| 摘要 |
PURPOSE:To diagnose dielectric breakdown or the deterioration of fixing force during operation by detecting an electric signal by the detection coil wound around a troidal core and detecting the magnetic field generated by the current flowing to a power cable by an optical fiber magnetic field detector. CONSTITUTION:Only by allowing the power cable 1 of a rotary electric machine to pierce through a troidal core 2, a high frequency pulse signal being a partial discharge signal can be detected by the detection coil 3 wound around the core 2. Since an optical fiber magnetic field detector 5 is based on a Faraday element 9, the linear polarized wave passed through a polarizer 12 is rotated in its plane of polarization by the magnetic field generated by the current flowing to the cable 1 during the propagation through the element 9 and converted to the luminous intensity corresponding to an angle of rotation by a detector 10. This luminous intensity is converted to voltage by a photoelectric converter 7 to detect the magnetic field of the cable 1 and the current and current phase thereof are detected. Since the coil 3 and the detector 5 can detect a current on the coating of the cable 1, even when they are not connected to the terminal or wire of the electric rotary machine, partial discharge necessary for detecting the dielectric breakdown or fixing force deterioration of winding can be accurately detected. |
