Stator Wedge Looseness & Failure
Problem: Wedges are essential for holding stator coils tight in their slots. They also help minimize vibration from steady-state related excitation forces. When wedges loosen, coils vibrate, wearing into the ground-wall and turn insulation. Such wear leads to ground failure or turn-to-turn shorts. Should a wedge become completely dislodged, damage to both the winding and core can be extensive as shown in the photo at the top left.