QEI Traction Drive Systems and Wire Rope 2 — Questions and Answers
Question 1: What parameter must a QEI inspector verify when checking drive sheave groove condition?
- Sheave rotational speed
- Groove wear and undercut depth relative to manufacturer limits (Correct answer)
- Sheave bearing lubrication interval
- Motor torque output
Correct answer: Groove wear and undercut depth relative to manufacturer limits
Inspectors must measure sheave groove wear and undercut to ensure ropes seat properly and traction is maintained within manufacturer and code limits.
Question 2: Which test verifies that the elevator braking system can hold the car with its rated load?
- Buffer test
- Brake torque test (Correct answer)
- Safety device test
- Governor overspeed test
Correct answer: Brake torque test
The brake torque test confirms the elevator brake can hold the car stationary with full rated load applied, as required by ASME A17.1.
Question 3: What is the ASME A17.1 requirement for traction elevator counterweight balance relative to the car?
- Counterweight equals car weight only
- Counterweight equals car weight plus 40% to 50% of rated load (Correct answer)
- Counterweight equals car weight plus 100% of rated load
- Counterweight equals 75% of car weight
Correct answer: Counterweight equals car weight plus 40% to 50% of rated load
ASME A17.1 requires the counterweight to equal the empty car weight plus 40–50% of rated capacity to optimize traction and energy efficiency.
Question 4: What does a 'traction loss' condition occur when in a traction elevator?
- The motor loses electrical power
- The friction between the hoist ropes and drive sheave is insufficient to move the car (Correct answer)
- The governor rope breaks
- The brake fails to release
Correct answer: The friction between the hoist ropes and drive sheave is insufficient to move the car
Traction loss occurs when the friction force between the hoist ropes and sheave grooves cannot overcome the load difference, causing the ropes to slip.
Question 5: Under ASME A17.1, what is the minimum factor of safety required for elevator hoist ropes?
- 5
- 8
- 10 (Correct answer)
- 12
Correct answer: 10
ASME A17.1 specifies a minimum factor of safety of 10 for elevator wire ropes used in passenger and freight elevators.
Question 6: Which condition would require a QEI inspector to flag the drive machine for corrective action?
- Normal operating temperature at rated load
- Excessive gear backlash in a geared machine beyond manufacturer tolerances (Correct answer)
- Slight vibration during acceleration within spec
- Normal motor current draw at full speed
Correct answer: Excessive gear backlash in a geared machine beyond manufacturer tolerances
Excessive gear backlash beyond manufacturer tolerances indicates gear wear that can cause rough operation, noise, and eventual failure requiring corrective action.
QEI Traction Drive Systems and Wire Rope 2
What parameter must a QEI inspector verify when checking drive sheave groove condition?