Which of the following is NOT one of the three main attributes used when sizing up the right lubrication?

When it comes to selecting the appropriate lubrication for machinery, three main attributes typically considered are speed, load, and temperature. These factors play a crucial role in determining the most effective lubricant to ensure optimal performance and reliability of the equipment.

Viscosity, while important in the context of lubrication, is not a standalone attribute used for sizing up lubrication requirements in the same way that speed, load, and temperature are. Instead, viscosity is a characteristic of the lubricant itself, influencing its ability to form a protective film under varying speeds and loads. It is a measure of the resistance of the lubricant to flow and changes with temperature, but it does not directly dictate the broader operational parameters needed for sizing the lubricant.

In summary, speed, load, and temperature are the key experiential variables analyzed during the lubrication selection process, while viscosity is a property of the lubricant that affects its performance but is not itself a sizing criterion.