A system that uses battery or capacitor backup power to move a stranded elevator car to the nearest floor and open its doors during a mains power failure.
Full Definition
Emergency power lowering (EPL) — also called automatic rescue device (ARD) or battery rescue operation — activates automatically when mains power is lost. The on-board battery or capacitor bank provides enough energy to drive the elevator car to the nearest landing floor, open the car doors, and release trapped passengers without requiring manual intervention. The system uses the existing VFD or a dedicated rescue drive. EN 81-20 does not mandate ARD in all lifts but it is required or strongly recommended in many national regulations and is standard in modern installations. The battery is maintained on a float charge and must be tested regularly. An EPL system dramatically reduces entrapment incidents and associated emergency call-outs. Some systems can serve multiple calls or even return to a preferential floor.
