What are the three main components of a belt drive?

• A. Driven sheave, drive sheave, belt
• B. Bearings, belt, motor
• C. Gear, belt, pulley
• D. Shaft, belt, chain

Answer: (B)

Power is transmitted in a belt drive by a belt looping around two pulleys, turning rotational motion from the driving point to the driven point. The three essential parts are the drive pulley (the pulley connected to the motor that provides the motion), the driven pulley (the pulley connected to the load that receives the motion), and the belt that links them and transmits the torque between them.

Bearings and the motor themselves are important in the overall machine, but they aren’t the core components of the belt drive itself. The motor is the power source that turns the drive pulley, while bearings support rotating parts—not the belt-drive trio. A gear or a chain represents a different type of drive system, and a pulley is part of a belt drive, but saying “gear, belt, pulley” blurs the specific role of the belt drive’s two pulleys plus the belt. A shaft and chain describe another arrangement altogether.