Why did it take 84 floors to stop a falling elevator? The two sets of emergency brakes tried to stop it but it fell 84 floors before the emergency brakes were able to get the falling elevator full of people to stop. So there were two major problems. The cable broke and the electric brake on the lift motor plus the free-fall brakes were able to save the people while the elevator dropped them 84 floors.
The brakes finally stopped the elevator on the 11th floor after the elevator fell almost 700 feet. (8 feet per floor times 84 floors is 672 feet).
The Free Fall Brake (or elevator safety) will stop and hold a free-falling or over speeding elevator in the down direction even if all of the hoisting cables are severed. It typically kicks in once the elevator has reached a speed greater than its regular operating speed. the free-fall brakes work by a wheel that spins while the elevator is moving. The faster the elevator moves the more centrifical force the spinning wheel generates and at a pre-set RPM the brakes fly out against the elevator tracks and jam the elevator car against the tracks
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