E+E Transmitter Series EE381 are specially designed
for the measurement of water content in oil. EE381 is
ideal for online monitoring of moisture in lubrication or
insulation oil, which is very important for the long-term
performance and preventive 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 oil
can be indicated 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 saturated oil)
aw = 0 corresponds to water-free oil, while aw = 1 indicates saturated oil. aw measurement with the EE381
transmitter is based on the outstanding long term stability and resistance to pollution of the E+E capacitive
sensor elements series HC.
The measured physical quantities are water activity aw and temperature T. With these quantities EE381
calculates the water content x (ppm) in mineral transformer oils. Calculation of water content (ppm) in
non-mineral oils and lubrication oils can be achieved by programming the specific parameters of the oil into
the EE381.
Outputs
The EE381 transmitter has two freely selectable and scaleable outputs for water activity, water content or
temperature.
The EE381 switch with two relay outputs is designed for control and alarm purposes. The status for early
warning and main alarm is indicated by LED's.
Adjustment of the aw/T/ppm set point and hysteresis can be achieved with the optional configuration software.
Configuration Software
The optional configuration software allows flexible and easy adjustment of the analogue resp. relay outputs
to the respective requirements.The adjustment / calibration of the transmitters can easily be performed.
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