Pulley

Pulley:
A rotating wheel where power transmission from a belt to an object occurs (such as on the serpentine belt, alternator, AC compressor, water pump, and tensioner, is called a pulley. The pulleys are often fastened to the component with a screw connection. The serpentine belt has longitudinal ribs. The pulleys have internal grooves where the ribs of the serpentine belt hook in, preventing the belt from slipping off.

For more information, see the chapter serpentine belt.