Detect change earlier
Trend changes continuously instead of waiting for the next scheduled sample interval.
ISO-Reliability Partners · Condition Monitoring
Oil Quality Sensors for Real-Time Condition Monitoring
Move beyond periodic oil sampling with continuous visibility of lubricant condition. Yateks oil quality sensors monitor critical parameters such as viscosity, density, dielectric constant, water activity, dissolved moisture and temperature—helping maintenance teams identify changes earlier and make better reliability decisions.
ViscosityWater in oilMoisture ppm
DensityDielectric constantTemperature
ViscosityTrend oil film condition
MoistureDetect dissolved water
DielectricTrend oil degradation
DensityMonitor fluid change
Water ActivityTrack saturation
TemperatureOperating context
Why online oil monitoring
Turn oil condition into a live reliability signal
A laboratory sample remains important for detailed diagnosis, but it is a snapshot. Online oil quality sensors add a continuous trend between samples, helping engineers detect shifts in fluid condition, water contamination and operating behaviour earlier.
Protect critical assets
Apply continuous monitoring to gearboxes, hydraulic systems, transformers and rotating machinery.
Improve maintenance timing
Use condition data to support inspection, filtration, dehydration, resampling and oil-change decisions.
Build useful trends
Combine sensor trends with laboratory analysis, vibration data and maintenance history.
What can be measured?
Monitor the parameters that matter to the application
The correct sensor depends on the failure mode you are trying to detect. A gearbox may need viscosity and contamination trending, while a transformer or turbine may place much greater emphasis on dissolved moisture.
Engineering note: sensor thresholds should be based on the oil type,
fresh-oil baseline, OEM limits, operating temperature, application criticality and trend history.
ViscosityTracks lubricant flow behaviour and can highlight dilution, degradation or incorrect fluid condition.
DensityProvides an additional physical-property trend that can support fluid identification and condition tracking.
Dielectric ConstantTracks changes in the electrical properties of the oil that may correlate with contamination and degradation.
Water Activity (aw)Shows the degree of water saturation in the oil and helps identify increasing moisture risk.
Dissolved Moisture (ppm)Measures micro-moisture in applications where low-level dissolved water is critical.
Free / Emulsified WaterTargets higher water-content conditions where bulk or emulsified water is the primary threat.
TemperatureAdds operating context because temperature directly influences viscosity, moisture behaviour and equipment condition.
Trend BehaviourThe strongest signal is often the rate of change from the asset's own normal operating baseline.
Yateks sensor range
Choose the right oil quality sensor
Start with the parameter you need to monitor, then select the smallest sensor set that covers the reliability objective. ISO-Reliability Partners can assist with application selection and integration.
YTS61
YTS 6-in-1 Oil Condition Sensor
The broadest multi-parameter option for continuous oil-condition trending.
6 parameters
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YTS41
YTS 4-in-1 Oil Condition Sensor
For applications requiring viscosity, density and oil-quality trending without dedicated moisture measurement.
4 parameters
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YTS31
YTS 3-in-1 Oil Condition Sensor
A focused physical-condition sensor for viscosity, density and temperature monitoring.
3 parameters
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YTS-D-1
Oil Quality / Dielectric Sensor
Designed to continuously trend dielectric constant and temperature as an indicator of oil-condition change.
Condition trend
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YTS-M-1
Micro-Moisture Sensor
For low-level dissolved moisture monitoring in transformer, lubricating and hydraulic oils.
Dissolved water
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YTS-W-1
Water-in-Oil Sensor
Purpose-built for higher water-content applications where free or emulsified water is the concern.
High water content
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Sensor comparison
Parameter selection matrix
Use this quick comparison to identify which sensor family best matches the required measurement.
| Measurement | YTS 6-in-1 | YTS 4-in-1 | YTS 3-in-1 | YTS-D-1 | YTS-M-1 | YTS-W-1 |
|---|---|---|---|---|---|---|
| Viscosity | ✓ | ✓ | ✓ | — | — | — |
| Density | ✓ | ✓ | ✓ | — | — | — |
| Temperature | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Dielectric constant | ✓ | ✓ | — | ✓ | — | — |
| Water activity | ✓ | — | — | — | ✓ | — |
| Dissolved moisture (ppm) | ✓ | — | — | — | ✓ | — |
| Free / emulsified water | — | — | — | — | — | ✓ |
Industrial applications
Designed for assets where oil condition affects uptime
Online sensing is especially valuable on critical, continuously operated or difficult-to-sample equipment.
Mining & ProcessingCrushers, mills, gearboxes, hydraulic power packs and circulation systems.
Power GenerationTransformers, turbines, generators and critical lubrication systems.
Industrial HydraulicsPresses, mobile equipment, actuators, pumps and servo-controlled systems.
Marine & TransportEngines, gearboxes, hydraulic systems and auxiliary machinery.
Steel & Heavy IndustryGear drives, furnaces, mills, circulating oil and high-load equipment.
Oil & GasRotating assets, compressors, hydraulic packages and process equipment.
ManufacturingProduction gearboxes, compressors, presses, bearings and automated systems.
Bulk FluidsOil storage, fuel storage and systems where fluid condition must be verified continuously.
Implementation
From sensor selection to useful maintenance data
A sensor only adds value when the measurement is tied to a defined reliability action.
1
Define the risk
Identify the dominant failure mode: water, viscosity shift, degradation or general oil-condition change.
2
Select the parameter set
Choose the Yateks sensor that measures the smallest useful set of parameters for that application.
3
Establish a baseline
Trend against healthy oil, normal operating temperature and known machine condition.
4
Connect the action
Define alarm, inspection, resampling, filtration or maintenance actions when trends move outside limits.
Technical FAQ
Oil quality sensor questions
What is an oil quality sensor?
An oil quality sensor continuously measures one or more physical or electrical properties of oil, allowing maintenance teams to trend lubricant condition while the machine is operating.
Can online oil sensors replace laboratory oil analysis?
No. Online sensors are best used for continuous early warning and trend monitoring, while laboratory analysis provides broader diagnostic information such as wear metals, additive condition and detailed contamination testing.
Which sensor should I use for water in oil?
Use the YTS-M-1 where dissolved moisture at ppm level is the main concern. Use the YTS-W-1 where higher free or emulsified water content must be monitored. The YTS 6-in-1 also includes water activity and dissolved moisture measurements.
Which sensor measures viscosity?
The YTS 3-in-1, YTS 4-in-1 and YTS 6-in-1 sensors measure viscosity together with additional oil-condition parameters.
Where are oil condition sensors normally installed?
Typical installations include lubrication circuits, hydraulic systems, gearboxes, transformer oil systems and other circulating-fluid applications where representative, stable flow conditions can be achieved.
How should alarm limits be set?
Alarm limits should consider the oil type, OEM requirement, fresh-oil baseline, normal temperature range, asset criticality and historical trend. A rate-of-change alarm can be as important as an absolute limit.
Application support
Not sure which oil quality sensor fits your machine?
Send ISO-Reliability Partners the asset type, lubricant, normal operating temperature, target parameters and available installation point. We can help narrow the sensor choice and define the monitoring objective.