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Transmitter for moisture in oil measurement

E+E Transmitter Series EE36 are specially designed for the measurement of water content in oil. They are certified in accordance with the regulations of the "Germanischen Lloyd (DNV GL)" and therefore can be utilized in the maritime field as well. EE36 is ideal for online monitoring of moisture in lubrication or insulation oil, which is very important for the long-term performance and adaptive maintenance of plant and machinery. For instance, moisture affects dramatically the insulation characteristics of electrical transformer oil and therefore continuous monitoring is extremely important.

Humidity measurement in oil
Similar to the humidity in the air, the water content in an oil can be described by the absolute value in ppm or by the relative value aw:

  • ppm (mass of water / mass of oil)
  • aw (actual water content as fraction of the water content in the saturated oil) aw = 0 corresponds to water-free oil, while aw = 1 describes fully saturated oil.

aw measurement with EE36 transmitter series is based on the outstanding long term stability and resistance to pollution of the E+E capacitive sensor elements series HC.

Product Versions
The physical quantities measured are water activity aw and temperature T. With these quantities EE36 calculates the water content (ppm) in mineral transformer oils. Calculation of water content in non-mineral transformer oils and lubrication oils can be accomplished by downloading specific parameters of the oil.

The measured and the calculated values are available on two free scaleable and configurable analogue outputs. In addition, an optional relay output can be used for alarms and process control.

The sensing probe is designed for inline monitoring and can be placed directly in the oil, at pressures up to 10 bar. In addition to direct mounting of the sensing probe, a ball valve installation provides mounting and removal of the probe without interrupting the process.

Easy Calibration and Adjustment of EE36
The user can easily readjust or calibrate the transmitter by using either a simple procedure with two push buttons on the printed circuit board or the configuration software.

Transmitter for moisture in oil EE36 Transmitter for moisture in oil EE36
Techn. data
Measuring valuesWater activity [aw] // Water content [ppm] // Temperature [°C or °F]
Measuring range 0...1aw // -40...80°C (-40...176°F)
Outputs0...1V / 0...5V / 0...10V / 4...20mA / 0...20mA
Switch 2 potential-free relays (normally open)
Accuracy ±0.02aw // ±0.2°C
Supply 10...30V DC