The elevator has been called the most-used mode of human transportation. Until now it has changed little since its inception. Elevators are known to have existed since about the 3rd century BC. More modern elevators were created in the 1800s. Until now the technology that is used to move them has advanced from a rope pulled by a person or animal, to one or more steel cables attached between the elevator cab and a motor.
A new elevator called MULTI is transformational and is being demonstrated in an 807 ft test tower in Germany. This April, ground was broken for a similar 18-shaft tower and innovation complex in Atlanta, GA to be completed in 2021, by multi-national company ThyssenKrupp. It will be next to SunTrust Park where the Atlanta Braves play.
The MULTI has no cables to support and move it. Instead it relies on linear motors, which work on electro-magnetic induction like an AC motor, except that the motion is linear instead of rotary. In an AC motor the rotor spins within a surrounding band of powered electromagnets that are static and called the stator. In a linear motor, the stator is ‘unrolled’ making it linear and in some cases superconducting magnets are used.
MULTI elevators are envisioned by the manufacturer to enable new building and city designs with multiple elevator cabs in each shaft traveling around vertical and horizontal “loops” as well as across sky-bridges connecting buildings.
Specifications for the MULTI include a top speed of 13.4 mph, 50% more transport capacity at up to 70% less peak power than conventional elevators, no limit on height, up to 50% less shaft space and waiting times reduced by an average of 15 to 20%.
Regarding safety, ThyssenKrupp states that, “the linear motors are safe because they need to be energized before they move. That means that without energy, the cabins can’t move. That’s why the cabins include batteries in case of energy breakdown. Additionally, we use a multi-step braking system that doesn’t allow cabins to move freely.”