CET CET Roping & Counterweight Systems 2

Question 1

What type of wire rope construction is most commonly used for elevator hoist ropes?

Accepted Answer

8×19 Seale, independent wire rope core (IWRC)

Answer

8×19 Seale construction with IWRC is the most common elevator hoist rope, offering a good balance of flexibility, strength, and fatigue resistance.

Question 2

What is the purpose of the counterweight guide rails?

Accepted Answer

Keep the counterweight traveling in a straight vertical path within the hoistway

Answer

Counterweight guide rails constrain the counterweight to a precise vertical path, preventing lateral movement that could cause contact with hoistway walls or the car.

Question 3

What is 'rope creep' in a traction elevator system?

Accepted Answer

Slow slippage of hoist ropes relative to the drive sheave under traction

Answer

Rope creep is the slow, controlled slippage of hoist ropes relative to the drive sheave, which occurs due to the difference in tension between the car and counterweight sides.

Question 4

Which condition would most likely cause loss of traction in a traction elevator?

Accepted Answer

Overloaded car creating too large a traction ratio between loaded and unloaded rope sides

Answer

An overloaded car creates an extreme tension ratio between the car-side and counterweight-side ropes, exceeding the traction limit and causing the ropes to slip on the sheave.

Question 5

What is the purpose of 'compensating ropes' or 'compensating chains' in a tall-rise traction elevator?

Accepted Answer

Compensate for the weight imbalance caused by hoist rope weight shifting as the car travels

Answer

Compensating ropes or chains loop under the car and counterweight to compensate for the changing weight of hoist ropes as the car moves up and down in high-rise applications.

(CET) Certified Elevator Technician Practice Test

(CET) Certified Elevator Technician Practice Test

CET CET Roping & Counterweight Systems 2