Escalator & Moving Walk Systems Flashcards
7 cards from real CET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Escalator & Moving Walk Systems flashcards as text
In a worm-gear escalator drive, what is the advantage of a self-locking worm gear ratio?
Answer: Prevents the escalator from overspeeding if the brake fails
A self-locking worm gear cannot be back-driven by the load, providing a mechanical backup that prevents runaway if the primary brake fails.
What action is required before performing maintenance work inside an escalator truss?
Answer: Install a lockout/tagout on the main line disconnect and test for zero energy
LOTO procedures require isolating and verifying zero energy state on the main disconnect before any personnel enter the truss for maintenance.
Which of the following is NOT a required safety device on a standard escalator per ASME A17.1?
Answer: Automatic passenger counter
Passenger counters are not required safety devices under ASME A17.1; broken step-chain, overspeed, and reverse phase protection are all code-mandated.
What is the purpose of the inner and outer decking on an escalator balustrade?
Answer: Covers the internal components and provides a smooth surface adjacent to the steps
Balustrade decking panels enclose the internal step-chain and guide mechanisms while presenting a smooth surface that reduces entrapment risk at the step-skirt interface.
An escalator controller's phase-reversal protection relay serves what purpose?
Answer: Stops the unit if incoming power phases are reversed, which would cause reverse travel
A phase-reversal relay detects incorrect three-phase sequence and shuts down the escalator to prevent unintended reverse direction of travel.
Under ASME A17.1, the escalator handrail must return to the newel within how many inches of the top edge of the balustrade?
Answer: 4 inches
The handrail centerline must be within 4 inches (102 mm) horizontally from the top edge of the balustrade at the point of entry into the newel.
What is the typical step riser height used on a standard escalator?
Answer: 8 inches
Standard escalator step risers are nominally 8 inches (203 mm) in height, a dimension established to match typical stair ergonomics for comfortable boarding.