Patent ID: 8224600
Filing Date: 2012-07-17
Classification: G01N

Abstract:
1. A method of monitoring deterioration of lubricating oil supplied via an oil path to rotating and sliding parts of a gas engine for driving an electric generator, the method comprising: obtaining and storing, beforehand, a predetermined correlation between relative permittivity and TBN (total base number) of the lubricating oil; applying high-frequency alternating voltage between a pair of electrodes located in the oil path; measuring values of applied voltage and resulting electric current; calculating relative permittivity of the oil based on the measured values of voltage and current; determining an actual TBN of the oil from the predetermined correlation between relative permittivity and TBN of the oil; and judging deterioration of the oil based on the determined actual TBN, wherein a permissible upper limit of relative permittivity of the lubricating oil is prescribed to correspond to a permissible lower limit of TBN, and that the oil is deteriorated is alarmed when detected relative permittivity reaches or exceeds the permissible upper limit of relative permittivity.