| 摘要 |
PURPOSE:To discriminate the degree of degradation of insulation of a coil nondestructively, by taking notice of the change of the oscillation characteristic for the thermal degradation of coil insulating materials and detecting this change. CONSTITUTION:Though oscillating components for a coil where insulation is not degraded are lower natural frequencies and exist in a low frequency region of several tens-200 Hz, oscillating components in a high frequency region are much generated for a coil where insulation is degraded. Then, the oscillation due to electromagnetic excitation in the operation of a rotary machine, percussion at the rotation stop time, or excitation due to an exciter 8 is detected by an oscillation trnasducer 7 attached to a coil end 6, and the detection signal is given to an oscillation amplitude measuring circuit 10 and an oscillation acceleration measuring circuit 11 through a preamplifier 9. Respective component signals are given to a divider 14 through peak detector circuits 12 and 13 to obtain a ratio of components, and this ratio is displayed quantitatively on a display equipment 15. Thus, the state of the degradation of insulation is detected quantitatively without applying a high voltage or the like. |
