14. September 2010 16:26
You need to record the period for which the car’s doors remain open at each floor. Elevator passengers typically can exit a car in two or three seconds, and can enter a car in about four seconds. Doors that remain open for much longer than this only slow down service. Also important in this exercise is the performance of the door reversing device. When the doors are blocked, they should open again immediately, and then attempt to close again right away. Again, any delays only reduce service. Once the doors are closed, the car should move away immediately.
When measuring the speed with which a car moves from floor to floor, managers must consider the type of hoisting mechanism, and its horsepower, employed by the elevator. A geared elevator, which typically moves at speeds up to 400 feet per minute, should be able to travel the height of ten floors in five or six seconds. Higher speed gearless elevators, which can move 500 feet per minute or faster, can cover the same ten-floor span in four or five seconds. Conversely, slower hydraulic elevators, which typically are limited to speeds of 150 feet per minute, take up to eight seconds to travel the ten-floor distance.
12. August 2010 14:56
Elevator installation consultant will inform you that installers put in electrical wires and controls by running tubing, called conduit, along a shaft’s walls from floor to floor. Once the conduit is in place, mechanics pull plastic-covered electrical wires through it. They then install electrical components and related devices required at each floor and at the main control panel in the machine room.
Installers bolt or weld together the steel frame of an elevator car at the bottom of the shaft; install the car’s platform, walls, and doors; and attach guide shoes and rollers to minimize the lateral motion of the car as it travels through the shaft. They also install the outer doors and doorframes at the elevator entrances on each floor.
For cabled elevators, these workers install geared or gearless machines with a traction drive wheel that guides and moves heavy steel cables connected to the elevator car and counterweight. Elevator installers also install elevators in which a car sits on a hydraulic plunger that is driven by a pump. The plunger pushes the elevator car up from underneath, similar to a lift in an auto service station. Installers and repairers also install escalators. They put in place the steel framework, the electrically powered stairs, and the tracks, and install associated motors and electrical wiring. In addition to elevators and escalators, installers and repairers also may install devices such as dumbwaiters and material lifts—which are similar to elevators in design—as well as moving walkways, stair lifts, and wheelchair lifts.