| 摘要 |
<p>PURPOSE:To exactly diagnose the local abnormal overheat of AC winding of an electric equipment operating and the extent by non-destructive means by applying DC voltage to the AC winding and detecting the current flowing through the insulating layer of the AC winding to display it. CONSTITUTION:A malfunction diagnosing device 5 is connected to the output terminals 3a-3c of stator windings 2a-2c of a rotary electric machine 1. Low level DC voltage is applied from a DC power supply 8 to the stator winding of the operating machine 1. When the stator iron core of the machine 1 is locally overheated or the stator winding is heated due to interlayer shortage thereof, the temperature of the portion corresponding to the insulating layer of the stator winding is locally increased to cause the decrease of the insulating resistor at the portion raised at its temperature to thereby increase the current at the portion. This current increase is detected by a DC current detector 10, and the change of the insulating resistance is recorded and displayed on a recorder 12. When the insulating resistance is decreased less than predetermined level, an alarm 13 is operated to thereby display the occurrence of abnormal overheat thereat.</p> |
