In Belt and Pulley Drive, what is the purpose of using a larger drive pulley after the initial reduction?

• A. To provide speed reduction and increase torque
• B. To increase chain wear tolerance
• C. To simplify installation
• D. To allow three-phase operation on a single-phase motor

Answer: (A)

The key idea is that belt and pulley drives trade speed for torque through pulley size ratios. Using a larger drive pulley after an initial reduction adds another reduction stage, so the final output turns more slowly but delivers more torque to the load. This helps meet high torque requirements at a lower speed without changing the motor, keeping the system within its efficient operating range.

In other words, each stage changes the speed and multiplies the torque. A larger drive pulley in the next stage increases that effect, giving the final shaft more torque at a reduced speed. The other options aren’t related to how pulley sizes affect speed and torque, which is why they don’t fit.