Many elevator installations now feature emergency power systems which allow elevator use in blackout situations and prevent people from becoming trapped in elevators.
When emergency power (from uninterruptible power supply) is detected, cars shall return to the main lobby one elevator at a time, and remain there with doors open. While each car is being returned, all other cars shall be shut down so as not to overload the emergency power generator. Once all cars have been returned to the lobby, one or more cars may be selected to run under emergency power, depending on the capability of the emergency power generator. Selection of cars that run under emergency power shall be done automatically by the group system. This automatic selection may be overridden through manual selection. The actual number of cars allowed to run under emergency power shall be a preprogrammed value and the number of cars allowed to run shall not exceed this value, usually works with the fireman's elevators only.
A means of lowering the elevator shall be provided when there is a power failure. This operation shall bring the car to the lowest landing and allow passengers to exit the elevator. This operation requires a separate battery operated power supply system (from uninterruptible power supply). Emergency power generator control is also available.
Buildings like hospitals and nursing homes usually size their emergency generators to accommodate this draw. However, the increasing use of current limiting motor starters, commonly known as "Soft-Start" contactors, avoid much of this problem and the current draw of the pump motor is less of a limiting concern.
Notable devices name
- Automatic Rescue Device (ARD) (Schindler)
- Emergenzamatic (Indolift)
- Mitsubishi Emergency Landing Device (MELD) (Mitsubishi)
- Emergency Lowering Kit (Dover)
|Elevator Special Modes|
Anti-Crime Protection (ACP) • Attendant service (AS) • Earthquake emergency return (EER) • Emergency power operation (EPR) • Fire service mode (EFS) (Fireman's elevator) • Independent service (ISC) • Inspection service (INS) • Medical emergency/Code Blue service (EHS) • Nudge mode • Out of service • Peak times modes (Up peak (MIT) • Down peak) • Pet mode • Sabbath service (SHO)
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