Maintenance & Reliability Glossary
OEE, MTBF/MTTR, predictive and condition-based maintenance, vibration analysis, and CMMS. 87 terms in this topic - each defined in plain English on its own page.
Reliability work turns maintenance from a repair crew into an engineering discipline. The vocabulary here spans the metrics (OEE, MTBF, MTTR), the strategies (preventive, predictive, condition-based), and the condition-monitoring techniques - vibration analysis and its plots, thermography, oil analysis, and NDT - that let a machine announce its own failure weeks in advance. SCADA and historian data increasingly feed these programs, which is why the topic sits in an automation glossary.
87 Terms
What is a 1x amplitude and phase vector?
Running-speed vibration as an amplitude-and-phase vector, and why acceptance-region monitoring catches change early.
Read → GlossaryWhat do 1X amplitude and phase indicate?
The running-speed vibration vector that fingerprints unbalance, tracks change over startups, and drives rotor balancing.
Read → GlossaryWhat is the 5 Whys root cause technique?
Asking why repeatedly to trace a failure from symptom to its process or management root cause.
Read → GlossaryWhat is accelerometer mounting resonance?
The resonant peak from how a sensor attaches, which caps usable bandwidth and can fake spectral peaks.
Read → GlossaryWhat are vibration alert and danger levels?
The two-tier alarm and trip setpoints in machinery protection, with time delays, voting, and API 670.
Read → GlossaryWhat Is Availability Rate in OEE?
The OEE availability formula, how planned and unplanned downtime split, and how SCADA state tags drive it.
Read → GlossaryBACnet Status_Flags and Reliability
The four Status_Flags bits and the Reliability enumeration, and why mapping them keeps a BACnet value trustworthy.
Read → GlossaryWhat Is a Bad Actor Alarm?
Why a handful of tags drive most alarm load, and the top-ten ranking and workflow to resolve them.
Read → GlossaryWhat Is the Bathtub Curve?
The three-phase failure-rate shape - infant mortality, useful life, wear-out - behind burn-in and replacement.
Read → GlossaryWhat is a bearing defect frequency?
The BPFO, BPFI, BSF, and FTF frequencies from bearing geometry that pinpoint which bearing element is failing.
Read → GlossaryWhat are Bode and polar plots for rotor vibration?
Paired runup and coastdown views of 1x amplitude and phase versus speed that pinpoint a critical speed.
Read → GlossaryWhat is a Bode plot in machinery diagnostics?
The amplitude-and-phase-versus-RPM plot from startup or coastdown that locates critical speeds and confirms resonance.
Read → GlossaryWhat is censored data in reliability analysis?
Why running survivors are right-censored suspensions and how ignoring them biases life estimates low.
Read → GlossaryWhat Is a CMMS (Computerized Maintenance Management System)?
The software system of record for work orders, PM schedules, and asset history - and how SCADA data feeds it.
Read → GlossaryWhat is CMMS work order writeback from SCADA?
Having SCADA create and update CMMS work orders from runtime and condition triggers, with dedup and confirmation.
Read → GlossaryWhat is a component importance measure in reliability?
Birnbaum and Fussell-Vesely measures that rank which parts most affect reliability, so budget hits the weak links.
Read → GlossaryCondition Monitoring
Tracking vibration, temperature, and oil to catch machine wear early - the foundation of condition-based and predictive maintenance.
Read → GlossaryWhat is condition-based alerting vs fixed-threshold alarms?
Alerting driven by an asset's current state rather than one static setpoint, cutting nuisance alarms.
Read → GlossaryWhat Is Condition-Based Maintenance (CBM)?
Triggering maintenance when a measured condition crosses a threshold, not on a fixed calendar schedule.
Read → GlossaryWhat Is the Difference Between Condition-Based Monitoring and Condition-Based Maintenance?
Monitoring is the continuous watching of asset health; maintenance is the decision to act on it.
Read → GlossaryHow do you optimize critical spares inventory?
Balancing carrying cost against stockout downtime using failure rate, lead time, and target availability.
Read → GlossaryHow do you diagnose pump vibration in the field?
Check the overall severity first, then let the dominant frequency name it: one-times unbalance, two-times misalignment, vane-pass hydraulic, or broadband cavitation.
Read → GlossaryWhat Is a Well Downtime and Deferment Report?
Quantifies lost production by reason code and asset, with SCADA auto-logging each outage that feeds it.
Read → GlossaryHow Does Eddy-Current Proximity Sensing Work?
How induced eddy currents change a coil's impedance to measure a gap, and why gap voltage maps to shaft position.
Read → GlossaryWhat is electrical thermography inspection?
Infrared survey of energized gear that finds hot spots and ranks them by delta-T for repair.
Read → GlossaryWhat Is EMAT Inline Inspection?
Couplant-free ultrasonic crack detection for dry gas lines, and where it sits versus liquid-coupled UT.
Read → GlossaryWhat Is Equipment Criticality Analysis?
Ranking assets by consequence and likelihood to decide which get monitored versus run to failure.
Read → GlossaryWhat is field balancing of rotating equipment?
Balancing a rotor in place with trial weights to cancel 1x unbalance vibration.
Read → GlossaryFix Bad Actor Alarms
Rank by activation count, classify each offender by pattern, and apply the matching fix to the vital few.
Read → GlossaryWhat Is FMEA (Failure Mode and Effects Analysis)?
The bottom-up worksheet that ranks failure modes by severity, occurrence, and detection to compute RPN.
Read → GlossaryWhat is a full spectrum in vibration analysis?
How combining two orthogonal probes into a forward and reverse spectrum sharpens rub and misalignment diagnosis.
Read → GlossaryHow Do Nucleonic Gamma Sensors Measure Level and Density?
The Beer-Lambert attenuation physics that lets gamma gauges read brutal media non-intrusively through a vessel wall.
Read → GlossaryWhat is ISO 10816 vibration severity?
Grading machine health by overall RMS velocity into zones A to D to set warning and trip vibration thresholds.
Read → GlossaryWhat is ISO 20816 for machine vibration?
The umbrella standard that consolidates ISO 10816 and 7919 into one A to D evaluation framework.
Read → GlossaryWhat is ISO 7919 relative shaft vibration?
The proximity-probe standard for peak-to-peak shaft displacement, and why turbomachinery uses both shaft and casing limits.
Read → GlossaryWhat is a keyphasor signal used for?
The once-per-turn timing pulse that anchors phase, RPM, orbit dots, and balancing for rotating-machinery diagnostics.
Read → GlossaryWhat is laser shaft alignment?
Measuring angular and parallel offset between coupled shafts precisely with a laser tool.
Read → GlossaryWhat Is a Maintenance Override Switch (MOS)?
The controlled bypass that inhibits a safety trip for testing or repair without a spurious shutdown.
Read → GlossaryWhat Is a Maintenance Work Order?
The unit of executable maintenance work - its lifecycle, planned versus reactive, and SCADA auto-generation.
Read → GlossaryWhat is a Markov model in reliability?
A state-transition model for repairable, redundant systems where simple block diagram math falls short.
Read → GlossaryWhat is Monte Carlo simulation for reliability?
Sampling component life and repair over many runs to estimate availability when formulas cannot.
Read → GlossaryMTBF
The average operating time between failures of repairable equipment - how it is calculated and how it drives availability.
Read → GlossaryWhat Is MTTR?
Mean time to repair - the average downtime per failure - how it is calculated, MTTR vs MTBF, and how it drives availability.
Read → GlossaryWhat Is OEE?
The manufacturing metric combining availability, performance, and quality into one effectiveness percentage.
Read → GlossaryWhat is a shaft orbit plot?
How two proximity probes draw the shaft's path in a journal bearing, and how orbit shape and keyphasor dots find faults.
Read → GlossaryWhat is order tracking in vibration analysis?
How angular resampling against a tacho keeps running-speed harmonics sharp on variable-speed machines.
Read → GlossaryWhat is an overall vibration level?
The single broadband RMS number a monitoring system trends and alarms on to screen machine health.
Read → GlossaryWhat Is the P-F Interval?
The warning window between detectable potential failure and functional failure that sets inspection frequency.
Read → GlossaryWhat is parts count reliability prediction?
Estimating a design's failure rate early from component counts and environment using MIL-HDBK-217 or Telcordia.
Read → GlossaryWhat Is Performance Rate in OEE?
How OEE performance is measured against ideal cycle time, and how count-rate data exposes hidden speed loss.
Read → GlossaryWhat is phased array ultrasonic testing (PAUT)?
How a multi-element probe steers and focuses beams to image welds and map corrosion in a single pass.
Read → GlossaryPredictive Maintenance
Forecasting equipment failure from condition data so you fix it just in time - versus reactive and preventive strategies.
Read → GlossaryWhat Is Preventive Maintenance?
Time- and usage-based scheduled servicing - the baseline PM that predictive approaches are compared against.
Read → GlossaryWhat Is a PM Schedule?
The plan that assigns time- and runtime-based maintenance tasks to assets, tracks compliance, and reacts to SCADA data.
Read → GlossaryPROFINET I&M records
Standardized identity and plant-data blocks I&M0 to I&M4 for consistent asset tracking.
Read → GlossaryWhat Is a Proximity Probe?
The non-contacting eddy-current sensor that measures shaft vibration and position on fluid-film machines, feeding API 670 protection.
Read → GlossaryWhat Is Quality Rate in OEE?
Good units over total units, how it differs from first-pass yield, and how reject and analyzer tags feed it.
Read → GlossaryWhat is reliability growth and the Crow-AMSAA model?
How MTBF improves through test-analyze-fix, tracked over time with the Crow-AMSAA and Duane models.
Read → GlossaryWhat Is Reliability-Centered Maintenance (RCM)?
The SAE JA1011 decision framework that picks the right maintenance strategy for each asset failure mode.
Read → GlossaryWhat Is Remaining Useful Life (RUL)?
The estimated time or cycles until an asset fails, produced by degradation trending and prognostic models.
Read → GlossaryWhat is risk-based inspection (RBI)?
Combining probability and consequence of failure to prioritize inspection and set risk-based intervals.
Read → GlossaryWhat is the difference between RMS, peak, and peak-to-peak vibration amplitude?
Three vibration amplitude conventions, how they relate, and how to match a SCADA setpoint to the sensor.
Read → GlossaryWhat Is Root Cause Analysis (RCA)?
The post-failure investigation - Five Whys, fishbone, causal tree - that stops the same failure from recurring.
Read → GlossaryWhat is route-based vibration monitoring?
Periodic handheld data collection on defined routes for balance-of-plant machines, versus permanent online monitoring.
Read → GlossaryWhat Is Run-to-Failure Maintenance?
When deliberately letting an asset fail is the cheapest correct strategy, and when it is simply negligence.
Read → GlossaryWhat is a runtime-hours maintenance trigger?
A SCADA running-hours counter that auto-schedules preventive maintenance at a threshold, then resets on completion.
Read → GlossaryRuntime/Downtime Tracking
Measuring run versus idle time to calculate availability and, with reason codes, pinpoint exactly where production is being lost.
Read → GlossaryWhat is SCADA to CMMS work order integration?
Auto-creating maintenance work orders from SCADA conditions, mapping to templates with dedup, failure codes, and status round-trip.
Read → GlossaryWhat is a seismic vibration sensor?
A case-mounted sensor measuring absolute housing vibration, versus a proximity probe measuring relative shaft motion.
Read → GlossaryWhat Is Shaft Alignment?
Aligning driver-to-driven shafts, offset vs angular misalignment, soft foot and laser tools, and the 2x vibration misalignment leaves.
Read → GlossaryWhat does a shaft centerline plot tell you?
How averaged DC gap maps the shaft's rest position in bearing clearance to reveal preload, wear, and oil-film condition.
Read → GlossaryWhat is the difference between shaft-relative and bearing-absolute vibration?
Proximity-probe shaft motion versus seismic housing motion, which machines need each, and dual-probe setups.
Read → GlossaryWhat is Smax in shaft vibration monitoring?
The largest peak-to-peak shaft displacement anywhere in the XY orbit, evaluated as the worst-case shaft metric.
Read → GlossaryWhat is a spectral band alarm?
Alarming on vibration energy within specific frequency bands to catch early defects the overall misses.
Read → GlossaryWhat Are the Six Big Losses?
The six loss categories OEE decomposes into and how each maps to availability, performance, or quality.
Read → GlossaryWhat are thermographic severity criteria?
Rules that rank an infrared anomaly by its delta-T and map it to repair urgency.
Read → GlossaryWhat is total acid number in oil analysis?
A measure in mg KOH/g of the acids from oil oxidation, tracked against a condemning limit.
Read → GlossaryWhat is two-plane rotor balancing?
The influence-coefficient method with cross-effect that corrects couple unbalance in two planes at once.
Read → GlossaryWhat is the difference between a velocity pickup and an accelerometer?
Two vibration transducers compared on output, frequency range, and why new installs pick accelerometers.
Read → GlossaryHow do you read a VFD fault log?
Read the fault sequence for the first cause, interpret the values latched at the trip, and find the pattern across repeated faults.
Read → GlossaryHow do you set skip frequencies on a VFD?
Sweep the range to find resonant bands, set a skip window on each with the right width, and verify no steady speed lands in one.
Read → GlossaryWhat Is Machinery Vibration Monitoring?
Continuous vibration measurement on rotating machines: sensors, overall vs spectral values, and the alarm-and-trip logic behind protection.
Read → GlossaryWhat is vibration phase analysis?
Using the timing of the 1x vibration to separate unbalance, misalignment, a bent shaft, and looseness.
Read → GlossaryHow do you mount a vibration sensor correctly?
Stud, adhesive, magnet, and probe methods, their frequency limits, and placement for repeatable measurements.
Read → GlossaryWhat is a vibration velocity spectrum?
The FFT frequency view of machine vibration, where peaks at 1x, 2x, and harmonics map to specific faults.
Read → GlossaryWhat is wear particle analysis?
Classifying wear debris by size, shape, and metal to find the failing bearing, gear, or seal.
Read → GlossaryWind Turbine CMS Points
The drivetrain, temperature, oil, and structural signals a wind turbine condition-monitoring system watches.
Read →Automation services
Need help turning this into a working system?
Merobix integrates SCADA, programs Allen-Bradley and Siemens PLCs, and designs and fabricates industrial control panels.
Meeting requests are reviewed before confirmation.