| 摘要 |
PURPOSE:To discriminate the degree of degradation of coil insulation nondestructively, by taking notice of the change of the periodic damping state for the degradation of coil insulating materials and detecting this change. CONSTITUTION:When the adhesive strength of an insulating layer is lowered by a thermal degradation and the insulating layer is peeled by the thermal stress in operation and the mechanical stress such as vibration to reduce the tightness of the insulating layer, this reduction of the tightness is detected clearly as a change of periodic damping. Then, when a machine to be tested is still, a coil end 6 is excited by a hammer ring or an exciter 12 is provided in the coil end 6 to excite the coil end 6, and the oscillation is amplified by a preamplifier 8 when the oscillation is detected by a detecting sensor 7, and this amplified oscillation is filtered by a band pass filter 9, and a periodic damping factor is detected by a damping factor measuring circuit 10 and is displayed quantitatively on a display equipment 11. Thus, the state of the degradation of insulation is accurately detected quantitatively without applying a high voltage or the like. |
