Downloaded from https://www.everyspec.com ADS-79D-HDBK Polyol Ester Lubricant: A synthetic lubricant base stock formed by the reaction of a fatty acid and a glycol. These lubricants exhibit good oxidation stability and low volatility. Rotorcrafts typically utilize MIL-PRF-23699F for engines and DOD-PRF-85734A for gearboxes. Rotary Disk Spectroscopy (Rotary Disk Electrode/ Rotrode): An AES that utilizes a rotating carbon disk to introduce the oil sample into an electric arc for excitation. Sample Interval: The nominal time between successive samples. An optimum (standard) sample interval is derived from failure profile data.
It is a fraction of the time between initiation of a critical failure mode and equipment failure. In general, sample intervals should be short enough to provide at least two samples prior to failure. The interval is established for the shortest critical failure mode. Shear Mixed Layer: Refers to the load-bearing surface layer of a bearing or gear that has been polished to a smooth, ductile, low-wearing surface during component run-in. Trend Analysis: Monitoring of the level and rate of change over operating time of measured parameters. Viscosity: The measure of the resistance to flow of a fluid that is being deformed by either shear or tensile stress or the "thickness" of a fluid.
X-Ray Fluorescence (XRF) Spectroscopy: An instrument that utilizes a high-energy x-ray source to excite atoms in a material. The elemental makeup of the material is identified and measured from the spectrum of light emitted. M.4 INTRODUCTION Oil condition and debris monitoring is the analysis of a lubricant‘s properties, suspended contaminants, and wear debris. In-service oil analysis provides information on the lubricant and machine condition. Typical analyses performed include: a. component wear (break-in, normal, and fault initiation/progression), b. lubricant condition (base stock degradation and additive depletion), and c. lubricant contaminants (dirt, water, fuel and incorrect fluid).
Fusion of this information with the physics of failure models, seeded fault testing , and vibration monitoring over the life of a component facilitates remaining useful life prediction. Additionally, new oil testing and periodic lubricant retesting [MIL-STD-3004] ensures a quality product prior to use. Pioneering development work in machinery oil analysis began in the early 1940‘s by the Denver, Rio Grande and Western Railway (DRGW) on their new diesel engines. These early programs quickly developed methods for determining the causes for catastrophic failure due to 239