Overlap Processing

– The concept of performing a new analysis on a segment of data in which only a portion of the signal has been updated (some old data, some new data).

Overall Amplitude

Total amount of vibration occurring in the frequency range selected.

Overall

A number representing the amount of energy found between two frequencies. The frequency range that the overall is derived from and the type (Average, RMS, Peak, Peak-to-Peak) are usually user selectable.

Outage

There are two types of outages, planned or forced. A planned outage is when the unit is shutdown and work is performed as planned. A forced outage is when the unit fails and work is performed usually on an emergency basis.

Orbit

The path of shaft centerline motion during rotation.

Oil analysis

A laboratory technique to analyze the composition of lubricating oil to determine if any foreign materials are present. Presence of bearing material would indicate wearing of the bearing and the quantity would indicate the amount of wear. Used primarily on plain bearings.

Overaging

Aging under conditions of time and temperature greater than those required to obtain maximum change in a certain property, so that the property is altered in the direction of the initial value. See aging .

Oxidation

(1) A reaction in which there is an increase in valence resulting from a loss of electrons. (2) A corrosion reaction in which the corroded metal forms an oxide; usually applied to reaction with a gas containing elemental oxygen, such as air.

Oxidized Surface (Steel)

Surface having a thin, tightly adhering, oxidized skin (from straw to blue in color), extending in from the edge of a coil or sheet. Sometimes called annealing border.

Oil Quenching

Hardening of carbon steel in an oil bath. Oils are categorized as conventional, fast, martempering , or hot quenching .