Mixed Deck — All CET Topics Flashcards

What does a 'step sag' or 'step level' device detect on an escalator?

Answer: A step that has dropped below the plane of adjacent steps

A step level switch detects when a step sags or rises out of the normal tread plane, triggering an emergency stop to prevent a tripping hazard.

Under ASME A17.1, what is the required frequency for performing a 'no-load safety test' on a traction elevator?

Answer: Every 6 months

ASME A17.1 requires a no-load safety test to be performed every 6 months to verify proper operation of the car safety device.

Which type of motor is commonly used in modern traction elevator systems?

Answer: AC gearless permanent magnet motor

AC gearless permanent magnet motors are widely used for their energy efficiency and smooth operation.

What is the purpose of a 'motor thermistor' or thermal overload device embedded in the elevator motor windings?

Answer: Detect excessive motor winding temperature and signal the controller to shut down

Embedded thermistors change resistance with temperature; when winding temperature exceeds safe limits, the controller detects the resistance change and shuts down the motor.

When testing Phase II firefighters' service, what verifies that the car will NOT move when the in-car Phase II switch is in the 'ON' position but no buttons are held?

Answer: The car should remain stationary; movement without a held button is a failure

In Phase II, the car must remain stationary until the operator holds a floor button and door close; spontaneous movement indicates a control system fault.

What issue is indicated by frequent elevator leveling problems?

Answer: Faulty leveling sensors or brakes

Frequent leveling issues can signal faulty sensors or brake malfunctions affecting stop accuracy.

What material are elevator guide rails most commonly made from?

Answer: Cold-drawn steel T-section

Guide rails are manufactured from cold-drawn steel in a T-section profile to provide the precise surface finish and strength needed for guide shoes and safeties.

What is the function of the oil buffer in the elevator pit?

Answer: Absorbs kinetic energy to decelerate the car or counterweight

Oil buffers absorb and dissipate the kinetic energy of an elevator car or counterweight running into them, preventing sudden impact.

What does ASME A17.1 specify regarding the use of a 'buffer' at the bottom of a hoistway?

Answer: Buffers must be oil type for elevators over 200 fpm

ASME A17.1 requires oil buffers (energy dissipation type) for elevators with rated speeds exceeding 200 fpm; spring buffers are only permitted at lower speeds.

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

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

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.

What is the purpose of 'rope clips' (Crosby clips) when used on elevator hoist rope installations?

Answer: Used for temporary field connections during rope installation or adjustment only

Rope clips are a temporary field tool used only during rope installation and adjustment, never as permanent load-bearing hoist rope terminations on elevators.

An escalator's rated speed is defined as speed measured at the:

Answer: Step tread surface in the direction of travel

Rated speed refers to the velocity of the step tread surface in the direction of travel, typically measured in feet per minute.

What type of lubrication system is commonly used on modern escalator step chains?

Answer: Automatic oil drip or spray lubrication system

Modern escalators use automatic chain lubrication systems that periodically apply oil or grease to minimize wear and reduce maintenance intervals.

A governor rope that has been kinked due to improper storage must be:

Answer: Replaced, as kinks create permanent weak spots that can cause failure

A kinked wire rope has permanently distorted wires that concentrate stress and reduce breaking strength, requiring replacement.

What is the purpose of the counterweight guide rails?

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

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

When firefighters activate Phase I Emergency Recall using the key switch, elevators should return to the designated level within how many seconds for a travel time not exceeding 60 seconds?

Answer: 60 seconds

ASME A17.1 requires elevators to return to the designated level within 60 seconds when travel time does not exceed 60 seconds.

When installing guide rails, what is the correct method for joining two rail sections together?

Answer: Using fish plates bolted to both rail sections

Fish plates (splice plates) are bolted to the web of each adjoining rail section to create a secure, aligned joint.

What is the function of the comb plate on an escalator?

Answer: Meshes with step cleats at the landing to prevent foot entrapment

The comb plate's fingers interlock with step cleats at each landing, bridging the gap and preventing feet or objects from becoming trapped.

A car operating panel (COP) replacement during modernization must comply with ADA requirements. What is the maximum mounting height for the highest operable control button?

Answer: 48 inches AFF

ADA requires the highest operable part of a control to be no more than 48 inches above the finished floor for a forward reach.

Conductors from different systems (such as lighting, power, and signal circuits) installed in the same elevator wireway must:

Answer: Be separated by a metal barrier or otherwise comply with NEC requirements for system separation

NEC Article 620 and ASME A17.1 require separation of conductors from different systems to prevent electrical interference, cross-talk, and safety hazards from mixing incompatible circuit types.