Abstract: An oil-degradation detecting apparatus that can more accurately judge oil degradation and a mechanical system having a rotating part or a sliding part and including the oil-degradation detecting apparatus are provided. Two plates (21, 22) are disposed in an oil flow path (11) so as to be parallel to each other, an ammeter (24) measures a current that flows when an AC voltage is applied between the two plates (21, 22), a voltmeter measures the voltage between the plates (21, 22), and a signal processor (processor) (31) determines the electrical conductivity and the dielectric constant of the oil (10) based on the measurement results from the ammeter (24) and the voltmeter (25) and judges degradation of the oil (10) based on the electrical conductivity and the dielectric constant.

Abstract: A method of monitoring deterioration of lubricating oil and a device therefore capable of judging deterioration of the oil with high accuracy suppressing measurement error due to mixing of foreign matter in the oil. Correlation between relative permittivity and TBN (total base number) of the lubricating oil is obtained beforehand (step S1), electric current and voltage are measured (step S2) when high-frequency voltage is applied between a pair of electrodes located in an oil path in a gas engine, permittivity of the oil is detected (step S3) based on the measurement of current and voltage, TBN of the oil is obtained (step S4) from the correlation between relative permittivity and TBN, and deterioration of the oil is judged by the obtained value of TBN.

Abstract: An oil-degradation detecting apparatus that can more accurately judge oil degradation and a mechanical system having a rotating part or a sliding part and including the oil-degradation detecting apparatus are provided. Two plates (21, 22) are disposed in an oil flow path (11) so as to be parallel to each other, an ammeter (24) measures a current that flows when an AC voltage is applied between the two plates (21, 22), a voltmeter measures the voltage between the plates (21, 22), and a signal processor (processor) (31) determines the electrical conductivity and the dielectric constant of the oil (10) based on the measurement results from the ammeter (24) and the voltmeter (25) and judges degradation of the oil (10) based on the electrical conductivity and the dielectric constant.

Abstract: A method of monitoring deterioration of lubricating oil and a device therefore capable of judging deterioration of the oil with high accuracy suppressing measurement error due to mixing of foreign matter in the oil. Correlation between relative permittivity and TBN (total base number) of the lubricating oil is obtained beforehand (step S1), electric current and voltage are measured (step S2) when high-frequency voltage is applied between a pair of electrodes located in an oil path in a gas engine, permittivity of the oil is detected (step S3) based on the measurement of current and voltage, TBN of the oil is obtained (step S4) from the correlation between relative permittivity and TBN, and deterioration of the oil is judged by the obtained value of TBN.