Traction Elevator Mechanics Flashcards
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Read the first 7 Traction Elevator Mechanics flashcards as text
When inspecting hoist ropes for removal from service, which criterion mandates immediate replacement according to ASME A17.1?
Answer: Six or more broken wires in one rope lay, or three broken wires in one strand in one lay
ASME A17.1 specifies that six broken wires per rope lay or three in a single strand per lay requires rope removal from service.
What is the purpose of equalizing hitches (rope shackles) on elevator hoist ropes?
Answer: To distribute load equally among all ropes by allowing slight individual adjustment
Equalizing hitches allow each individual rope to self-adjust so all ropes share the load equally, preventing one rope from carrying excess tension.
In a traction elevator, what condition is indicated when the car and counterweight arrive at the same level simultaneously?
Answer: The elevator is properly balanced
When car and counterweight are at the same level at the same time, the system is correctly balanced, with the counterweight at mid-travel when the car is also at mid-travel.
What is the function of the car safety device in conjunction with the governor rope?
Answer: To mechanically stop the car by clamping the guide rails when overspeed is detected
The car safety device is triggered by the governor rope and physically clamps the guide rails to stop an overspeed car.
Which of the following best describes 'roping' in the context of traction elevators?
Answer: The arrangement and path of hoist ropes connecting the car, sheave, and counterweight
Roping refers to the configuration (1:1, 2:1, etc.) and physical path of hoist ropes through the elevator system.
What is the primary disadvantage of a geared traction machine compared to a gearless machine?
Answer: Energy losses and noise from the gearbox, plus oil maintenance requirements
Geared machines have inherent gearbox inefficiencies, require oil changes, and produce more noise than direct-drive gearless machines.
How does counterweight percentage of balance affect traction elevator energy consumption?
Answer: A counterweight balanced at 40–50% of rated load minimizes energy use by offsetting load in both directions
Balancing at 40–50% of rated capacity means the motor does minimal work for light up-trips and light down-trips, optimizing energy across typical traffic patterns.