When a roller chain is employed, shaft positions is usually arbitrarily established. However, in principle, adhere to the illustration shown under. That is, in the event the chain is tensioned horizontally, retain the top tensioned. Avoid vertical transmission when achievable. In an inevitable situation, spot the massive sprocket on the bottom regardless from the path of rotation.
Once the chain layout is undesirable:
?When the leading is sagging along with the sprocket center distance is brief:
As illustrated beneath, modify the sprocket center distance shaft to reduce the sag.
?When the top is sagging plus the sprocket center distance is lengthy:
As illustrated beneath, set up an idler from inside to remove the sag.
?Once the chain is vertical or inclined:
Reduce the extra sag by a tensioner. In this instance, a tensioner that immediately eliminates the sag gives superior results.
When a pulsating load acts in large speed operation:
The chain’s vibration along with the load influence frequency or chordal action could synchronize to amplify vibration over the chain. Given that vibration influences the chain, consider countermeasures to avoid vibration from the following measures:
?Alter the chain pace.
?Increase chain stress. Having 
said that, note that over-
tensioning can shorten the life in the chain. ?Use an idler or tensioner to divide the span
?Set up a guide stopper to avoid vibration.
Note: Chordal action refers to the vertical movement of chain triggered when it is engaged with sprockets.
