Describe the difference between traction and hydraulic elevators.

Traction elevators are engineered to utilize a cable and pulley system, in which the elevator car is lifted by a motor that drives a pulley. The mechanism allows for efficient movement over significant heights, making these elevators suitable for high-rise buildings. The system works by winding a steel cable around a sheave, which is attached to the elevator car, providing a smooth and controlled ascent and descent.

On the other hand, hydraulic elevators operate using fluid pressure. They are equipped with a hydraulic cylinder that moves when pressurized hydraulic fluid is sent into it, elevating the elevator car. This design is typically employed in low to mid-rise buildings because of its limitation in height and slower speed compared to traction systems.

The choice reflects distinct operational principles between the two systems, highlighting how one employs mechanical lifting through cables and pulleys, while the other relies on hydraulic fluid dynamics. Additionally, the performance characteristics, including speed and application, further differentiate these two elevator types.