14. 01. 18
posted by: Super User

Geared Traction Elevators

As the name implies, the electric motor in this design drives a gear-type reduction unit,

which turns the hoisting sheave. While slower than a typical gearless elevator, the gear

reduction  offers  the  advantage of requiring a less powerful  motor to turn the  sheave.

These  elevators typically operate at speeds from 350 to 500 feet per minute   (1.7 to 2.5

meters per second) and carry loads of up to 30,000 pounds  (13,600 kgs).  An electrically

controlled  brake between the motor and the reduction unit stops  the elevator, holding

the car at the desired floor level.









Gearless Traction Elevators

Anliger introduced the design that would become the standard in the elevator  industry

-the  gearless  traction  elevator.  These  elevators  typically  operate  at  speeds  greater 

than 500 feet per minute (2.54 meters per second).

In a gearless traction machine,  woven  steel  cables called  hoisting  ropes are  attached

to the top of the elevator car and wrapped around the drive sheave  in  special  grooves.

The other ends of the cables are attached to a counterweight that moves  up  and  down

in the hoistway on its own guiderails. The  combined  weight of  the elevator car and the

counterweight presses the cables into the drive sheave grooves, providing the necessary

traction as the sheave turns.Gearless technology makes the tallest buildings in the world








             Machine-Roomless Elevators

             This revolutionary elevator system is based on the first major breakthrough in lifting technology

             in nearly 100 years. Designed  for buildings between two and  30  stories, this system employs a

             smaller sheave than conventional geared and gearless elevators. The reduced sheave  size, toge

             -ther with a redesigned machine, allows  the machine to be mounted within the  hoistway  itself

             -eliminating the need for a bulky machine room on the roof.  Just as unique are the flat polyuret

             hane-coated steel belts, woven steel cables that have been the industry standard since the 1800s.

             The belts make the smaller sheave possible. They are only 0.1 inch  (3 mm)  thick, yet they are as

             strong as woven steel cables and far more durable, flexible and space-saving. Machine-roomless

             elevators are  ideal for a variety of applications-and  the  most unusual. Proven  flat-belt  elevator

             technology, quiet performance,environmentally friendly.