/50 and other global standards.
- High-speed elevators where precise speed monitoring and feedback are critical.
Product Advantages
| Governor Type | Centrifugal Flyweight Type, Horizontal or Vertical Axis |
| Speed Range Covered | 0.25 m/s to 10.0 m/s+ |
| Tripping Speed Accuracy | ±3% to ±5% of set value, tested per EN 81-20 |
| 100W30 hydraulic oil or equivalent synthetic oil | |
| Sealing System | Multiple lip seals and O-rings, often in Nitrile rubber (NBR) or Fluorocarbon (FKM) for high temperature. |
| Cylinder Construction | Seamless steel tube, precision honed interior. |
| Mounting Options | Top or bottom guided; fixed base or compact spring return designs. |
| Key Standards | EN 81-20/50, ASME A17.1, GB 7588 |
Selection & Compliance Considerations
Single vs. Dual Directional: Standard governors trip for overspeed in the down direction. For UCMP compliance, a bi-directional governor or a second, separate governor for the up direction is required to detect unintended upward movement.
Encoder Integration: An encoder provides real-time speed feedback to the elevator controller, enhancing ride comfort and control. Specify the required pulses per revolution (PPR) and output signal type (e.g., push-pull, open collector).
Rope Size Compatibility: The governor sheave groove must match the diameter and type of the governor rope (typically 6mm to 10mm). The rope's flexibility and construction affect tripping accuracy.
Ambient Conditions: In dusty, humid, or corrosive environments, sealed bearing units and protective coatings on the housing are recommended.
FAQ
- Q: What is the difference between a mechanical governor and an electronic speed monitor?
- A: A mechanical governor is a standalone safety device that uses centrifugal force to trigger a physical switch. An electronic monitor is part of the control system for operational feedback. Safety codes often require a redundant, independent mechanical governor as a backup, even with electronic monitoring.
- Q: How is the tripping speed determined and set?
- A: The tripping speed is defined by standards (e.g., EN 81-20 specifies a range) and is calculated based on the elevator's rated speed. It is factory-set using calibrated test equipment and can be field-adjusted within a small range using adjustable springs or weights, following strict procedures.
- Q: Is a separate governor needed for UCMP?
- A: It depends on the system design. One solution is a bi-directional governor that can trip for both up and down overspeed. Another common solution is to use two standard governors, one set for down overspeed and a second, independent one set for up direction UCMP activation.
About Us
Shanghai Liftech Elevator Accessories Co., Ltd.
Founded in 2004, Shanghai Liftech Elevator Accessories Co., Ltd. is a specialized enterprise dedicated to the R&D, manufacturing, testing, and sales of elevator safety components. With over two decades of sustained development, Liftech has established itself as a leading manufacturer in China's elevator safety sector, providing high-quality products and solutions to a wide range of major elevator brands and engineering clients across domestic and international markets. We are ,China Wholesale Elevator Overspeed Detection and Governing Systems Suppliers and Elevator Overspeed Detection and Governing Systems OEM/ODM Manufacturers
For over 20 years, LIFTECH (est. 2004) has been a trusted force in the R&D, manufacturing, and full lifecycle support of premium elevator safety components.
Material Selection Guide
| Component | Standard Duty | Extended Life / Low Maintenance | Harsh Environment |
| Governor Sheave | Ductile Iron (GGG40), machined grooves | Steel, hardened groove edges for reduced rope wear | Stainless Steel or coated sheave |
| Flyweights & Pivots | Steel, precision machined | Hardened steel pivots on bronze bushings | Stainless steel components |
| Governor Rope Clamp | Steel jaws with serrated surface | Replaceable hardened steel inserts | Coated or stainless steel clamp |
| Shaft Bearings | Deep Groove Ball Bearings, shielded | Lubricated-for-Life or Ceramic Hybrid Bearings | Double-sealed or Corrosion-Resistant Bearings |
| Housing | Aluminum Alloy or Pressed Steel | Cast Iron for dampening vibration | Epoxy Painted or Zinc-Plated Steel |
