How governor work in an elevator?
What is a governor in lift?
The elevator governor is a crucial safety device in an elevator system. Its primary function is to monitor and control the speed of the elevator car, preventing it from moving too quickly, and activating the safety brakes in case of overspeed. Here's a detailed explanation of how the elevator governor works.
How does elevator overspeed governor work?
Working Principle of an Elevator overspeed Governor :-
1. Centrifugal Force Detection: -
The elevator governor consists of a set of rotating weights, typically referred to as "flyweights" or "governor balls." These flyweights are attached to a spindle that is connected to the elevator's drive sheave, which is responsible for moving the elevator car.
2. Tension on Governor Rope: -
The governor rope is attached to the elevator car and wraps around a pulley on the drive sheave. As the elevator car moves, it causes the drive sheave to rotate, which, in turn, rotates the governor flyweights.
3. Centrifugal Force vs. Spring Force:-
The governor flyweights are designed to pivot outward as they rotate due to centrifugal force. This outward movement is opposed by a set of adjustable springs. The spring force and the centrifugal force acting on the flyweights create an equilibrium when the elevator is operating at the desired speed.
4. Overspeed Detection:-
If the elevator car starts to move too quickly, such as in the event of a malfunction or a free fall, the centrifugal force on the flyweights exceeds the spring force, causing the flyweights to pivot outward even further.
5. Tripping Mechanism:-
The governor assembly includes a tripping mechanism that, when the flyweights pivot outward beyond a certain angle (indicating overspeed), triggers an electrical or mechanical switch.
6. Brake Activation:-
When the switch is triggered, it sends a signal to activate the safety brake system within the elevator's machine room. The safety brake engages, applying friction to the guide rails or the drive sheave, which quickly and forcefully brings the elevator to a stop.
7. Emergency Stop:-
Simultaneously, the overspeed detection also triggers the elevator's emergency stop circuit, cutting power to the elevator motor and bringing the elevator to a complete halt. The emergency interlock system also engages, preventing the doors from opening until the elevator is safely brought to a stop.
Key Points to Note:-
The governor's function is to prevent dangerous overspeed conditions in the elevator.
The governor assembly is a redundant safety feature, often with multiple flyweights and redundant systems to ensure reliability.
Regular maintenance and calibration of the governor system are essential to ensure its proper operation.
The governor is just one of several safety systems in an elevator, working in conjunction with other devices like the safety gear and emergency brakes to ensure passenger safety.
In summary, the elevator governor relies on centrifugal force and a spring-based mechanism to detect overspeed conditions and trigger the safety brake system, ultimately bringing the elevator to a controlled stop in the event of an emergency. This crucial safety feature helps prevent accidents and ensures the safety of passengers and property.