Which type of pulley turns faster?

In a pulley system, the speed of rotation is inversely related to the size of the pulley when both are connected by a belt or rope. A smaller pulley will turn faster than a larger pulley because, for the same length of belt or rope that is moving, the smaller circumference of the smaller pulley requires it to complete more rotations in the same amount of time.

When you consider the relationship between the diameter of the pulleys and their rotational speeds, the smaller pulley must turn more times to cover the same distance along the belt compared to a larger pulley. This principle is often employed in mechanical systems and machinery where speed adjustments are necessary. By having a smaller pulley drive the larger one, the system can achieve higher speeds at the smaller pulley while reducing speeds at the larger pulley.

In contrast, larger pulleys cover more distance with each rotation but take longer to move the same length of rope or belt, leading to a slower rotation speed. Understanding this dynamic is crucial in applications involving gear systems or belt drives, where controlling speed and torque is essential for performance.