What component can be adjusted to increase chain tension?

To increase chain tension in a mechanical power system, the component that is specifically designed for this purpose is the tensioner. A tensioner allows for the adjustment of the tension in the chain, ensuring that it is neither too loose nor too tight. Proper tension is crucial for the efficient operation of the system, as it prevents slippage and reduces wear on the chain and associated components.

While other components may play a role in the overall system, they do not directly serve the purpose of adjusting chain tension. The idler sprocket can also change the path of the chain or influence tension to some degree, but it is not primarily used for adjusting chain tension. The drive motor powers the system and does not adjust chain tension directly, and the chain guard is primarily a safety feature that protects users from the moving parts and does not impact the tension of the chain itself. Hence, the tensioner is the correct choice for increasing chain tension.