topic 14: building conveying systems Flashcards
_____ is a platform or compartment housed in a shaft for raising and lowering people or things to different floors or levels.
elevator
______ is a small elevator for carrying things, especially food and dishes, between the floors of a building.
dumbwaiter
What are the 2 types of elevators?
- electric elevators
- oil hydraulic elevators
_____ are a type of elevator that operates using electric power for various components of its system.
electric elevators
Unlike traditional hydraulic elevators that use a system of pistons and fluid for movement, electric elevators rely on a system of _____, powered by an electric motor.
ropes and sheaves
What are the 9 parts of an electric elevator?
- shaft
- car
- cables
- counter weights
- guide rails
- machine room
- elevator machine
- controls
- safety devices
______ is the vertical passageway for car and counterweights.
shaft
______ is a cage of light metal supported on a structural frame, the top member of which the cables, that carry the car, are fastened.
car
_____ are the means for lifting or lowering the car, usually 3 to 8 cables placed in parallel fastened to top of car by cable sockets passing over a motor driven cylindrical sheave to the counterweights.
cables
Cables for electric elevators are usually ______ cables placed in parallel.
3-8
____ are rectangular blocks of cast iron stacked in one frame which is fastened to the opposite ends of the cables to which the car is fastened.
counterweights
_____ are vertical tracks that guide the car and the counterweights.
guide rails
_____ is a room usually placed directly above the shaft in which the elevator machine is housed.
machine room
The _____ contains the motor-generator (MG) set which supplies energy to the elevator machine, the control board and the control equipment.
machine rooms
The _____ turns the sheave that lifts and lowers the car.
elevator machine
The _____ is a combination of push buttons, contacts, relays, and devices, operated manually or automatically to initiate door opening, starting acceleration, retardation, leveling and stopping of the car.
controls
What are the 4 safety devices?
- main brake
- safety switch
- electrical final limit switches
- oil or spring buffers
The ____ is mounted directly on the shaft of the elevator machine.
main brake
The _____ is designed to stop an elevator car automatically before car speed becomes excessive.
safety switch
On overspeed, the _____ will cut off power to the motor and set the brake.
speed governor
The ______ usually stops the car, but should speed still increase, the governor will actuate rail clamps mounted at the bottom of the car one on each side.
speed governor
_____ are located a few feet below and above safe travel limits of elevator car.
electric final limit switches
If car over-travels, either down or up, these switches de-energizes the motor and sets the main brake.
electric final limit switches
_____ are placed at the bottom of the elevator pit, not to stop a falling car, but to bring it to a partially cushion stop if the car should overshoot the lower terminal.
oil or spring buffers