Test Description The DR unit separates wear debris from the lubricant according to size. A sample is pumped across a high-gradient magnetic field at a slow rate. The ferrous particles are attracted to the magnetic field and deposited in two locations depending upon the amount of attraction. There are two size ranges: Density Large (DL) and Density Small (DS). The DL represents particles >5 um and DS represents particles <5 um. The results are an optical density equivalent and not a particle count.

Purpose of Test The WPC, summation of DL and DS, provides a trendable quantity for monitoring the wear condition of a piece of equipment. Fluctuations in the WPC suggest an abnormal condition in the component or possible contamination.

Test Description Particles are separated from the lubricant sample by magnets and gravity, allowing for the examination of the individual particles present in the sample. Debris are examined microscopically at magnifications between 100x and 1000x. Particles’ size, shape, composition, and concentration can be determined.

Purpose of Test By identifying the size, shape, composition, and concentration of the abnormal wear particles, the wear mechanism and its possible origin can be determined. Solid contaminants can also be identified. Equipment and component metallurgical information aids the analyst in determining the root cause for the formation of these particles.

Test Description Elemental analysis is performed in accordance with atomic emission spectroscopy (AES). A specific volume of lubricant is energized using an electrical arc. The light frequencies and intensities are measured and reported in parts per million of various elements. The elements consist of wear, additive, and trace elements.

Purpose of Test Elemental analysis is useful for identifying contamination, confirming additive content, and indicating system wear. The following elements are analyzed: Iron, Chromium, Aluminum, Lead, Tin, Copper, Silver, Nickel, Sodium, Vanadium, Titanium, Molybdenum, Calcium, Barium, Phosphorus, Zinc, Boron, Potassium, Magnesium and Silicon.

Test Description Particle count measurements are performed on a 10 mL oil sample, with results standardized to 1 mL. Samples must be homogenized and are then diluted 1:1 with a solvent mix (toluene and isopropanol) to ensure water and soft particles do not cause inaccuracies. The prepared sample is loaded into a syringe and passed through a laser sensor at a controlled flow rate, counting particles in different size ranges.

Purpose of Test Particle count is performed to detect and quantify contamination, ensuring the oil's cleanliness and the machinery's protection, thereby preventing wear and extending equipment life.

Test Description An electrical impulse is created when water reacts with iodine. The intensity and duration of the electrical impulse is measured and converted to a concentration of water.

Purpose of Test Tracking the actual water quantity in a sample of in-service lubricant is crucial in identify the source of the water and noting changes in this contamination over time since water not only promotes component damage through pitting and corrosion, but lubricant breakdown through oxidation as well.

Test Description AN is determined by titration with potassium hydroxide (KOH) which neutralizes the acids in the oil sample.

Purpose of Test AN of a used lubricant is one measure of its degree of degradation by oxidation.

Test Description BN is determined by titration with Hydrochloric acid (HCl) which neutralizes the basic compounds in the oil sample and then is converted to grams of potassium hydroxide (KOH). 

Purpose of Test TBN of a used lubricant is a measurement of its ability to neutralize the acid commonly found in combustion engines.

Test Description The infrared absorption spectrum of a lubricant furnishes a means of fingerprinting organic compounds and functional groups. Test results are trended and qualitative determinations can be made. 

Purpose of Test Infrared analysis is often used to identify trends in lubricant degradation due to oxidation or contamination such as nitration or water.

Test Description A visual inspection of the oil is performed upon arrival and a small amount of oil is placed on a hot plate heated to 265 °C which will indicate the presence of water with a crackling sound. Unfortunately, this test is imprecise and can be inaccurate which is why the Karl Fisher test for water is crucial to a well-maintained oil analysis program. 

Purpose of Test This screening is used to provide a description of any egregious issues with the sample.

Test Description A portion of the sample is heated to the correct temperature (40 or 100 °C) and pulled into a tube. The pressure is released allowing the lubricant to fall with gravity and the time is measured as the lubricant passes two specified points in the tube. The shorter the time, the lower the viscosity. 

Purpose of Test The viscosity is the most important characteristic for oil. If the viscosity is too low, components will not have separation during operation and wear will be generated. If the viscosity is too high then the operating temperatures will be higher and the lifespan of the motor may be diminished.