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Moisture Oil Transmitter are specially designed for the measurement of water content in oil. It 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. 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 model. Technical data Measuring range: 0...1aw // -40...80°C (-40...17°F) Outputs: Transmitter: 0...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 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 transmitter is based on the outstanding long term stability and resistance to pollution of the capacitive sensor elements series HC.
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