CET Escalator & Moving Walk Systems 5

Question 1

In a worm-gear escalator drive, what is the advantage of a self-locking worm gear ratio?

Accepted Answer

Prevents the escalator from overspeeding if the brake fails

Answer

A self-locking worm gear cannot be back-driven by the load, providing a mechanical backup that prevents runaway if the primary brake fails.

Question 2

What action is required before performing maintenance work inside an escalator truss?

Accepted Answer

Install a lockout/tagout on the main line disconnect and test for zero energy

Answer

LOTO procedures require isolating and verifying zero energy state on the main disconnect before any personnel enter the truss for maintenance.

Question 3

Which of the following is NOT a required safety device on a standard escalator per ASME A17.1?

Accepted Answer

Automatic passenger counter

Answer

Passenger counters are not required safety devices under ASME A17.1; broken step-chain, overspeed, and reverse phase protection are all code-mandated.

Question 4

What is the purpose of the inner and outer decking on an escalator balustrade?

Accepted Answer

Covers the internal components and provides a smooth surface adjacent to the steps

Answer

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.

Question 5

An escalator controller's phase-reversal protection relay serves what purpose?

Accepted Answer

Stops the unit if incoming power phases are reversed, which would cause reverse travel

Answer

A phase-reversal relay detects incorrect three-phase sequence and shuts down the escalator to prevent unintended reverse direction of travel.

(CET) Certified Elevator Technician Practice Test

(CET) Certified Elevator Technician Practice Test

CET Escalator & Moving Walk Systems 5