What is the function of an idler pulley?

The function of an idler pulley is to guide and support a belt in a mechanical system. Idler pulleys play a critical role in ensuring that the belt remains aligned and maintains proper tension within the system. By doing so, they help improve the efficiency and longevity of the belt, reducing wear and the risk of slipping. The presence of an idler pulley can also help manage the path of the belt, allowing it to navigate around obstacles or changes in direction within the machinery.

In contrast, other choices do not accurately describe the function of an idler pulley. The first option implies a driving force, which is not the primary role of an idler pulley. Changing the direction of electrical currents is unrelated to mechanical systems, and storage for excess belts does not pertain to the operation or necessity of idler pulleys within a belt-driven system.