An escalator is a moving staircase–a conveyor transport device for carrying people between floors of a building. The device consists of a motor-driven chain of individual,linked steps that move up or down on tracks, allowing the step treads to remain horizontal.
Escalators, likemoving walkways, are powered by constant-speed alternating current motors and move at approximately 1–2 feet (0.30–0.61 m) per second.
The maximum angle of inclination of an escalator to the horizontal floor level is 30 degrees with a standard rise up to about 60 feet (18 m).
Uses of Escalators
Escalators are used to move pedestrian traffic in places where elevators would be impractical
They have the capacity to move large numbers of people,
They can be placed in the same physical space as one might install a staircase. They have no waiting interval (except during very heavy traffic).
They can be used to guide people toward main exits or special exhibits,
They may be weatherproofed for outdoor use.