Condition Monitoring and Fault Diagnosis Systems of Power Generators with Non-Contact Shaft Runout Electrocapacitive Transducer

In the paper condition monitoring and fault diagnosis systems structure with electrocapacitive transducer is considered. To improve the efficiency and accuracy of defect identification, the system showed the need to use data from noncontact shaft runout sensors. To reduce the influence of external fields and non-uniformity of equipotential lines on the response characteristic of the electrocapacitive sensor, is substantiated the necessity of using a guard electrode in the form of a Kelvin ring. Secondary measuring transducer has been developed for a capacitive sensor with a Kelvin guard electrode. And designed to measure runout of shaft in powerful hydrogenerators. Secondary measuring transducer in proximity to the sensor electrodes, in order to eliminate the influence of parasitic capacitance, through a connecting triaxial cable between the sensor and the secondary transducer is proposed. Presented the results of experimental tests of the sample shaft runout electrocapacitive transducer for condition monitoring and fault diagnosis systems. It is shown that the shaft runout electrocapacitive transducer provides a measurement error of no more than 0.2–0.5% of the measurement range.