EQUIPMENT AND METHOD FOR DETECTING FLAW IN INSULATING MATERIAL

摘要

PURPOSE: To provide a system to accurately and reliably detect detectives on the insulation contact surface between a generator shaft and a bearing pedestal supporting the shaft rotatably, and a sealing device. CONSTITUTION: An annular transformer 37 is provided which selectively induces a voltage at both ends of a shaft 1 while the shaft 1 is stationary. The induced voltage has the substantially same characteristic with asymmetrical voltage generated at the time of rotation of the shaft 1. A voltage meter 38 is provided to detect whether the selectively induced voltage is transmitted to the inside of structural parts through an insulation material or not. The number of windings used for the transformer 37 is preferably selected so that the AC voltage induced in the shaft 1 has the same characteristic as that of the AC voltage generated by the asymmetric al voltage at the time of the shaft 1 rotated by a turbine 13 driving a generator 3.