Vaisala

MMP8

HUMICAP® moisture-in-oil probe for transformers and lubricants

MMP8

A probe for continuous measurement of dissolved moisture and temperature in oil, featuring the HUMICAP® 180L2 sensor developed for transformer oils, lubricants and hydraulic fluids. It measures water activity and relative saturation — the real margin to free-water formation, independent of oil type and age — and can output ppm concentration for known oils such as mineral transformer oil.

Download datasheet (PDF)

Specifications

Technical specifications

Water activity
0–1 aw / 0–100 %RS (exactitud hasta ±0,01 aw / ±1 %RS; sensor HUMICAP® 180L2)
Water concentration
ppm de agua en aceite (exactitud típica 10 % de la lectura; conversión disponible para aceite mineral de transformador)
Temperature
-40 °C a +180 °C en el cabezal de la sonda (exactitud ±0,2 °C)
Operating pressure
0–40 bar absolutos (instalación hasta 10 bar; kit de válvula esférica opcional)
Outputs
Modbus RTU sobre RS-485; %RS, temperatura, aw y ppm
Materials and rating
Sonda y cuerpo AISI 316L; IP66; certificación DNV GL (modelo de 262 mm)

Features

Key features

  • Latest-generation HUMICAP® 180L2 sensor with excellent dry-end sensitivity
  • Measurement independent of oil type and age
  • Water activity and relative saturation directly indicate the risk of free-water formation
  • ppm output with factory conversion for mineral transformer oil
  • Two probe lengths (262 and 448 mm) with adjustable installation depth
  • Install and remove while the process is running, using the ball valve kit
  • Traceable factory calibration certificate
  • Compatible with the Vaisala Indigo family and Insight PC software

Applications

Typical applications

  • Power transformer condition monitoring
  • Lubrication oils — water ingress detection
  • Hydraulic fluids and oil circulation systems
  • Preventing free-water formation in machinery
  • Integration into monitoring platforms with Indigo transmitters

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