Which configuration is commonly used for belt-driven machines?

The 2:1 configuration is commonly used for belt-driven machines due to its ability to effectively balance torque and speed. This configuration means that for every two rotations of the driving pulley, the driven pulley makes one rotation. This is particularly beneficial in applications where increased torque is required, such as in conveyor systems or machinery that requires more power to move heavier loads.

Additionally, a 2:1 ratio helps in reducing wear on the belts and the pulleys while allowing for smoother operation compared to other configurations. By creating a favorable balance between speed and torque, the 2:1 setup ensures that machines can operate efficiently under various load conditions, making it a preferred choice in many industrial applications.

The other configurations mentioned, while valid in specific contexts, are less commonly employed in general belt-driven machine applications. The 1:1 configuration, for instance, maintains the same speed and torque, which can be less efficient in achieving desired performance levels under heavy loads. The 3:1 configuration may provide high speed but at the cost of torque, which isn't ideal for many machine operations. Variable speed configurations offer flexibility but involve more complex setups and controls, often requiring additional components that may not be necessary for standard operations.