Oil-degradation detecting apparatus

An oil-degradation detecting apparatus comprising:

• two plates disposed so as to be parallel to each other in a path in which oil flows;
• an ammeter measuring the current that flows when an AC voltage is applied between the two plates;
• a voltmeter measuring the voltage between the plates when the AC voltage is applied to the two plates;
• a processor determining the electrical conductivity and the dielectric constant of the oil based on measurement results from the ammeter and the voltmeter and judging degradation of the oil based on the electrical conductivity and the dielectric constant;
• a viscometer disposed in the oil flow path measuring viscosity of the oil;
• and
• a moisture meter disposed in the oil flow path measuring moisture in the oil, wherein
• the processor judges degradation of the oil by additionally using a measurement result from the viscometer and a measurement result from the moisture meter with the electrical conductivity and the dielectric constant of the oil,
• the processor judges that the condition of the oil is normal when the electrical conductivity of the oil and the dielectric constant of the oil are within predetermined acceptable ranges,
• the processor judges that the condition of the oil is abnormal due to an increase in an amount of soot intrusion when the electrical conductivity of the oil is outside the acceptable range and the dielectric constant of the oil is within the acceptable ranges,
• the processor judges that the condition of the oil is abnormal due to an increase in an amount of water intrusion when the electrical conductivity of the oil is within the acceptable range and the dielectric constant of the oil is outside the acceptable ranges, and
• the processor judges that the condition of the oil is abnormal due to thermal degradation when both the electrical conductivity of the oil and the dielectric constant of the oil are outside the acceptable ranges.