Vaisala MMT310 Moisture and Temperature Transmitter for Oil
The Vaisala HUMICAP® MMT310 Series is a compact online transmitter for continuous moisture and temperature measurement in oil. It is designed for demanding liquid-hydrocarbon applications, including transformer oil, lubrication systems and hydraulic fluids.
Continuous monitoring detects changes in oil condition without repeated manual sampling. Measurement data can also be used by an automation system to start oil separators, dryers or purification equipment only when required.
Why Measure Moisture in Oil?
Excess moisture can reduce the insulating capability of transformer oil, accelerate oil ageing, promote corrosion and damage lubrication or hydraulic equipment. Dissolved water can also become free water when the oil cools or approaches saturation.
The MMT310 measures the oil's water activity or relative saturation. These parameters indicate the actual margin to water saturation even when the oil type, temperature or condition changes.
| Parameter | What it indicates |
|---|
| Water activity (aw) |
A scale from 0 to 1 showing the oil's proximity to water saturation. An aw value of 1 represents saturation. |
| Relative saturation (%RS) |
The same saturation condition expressed on a scale from 0 to 100%. |
| Water content (ppm) |
The calculated mass concentration of water. Optional calculation is available for mineral transformer oil and configured oil types. |
| Temperature |
Provides the oil temperature required for condition assessment and ppm calculation. |
Key Benefits
- Continuous online measurement: Detects moisture changes without waiting for laboratory sampling.
- Direct saturation indication: Shows the risk of free-water formation under changing oil conditions.
- Proven HUMICAP® technology: Designed for demanding moisture measurement in liquid hydrocarbons.
- Wide operating capability: Suitable for high-temperature and pressurised oil systems.
- Compact construction: Easy to integrate into machinery, pipelines and monitoring systems.
- Flexible outputs: Two configurable analogue channels and an RS-232C serial interface.
- Serviceable installation: MMT318 can be installed with a ball-valve assembly for probe insertion and removal without draining the complete oil system.
- Traceable calibration: Calibration certificates are included for the measurements and analogue outputs.
MMT317 and MMT318 Model Comparison
| Feature | MMT317 | MMT318 |
|---|
| Probe design |
Small pressure-tight probe |
Adjustable-length pipeline probe |
| Best suited to |
Confined installations and fixed process connections |
Pressurised pipelines and ball-valve installations |
| Maximum pressure |
10 bar |
40 bar with ball-valve installation at temperatures up to 120°C |
| Process connections |
Swagelok® NPT 1/2, ISO 3/8 or ISO 1/2 options |
ISO 1/2 or NPT 1/2 fitting-body options |
| Probe cable |
2, 5 or 10 m |
2, 5 or 10 m |
| Probe-length options |
Compact fixed probe |
226 or 448 mm adjustable probe |
Measurement Performance
| Water-activity range |
0 to 1 aw or 0 to 100% RS |
|---|
| Water-activity accuracy |
±0.02 aw from 0 to 0.9; ±0.03 aw from 0.9 to 1.0 |
|---|
| Response time |
Approximately 10 minutes for 90% response at +20°C in still oil with the stainless-steel filter |
|---|
| Moisture sensor |
Vaisala HUMICAP® 180L2 |
|---|
| Temperature range |
-40 to +180°C |
|---|
| Typical temperature accuracy |
±0.2°C at +20°C |
|---|
| Temperature sensor |
Pt100 RTD Class F0.1 according to IEC 60751 |
|---|
Outputs and Electrical Specifications
| Analogue outputs |
Two independently selectable and scalable channels |
|---|
| Current-output options |
0 to 20 mA or 4 to 20 mA |
|---|
| Voltage-output options |
0 to 5 V, 0 to 10 V or 1 to 5 V through scaling |
|---|
| Serial output |
RS-232C |
|---|
| Operating voltage |
10 to 35 VDC; minimum voltage depends on output and operating-pressure configuration |
|---|
| Analogue-output accuracy |
Typically ±0.05% of full scale at +20°C |
|---|
| Connection |
8-pole connector carrying power, analogue outputs and RS-232C |
|---|
| Start-up time |
Approximately 3 seconds |
|---|
Mechanical and Environmental Specifications
| Electronics operating temperature |
-40 to +60°C |
|---|
| Storage temperature |
-55 to +80°C |
|---|
| Maximum MMT317 pressure |
10 bar |
|---|
| Maximum MMT318 pressure |
40 bar with ball valve at temperatures up to 120°C |
|---|
| Ingress protection |
IP66 |
|---|
| Standard sensor protection |
Stainless-steel grid filter |
|---|
| High-flow filter option |
Stainless-steel grid filter for oil-flow speeds above 1 m/s |
|---|
| EMC compliance |
EN 61326-1 for industrial environments |
|---|
Typical Applications
- Transformer oil moisture monitoring
- Marine-engine lubrication systems
- Paper-machine lubrication systems
- Hydraulic power units
- Turbine and generator lubrication systems
- Oil purification and dehydration systems
- Condition-monitoring systems
- Industrial liquid-hydrocarbon processes
Using Moisture Data for Process Control
The MMT310 can transmit moisture and temperature values continuously to a PLC, recorder or monitoring system. Alarm or control limits can then be used to operate an oil separator, purifier or dryer when the measured moisture condition reaches the selected threshold.
This demand-based approach helps avoid unnecessary purifier operation while providing an early indication of water ingress or deterioration in oil condition.
Installation Options
The MMT317 uses a small pressure-tight probe for compact installations. Optional Swagelok® fittings are available for different threaded connections.
The MMT318 has an adjustable probe for pipeline installation. When used with the optional ball-valve assembly, the probe can be inserted or removed without emptying the complete oil system, subject to the approved installation procedure and pressure limits.
An optional rain shield is available when the transmitter electronics are installed outdoors.
Model Selection Information
Provide the following information when requesting a quotation:
- Oil type and application
- Required parameter: aw, %RS, ppm or temperature
- Normal and maximum oil temperature
- Normal and maximum process pressure
- Pipeline size and process connection
- Required probe length and cable length
- Required analogue-output type and scaling
- Whether ball-valve installation is required
- Indoor or outdoor installation
Vaisala Moisture in Oil Transmitter Supplier in Malaysia
SEACOM supplies Vaisala moisture-in-oil measurement instruments for transformer, marine, lubrication, hydraulic and industrial applications in Malaysia.
Contact SEACOM with your oil type, temperature, pressure, process connection and output requirements for MMT317 or MMT318 selection and quotation.
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MMT310 Series Catalogue
(226.84k)
