Acronyms

A

AEM: Spanish Maintenance Association
AM:Amplitude modulation. Process in which the amplitude of a signal varies as a function of the instantaneous value of another signal.
API: American Petroleum Institute

B

BPFO, BPFI: Common abbreviations for the ball pass frequencies of defects in the raceways of the outer and inner rings of a bearing.
BSF (Ball Spin Frequency): Rotating frequency of the rolling element.

C

CBM: Condition Based Maintenance

D

DSA: Dynamic Signal Analyzer (DSA). A vibration analyzer that uses digital processing and the Fast Fourier Transform to represent the frequency components of vibration. Vibration analyzers also display time domain and phase, and can be connected to a computer.

E

EU (Engineering units). Engineering units, user programmable.

F

FAT: Factory Acceptance Test
FFT: Fast Fourier Transform. A computer (or microprocessor) calculation procedure to obtain the discrete frequency components of sampled data. If the number of samples is limited to a power of 2, it is a special case of the discrete Fourier transform.
FRA: Forced Response Analysis (FRA; FRS, Forced Response Simulation) Mathematical computation of the response of an arbitrary force function using data from the modal analysis of the modeled system.
FRF: Frequency response function.
FTF (Fundamental Train Frequency): Frequency of cage rotation.

G

GMF: Gearing frequency. Vibration frequency that appears in any machine containing gears and is equal to the number of teeth multiplied by the frequency of rotation of the gear wheel.

H

Hz: Hertz. It is the I.S. frequency unit that corresponds to one cycle/second.

I

ISO: International Standards Organization

M

μm: Micron. Millionth part of a meter

P

PdM: Preventive Maintenance according to Condition

R

RCA: Reliability Centered Analysis or Root Cause Analysis
RCM: ReliabilityCentered Maintenance
RMS: Global (value). Root Mean Square Value (RMS). Square root of the mean value of the square of the instantaneous values.

S

SAT: Acceptance test

T

TMF: Gearing frequency (GMF). Vibration frequency that appears in any machine containing gears and is equal to the number of teeth multiplied by the frequency of rotation of the gear wheel.
TPM: Total Productive Maintenance