A DSP based stator slot wedge tester for large generators

Loose stator slot wedges could result in excessive vibration of the stator coils in large generators, which would accelerate the deterioration of the groundwall insulation and even eventually lead to catastrophic failure of large generators. So it is significant to detect loose slot wedges in stator slots to ensure generatorpsilas normal operation. Up to now, the slot wedges used to be tapped by hand using a small hammer with the operator making a judgment of tight or loose based on the sound from the slot wedge. This method is workable and has provided much useful data on the condition of the generators, but suffers from a few of major problems. This paper was concerned with its vibration characteristics in the loosening process of slot wedge with different fixing style and, introduced a slot wedge automation tester which was developed with Digital Signal Processor (DSP) technology and embedded system theory. It is a portable tester, and easier for workers to use to judge the tightness of slot wedges than the traditional manual method. It has also been applied to test stator slot wedges of some large generators in China.