I understand there have been some multi-day power failures some places in the states because of storms. I am curious about elevators, particularly in old buildings (I assume new buildings are more likely to have better safety measures?). Do ALL elevators have provisions for emergency power? If so, do they automatically go to the ground floor (and presumably turn themselves off) when there is a power failure? Or is there some sort of manual rescue necessary (which I’d gues would take a LONG time in a major power failure)? I’d really rather not live in a blacked out elevator for a week or two. :eek:
There are many different provisions for elevators in power failure from FD and elevator service company gets you out to full back up power for building.
If the building has an emergency generator and one elevator that elevator will normally be on the emergency buss. Power goes off elevator comess to sudden stop. After the generator starts and comes up to speed it then connects to the emergency buss and elevator resumes operation.
If building has generator and more than elevator, but the emergency buss can not handle all the elevators. Full auto system. Power goes out all elevators suddenly stop, generator starts. After the emergency buss has power then one elevator will start go the ground floor doors open, stay open and elevator shuts off. 2nd elevator then starts goes to ground floor and repeats the 1st elevator. This will repeat until all elevators are on the ground floor. At that time one elevator (preselected by building operator) will return to normal operation. The doors of the elevator will close and it will begin to answer hall calls.
Same situation but not full auto. Power goes off all elevators stop, generator starts. When the emergency buss has power the preselected elevator will begin normal operations. If the building allows security or the elevator service company gets to the building there is a keyswitch that will determine which elevator will operate under emergency power. The operating elevator is recalled to the ground floor, when the doors open it is sshut off. The key switch is moved to recall the next elevator and shutting off the elevator with the doorss open is repeated. When the last elevator is recalled the descision is made as to which elevator will be left operating.
Some buildings all this can be done from the security control room.
Then there are some buildings with large enough generators that the whole building main buss is connected to the emergency buss and everything in the building operates as if there is nopower outage.
The final case that I know of is battery stand by operation. Otis elevator made elevators that had battery back up. As most elevator motors are DC motors they used batterys as back up. But to keep theload frombeing too great on the batteries the elevators only operated at slow speed. It could take a few minutes for the elevator to reach a floor, but you were not trapped.
Thanks. Thats the second elevator question I’ve had answered here (asked about the “Fire” key a while back). Amazing amount of knowledge around here! 
I forgot to also post, when there is a power outage and I am going just a few floors I never take an elevator. What if the generator or switch gear should fail. I would get borde waiting for someone to get me out. Plus if I am traped in the elevator in my building then who will make sure any problems are taken care of?
Börde, a district in Saxony-Anhalt in Germany, is arguably best known as the area of the former repository for radioactive waste Morsleben. The disposal of waste into the facility ended in 1998.
Trape, v. i. [See Tramp, and cf. Traipse.] To walk or run about in an idle or slatternly manner; to traipse. [Obs. or Colloq.]
TrapeNoun; a type of trade in fantasy sports when one team beats the other team clearly in a trade. Derived from the terms trade and rape.