It is well worthwhile to review some basic tenets of oil analysis and its application to condition monitoring. There are many different types of tests that are used to evaluate lubricants. The tests specified must cover three areas: machine condition, contamination condition, and lubricant condition. (Figure I.2).

Figure I.2: Three components of oil analysis

The purpose of which:

• To monitor for the presence of contamination detrimental to the oil and its application,

• To compare the chemicals and physicals of the oil against the virgin oil to determine if the oil is still an adequate lubricant, and

• To analyze for metal particles to determine the condition of the machine's oil wetted (wearing) parts.

Failure to test in all three areas may result in an unnoticed system failure, thus showing up a disregard for the equipment and the technology by both maintenance technicians and the laboratory. The tests are the most applicable to condition monitoring. Some may overlap the three areas of interest, but that is reassuring as it provides corroborating evidence of an abnormality.