What effect does increasing the diameter of a driving pulley have on the speed of a driven pulley in a belt system?

Increasing the diameter of a driving pulley in a belt system affects the speed of the driven pulley due to the relationship between the diameters of the pulleys and their rotational speeds. In a belt drive system, the belt that connects the two pulleys moves at a constant linear speed regardless of the sizes of the pulleys.

When the diameter of the driving pulley is increased, it results in a larger circumference. As a consequence, for each complete rotation of the driving pulley, the belt moves further along, causing the driven pulley to rotate fewer times to cover the same distance.

This principle is based on the fact that speed is inversely proportional to the diameters of the pulleys in a simple belt drive system. Therefore, increasing the diameter of the driving pulley will lead to a decrease in the rotational speed of the driven pulley. This principle is critical in applications where gear ratios and pulley sizes are engineered to achieve desired output speeds.