Safety Systems: More Backups

Elevators also have electromagnetic brakes that engage when the car comes to a stop. The electromagnets actually keep the brakes in the open position, instead of closing them. With this design, the brakes will automatically clamp shut if the elevator loses power.

Elevators also have automatic braking systems near the top and the bottom of the elevator shaft. If the elevator car moves too far in either direction, the brake brings it to a stop.

If all else fails, and the elevator does fall down the shaft, there is one final safety measure that will probably save the passengers. The bottom of the shaft has a heavy-duty shock absorber system -- typically a piston mounted in an oil-filled cylinder. The shock absorber works like a giant cushion to soften the elevator car's landing.

In addition to these elaborate emergency systems, elevators need a lot of machinery just to make their stops. In the next section, we'll find out how an elevator operates under normal conditions.