CET CET Machine Room & Pit Equipment 2 — Questions and Answers
Question 1: What is the purpose of the terminal stopping device (final limit switch) in a traction elevator?
- Slows the car as it approaches a floor
- Stops the car if it passes beyond normal travel limits (Correct answer)
- Activates the door operator at each landing
- Controls the speed of the motor
Correct answer: Stops the car if it passes beyond normal travel limits
Terminal stopping devices (final limits) are safety switches that cut power if the car travels beyond the normal upper or lower terminal landings.
Question 2: What machine room component controls the starting, stopping, and speed of a traction elevator motor?
- The governor
- The motor-generator set
- The controller (Correct answer)
- The selector
Correct answer: The controller
The elevator controller is the brain of the system, managing motor starting and stopping, speed regulation, floor selection, and safety circuit monitoring.
Question 3: What does the term 'rope equalizer' refer to in an elevator machine room?
- A device that evenly distributes tension across all hoist ropes (Correct answer)
- A component that adjusts rope speed to match door timing
- A rope lubrication system
- A device that measures rope elongation
Correct answer: A device that evenly distributes tension across all hoist ropes
A rope equalizer distributes the load evenly among all hoist ropes to prevent individual ropes from being overloaded due to unequal tension.
Question 4: Which standard governs the design and installation requirements for elevator machine rooms in the United States?
- NFPA 13
- ASME A17.1/CSA B44 (Correct answer)
- ANSI Z535
- NEC Article 620
Correct answer: ASME A17.1/CSA B44
ASME A17.1/CSA B44 is the Safety Code for Elevators and Escalators and is the primary standard governing machine room design and equipment in the US.
Question 5: What minimum temperature must be maintained in an elevator machine room to protect electrical and mechanical components?
- 32°F (0°C)
- 50°F (10°C) (Correct answer)
- 60°F (15°C)
- 40°F (4°C)
Correct answer: 50°F (10°C)
ASME A17.1 requires machine room temperatures to be maintained above 50°F (10°C) to protect lubricants, electrical components, and control systems.
Question 6: What is the required means of access to an elevator pit?
- A trap door accessible from the hoistway only
- A pit access door or a hoistway access panel meeting code dimensions (Correct answer)
- A rope ladder attached to the pit wall
- Any opening at least 18 inches square
Correct answer: A pit access door or a hoistway access panel meeting code dimensions
ASME A17.1 requires a properly sized pit access door or hoistway access panel that allows safe entry for maintenance personnel.
CET CET Machine Room & Pit Equipment 2
What is the purpose of the terminal stopping device (final limit switch) in a traction elevator?