Which component stops the lift if there is a mechanical failure?

• A. Electrical Contact
• B. Mechanical Pawl
• C. Limit Switch
• D. Speed Sensor

Answer: (A)

When something in the drive train goes wrong, you need a fail‑safe way to stop the escalator quickly. An electrical contact in the safety circuit is designed to do just that: when a fault is detected, it opens the circuit and interrupts power to the drive, allowing the brake to engage and bring the steps to a stop. This provides a direct, reliable shutdown that doesn’t depend on a mechanical path remaining intact.

A mechanical pawl part of the governor may trip the brake during an overspeed condition, but it isn’t the general mechanism for stopping on any mechanical failure. Limit switches control end-of-travel conditions, not fault protection, and a speed sensor monitors speed but may not guarantee a stop on a fault unless paired with the electrical interlock.