gearless traction
Traction elevators whose motor turns the cable sheave directly, without an intervening gear mechanism.
Gearless traction elevators are vertical transportation cabs which are balanced within a shaft by a counterweight, each hung on cables slung over a cylindrical sheave, around which the woven cables are wrapped in tight grooves to provide traction. The motor turns the sheave without an intervening gear mechanism.
These are the fastest kind of elevators, generally achieving speeds greater than 2.5 meters per second, and in the fastest cases over 17 meters per second. Gearless traction elevators are commonly used in skyscrapers, as well as other tall buildings and towers.
Gearless traction elevators can be machine roomless or have a separate machine room. Machine-roomless construction is not exclusive to gearless traction; hydraulic systems can also use that arrangement.