Automatic switch to emergency power after failure.

• A. Power Transfer
• B. Hydraulic Driving Machines
• C. Floor Area Limit
• D. Mechanical Locking

Answer: (A)

The concept tested is automatic power switching to a backup source when normal power fails. This is accomplished by a Power Transfer device, which automatically disconnects the normal supply and connects the emergency power source to the escalator’s control circuits and drive system. This ensures the escalator can continue to be controlled or safely halted without manual intervention, preserving safe operation during a power outage.

The other terms don’t describe this automatic changeover: Hydraulic Driving Machines refer to the drive system itself, not the switch to emergency power; Floor Area Limit is a safety boundary device; Mechanical Locking is a safety mechanism used to prevent movement during maintenance.