Elevator Installation & Components Flashcards
7 cards from real CET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Elevator Installation & Components flashcards as text
What is the purpose of the leveling zone in an elevator control system?
Answer: Defines the area within which the car may move to achieve accurate floor-level positioning
The leveling zone is a short distance above and below the landing where the car is permitted to move at creep speed under door-open conditions to achieve precise floor alignment.
Which component seals the hoistway opening at each floor and must be interlocked to prevent opening unless the car is present?
Answer: Hoistway door (landing door) with interlock
Hoistway landing doors are equipped with interlocks that electrically and mechanically prevent the door from being opened unless the car is within the unlocking zone at that landing.
During installation of wire hoist ropes, why is equalizing the tension among all ropes critical?
Answer: To ensure each rope carries its proportional share of the load and prevents premature wear or breakage of individual ropes
Unequal rope tension causes overloaded ropes to wear and fatigue faster, reducing system safety factor; equalization distributes load evenly across all ropes.
What is the minimum number of hoist ropes required for a passenger elevator under ASME A17.1?
Answer: The code requires a minimum safety factor, not a specific rope count
ASME A17.1 mandates that the aggregate rope strength meet a required safety factor relative to the load; the actual rope count depends on rope size, strength, and design load.
What is the function of the electromagnetic brake on a traction elevator machine?
Answer: Holds the drive sheave stationary when the motor is de-energized to prevent car drift
The electrically released brake grips the brake drum or disk whenever the motor is not powered, preventing the car from moving under gravity.
What is the purpose of the traveling cable in an elevator installation?
Answer: Carries power and signal wiring between the fixed controller and the moving car
The traveling cable is a flexible multi-conductor cable that follows the car's movement and provides a continuous electrical connection for car lighting, door operator, communication, and control signals.
When setting buffer stroke during a new installation, which factor primarily determines the minimum required oil buffer stroke?
Answer: Rated car speed
Oil buffer stroke is calculated based on rated speed because the buffer must absorb the kinetic energy of the car (or counterweight) traveling at governor trip speed, which is proportional to rated speed.