Machine Condition Monitoring: Definition of an Oil Condition Index

Based on a previous paper of the author [1] an oil condition index O_C is defined. The index is composed of the values of a set of normalized oil parameters weighted by their importance to the machine and the application. The concept of Dimensional Analysis is used to determine the relationships between machine, oil and operating parameters. This process leads to dimensionless groups, which characterize the oil condition monitored for a machine. Defining O_C for a specific machine or machine type and including specifics of the use and the environment the machine is operated in, provides operators and managers with Statistical Process Control (SPC) tools to predict maintenance and prevent catastrophic failure. Data from a reliability experiment are presented which illustrates the relationship between the oil properties, machine operating parameters and oil contamination.