| 摘要 |
<p>In devices for protection of a stator laminated core, provided with core tightening bolts in electrical machines, it is possible for the cable to the indicator to melt through at relatively high current levels, so that there is no indication. This results in major damage to the stator laminator core. The object of the invention is to avoid such consequential damage and to indicate even intermittent earth faults. The device is based on resistive earthing of the stator compression bolts, when the machine is operating without any faults, each compression bolt is thus kept at earth potential; in the event of an earth fault, a short- circuit current flows via this resistive earthing and initiates a visual indication. This visual indication may now be used directly for fault display and/or the signal transmitted using an optical conductor may be supplied to a receiver which, for its part, emits a logic signal. <IMAGE></p> |
