A control mode that allows elevator operation on a backup generator or UPS during a mains power failure.
Full Definition
Emergency power operation (EPO) is a controller mode activated when the building mains supply fails and power is provided by a generator or UPS. In EPO mode, the system may operate only one elevator at a time (selected car) to minimise load on the generator. The selected car completes its current trip, then parks at a designated landing, opens its doors, and waits. Where a dedicated rescue car is specified, it will automatically move to the nearest landing to discharge passengers before returning to the lobby. EN 81-73 (behaviour of lifts in the event of fire) and EN 81-77 (seismic) also address emergency power scenarios. Battery backup ARD (automatic rescue device) is an alternative for installations without a generator.
