Define Rotation - Actions in POT Bearings?

POT bearings are associated with large rotations which are accommodated by the deformation of elastomeric pad. Large cyclic rotations can be very damaging to POT bearings due to abrasion and wear of the sealing rings and elastomeric pad. In fact, during rotation, the elastomeric pad compresses on one side and expands on the other, so the elastomer is in contact with the POT wall and slips against it. This causes elastomer abrasion and sometimes contributes to elastomer leakage. To mitigate this problem, silicon grease is generally used.