The answer depends on the type of residential elevator you have. Here we address the 3 types we sell, install, and service.
Before Automatic Lowering Systems
But, first, let us discuss how it used to be before all home elevators had emergency battery lowering systems installed. This may be helpful information in case you ever encounter an outage in an older home elevator or commercial elevator.
Before today’s technologies gave homeowners complete peace of mind when riding in their elevators, when the electricity service went out the traditional hydraulic or traction elevator immediately and, most often, abruptly stopped where it is. Perhaps, between floors if you were riding in the elevator. While the sudden stop was likely disconcerting, it is an excellent safety feature as the elevators were (and are) equipped with electromagnetic brakes. Without an emergency battery lowering system installed, the cab with you safely locked inside remained stopped until the electricity came back on or a professional elevator technician comes to your rescue.
Behavior and mechanical solutions to power outages are different for traditional hydraulic or traction elevators and pneumatic vacuum elevators. We begin with traditional elevators. Jump to vacuum elevators.
How Electro Magnetic Brakes Work
The electromagnets (electrical coils) force the brakes to remain in the open position. While there is electricity, the brakes are held open.
By design when power ceases, the brakes automatically clamp shut, applying the brakes rapidly.
Thus, there is no worry about free fall when a traditional hydraulic elevator is maintained.
We Install Emergency Battery Lowering on All Our Traditional Elevators
While loss of power without such a safety system is no valid reason to panic, our human nature can get the best of us in situations in which we are not accustomed, like being stuck in an elevator. Power outages can take a long time. In a hurricane or heavy windstorm here in the Houston area, it can be days. So, we install automatic lowering systems using DC battery power so that the brakes do not engage with an abrupt stop.
This elevator’s automatic battery lowering system activates as soon as power is lost. Generally, the elevator will make one trip on battery power, in most cases the ground floor. The doors will open, and then the elevator will shut down. This allows you to swiftly exit, but the elevator remains unusable until power is restored.
After the Power Comes Back On
If the elevator does not resume operation following a power failure, do not re-enter it until it has been placed back in service by a licensed elevator technician. Elevators contain many electrical components that provide a smooth operation that should be evaluated for damage.
A power outage may involve flickers and power surges damage delicate components to fail. By design, fuses and breakers protect the more expensive components in this event. So, a blown fuses or tripped circuit breakers may be the sole source of failure. But a licensed elevator maintenance technician can test components and review information in the logs of the software that runs the elevator to make the appropriate repairs.
Pneumatic elevators work using gravity and air. Its design makes free fall impossible. When operating normally, you select a stop on a higher floor and then the vacuum pump engages to reduce the air pressure in the chamber above the cab. The now higher pressure below the cab pushes the cab upwards. While the vacuum pump is operating a to create low pressure above the car, it will rise.
During a power failure, the same design takes over naturally as no energy is required to descend. When the electricity is cut and the pump will no longer run, the air pressure above the car is no longer being vacuumed out to create low pressure and the car will be gently, actually more slowly than usual, pulled to the lowest floor by gravity. Note if the car is not in use, it will just stay where it is.
No battery back-up or lowering system is required.
Power outages highlight a big advantage of the vacuum elevator.